Residential Plumbing Overview

Table of Contents

General Comments 4

Introduction 4 Four Defects 4 Quiz #1 5

InterNACHI® Standards of Practice 6

Quiz #2 8

Glossary of Terms 9

Quiz #3 17

Fixtures 19

Faucet and Fixture Temperature Control 22 Dishwashing Machines 28 Automatic Clothes Washer 37 Quiz #4 41

Water Heaters 43

Quiz #5 52

Potable Water 54

Valves 66 Quiz #6 68

Sanitary Drainage 70

Quiz #7 76

Vents 78

Quiz #8 81

Traps 82

Quiz #9 86

Protection 87

Plumbing Support 87 Quiz #10 90

Storm Drainage 91

Quiz #11 92

Dryer Systems 93 Fuel 95

Quiz #12 106

Inspection Checklist 107

Quiz #13 111

Appendix I: Answer Keys 113

Answer Key for Quiz #1 113 Answer Key for Quiz #2 113 Answer Key for Quiz #3 113 Answer Key for Quiz #4 114 Answer Key for Quiz #5 114 Answer Key for Quiz #6 115 Answer Key for Quiz #7 115 Answer Key for Quiz #8 116 Answer Key for Quiz #9 116 Answer Key for Quiz #10 116 Answer Key for Quiz #11 116 Answer Key for Quiz #12 116 Answer Key for Quiz #13 117

Residential Plumbing Overview 4

General Comments

This is not a code-compliance course. There are many plumbing codes, and they change regularly. This course should provide you with a sound introduction to standards and requirements for the proper installation and inspection of residential plumbing. You will learn the components of a plumbing supply and drainage system. You will learn about water heaters, “xtures and faucets. An inspection report should describe and identify, in written format, the inspected plumbing system of the dwelling, and should also identify material defects observed.

Introduction

The term “plumbing” refers to the practice, materials, and the collective system of piping, “xtures, appliances, equipment, “ttings and components within a structure that are related to the sanitary drainage system, storm drainage, venting systems, and public or private water supply systems.

The word “plumbing” comes from the Latin word plumbum, which is the element lead, and was so named because lead was used extensively in the development of piping systems. The practice of installing pipes and using the piping materials became known as plumbing.

Potable water is water that is drinkable, safe to drink, and free from impurities and contamination. Contaminated water is not drinkable – not potable. Contamination is an impairment of the quality of the potable water that is a hazard to the public health either by poisoning or by the spread of disease.

Piping, “ttings, devices, faucets, tanks, containers and receptacles that are used to supply, distribute, receive and transport potable water, liquid wastes and solid wastes are now considered plumbing.

A plumbing “xture could refer to a receptacle or device that is either permanently or temporarily connected to the water distribution system of the property, and which demands a supply of water. Or the “xture could discharge wastewater, liquid-suspended waste materials, or sewage to the drainage system of the property. The “xture could also require both a water supply connection and a discharge to the drainage system of the property. Plumbing “xtures include water closets, urinals, bidets, lavatories, sinks, showers, bathtubs and #oor drains.

A separate class of plumbing “xtures de”ned as plumbing appliances includes clothes washers, dishwashers, water heaters, water softeners, hot water dispensers, garbage disposals, and water puri”ers.

Four Defects

There are four basic defects that can exist in a plumbing system that should be identi”ed in an inspection. They include:

1. a leak;
2. inadequate water supply;
3. water contamination; and/or

4. the incorrect installation of a component.

Quiz #1

1. T/F: This is a code-compliance plumbing course.

True False

2. “Plumbing” comes from the Latin word meaning ________.

“lead”
“toilet”
“aluminum”

3. T/F: Contamination can aect the water’s potability.

True False

Answer Key is on page 113.

General Comments 5

Residential Plumbing Overview 6 InterNACHI® Standards of Practice

The following is excerpted from the InterNACHI® Standards of Practice for Performing a General Home Inspection.

3.6. Plumbing

I. The A. B. C.

D. E. F. G. H.

inspector shall inspect:
the main water supply shut-o valve;

the main fuel supply shut-o valve;

the water heating equipment, including the energy source, venting connections, temperature/ pressure-relief (TPR) valves, Watts 210 valves, and seismic bracing;

interior water supply, including all “xtures and faucets, by running the water; all toilets for proper operation by #ushing;
all sinks, tubs and showers for functional drainage;
the drain, waste and vent system; and

drainage sump pumps with accessible #oats.

II. The inspector shall describe:
A. whether the water supply is public or private based upon observed evidence;

B. the location of the main water supply shut-o valve; C. the location of the main fuel supply shut-o valve; and D. the location of any observed fuel-storage system.

III. The inspector shall report as in need of correction:

de”ciencies in the water supply by viewing the functional #ow in two “xtures operated simultaneously;
de”ciencies in the installation of hot and cold water faucets;
mechanical drain stops that were missing or did not operate if installed in sinks, lavatories and tubs; and
toilets that were damaged, had loose connections to the #oor, were leaking, or had tank components that did not operate.

IV. The inspector is not required to:

light or ignite pilot #ames.
determine the size, temperature, age, life expectancy or adequacy of the water heater.
inspect the interior of #ues or chimneys, combustion air systems, water softener or “ltering systems, well pumps or tanks, safety or shut-o valves, #oor drains, lawn sprinkler systems, or “re sprinkler systems.

InterNACHI® Standards of Practice 7

determine the exact #ow rate, volume, pressure, temperature or adequacy of the water supply.
determine the water quality, potability or reliability of the water supply or source.
open sealed plumbing access panels.
inspect clothes washing machines or their connections.
operate any valve.
test shower pans, tub and shower surrounds or enclosures for leakage or functional over#ow protection.
evaluate the compliance with conservation, energy or building standards, or the proper design or sizing of any water, waste or venting components, “xtures or piping.
determine the eectiveness of anti-siphon, back-#ow prevention or drain-stop devices.
determine whether there are sucient cleanouts for eective cleaning of drains.
evaluate fuel storage tanks or supply systems.
inspect wastewater treatment systems.
inspect water treatment systems or water “lters.
inspect water storage tanks, pressure pumps, or bladder tanks.
evaluate wait-time to obtain hot water at “xtures, or perform testing of any kind to water heater elements.
evaluate or determine the adequacy of combustion air.
test, operate, open or close safety controls, manual stop valves and/or temperature/pressure- relief valves.
examine ancillary or auxiliary systems or components, such as, but not limited to, those related to solar water heating and hot water circulation.
determine the existence or condition of polybutylene, polyethylene, or similar plastic piping.
inspect or test for gas or fuel leaks, or indications thereof.

Residential Plumbing Overview 8

Quiz #2

1. The inspector is required to _______ all the toilets.

unbolt and lift flush
clean

2. T/F: The inspector is required to light or ignite pilot lights.

True False

3. T/F: An inspector is not required to determine whether the water supply is public or private.

True False

4. T/F: The inspector is required to determine the existence of polybutylene plumbing in a home.

True False

Answer Key is on page 113.

Glossary of Terms 9

Glossary of Terms

• ABS (acrylonitrile butadiene styrene): rigid black plastic pipe used only for drain, waste and vent lines. • access cover: removable plate that permits access to a pipe or pipe “tting for the purpose of

inspection, maintenance, repair and replacement.

• access panel: an opening in the wall or ceiling near a “xture that allows access for servicing the plumbing/electrical system.

• accessible: in the opinion of the inspector, can be approached or entered safely, without diculty, fear or danger.

• activate: to turn on, supply power, or enable systems, equipment or devices to become active by normal operating controls. Examples include turning on the gas or water supply valves to the “xtures and appliances, and activating electrical breakers or fuses.

adaptor: a “tting that unites dierent types of pipe together, such as ABS to cast-iron pipe.
adversely aect: constitute, or potentially constitute, a negative or destructive impact.
aerator: an apparatus that mixes air into #owing water. It is screwed onto the end of a faucet spout to help reduce splashing. • air-admittance valve: one-way valve designed to admit air into the plumbing system to protect the traps from siphonage; a device used as an alternative to vents for individual “xtures and branches in the plumbing drainage system. • air chamber: a vertical, air-“lled pipe that prevents water hammer by absorbing pressure when the water is shut o at a faucet or valve. • air gap (drainage): the unobstructed vertical distance through free atmosphere between the outlet of the waste pipe and the #ood-level rim of the receptacle into which the waste pipe is discharged. • air gap (water distribution): the unobstructed vertical distance through free atmosphere between the lowest opening from any pipe or faucet that supplies water to a receptacle (sink, tank, “xture, or other device) and the #ood-level rim of that receptacle. • anti-scald: a valve that restricts water #ow to help prevent burn injuries. Some jurisdictions’ plumbing codes require anti-scald valves. See pressure-balancing valve and thermostatic valve. • anti-siphon: a device that prevents wastewater from being drawn back into supply lines and possibly contaminating the water supply. • aperture: an opening in a pipe.
• appliance: an apparatus, device, or equipment operated by use of electricity or fuel gas to produce heat, light, power, refrigeration or air conditioning. • approved: accepted by the code ocial, third-party agency, or authority having jurisdiction (AHJ), or conforming to a standard, such as ANSI. • back-pressure: pressure created in a non-potable system in excess of the water supply mains, causing back#ow. Back-pressure can be created by mechanical means (such as a pump), by static head pressure (including an elevated tank), or by thermal expansion from a heat source (such as a water heater).

Residential Plumbing Overview 10 • back-siphonage: the back#ow of water caused by system pressure falling below atmospheric

pressure. Atmospheric pressure supplies the force that reverses the #ow.

• back“ow: the #ow of liquids in potable water distribution piping in reverse of their intended path. There are two types of pressure conditions that cause back#ow: back-siphonage and back-pressure.

• back“ow preventer: a device or means to prevent back#ow into the potable water supply.
• basket strainer: basket-shaped strainer with holes allowing water to drain while catching food or

other solids; can also be closed to “ll the sink with water.

• bell reducer: a “tting shaped like a bell that has one opening of a smaller diameter used to reduce the size of the pipe in the line, and the opposite opening of a larger diameter.

• bidet: a toilet-like plumbing “xture designed to promote posterior hygiene; not a toilet.
• building drain: the part of the drainage system that receives the discharge from inside the dwelling

and transports it to the building’s sewer, and ends 30 inches outside the dwelling’s foundation wall.

• building sewer: that part of the drainage system that extends from the end of the building’s drain onward.

• cistern: an exterior reservoir for a home’s water supply.
• cleanout: a plug in a trap or drainpipe that provides access for the purpose of clearing an

obstruction.

• closet bend: a curved “tting that connects the closet #ange to the toilet drain.

• closet bolt: a bolt whose head is “tted to a closet #ange and protrudes up through a toilet base. A nut is tightened around it on the toilet base. Two (or four) bolts serve one toilet.

• closet “ange: an anchoring ring secured to the #oor. The base of the toilet is secured to this ring with bolts.

• combustion air: the air provided to fuel-burning equipment, including air for fuel combustion, draft hood dilution, and ventilation of the equipment enclosure.

• component: a permanently installed or attached “xture, element or part of a system.
• compression #tting: a “tting used to join or connect pipes and conduit by causing a ring to

compress against the connecting tube when tightening with a wrench.

• condensate drainpipe: condensate drainage from air-conditioning equipment must be drained properly. This drainage pipe must be sized and designed as an indirect waste pipe, with a minimum diameter of 3/4-inch, and a water trap installed on the line.

• condition: the visible and conspicuous state of being of an object.
• console lavatory: a table-like lavatory whose basin is attached to a wall at the back and by table or

piano legs at the front.

• copper pipe types: Type K has the heaviest or thickest wall and is generally used underground. It has a green stripe. Type L has a medium wall thickness and is most commonly used for water service and for general interior water piping. It has a blue stripe. Type M has a thin wall, and many codes permit its use in general water piping installation. It has a red stripe.

• CPVC (chlorinated polyvinyl chloride): rigid plastic pipe used in water supply systems where code permits.

Glossary of Terms 11 • cross-connection: any arrangement of plumbing devices, “ttings, “xtures or pipes that connects a

potable water supply directly to a non-potable source. This is an undesirable arrangement.

• cut-o valve: a valve used to shut water o, generally located under a sink or behind a bathtub or shower access panel. It cuts o the hot and/or cold water at the source without cutting o the entire water supply throughout the house.

• describe: to report, in writing, on a system or component by its type or other observed characteristics to distinguish it from other components used for the same purpose.

• determine: to arrive at an opinion or conclusion pursuant to examination.

• developed length: the distance measured along the centerline of a pipe.

• dismantle: to open, take apart, or remove any component, device or piece that would not typically be opened, taken apart, or removed by an ordinary occupant.

• disposer: a device that grinds food suciently to enter a drain for disposal without clogging it. See also food waste grinder and garbage disposal.

• diverter: a valve that has a single inlet and directs water to one of two outlets. Diverters are used with hand showers, shower risers, tub-and-shower combinations, and kitchen faucet sprayers.

• drainage system: piping within a dwelling that conveys sewage, rainwater, or other liquid waste to a point of disposal. It does not include the main of a public sewer system, or a private or public sewage treatment or disposal plant. A sanitary drainage system carries sewage and excludes storm water, surface water, rainwater, and groundwater.

DWV (drainage, waste and vent system): See drainage system.
elbow (or L): an angled “tting that alters the direction of the line. Also called an L, it comes in a variety of angles, from 22 to 90 degrees. • escutcheon: a trim piece or decorative #ange that “ts beneath a faucet handle to conceal the faucet stem and the hole in the “xture or wall.

evaluate: to assess the systems, structures and components of a dwelling.
examine: to visually look at. See inspect.
fall (or “ow): the proper slope or pitch of a pipe for adequate drainage.
faucet: a device for regulating the #ow of liquid from a reservoir, such as a pipe or drum.
#tting: a general term that usually refers to faucets, shower valves, tub “llers, and various piping parts, such as tees and elbows. • #xture: in plumbing, the devices that provide a supply of water and/or its disposal, such as sinks, tubs and toilets. • “ex hose: a #exible pipe or tube, usually made of braided stainless steel, and commonly used with widespread or Roman tub faucets to provide variable centers. • “ood-level rim: the edge of the “xture or receptacle above which water will #ow over and out of that “xture or receptacle. • “ow rate: the rate at which water is discharged from an outlet. For example, the standard #ow rate of a showerhead is 2 gallons per minute (gpm).

Residential Plumbing Overview 12 • “ue: a pipe used to exhaust smoke, gas or air.

• “ue lining: “red clay or terracotta pipe, round or square, usually made in all ordinary #ue sizes and in 2-foot lengths, and used for the inner lining of a chimney with the brick or masonry work around the outside. A #ue lining in a chimney runs from about a foot below the #ue connection to the top of the chimney.

“ush valve: the valve separating the water in a toilet tank from the bowl.
“ux: a material applied to the surface of copper pipes and “ttings to assist in the cleaning and bonding process.
• food waste grinder: a device that grinds food suciently to enter a drain for disposal without clogging it. See also disposer and garbage disposal.
• function: the action for which an item, component or system is specially “tted or used, or for which an item, component or system exists; to be in action or perform a task.
• garbage disposal: a device that grinds food suciently to enter a drain for disposal without clogging it. See also disposer and food waste grinder. • gasket: a pre-formed shape, such as a strip, grommet, etc., of rubber or rubber-like composition used to “ll and seal a joint or opening, either alone or in conjunction with the supplemental application of a sealant. • gate valve: a valve that permits one to completely stop, but not modulate, the #ow within a pipe.
• GPM or gpm (gallons per minute): the unit of measurement by which the #ow rate of faucets and showerheads is measured and regulated. • groundwater: water from an aquifer or sub-surface water source. • hose bibb (or bib): an outdoor faucet with hose threads on the spout, also commonly used to supply washing machines and wash basins. • hot water: water at a temperature of 110° F (43° C) or higher.
• ID (inside diameter): the diameter measurement taken from the inside of a pipe; a common method for sizing pipe. • inspect: to examine readily accessible systems and components safely, using normal operating controls, and accessing readily accessible areas, in accordance with InterNACHI’s Standards of Practice.
- installed: attached or connected such that the installed item requires the use of a tool for removal.
- lavatory: bathroom or washroom sink.
- lead: a malleable metal that was used for drainage pipes and was installed for water service entry pipes until its use was prohibited in the U.S. for health and safety reasons. • main vent (or stack): principal vent to which branch vents may be connected. • mixing valve: a valve that mixes hot and cold water in order to obtain a set temperature prior to delivery. • non-vitreous: a relative term as applied to ceramic products based on their water-absorbing characteristics; that degree of vitri”cation evidenced by relatively high water absorption, usually more than 10%, except for tile materials that are considered non-vitreous when water absorption exceeds 7%.

Glossary of Terms 13 • notch: a crosswise rabbet at the end of a board.

• O-ring: a round rubber washer or gasket that is compressed to create a watertight seal, typically in a compression “tting.

• oakum: loose hemp or jute “ber that is impregnated with tar or pitch and used to caulk large seams and for packing plumbing pipe joints.

• observe: to visually notice.

• operate: to cause systems to function or turn on with normal operating controls.

• P-trap: a P-shaped section of drainpipe that prevents sewer odors from escaping into the home. Water is trapped in the pipe, blocking gases from escaping through the drain.

• PB (polybutylene): #exible plastic tubing used in water supply systems.

• pedestal lavatory: a lavatory whose bowl is supported by a single pedestal leg.

• percolation test (perc test): a test that a soil engineer performs on earth to determine the feasibility of installing a leach”eld-type sewer system on a lot; a test to determine if the soil on a proposed building lot is capable of absorbing the liquid euent from a septic system.

• plumbing boot: a metal saddle used to strengthen a bearing wall/vertical stud(s) where a plumbing drain line has been cut through and installed.

• plumbing rough: the work performed by the plumbing contractor after the rough heat is installed. This work includes installing all plastic ABS drain and waste lines, copper water lines, bathtubs, shower pans, and gas piping to furnaces and “replaces. (Lead solder should not be used on copper piping.)

plumbing stack: a plumbing vent pipe that penetrates the roof.
plumbing trim: the work performed by the plumbing contractor to get the home ready for the “nal plumbing inspection; includes installing all toilets (water closets), hot water heaters, sinks, disposal, dishwasher, and all other plumbing items, and connecting all gas pipes to combustion appliances.
plumbing waste line: see drainage system.
polyvinyl chloride (PVC): a polymer formed by the polymerization of vinyl chloride monomer, sometimes called vinyl; a type of white plastic pipe commonly used for DWV systems. • potable water: drinkable water “t for human consumption; “t to drink. • pressure-reducing valve: a valve installed in the water service line where it enters a home to reduce the pressure of the water in the line to an acceptable and desirable level, typically 40 to 55 psi. • pressure tank: a tank used in conjunction with a well to maintain pressure. • reducer: a “tting that connects pipes of dierent sizes. • relative humidity (RH): the amount of water vapor in the atmosphere expressed as a percentage of the maximum quantity that could be present at a given temperature. The actual amount of water vapor that can be held in space increases with the temperature. • report: a written communication (possibly including photos/images) of any material defects observed during an inspection.

Residential Plumbing Overview 14 • residential property: four or fewer residential units.

• residential unit: a home; a single unit providing complete, independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking and sanitation.

• riser: a vertical assembly of “ttings and pipes that distributes water upward.
• rough-in: the portion of a plumbing installation that includes running the water supply lines and

drain, waste and vent lines to the proposed location of each “xture.

• run: a complete or secondary section of pipe that extends from supply to “xture, or from drain to stack.

• sanitary #tting: a “tting that joins the assorted pipes in a drain, waste and vent system designed to allow solid material to pass through without clogging.

• sanitary drainage system: a drainage system that carries sewage and excludes storm water, surface water, rainwater and groundwater.

• scupper: an outlet in the wall of a building or a parapet wall for the drainage of water from a #at roof.

• seat: the “xed part of a valve. The stem assembly moves up and down against the seat to open and close the valve.

• self-rimming: a style of bathroom lavatory or kitchen sink with a “nished lip or rim that installs on top of a counter without requiring a metal sink rim.

• sewage: a general term referring to the discharge from all plumbing “xtures, and primarily includes human bodily waste, and the waste associated with cleaning, washing, bathroom use, and food preparation.

• sewage ejector: a pump used to lift wastewater to a gravity sanitary sewer line, usually used in basements and other locations that are situated below the level of the side sewer.

• sewer lateral: the portion of the sanitary sewer that connects the interior wastewater lines to the main sewer lines. The side sewer is usually buried in several feet of soil and runs from the house to the sewer line. It is usually owned/operated by the sewer utility, must be maintained by the owner, and may be serviced only by utility-approved contractors; sometimes called a side sewer.

sewer stub: the junction at the municipal sewer system where the home’s sewer line is connected.
sewer tap: the physical connection point at which the home’s sewer line connects to the main municipal sewer line. • shut down: turned o, unplugged, inactive, not in service, not operational, etc. • shut-o valve: the valve that allows the water supply to be cut o to one “xture without aecting the water supply to the entire house or building; commonly used at bathroom sinks and toilets. Also called a cut-o valve. • side sewer: the portion of the sanitary sewer that connects the interior wastewater lines to the main sewer lines. The side sewer is usually buried in several feet of soil and runs from the house to the sewer line. It is usually owned/operated by the sewer utility, must be maintained by the owner, and may be serviced only by utility-approved contractors; sometimes called a sewer lateral. • sillcock: an exterior water faucet. Also called a hose bibb.

Glossary of Terms 15 • sleeve: pipe installed under a concrete driveway or sidewalk that will be used later to run sprinkler

pipe or low-voltage wire.

• sludge: term for the waste material found in sump pump pits, septic systems and gutters.

• soil pipe: pipe that transports solid waste from toilets.

• stack: a vertical drainpipe that extends more than one #oor level or story in a dwelling and carries liquid or air.

• stack vent: an extension of the soil or waste stack above the plumbing “xtures; a vent.
• stem: a small shaft or rod that projects through the faucet valve and to which the handle is

installed.

• stop valve: a valve that controls the #ow of water to an individual “xture, allowing the water supply to be stopped to one “xture without aecting the water supply to other “xtures.

• storm sewer: a sewer system designed to collect storm water and which is separated from the wastewater system.

• straight stop: a shut-o valve that is installed on a supply line between the #oor and the faucet or toilet. Unlike an angle stop, a straight stop does not change the direction of water #ow.

• sump pump: a submersible pump in a sump pit that pumps any excess groundwater to the outside of the home.

system: an assembly of various components that function as a whole.
tailpiece: the tubular part of a drain that runs from the plumbing “xture to the trap.
tee (or T): a T-shaped “tting with three openings used to create branch lines.
trap: a “tting or device that provides a liquid seal to prevent the emission of sewer gases without aecting the #ow of sewage or wastewater through the trap. • trap seal: the vertical distance between the crown weir and the top dip of a trap. The crown weir is the lowest point in the cross-section of the horizontal waterway at the exit of the trap. • tub trap: a curved, U-shaped section of a bathtub drainpipe that holds a water seal to prevent sewer gases from entering the home through the tub’s water drain. • underground plumbing: the plumbing drain and waste lines that are installed beneath a basement #oor. • union: a three-piece “tting that joins two sections of pipe, but allows them to be disconnected without cutting the pipe; used primarily with steel pipes, but never in a DWV system. • unsafe: in the inspector’s opinion, a condition of an area, system, component or procedure that is judged to be a signi”cant risk of injury during normal, day-to-day use. The risk may be due to damage, deterioration, improper installation, or a change in accepted residential construction standards. • vacuum breaker: an anti-siphon device that prevents wastewater from being drawn back into supply lines, potentially contaminating the water supply. • vent: a passageway for conveying #ue gases from fuel-burning appliances to the outside air.

Residential Plumbing Overview 16 • vent stack: the vertical, upper portion above the top-most “xture through which gases and odors

escape the sanitary drainage system. This pipe carries no liquids or solids.

• vent system: piping that prevents trap siphonage and back-pressure, or equalizes the air pressure within the sanitary drainage system.

• verify: to con”rm or substantiate.

• waste: wastewater; drainage discharge that does not contain solid human waste.

• waste and over“ow: a bathtub drain assembly that has an outlet at the top to remove over#ow water when “lling the tub, and an outlet at the bottom to remove wastewater when the tub is drained.

waste stack: vertical pipe that carries liquid or air through one or more stories of a dwelling.
wastewater: drainage discharge that does not contain solid human waste.
water closet (WC): toilet; commode.
water tap: the connection point at which a home’s water line connects to the main municipal water system. • wax ring job: removing a toilet from the #oor so that a blockage can be manually removed, or to replace a degraded wax ring; replacing a wax ring on the bottom of the toilet to create a seal. • well casing: a steel or plastic pipe that serves as the lining of a well, preventing it from caving in, and protecting groundwater from contamination by surface water. • whirlpool bathtub: a plumbing appliance consisting of a bathtub “xture that is equipped and “tted with a circulating piping system designed to accept, circulate, agitate and discharge bathtub water for relaxation and therapeutic purposes. • wye (or Y): a Y-shaped “tting with three openings used to create branch lines.
• yoke: the location where a home’s water meter is installed between two copper pipes, and located in the water meter pit in the yard. • zone valve: a device placed near a heater or cooler that controls the #ow of water or steam to parts of a building. A zone thermostat controls it.

Glossary of Terms 17

Quiz #3

1. The unobstructed vertical distance through the free atmosphere between an outlet and the rim best describes ___________.

an air gap in a drainage system
a connection problem
an indirect drainage space
the best way to vent contaminated water

2. Air-admittance valves protect traps from ______.

siphonage
leaking
admitting water into the drainpipe admitting air into the vent pipe
clogging

3. The vertical, upper portion above the top-most “xture through which gases and odors escape the sanitary drainage system, carrying no liquids or solids, best describes ____________.

a vent stack
a supply vent
an air-admittance valve a sewer drainpipe

4. A lavatory is __________.

any type of sink
a bathroom with a toilet but no sink a bathroom
a bathroom or washroom sink

5. A __________ is an anchoring ring secured to the #oor, and a toilet is secured to this ring with bolts.

water closet flange toilet ring
wax ring device

6. A toilet or commode is referred to in plumbing standards as a ________.

toilet fixture
toilet receptacle
water closet
water-flushing device

Residential Plumbing Overview 18 7. The #ow of liquids in potable water distribution piping in reverse of its intended path caused by

back-siphonage or back-pressure best describes ________.

backflow
gravitational mass equilibrium flow-back
contamination

8. Hot water is ___________.

water at a temperature between 85° F and 110° F water at a temperature of 110° F
water at a temperature of 110° F or higher
water at a temperature of 120° F or higher

9. ABS stands for __________________.

acrylonitrile butadiene styrene acryline butta styrofoam
alternate buss strand

Answer Key is on page 113.

Fixtures 19

Fixtures General Comments

A dwelling should have the proper number of “xtures of a speci”c quality. The “xtures should be properly installed to be both accessible and usable by the occupants. There are standards to which each “xture’s design and quality must conform.

Minimum Number of Plumbing Fixtures

Surfaces of plumbing “xtures and faucets should be smooth and impervious. The “xtures should be properly installed to be both accessible and usable by the occupants. Plumbing “xtures must be free from defects. There are standards to which each “xture’s design and quality must conform. Let’s begin with the number of plumbing “xtures required for a house.

In general, for one- and two-family residential dwellings, each dwelling is required to have at least one water closet (toilet), one lavatory (bath sink), one bathtub or shower, one kitchen sink, and one automatic clothes washer connection. For an apartment house, the standard is to have one automatic clothes washer connection per 20 dwelling units.

Access

Plumbing “xtures should be installed so as to provide access for cleaning. Every “xture should be capable of being cleaned. There must not be any concealed spaces that do not facilitate proper cleaning.

Plumbing connections with slip-joints should have access provided for inspection and repair. The access panel or utility space should be least 12 inches in its smallest dimension.

Connection to Sewer Is Required

Plumbing “xtures, drains, appurtenances and appliances used for liquid waste or sewage must be connected directly to the sanitary drainage system of the building. Sanitary drainage from the plumbing “xtures in a house must be connected to a public sewer. If a public sewer

is not available, the sanitary drainage piping must be connected to a private, code-compliant septic system.

Residential Plumbing Overview 20

Flange

A #oor #ange should be used in the connection between the drain and the #oor outlet plumbing “xture. The #ange should be securely attached to the drain and anchored to the structure. A wall- mounted water closet should be bolted to the hanger with corrosion-resistant bolts or screws. Joints should be sealed with an approved elastomeric gasket, a #ange-to-“xture connection, or a setting compound. The most commonly used setting compound is a wax ring made of beeswax or synthetic wax.

Connections

Closet bolts are usually made of brass because of its strength and corrosion resistance. They alone hold the closet to the #ange. A water closet #oor #ange receives the closet bolts. The #ange attaches the closet “rmly to the structure. The #ange should be secured to the structure with corrosion- resistant screws. The #ange holds the closet to the structure “rmly without putting any load on

the drainage pipe that is attached to the #ange. A wall-hung water closet bowl should be supported to the wall structure with a concealed carrier so that no load is transferred to the drainage pipe or connection. One may use the side of their leg positioned against the side of the water closet (toilet) to help in determining how securely attached to the #oor it is.

Fixture Tailpieces

Consumption and Distribution Flow Rates

There are many standards to which faucets and other “xture “ttings should conform. There are speci”c standards with which faucets and “xture “ttings that supply drinking water for human consumption must comply. Faucet and supply “ttings should comply with the water consumption requirements shown in the table below.

Tailpieces are short lengths of pipe attached directly to a “xture by means of a #ange for connection to other piping or traps. Tailpieces should be at least 1 inches in diameter for sinks, dishwashers, laundry tubs, bathtubs and similar “xtures, which is consistent with the minimum sizes for “xture drains, traps and trap arms. Tailpieces should be at least 1 inches in diameter for bidets, lavatories and similar “xtures. Some standards limit the maximum vertical length of a tailpiece to between 24 and 36 inches.

Fixtures 21

Maximum Flow Rates and Consumption
Fixture or Fixture Fitting	Maximum Flow Rate or Quantity
lavatory	2.2 gpm at 60 psi
showerhead	2.5 gpm at 80 psi
sink faucet	2.2 gpm at 60 psi
urinal	1 gallon per #ushing cycle
water closet	1.6 gallons per #ushing cycle

Water distribution to “xtures should conform to standards, including the following table of “xtures and #ow rates under certain #ow pressure.

Fixture Supply Outlet	Rate of Flow in Gallons Per Minute (gpm)	Flow Pressure in Pounds Per Square Inch (psi)
Bathtub (thermo mixing valve)	4	20
Bidet	2	20
Dishwasher	2.75	8
Laundry Tray (tub)	4	8
Lavatory (bath sink)	0.8	8

Residential Plumbing Overview 22

Fixture Supply Outlet	Rate of Flow in Gallons Per Minute (gpm)	Flow Pressure in Pounds Per Square Inch (psi)
Shower (thermo mixing valve)	2.5	20
Sink	1.75	8
Sillcock (hose bib)	5	8
Water closet (toilet, one piece)	6	20

Faucet and Fixture Temperature Control Hot Is on the Left

Fixtures that have both hot and cold water supplied to them must be installed and adjusted so that the left-hand side of the water temperature control represents the hot water when facing the “xture outlet. The exception could be a shower and tub/shower mixing valve, where the water temperature is marked on the “xture device.

Temperature Control

A temperature-control valve protects against rapid temperature #uctuations by automatically maintaining the discharge temperature to +/- 3° F (+/- 2° C) of the selected temperature. Every shower and combination tub-shower must have a control valve that is capable of protecting an individual from being scalded while taking a shower. Such a control valve must be installed at the point of use. The thermostat control on a water heater is not acceptable to serve as the temperature limiting means. To prevent an accidental scald, a maximum set-point feature is required for the valves.

The water temperature-limiting device can be adjusted to prevent the water temperature from rising above a certain temperature, typically 120° F (49° C). Bidets are typically set to 110° F (43° C).

Showers and tub-shower valves must be equipped with control valves (individual shower valves)
of the pressure-balance, thermostatic-mixing, or combination of those two types with a high
limit stop. The high limit stop must limit the water temperature to a maximum of 120° F (49° C). Individual shower and tub-shower combination valves must be balance-pressure, thermostatic, or a combination of balance-pressure/thermostatic-type valves. These valves can be adjusted in the “eld.

Hot water supplied to bathtubs and whirlpool tubs have water temperature-limiting devices that limit the water temperature to 120° F (49° C).

For commercial “xtures, the temperature for hot water or tempered water is typically set to 110° F (43° C) for “xtures such as a public hand-washing sink, a public bath or wash facility.

Fixtures 23

Temperature Burn Chart
Water Temperature	Time it takes for an adult to become scalded with a third-degree burn:	Time it takes for a child to become scalded with a third- degree burn:
155° F (68° C)	1 second	0.5 seconds
133° F (56° C)	15 seconds	4 seconds
120° F (49° C)	5 minutes	2:30 minutes
100° F (38° C)	safe temperature for bathing	safe temperature for bathing

The hot water supplied to the bathtub and whirlpool bathtub valves should be set to a maximum temperature of 120° F (49° C) by a control valve.

Fixture “ttings and faucets that are supplied with both hot and cold water should be installed and adjusted so that the left-hand side of the water temperature control (when facing the outlet) represents the #ow of hot water.

Sauna Temperature Control

Sauna heaters should be equipped with a thermostat that limits the room temperature to no greater than 194° F (90° C). Where the thermostat is not an integral part of the heater, the heat-sensing element should be located within 6 inches of the ceiling.

Overflows

An over#ow is designed to prevent “xtures from #ooding (or over#owing into) the area when
the stopper is closed or the drain is obstructed. A watertight stopper must not interfere with the over#ow opening or the water over#owing from the “xture. Bathtubs must be equipped with both a waste outlet and an over#ow outlet. The outlets must be connected to a waste drain pipe at least 1-1/2 inches in diameter.

Bathtubs and Sinks

Bathtubs and lavatories can have over#ows installed. These two “xtures are often used without close observation. A person preparing to take a bath will typically turn on the water and leave while the tub is “lling up. If left for a long time, the tub water may rise to a level where the over#ow will take the excess water to the drain, preventing #ooding of the area. Many tubs are capable of supplying water at rates greater than the #ow rate of the over#ow. With such “xtures, over#owing and #ooding

Residential Plumbing Overview 24 may not be prevented. Bathtubs must be equipped with both a waste outlet and an over#ow outlet.

The outlets must be connected to a waste drainpipe at least 1-1/2 inches in diameter.

Inlet Side

An over#ow discharges on the inlet side (or “xture side) of the water trap. The over#ow is installed so as to prevent sewer gases from the drainage system from entering the dwelling. The exception is the over#ow from a #ush tank serving a water closet that discharges into the “xture served. Flush tanks normally have an open standpipe inside the tank that allows over#ow to drain directly into the water closet.

Clearance for Water Closets and Lavatories

There should be at least 15 inches of space from the center of a water closet, lavatory or bidet to any sidewall, partition, cabinet, or any other obstruction. There should be at least 30 inches of space between adjacent “xtures. There should be a space of at least 21 inches in front of the water closet, lavatory or bidet to any wall, “xture or door. This clearance is for comfortable, adequate space for cleaning and use of the “xture. The location of the water pipes, “xtures, or equipment must not interfere with the operation of doors and windows.

Water Closets

A water closet in the U.S. is commonly referred to as a toilet. The term “water closet” originates from the time when plumbing was brought indoors, and defecation took place in a small, closet-size room with a pot.

Water Closet Styles

There are three styles of water closets: close-coupled, one-piece, and #ushometer valve. The most common is the close-coupled water closet, which has a bowl and separate gravity-type tank or #ushometer tank that is supported by the bowl. A one-piece water closet is constructed with the gravity-type tank or #ushometer tank and bowl as one integral unit. A #ushometer valve water closet is a bowl with a #ushometer valve.

Water closet bowls come in six styles: blowout, siphon jet, reverse trap, wash-down, siphon vortex, and siphon wash.

Flushing Devices for Water Closets and Urinals

There are three types of devices that are required to #ush a water closet or urinal: a #ush tank,
a #ushometer valve, and a #ushometer tank. The #ush tank works with gravity, using only the pressure of the water inside the tank. That’s a very common tank type. The #ushometer valve is a device used to discharge water at the full-line pressure of the water supply. The #ushometer tank incorporates a hydropneumatic tank that #ushes the “xture at full-line pressure.

Water Closet Measurements

A water closet has a water consumption limit of a maximum average of 1.6 gallons (6.1 L) of water per #ush.

The general bowl rim height above the #oor is between 14 inches minimum and 15 inches maximum. Other rim heights may be needed for water closets used by children (10 inches

Fixtures 25 maximum), the elderly (18 inches), and persons with physical disabilities (18 inches maximum).

Elongated water closet bowls are required for public or employee use, but are often installed in residential dwellings. An elongated bowl is 2 inches longer than a regular bowl.

Connection to Drainage

To connect a water closet to the drainage line, a 4×3-inch closet bend should be allowed, and it is not considered a reduction in the drainage pipe size. If a 3-inch bend is used, then a 4×3-inch #ange can be installed to receive the horn of the water closet.

Defects at Water Closets

The water closet (toilet) may have a clogged drain. While #ushing the toilet, watch the #ush performance. As part of the inspection, some inspectors put about 4 feet of toilet paper in a water closet and #ush the toilet. There should not be excessive odors around the water closet. Check
the #ooring around the toilet with your foot. Using the side of your leg, you can check to see if the toilet is securely attached to the #oor. Look for dampness around the bottom of the toilet base. Toilets sometimes run continuously. Check for a water shut-o valve. Some toilets are mistakenly connected to the hot water system. Tank lids are often cracked.

Urinals

A urinal is a “xture that has been designed for urination, as opposed to a water closet (toilet) that is designed for defecation. There are four types of water-supplied urinals: stall, siphon jet, wash-down, and blowout. The water consumption limit for a urinal is 1 gallon (3.785 L) per #ush. Waterless urinals are becoming popular, considering sustainable “green” building methods. Wall and #oor space must be waterproofed to a point 2 feet in front of the urinal lip, 4 feet above the #oor, and at least 2 feet to each side of the urinal. Waterproo”ng material should be smooth, readily cleanable, and non-absorbent.

Bidets

A bidet is a small bathing “xture used by both sexes. It is not designed for the elimination of human waste, but for cleaning the perineal area, and other body parts, including feet. It is typically equipped with a water spray that directs water upward in a jet toward the body part.

Most bidets present back- siphonage problems because the spray nozzle is located below the #ood-level rim of the “xture. The water supply to the bidet should have protection against back#ow. The temperature of the discharging water from the bidet should be set to a maximum temperature of 110° F (43° C) by a water temperature-limiting device. This temperature device is required because of the potential for scalding sensitive parts of the body.

Residential Plumbing Overview 26

Lavatories and Washbasins

A lavatory is a washbasin or sink located in a bathroom or washroom. “Lavatory” means washbasin or sink, and is derived from the Latin word lavatorium, which means “washing vessel,” and the French word laver, meaning “to wash.” Lavatories come in a variety of shapes and sizes. They are available in enameled cast-iron, vitreous china, stainless steel, porcelain-enameled formed steel, plastic, and non-vitreous ceramic. They can be wall-mounted, hanger-mounted, under-mounted, pedestal, rimmed, and above-center basin types.

Countertops integrated with lavatories are constructed of a variety of materials, including ABS, PVC, gel-coated “berglass-reinforced plastic, acrylic, polyester, and cultured marble. Plastic vanity tops should be impregnated with “re-resistant chemicals to reduce the fuel contribution of the lavatory during a house “re or the accidental “re from a plumber’s torch. They are also made to resist the eect of a burning cigarette left unattended on the vanity top.

Lavatories should have a waste outlet of at least 1 inches in diameter. Each lavatory must have a strainer, a pop-up stopper, a crossbar, or other mechanism to prevent items such as rings, toothbrushes and cosmetic items from dropping into the drain.

Lavatory Overflows

In the past, the standard required lavatories (bathroom sinks) to have an over#ow. That is no longer the standard in many adopted plumbing codes. The over#ow is now an option of the manufacturer. The reason for not requiring an over#ow at a lavatory is because of the lack of use of the over#ow. The lack of use causes bacterial and micro-organism growth. In the United States, an over#ow is not required at the kitchen sink.

Where a lavatory does have an over#ow installed, the cross-sectional area of the over#ow should be a minimum of 1 inches. This minimum prevents the over#ow from being too small, which could promote bacterial and micro-organism growth. The over#ow should be able to prevent over#owing of the sink for a minimum of “ve minutes when tested from the onset of water #owing into the over#ow’s opening.

Lavatory Rims

The rim of the lavatory can be used to determine the number of “xtures for which the sink is designed, with 20 inches of rim to one lavatory “xture. A rim greater than 20 inches is designated as a group wash-up “xture.

Sinks

Sinks are plumbing “xtures that include kitchen sinks, service sinks, bar sinks, mop sinks and wash sinks. A sink is considered a dierent item than a lavatory (or a bathroom sink), although the terms are often used interchangeably.

Sinks can be made of enameled cast-iron, vitreous china, stainless steel, porcelain- enameled formed steel, non-vitreous ceramic, and plastic materials.

Fixtures 27

Sink waste outlets should have a minimum diameter of 1 inches. Most kitchen sinks have an opening of 3 inches in diameter. A food waste grinder has a standard opening of 3 inches, and so do most kitchen sink basket strainers. A strainer or crossbar should be provided to restrict the clear opening of the waste outlet.

The illustration above shows the dierence between an S-trap and a P-trap. S-traps are not permitted due to siphoning problems.

Food Waste Grinders

Food waste grinders (also known as garbage disposals and disposers) are designed to grind foods, including bones, into small- sized bits that can #ow through the drain line. Using them to dispose of “brous and stringy foods, such as corn husks, celery, banana skins and onions, is not recommended because “bers tend to pass by the grinder teeth, move into the drainpipe, and cause drains to clog.

Water must be supplied to the grinder to
assist during its operation in transporting
waste. The water #ushes the grinder chamber
and carries the waste down the drainpipe.
Blockages may result if the grinder is used
without running the water during operation.
Grinders should be connected to a drain of not less than 1 inches in diameter. Food waste grinders are supplied with water from the sink faucet. They do not add to the load used to compute drainage pipe sizing. The drain size required for a grinder is consistent with that for a kitchen sink.

Residential Plumbing Overview 28

Cords and Plugs

According to the 2014 NEC®, Section II, 422.16.A.1, #exible cords are permitted to be used for connecting appliances to help with their frequent interchange or to assist in the removal of an appliance fastened in place for maintenance and repair.

Food waste disposers may use a #exible cord connected to a plug when the cord is identi”ed as suitable according to the installation instructions of the appliance manufacturer. The #exible cord must terminate with a grounding-type attachment plug. It cannot be less than 18 inches in length or longer than 36 inches. The receptacle should be accessible and located so as to avoid damage to the cord (out of a high-trac footpath).

Dishwashing Machines Backflow Prevention

The water supply to a residential dishwashing machine should be protected against back#ow
by an air gap or back#ow preventer. The machine must be equipped with an integral back#ow mechanism, or the potable water supply must have either a back#ow preventer or an air gap. The air gap is actually the open space within the dishwasher’s interior itself.

The ASSE 1006 standard for residential and domestic-type dishwashing machines is the requirement for the protection of the potable water supply against back#ow. If the unit conforms to the standard, there is an internal integral back#ow prevention device installed, and additional precautions are unnecessary. Prior to installing, the installer should con”rm that the machine conforms to the standard. The water line to the dishwasher should have a manual shuto valve. The water temperature supplied to the dishwasher is commonly recommended to be 120o F.

Fixtures 29

GFCI Protection

Ground-fault circuit-interrupter protection must be provided for outlets that supply dishwashers installed in the house, according to the 2014 NEC®, Section 210.8.D. GFCI devices must be readily accessible.

Cords and Plugs

The dishwasher appliance should be on its own dedicated electrical circuit. Check the main electrical panel for a dedicated and identi”ed breaker.

Built-in dishwashers and trash compactors may each use a #exible cord connected to a plug when the cord identi”ed as suitable for the purpose in the installation instructions of the appliance manufacturer. The #exible cord shall be terminated with a grounding-type attachment plug. It must be 3 feet to 4 feet long measured from the front surface of the plug to the rear of the appliance.

The receptacle should be accessible, located in the space occupied by the appliance, or in a space adjacent to it.

Discharge, Loop and Air Gap

The dishwasher discharge hose should be connected to the waste tee or disposer inlet above the drain trap. It is recommended that the drain hose either be looped up and securely fastened to the underside of the counter, or be connected to an air gap.

The dishwasher must be connected to the waste line with a minimum 32-inch-high drain loop or an air gap above the countertop surface, depending on local codes, in order to prevent back#ow into the dishwasher.

An air gap must be used if the waste tee or disposer connection is less than 18 inches above the #oor so as to prevent siphoning.

Before connecting to the sink tailpiece or food waster grinder, the dishwasher waste line should rise and be securely fastened as high as possible to the underside of the countertop. It should be fastened or held in place before connecting to the food waste grinder or to the wye “tting in the kitchen sink tailpiece.

The discharge hose from the dishwasher could be increased to a minimum of 3/4-inches in diameter. It should be connected with a clamp to the wye “tting at the sink tailpiece or to the food waste grinder connection.

The combined discharge from a sink, dishwasher, and waste grinder is allowed to discharge through a single 1-1/2-inch drain trap.

During a home inspection, you may notice that the dishwasher drain makes this loop underneath the countertop next to the sink. This is considered a minimum installation requirement on every

Residential Plumbing Overview 30 dishwasher drain installation. It is required by many (if not every) dishwasher manufacturer. The

high loop is required by municipalities that have adopted a plumbing code or standard.

Air Gap

The alternative component
to the high loop is the air gap. The air gap is a device that is actually mounted above the countertop surface. An air gap device may be required by the authority having jurisdiction (AHJ). If an air gap device is not required, the dishwasher drain hose must have a high loop installed to prevent the back#ow of water into the dishwasher and prevent water from siphoning out during operation.

New dishwashers are assembled by the manufacturer with the high drain loop already installed on the side of the dishwasher. However, most manufacturers still require another high loop installed in the discharge hose underneath the sink countertop at the dishwasher area.

Securing the Dishwasher

The dishwasher must be secured to the cabinet. There are usually two brackets on top of the dishwasher that can be attached to the countertop if it is wood, laminate or another similar surface. If the countertop is marble, granite or another hard surface, the brackets may be moved to the sides of the dishwasher. The dishwasher should be level from front to back and from side to side. Check that the top of the door does not contact screws, brackets or the countertop. If it does, the leveling legs may need to be adjusted.

Dishwasher Door

If the door closes or falls open under its own weight, the door tension will need to be adjusted.

Checklist

Here’s a simple checklist for inspecting a dishwasher.
The inspector should report as a defect in need of correction:

• inoperative unit;
• rust on the interior of the cabinet or components; • failure to drain properly; and/or
• the presence of active water leaks.

The inspector should report indications of problems in the following: • door gasket;

Fixtures 31

• control and control panels; • dish racks;
• rollers;
• spray arms;

• operation of the soap dispenser; • door springs;
• dryer element;
• door latch and door disconnect; • rinse cap;

• secure mounting of the unit; and/or • back#ow prevention.

Report Narratives

The inspector may perform the inspection and report his/her “ndings based on the following sample narratives:

The dishwasher was operated through a normal cycle and appeared to be in serviceable condition at the time of the inspection.
The dishwasher lacks an anti-siphon device. The dishwasher did not appear to have an anti- siphon device installed in the drain line. An anti-siphon device prevents the wastewater from the dishwasher from being siphoned back into the dishwasher and contaminating its contents. The inspector recommends that an anti-siphon device be installed by a quali”ed technician.
The drain line was improperly installed. The dishwasher drain line was improperly con”gured and should be corrected by a quali”ed contractor.
The dishwasher had a high loop installed in the drain line at the time of the inspection. The high loop is designed to prevent wastewater from contaminating the dishwasher.
The dishwasher had an air gap device installed in the drain line at the time of the inspection. The air gap is designed to prevent wastewater from contaminating the dishwasher.
The dishwasher did not respond when controls were operated. The inspector recommends further evaluation, with any necessary repairs performed by a quali”ed technician.
The dishwasher made an unusual noise that indicated that it was not operating properly. The inspector recommends further evaluation and any necessary repairs performed by a quali”ed technician.
The dishwasher’s installation was incomplete at the time of the inspection. The inspector recommends that installation be completed by a quali”ed technician.
The dishwasher leaked onto the #oor during operation. Further evaluation and repair are recommended to be performed by a quali”ed technician.
The dishwasher was not operated. The dishwasher appeared to be old, did not appear to have been run recently, and may leak. The inspector disclaims its proper operation. The client should ask the seller about its condition, if applicable.
The home had no dishwasher installed at the time of the inspection.

Residential Plumbing Overview 32

Bathtubs

Bathtubs are made from many dierent types of materials, including enameled cast-iron, porcelain- enameled steel, and plastic. Plastic tubs are made from materials such as ABS, PVC, “berglass, “berglass-reinforced plastic, acrylic, and cultured-marble acrylic. Bathtubs that are equipped with shower “xtures are typically manufactured with slip-resistant surfaces. Bathtubs should have a drainage outlet (tailpiece) with a minimum diameter of 1 inches. Every tub should be equipped with
a watertight stopper. The bathtub should have an over#ow outlet installed. The over#ow prevents #ooding if the tub is being “lled while unattended, and prevents over#ow of the water when a person enters a tub that is full. Hot water supplied to bathtubs and whirlpool tubs should not exceed 120° F (49° C) and be limited by a water temperature-limiting device, except where that type of temperature protection is provided by a combination tub-shower valve.

Inspection Procedure Suggestions

Inspectors may look for indications of defects with:

• water drainage;
• the water supply by viewing the functional #ow in two “xtures operated simultaneously; • the installation of hot and cold water faucets;
• the mechanical drain stops that are missing or did not operate at the tub; and
• loose-sounding tiles at the tub or shower walls.

Additionally,

Many inspectors will inspect the walls and tub bottom, including tiles, surfaces, sealant, grout, and caulking. Some inspectors tap on the tile walls with their hand to “nd loose tiles or water- damaged backing. Loose tiles in the bathtub and shower may feel soft.
Tubs and showers should have plumbing access panels installed. Inspectors may check for a plumbing access panel on the opposite side of the tub “xture.
Inspectors may check the bottom corners of the tub and shower where the “xture meets the bathroom #oor, and look for water damage or indications of water leaks.
Inspectors may check the installation of the showerhead and tub faucet and handles for functional performance or loose installation.
If the shower has a tile base, the inspector may check the shower pan by stopping the drain and “lling up the shower bottom.
The inspector may check that safety glass is installed where required.
If the bathtub is jetted, the inspector may check whether the jets function, whether the jetted tub motor is GFCI-protected, and if there is access to the motor. Fire Resistance Bathtubs made of plastic are tested for “re ignition. They are made with “re-resistant chemicals to reduce their fuel contribution in a house “re, or an accidental exposure to a plumber’s torch. Large Bathtub Loads Some bathtubs are so large that they can accommodate more than one person at a time. These larger bathtubs may need special and additional structural support underneath them to adequately

Fixtures 33

support the load.

A 3×4-foot bathtub may have a capacity to hold 200 gallons or more. The weight of the bathtub, water and occupants may total over 1 ton, considering:

200 pounds for the bathtub

+ 1,600 pounds of water

+ 350 pounds for two people ___________________________

= 2,150 pounds

A very large tub may cause structural problems because live loading for a typical residential home is 40 pounds per square foot. The live load for a 3×4-foot occupied tub may be assumed to be only 480

pounds, but may weigh over 2,000 pounds while it is in use.

Whirlpool Tubs

Whirlpool bathtub “xtures must be installed according to the manufacturer’s recommendations. The bathtub should be “lled with water and tested during the rough-in plumbing inspection. The pump must be located above the tub trap weir so that the pump drains fully each time that the tub is drained. The tub,

pump and the piping should all be sloped to drain water completely after every use. Standing water will cause bacterial growth. If the pump is

located more than 2 feet from the access opening, an 18×18-inch minimum sized opening should be installed.

Whirlpool/Jetted Tub Access

The pump must be accessible to make repairs and perform maintenance. One should have access to the mounting bolts, pipe unions and electrical connections in order to physically remove the pump, all without damaging the tub or surrounding “nished walls or ceiling. The inspector should “nd installed a minimum 12×12-inch opening that provides access to the circulation pump. If the pump is located more than 2 feet from the access opening, the opening is typically at least 18 x 18 inches.

Recommended Whirlpool Tub Inspection Procedure

Fully open the hot and cold water faucets and “ll the whirlpool tub with water at least 1 to 3 inches above the whirlpool jets.
Do not operate the pump until all jets are submerged.
Direct the jets downward before activating the pump.
Inspect the amount of bubbling with the controls.

Residential Plumbing Overview 34

The suction inlets typically have very small openings, less than 1/8-inch in diameter, to prevent catching hair and pulling someone’s head under water. This has happened in the past and some suction inlets have been recalled.
If dirty water comes out of the jets, the circulation system is probably dirty and the tub is not sanitary, and the inspector should recommend a professional cleaning.
There should not be any odor emanating from the tub.
All whirlpool tubs should have a dedicated electric circuit protected by a GFCI (ground-fault circuit interrupter).
Inspect and measure the area of the access panel. Showers Plastic, pre-fabricated shower units are constructed of various synthetic materials, including ABS, PVC, gel-coated “berglass-reinforced plastic, cultured marble, cast-“lled “berglass, polyester, cultured marble acrylic, and acrylic. These shower units are impregnated with “re-retardant chemicals to reduce the fuel contribution during a “re, and protection against an accidental burn by a plumber’s torch. The showerhead height is not typically regulated by building codes, but the head is commonly installed 70 to 80 inches above the shower #oor. Shower Water Pipes Water supply pipes from the shower valve to the showerhead outlet—referred to as the shower riser pipes—whether exposed or not, must be “rmly attached to a structural component to prevent the pipes from leaking caused by stress fractures or joint failures. Movement of the showerhead may move the riser piping, possibly causing failure of the piping. The risers must be “rmly secured in an approved manner. The common practice for installing the riser pipe is to place a drop-ear elbow at the top of the riser pipe. The elbow has two wing connections. They can be screwed to a structural backing board, such as a 2×4. A pipe strap can be used instead of a drop-ear elbow. When the riser is exposed, the manufacturer will typically provide a strap or attachment device to match the “nish of the “xture and pipe. The strap or attachment device should be “rmly secured to a structural component. Shower Outlets The waste outlet for a shower should have minimum diameter of 1 inches. The shower outlet should have a strainer that is at least 3 inches in diameter, with dimensional openings in the strainer of at least -inch. The strainer should be removable. In gang or multiple showers, the shower room #oor should be sloped toward the respective shower drains to prevent wastewater from #owing from one shower #oor area to another. Shower Area A shower compartment should have an interior cross-sectional area of at least 900 square inches. This will allow an average adult to clean his/her lower body while bending over. A shower any smaller would be inadequately sized. Shower compartments should be at least 30 inches in minimum dimension. This measurement is based on the movement of an adult inside a shower. This is measured from the “nished interior dimension of the compartment, excluding “xture

Fixtures 35

valves, showerheads, soap dishes and grab bars. There are exceptions for showers having fold- down seats, and those with compartments at least 25 inches wide and 1,300 square inches in cross- sectional area. The exception allows for a shower with one dimension being 25 inches, provided the compartment has at least 1,300 square inches of cross-sectional area. This is useful for contractors who must remove an old bathtub to install a standup shower unit in the same space.

Shower Walls

Showers and bathtubs with installed showerheads shall be “nished with a non-absorbent surface that extend to a height of not less than 6 feet above the #oor level of the room, or 70 inches above the #oor. It should be constructed of smooth, corrosion-resistant and non-absorbent materials to protect the structural components from moisture damage. The gypsum or cement wallboard behind ceramic tiles of a shower wall should be water-resistant. Water-resistant material, such as water- resistant gypsum wallboard, is not required to be installed in the rest of the bathroom, although it is a common practice to do so because of the moisture levels.

Shower Access and Egress Opening

Many injuries in a dwelling are related to accidents in the bathtub or shower. The minimum opening requirements for access and egress allow an adult enough room to safely step into and exit the shower area without having to twist or turn through a narrow opening. The shower opening (or access and egress opening) should be at least 22 inches of clear and unobstructed “nish width. The

22-inch width is based on the approximate shoulder width of an average-sized adult. This minimum opening dimension also provides comfortable access to service the valves, showerheads and drain. It also allows for emergency response and rescue access, and emergency egress.

Shower Floors and Pans

The shower #oor surface must be watertight with smooth, corrosion-resistant, non-absorbent, waterproof materials. Joints between the #oor and walls of the shower must be sealed or #ashed to prevent water penetration. Ideally, there should be some type of slip-resistant #oor surface. The shower #oor structure needs proper support by a smooth and structurally sound base. The base of the shower #oor should be designed for dead and live loads.

Shower #oors that are built in place and not pre-fabricated require a shower pan under the shower’s “nished #oor. The #oor should be lined and made watertight, utilizing various materials that can include sheet lead, sheet copper, polyethylene sheet, chlorinated polyethylene sheet, or pre-formed ABS. The liner, such as a 40-mil PVC plastic sheet, should turn up on all sides at least 2 inches above the “nished threshold level.

The liner should not be nailed or perforated at any point below the #ood-level rim of the shower compartment. Liners should have a slope of a -inch per foot (2% slope) toward the “xture drain.

Residential Plumbing Overview 36

The pan is designed to catch water that penetrates through the “nished #oor. The shower pan must securely connect to the shower drain outlet with a #ashing #ange or clamping device, and weep holes or seepage openings. This will allow the penetrating water to enter the drainage system. The #ange or clamping device will make a watertight joint between the outlet and the waterproof membrane liner.

Shower Liners

A PVC sheet that is installed as a shower liner must be 0.040 inches (1.02 mm) thick, commonly referred to as 40 mil. It is a #exible plastic membrane that is “tted into a shower compartment on top of the sub#oor to catch water penetration and prevent moisture damage.

CPE (chlorinated polyethylene) sheets are manufactured as one piece. They are impervious to water and resistant to permeation of water vapor. They should be a minimum 0.040 inches (1.02 mm) thick.

Sheet lead liners should not weigh less than 4 pounds per square foot. They are coated with an asphalt paint or other approved coating. Sheet lead should be joined by burning or hot-mopping.

Sheet copper liners should not weigh less than 12 ounces per square foot. The copper should be joined by brazing or soldering. Annealed copper sheets are typically used for pan liners.

Shower Glazing

Glass doors enclosing the shower should be made of safety glazing. If a window is installed in the shower, the window should be made of safety glazing to provide protection. If a person slips or falls inside the shower, s/he may be seriously injured by broken glass if the glass is not made of safety glazing. The safety glazing should be correctly labeled by being permanently marked in a corner, legible, and visible after installation, and indoor applications should be marked “indoor use only.” For glass, the glazing for human-impact loads should meet CPSC 16-CFR, Part 1201 requirements. For plastic, the glazing should meet CPSC 16-CFR, Part 1201.4(c)(2)(ii) requirements. The glazing label for polished wire glass should meet ANSI Z97.1 requirements.

Glazing

Windows and doors within the area of a tub, shower and sauna require safety glazing. Those areas are speci”c hazardous locations because the occupant could break the glazing, causing serious injury. Glass wall partitions and windows that enclose tub and shower areas are also speci”c hazardous locations that should have safety glazing. A glass door enclosing a tub or shower area should be of safety glazing. An exterior window at an exterior wall must be of safety glazing unless the bottom exposed edge of the glass is 60 inches or more above the tub #oor’s surface.

In some bathrooms, there is a sitting ledge or other horizontal surface around the tub with large glass windows. The ledge may not decrease the hazard potential; therefore, safety glazing is required. If the width of the ledge or surface surrounding the tub is widened signi”cantly to become a walking surface, then safety glazing may have to be evaluated by other safety glazing standards. With regard to tubs and showers, safety glazing does not depend upon the size of the glass area. Safety glazing is important wherever the possibility exists of someone falling into or thrusting through glass around the tub or shower area.

Fixtures 37

Automatic Clothes Washer Water Supply Connection

The water supplied to the clothes washer must be protected against back#ow, and this is achieved by the integral air gap within the machine itself or a back#ow preventer.

Discharge and Waste Connection

An automatic clothes washer protects the potable water supply by having an air gap or back#ow preventer installed. The waste from an automatic clothes washer must discharge its water through an air break into a standpipe or into a laundry tub. Without an air break, a blockage in the drain would allow the sewer to back up and enter the washer.

Standpipe, Trap and Weir

A standpipe is typically used for capturing the waste #ow from a pumped discharge plumbing appliance, such as a dishwasher or a clothes washer. The standpipe for the clothes washer must be trapped. The standpipe height should be at least 18 inches and no more than 42 inches above the trap weir.

A washer typically discharges into an individually trapped standpipe or laundry sink/tub. The use of a laundry sink/tub is common.

If a standpipe is used, the standpipe and its trap should be at least 2 inches in diameter. The clothes washer drain should connect to a “xture branch, horizontal branch, or drainage stack that should be at least 3 inches in diameter. If it is less than 3 inches, there might be a problem because the discharge rate for a modern automatic clothes washer is 21 gallons per minute. Where a clothes washer discharges into a laundry sink/tub, there is no problem because the size or holding capacity of the laundry sink/tub should hold the accumulated discharged water and allow drainage with a slow #ow rate into

Residential Plumbing Overview 38

the drainage pipe.

If a laundry tub waste line connects to a clothes washer standpipe, the standpipe should be
at least 30 inches above the standpipe trap
weir and should extend above the #ood level rim edge of the laundry tub. The outlet of the laundry tub must not be more than 30 inches horizontally away from the standpipe trap.

Laundry Tubs and Trays

A laundry tray is essentially a sink used in a
laundry room of a dwelling. The material of the tray can be enameled cast-iron, stainless steel, non- vitreous ceramic, plastic or soapstone. Laundry trays made of concrete are not permitted because they do not provide a smooth, impervious, sanitary surface. The laundry tray is commonly used to receive the discharge of an automatic clothes washer.

The laundry tray should have a waste outlet with a minimum of 1 inches in diameter, and a strainer or crossbar to restrict the clear opening of the waste outlet to catch debris and materials that could be discharged into the sink and cause drain clogging.

Floor and Trench Drains

Floor drains are typically installed as an emergency “xture to prevent #ooding a room or space. They should be constructed of cast iron, ductile iron, bronze, aluminum alloy, copper alloy, ABS, PVC, PE, PP or stainless steel. Floor drains are usually installed at the discretion of the design professional in areas where standing water is common and may represent a hazard or cause damage to the dwelling. Such drains do not

add to the load used to compute drainage pipe sizing because their sole purpose is to serve only in the event of an emergency.

Floor drains must be installed or constructed such that they can be properly cleaned so that the drain will continue to function properly. Floor drains should have a minimum 2-inch-diameter drain outlet. For central washing facilities of multiple-family dwellings, the room containing clothes washers should be provided with a #oor drain with a minimum 3-inch-diameter outlet. Floor drain installations must be trapped. The actual #oor drain body may have an integral trap. Floor drains should have strainers, and they should be removable. The strainer can be #ush with the #oor surface or may have a dome grate. The free area of the strainer or grate should not be less than the transverse area of the connecting pipe. Floor drains with funnels may extend above the #oor surface about an inch, and these do not need a grate or strainer.

Fixtures 39

Water Supply: Inadequate Street Pressure

If the water pressure from the street main or other water supply source is not sucient to provide an adequate #ow pressure at the “xture outlets, a water pressure booster could be installed to the water supply system of the house.

Pressure-Reducing Valve

If the water pressure within a dwelling is greater than 80 psi, a water pressure-reducing valve with a strainer should be installed to reduce the pressure in the water distribution pipe system in the house to a maximum of 80 psi static. And the pressure-reducing valve should be designed to remain open for uninterrupted water #ow.

Water Hammer

The velocity of water #ow in the water distribution system should be controlled to reduce the possibility of water hammer. A water-hammer arrestor can be installed according to the manufacturer’s recommendations.

Lead Content

Pipes and pipe “ttings, including valves and faucets, used in the house’s water supply system must not have a lead content greater than 0.25 percent (NSF 372).

Minimum Water Supply Size

The minimum size of a water supply pipe to a “xture is described in general terms below. There should be a water shut-o valve no more than 30 inches from the “xture connection.

Fixture	Minimum Size of Pipe (in inches)
Bathtub (max 5 feet in length)	1/2
Bidet	3/8
Dishwasher	1/2
Hose Bibb	1/2
Kitchen Sink	1/2
Laundry	1/2

Residential Plumbing Overview 40

Fixture	Minimum Size of Pipe (in inches)
Lavatory	3/8
Shower (one showerhead)	1/2
Sink	1/2
Water Closet (#ush tank)	3/8

Backflow

The water supply system (pipes and “ttings) for the plumbing “xtures should be installed to prevent back#ow. Fixture “ttings should provide back#ow protection.

Fixtures 41

Quiz #4

1. There should be a space of at least _______ in front of the water closet, lavatory or bidet to any wall, “xture or door.

15 inches 1 foot
21 inches 18 inches

2. Closet bolts are often made of ______ because they resist corrosion.

aluminum
brass
chromed galvanized steel

3. The waste from an automatic clothes washer must discharge its water through a(n) ________ into a standpipe or into a laundry tub.

trap seal
air-admittance vent
air break or air gap
1-inch diameter discharge hose

4. If a standpipe for an automatic clothes washer is used, the standpipe and its trap should be at least ___ inches in diameter.

1 2 3

5. Plastic bathtubs are made with _________ in case of accidental exposure to a plumber’s torch.

fire-resistant chemicals
metallic particles and shavings reinforced mesh

6. An exterior window at an exterior wall must be made of safety glazing unless the bottom exposed edge of the glass is _________________ above the tub #oor’s surface.

24 inches
60 inches or more
two-thirds the width of the window

Residential Plumbing Overview 42 7. Laundry trays made of ________ are no longer permitted because they do not provide a smooth,

impervious, sanitary surface.

formed plastic concrete
galvanized steel

8. The shower opening (or access and egress opening) should be at least ___________ of clear and unobstructed “nish width.

36 inches 22 inches 18 inches

9. If the pump at a whirlpool bathtub is located more than 2 feet from the access opening, the opening is typically at least ______ inches.

22 x 22 inches 12 x 12 inches 18 x 18 inches 24 x 36 inches

10. _________ are best described as short lengths of pipe attached directly to a “xture by means of a #ange for connection to other piping or traps.

Trap arms Trap primers Standpipes Tailpieces

Answer Key is on page 114.

Water Heaters

General Comments

Water Heaters

A water heater is any appliance that heats potable water and supplies heated water to the distribution system. Some water heaters can be used for space heating. Water heaters are potential explosion hazards if not properly installed. There are instances where hot water tanks with improperly installed safety devices have propelled through #oor and roof structures and over 100 feet into the air. Because of the potential hazards, there are standards that regulate the materials, design and installation of water heaters and their related safety devices. Certi”cation marks from approved agencies on water heaters are required to indicate compliance with approved standards.

Residential Plumbing Overview 44

Most tanks are insulated steel cylinders with an enamel coating on the inner surface. They are referred to as glass-lined tanks. The lining helps prevent corrosion. Conventional residential water heaters have life expectancies that vary greatly.

Water Heater as Space Heater

If a water heater has a dual purpose of supplying hot water and serving as a heat source for a hot water space heating system, the maximum outlet water temperature for the potable hot water system is limited to 140° F (60° C). A master thermostatic mixing valve should be installed to limit the water temperature to 140° F (60° C) or less. A water heater used as a part of a space heating system, such as for an under-#oor radiant system, must be protected from any conditions that could cause contamination of the potable water system. If the water heater is part of the potable water system, materials used in the heating system must be approved for use in a potable water system. The water potability must be maintained throughout the system. Chemicals of any type must not be added to the heating system because this would directly contaminate the water supply.

Sacrificial Rods

Water circulating through a hot water circulation system becomes chemically inert and does not rust the piping. But water heaters have a constant supply of fresh water with lots of corrosion-causing oxygen. Because of this, water heaters are prone to corrosion. As a result, water heaters usually have an anti-corrosion rod or sacri”cial rod installed. Sacri”cial anodes are typically made of magnesium or aluminum. The rod is immersed inside the water heater tank, allowing the chemical reaction from the fresh water to attack it rather than the tank. In some areas, rods are replaced regularly.

Drain Valves

A water heater must have a drain valve installed for service, maintenance, sediment removal, repair and replacement. The valve inlet is a *-inch nominal pipe size. The outlet is a standard *-inch male hose thread and a straight-through waterway of at least -inch in diameter.

Access

Water heaters should be accessible for routine inspections, maintenance, adjustment, repairs and replacement. Manufacturers usually make access recommendations. “Access” means to be able to reach the water heater by possibly “rst removing a panel, door or similar enclosure. “Accessible” does not include or imply the removal or destruction of “nish materials, such as drywall, paneling or built-in cabinets. A walkway, work space or platform may be necessary to

provide a safe path to travel to and work on a water heater.

Water Heater Labeling

All water heaters must be certi”ed by an approved third-party agency, such as ANSI and UL (Underwriters Laboratories). The certi”cation mark indicates that the heater has been tested and has been determined to perform safely when installed and operated properly, in accordance with the manufacturer’s recommendations.

Water Heaters 45

Tankless Water Heaters

Tankless or point-of-use water heaters have become increasingly popular in recent years for heating potable water in residential homes in the U.S. There are several major factors in the trend of installing tankless water heaters. One is an increasing demand for continuous, unlimited streams of hot water for simultaneous operation of hot water-consuming appliances and “xtures. Another
is a desire to save #oor space and to conserve energy by reducing standby losses. There are many dierent models of fuel-gas and electric tankless water heaters, each having a speci”c rating. Tankless water heaters are rated at gallons per minute (gpm) and degrees of water temperature rise.

Tankless Temperature Control

Since tankless water heaters can discharge water at an uncertain range of temperatures at any
given time, depending on the use, a temperature-control device is needed to protect the user from scalding water being discharged. A tempering valve can be adjusted to deliver water at a maximum temperature of 140° F (60° C), or the heater can be equipped with a temperature-limiting device
or thermostat that has the maximum setting. When a tankless water heater supplies a shower or tub-shower combination, the maximum temperature of the outlet control valve of the shower or tub- shower must be set at 120° F (49° C).

Tankless Size

One challenge in sizing a tankless water heater is to determine the demand in gallons per minute. The second challenge is determining what temperature rise is required for that #ow. Because tankless water heaters are designed to accommodate a given maximum #ow, there is a pressure loss associated with #ows in excess of a unit’s usable #ow rating.

In a house with a tankless water heater, it’s possible to have a “xture with almost no #ow of water if too many faucets are opened simultaneously. Occupants may have to adjust their expectations concerning when and to what extent simultaneous demands for hot water can be made before temperature and #ow of hot water are aected.

Tankless Coils from Boilers

Located in Attics

Residential Plumbing Overview 46

Tankless coils are indirect water heaters that take their heat from the steam or hot water boiler that is used to heat the house. A cold-water supply pipe extends into the hottest part of the boiler water. The water in the copper tube is kept hot by the boiler water. When there is a demand for hot water, water #ows through the tube through the hot boiler water, and water is delivered to the “xture.

Water Heater Tank Locations

Installation of water heater tanks that use solid, liquid or gas fuel should not be permitted in a room containing air-handling machinery if such room is used as a plenum. If there’s a malfunction of the water heater or its venting system, there is a potential for toxic combustion byproducts to spread throughout the dwelling. The air-handling system can also produce negative and positive air pressures and aect the drafting or venting of the water heater. The negative pressure produced by a plenum could overcome the natural draft of the heater’s venting system and pull #ue gases into the room.

Located in Storage Closets, Bedrooms and Bathrooms

Fuel-“red water heaters should not be installed in a room used as a storage closet. Fuel-“red water heaters cannot obtain combustion air from sleeping rooms, bathrooms or toilet rooms. There are two exceptions: 1) a water heater located in a bedroom or bathroom could be installed in a sealed enclosure so that combustion air will not be taken from the living space, and a solid, weatherstripped door with a self-closing device should be provided; and 2) a water heater could be installed in a room that is not a con”ned space and the building is not of unusually tight construction.

Located in Garages

A suitable access opening, passageway and work space are required when a water heater is installed in an attic. The opening, passageway and work space should be large enough to accommodate
the removal and replacement of a water heater. The passageway should not be less than 30 inches high or less than 22 inches wide. The access opening should be at least 20 x 30 inches to allow

the removal of the water heater. It should not be longer than 20 feet when measured along the centerline of the passageway from the opening to the water heater. The passageway should have continuous, solid #ooring not less than 24 inches wide. There should be a work space that is level, and at least 30 inches deep and 30 inches wide in front of the water heater.

Gasoline leakage or spillage in a garage is a possible danger. Gasoline vapors will evaporate from liquid puddles at the #oor level. Any potential ignition source should be elevated to keep open-#ame, spark- producing elements and heating elements above the gasoline vapor level. A hot water tank with a source of ignition should be elevated not less than 18 inches above the #oor. There is an exception for appliances that are listed as #ammable vapor ignition- resistant.

Dip Tube Hole Inside Tanks

Water Heaters 47

Confined Space and Combustion Air

If the volume of space in which the appliance is located is not greater than 50 cubic feet per 1,000 BTU/h (4.83 L/W) of the aggregate input-rating of the appliance, then it is considered a con”ned space. Two permanent openings to adjacent spaces could be provided so that the combined volume of all spaces meets the criterion. If the building is sealed so tightly that in”ltration air is not adequate for combustion, combustion air could be obtained from outdoors.

If all combustion air is taken from the inside of the dwelling, then two permanent openings should be installed. One opening should be within 12 inches of the top and the other within 12 inches of the bottom of the space. Each opening shall have a free area equal to a minimum of 1 square inch per 1,000 BTU/h input rating of all appliances installed within the space, but not less than 100 square inches.

If all combustion air is taken from the outdoor air, then one opening should be within 12 inches of the top and the other within 12 inches of the bottom of the space. The openings are permitted to connect to spaces directly communicating with the outdoor air, such as a ventilated crawlspace or ventilated attic space. Each opening should have a free area of at least 1 square inch per 4,000 BTU per hour of total input rating of all appliances in the space when using vertical ducts (and 2,000 BTU per hour if using horizontal ducts).

Seismic Supports for Tanks

In areas that have a high earthquake risk, it is important that a water heater be fastened in place to avoid damage. Strapping should be done at points within the top and bottom thirds of the tank’s vertical dimensions. At the lower point, the strapping should maintain a minimum distance of 4 inches above the controls. Water heater supports and piping supports should be designed to resist seismic loads. Failure of water heater supports has been shown to be a threat to health and safety. In addition to strapping, approved #exible connectors should be used.

Water Valves for Tanks

A typical design of a water heater tank includes a cold-water dip tube. The tube directs the cold water to the bottom of the tank. At the top of the tank, a hole is installed in the dip tube to prevent water from being siphoned from the tank through the tube. The hole is required to be located within 6 inches of the top of the tank. A vacuum relief valve may be installed in lieu of an anti- siphoning hole in the dip tube.

A valve should be installed on the cold-water branch line from the main water supply line to each hot water storage tank or water heater. The valve should be conspicuously located and near the water heater, and accessible from the same #oor level as the water heater that it serves. The valve is to be installed so that if the heater is taken out of service, the other areas of the water distribution system are not disrupted.

Residential Plumbing Overview 48 Fuel Shut-Off Valves and Disconnects

TPR Valves

A fuel shut-o valve is required for all fuel-“red water heaters. An electric disconnect should be installed for all electric water heaters. They are necessary for service, repair, and emergency shut-down. The electric disconnect should be located within sight of the appliance (meaning visible and no more than 50 feet away), or the circuit breaker should be capable of being locked in the “open” position.

Temperature and pressure-relief (TPR) valves should be installed on all storage water heaters operating above atmospheric pressure. Tankless water heaters must have TPR valves installed. Water heaters without this protection can produce explosions. They have been responsible for many deaths. A pressure-relief valve relieves excessive pressure that may develop in a closed storage tank. A temperature-relief valve responds to excessive temperatures and discharges scalding water from the storage tank.

A TPR valve should be installed in the shell of a water heater tank. It should be located in the top 6 inches of the tank. Typically, water heater tanks have an opening in the tank shell installed by the manufacturer. The TPR valve is located at the top of the tank, which contains the hottest water in the tank.

The valve must be set to open at the maximum working pressure of
the water heater, or 150 pounds
per square inch/psi (1,035 kPa), whichever is less. An undersized valve would not be able to prevent pressure from exceeding the maximum capacity, and a dangerous situation could result. The consequences could include

an explosive tank rupture
accompanied by an instantaneous release of enormous thermal energy, which is stored in super- heated water inside the tank. It could propel a water heater like a rocket through multiple stories, including the roof of a dwelling.

A boiler should be equipped with a pressure-relief valve with a minimum rated capacity for the equipment served. A boiler operates at a maximum water pressure of 160 psig, and at a maximum water temperature of 250° F (121° C).

A pressure-relief valve should be set at the maximum rating of the boiler. Discharge should be piped to drains by gravity to within 18 inches of the #oor or to an open receptor.

Relief valves must be third-party tested. The certi”cation mark is the indicator that the valve has been tested. Temperature-relief valves must be set to discharge at a temperature not higher than

Water Heaters 49

210° F (99° C). The valve is designed to dissipate energy at a rate equal to or greater than the energy/heat input rate of the water heater. A relief valve opens in proportion to the temperature and pressure forced upon its closure disk. The higher the temperature or pressure, the greater the force, and the more the valve opens.

Discharge Pipe on TPR Valve

The following are 13 requirements for a discharge pipe serving a TPR valve:

1. the pipe should not be directly connected to the drainage system;
2. the pipe should discharge through an air gap located in the same room as the water heater; 3. the pipe should be constructed of materials tested, rated and approved for such use;

4. the pipe should not be smaller than the diameter of the outlet of the valve served, and should discharge full size to the air gap;

5. the pipe should not have valves or tee “ttings installed;

6. the pipe should not have a threaded end;

7. the pipe should serve a single relief device, and should not connect to piping serving any other relief device or equipment;

8. the pipe should discharge to the #oor, to an indirect waste receptor, or to the outdoors. Where discharging to the outdoors in areas subject to freezing, discharge piping should be “rst piped to an indirect waste receptor through an air gap located in a conditioned space;

9. the pipe should not terminate more than 6 inches above the #oor or waste receptor;

10. the pipe should discharge in a manner that does not cause personal injury or structural damage;

11. the pipe should be installed so as to #ow by gravity;

12. the pipe should discharge to a termination point that is readily observable by the building occupants; and

13. the pipe should not be trapped.

The termination of a relief valve discharge pipe should always be visible and conspicuous. An air gap is necessary to prevent back#ow and contamination of the potable water system. The discharge pipe must not be reduced in size, and must not be less than the size of the relief valve outlet. A reduction in size will act as a restriction and would reduce the #ow rate of the discharge. Relief valves must not be exposed to freezing temperatures. The slow drip of a leaking valve in freezing temperatures could cause ice to form and restrict the discharge, and eventually disable the valve.

An air gap is the unobstructed vertical distance through the free atmosphere between the outlet
of the waste pipe and the #ood-level rim of the receptacle into which the waste pipe is discharging.

The discharge pipe should have a minimum pressure rating of 100 psi (690 kPa) at 180° F (82° C). Water heater temperature-relief valves are usually set to open and discharge at 210° F (99° C).

Residential Plumbing Overview 50

Expansion Tank on Boiler

Hot water boilers should be provided with expansion tanks. There are two types of expansion tanks designated for use with a residential boiler system. A non-pressurized tank is simply a cylinder “lled with air set at atmospheric pressure. A pressurized tank is a sealed cylinder divided by a #exible diaphragm. An expansion tank provides space for the water to expand as it is heated, and it keeps the water pressure within the normal operating range while the boiler is working.

Water Leak Catch Pan

A water heater tank should be installed inside a pan in
locations in a dwelling where a leak from the tank could cause damage to the structure or property. The pan is intended to catch water leaks from the tank or associated connections, or condensate from the tank. The pan should be made of galvanized steel or other material approved for that use. Pre-fabricated aluminum and plastic pans are common and widely used. Aluminum and plastic pans may not be allowed by every authority having jurisdiction (AHJ) or code ocial because they are not made of galvanized steel, and some tank manufacturers require the use of a metal pan only.

A relief-valve pipe terminating into a water leak catch pan is not permitted because the pan is not an indirect waste receptor. Most pans have only a *-inch-diameter drain outlet, which is not capable of using gravity to drain the pressurized discharge of the relief valve at full #ow.

The pan should not be less than 1 inches deep. The pan should be of sucient size and shape to catch all dripping water or condensate leaks. The pan should be drained by an indirect waste pipe having a minimum diameter of *-inch. The pan drain must not be reduced in size over its entire length because a reduction will act as a restriction and will impede the discharge.

The pan must not connect directly to the drainage system. The pan should terminate over a suitably located indirect waste receptor or #oor drain, or extend to the exterior. An air gap must be provided to prevent back#ow when the pan drain terminates into an indirect waste receptor or a #oor drain.

When the pan terminates to the exterior of the dwelling, it should terminate at least 6 inches (or,
at most, 24 inches) above the adjacent ground surface. This makes the pan low enough not to be a nuisance, and high enough to prevent the pan drain from becoming blocked by vegetation, snow or ice.

Hot Water Tank Defects

Check for physical damage to the tank, particularly rust and corrosion on the bottom of the tank. Check for water marks on the #oor of the tank. Check for a leaking TPR valve. The covers at the electric heating elements should not be disturbed. Corrosion can
be found where the water pipes are connected to the top of the tank. The electricity or the fuel may be shut o. There could be scorching at the burner cover area. The heat rollout shield should be in place. The draft hood and vent connector are often loosely attached. All tanks should be accessible with at least 24 inches of working space around them. Check the burner and #ame. A damaged bae (turbulator) could fall down on the burner.

Water Heaters 51

Tankless coils inside boilers can leak. The coil can damage the boiler. The coil is prone to clogging. There should be a temperature-control valve installed to control the scalding water coming from the coil in the boiler.

Residential Plumbing Overview 52

Quiz #5

1. Fuel-“red water heaters may not obtain combustion air from __________________.

the outdoors or through an open window sleeping rooms, bathrooms or toilet rooms air-to-air changing devices
automatic damper controls

2. A suitable access opening, passageway and work space is required when a water heater is installed in a(n) __________.

sleeping room bathroom
toilet room
attic

3. If the volume of space in which the appliance is located is not greater than 50 cubic feet per 1,000 BTU/h (4.83 L/W) of aggregate input rating of the appliance, then it is designated as a(n) _________ space.

confined
50 / 1000 BTU
unusually tight construction combustion-air dependent

4. T/F: A shut-o switch or disconnect is required on all electric water heaters.

True False

5. ________________ must be set to discharge at a temperature not higher than 210° F (99° C).

Temperature-isolation valves
Fuel-gas valves
Backflow pressure valves
Temperature/pressure-relief (TPR) valves

6. The TPR discharge pipe should discharge through a(n) ________ located in the same room as the water heater.

Schrader valve
sump pump system sewer drainpipe
air gap

Water Heaters 53 7. A relief-valve pipe terminating into a water leak catch pan is not permitted because the pan is not

_______________.

an indirect waste receptor
shallow enough
designed for hot temperatures
intended to catch leaking water from a fixture

Answer Key is on page 114.

Residential Plumbing Overview 54

Potable Water General Comments

Potable water is a precious commodity. The U.S. Environmental Protection Agency’s (EPA’s) Oce of Drinking Water controls the quality requirements for water to be classi”ed as potable. Requirements related to levels of contaminants allowed in potable water are becoming increasingly restrictive. Manufacturers of plumbing equipment carefully select the materials that are exposed to potable water. All materials are tested for their potential eects on potable water. There are standards and requirements for the delivery of potable water from the source to the point of use that apply to both public water sources and private water supplies, including wells, springs, streams and cisterns.

Potable water should be provided to every dwelling that is intended for human occupation or habitation. Potable water should be supplied to all plumbing “xtures unless non-potable water, otherwise known as gray water, is used for other purposes, such as irrigation and #ushing water closets and urinals. The use of non-potable water supplies may become increasingly prevalent as a means to conserve water. Today, non-potable water is typically used in factory and industrial buildings.

Wells, Casings, Pumps and Tanks

Inspection of private water sources, such as a well, is beyond the scope of a home inspection.

A private water source must provide water that is potable. Wells are the most common source of individual water supplies today. A well pump must be accessible for service, repair and replacement without requiring the removal or movement of any panel, door or obstruction, and without the use of a portable ladder. When a pump and its components are in direct contact with the potable water, they must be rated for use in potable water systems, or the pump must be located so as to prevent contamination of the well. When located in a basement, the pump should be elevated. Pumps outside a dwelling must be protected from freezing.

A well must be separated from sources of contamination, such as a sewer drainage “eld and tank, to reduce the possibility of aecting the potability of the water supply. The ground surface around the well area should be sloped and drained positively away. Surface water should be directed away from the well, since one of the greatest threats to a well is the risk of contamination from surface drainage. The well should be at least 10 feet deep.

Well Casings

Casings should be watertight to at least 10 feet below the ground surface. When a well is drilled and the casing is inserted, the space between the outside of the casing and the earth is typically “lled with slurry to prevent surface water from running down the well casing and contaminating the water supply.

The casing should extend above the ground surface 6 to 12 inches. The well casing cover should be overlapping and watertight. Covers should extend downward at least 2 inches over the outside of the well casing.

Well Pumps

Potable Water 55

There are deep wells (more than 25 feet deep) and shallow wells (25 feet or less). A typical well pump can pull up about 25 feet of water. If the well is deeper than 25 feet, the pump will have to be installed at the bottom of the well to push the water up. Pumps are better at pushing than pulling.

The most powerful pump is a submersible pump that is installed in a deep well, and it won’t always be visible. A single-line jet pump indicates a shallow well. A two-line jet pump indicates a deep well where the pump is visible.

Well Pressure Tanks

A well pressure tank functions to deliver water at a relatively consistent pressure to the dwelling “xtures. A pressure tank can be a simple cylindrical tank “lled with air or a tank with a bladder or diaphragm inside. Pressure tanks can be as small as 5 gallons or as large as 80 gallons. These tanks usually sweat condensate; therefore, insulating a tank’s lower half is recommended.

There should be a pressure gauge installed at the tank. A pressure switch that operates the pump should be installed. The main water shut-o valve should be nearby. An air valve of some type is usually installed on the tank’s top.

There should be a 20-psi minimum dierential between the cut-in and cut-out points. Submersible pumps are typically set at 40 and 60 psi.

Well System Defects

Inadequate water supply is a defect for a well system. Wells can be tested with draw-down, capacity, #ow-rate and recovery tests. Water quality of a private water source should be tested every year
for bacteria, such as coliform. Contamination of the water supply is a health hazard and a defect. There could be poor surface grading around the well head. The casing could be too short. The cover could be damaged or not watertight. The pump may not be working properly. If the pump is visible, observe and listen to the pump while it is operating.

Check the pump system with a voltage-meter detector before touching it. Inspect all components. The electrical wiring at the pump may be damaged, loose or incorrectly installed. Check for over- fusing. Check for incorrect type of wire or incorrect wire size. Check grounding. The tank may be rusted, leaking, producing excessive condensate, water-logged, or unstable.

Potable Water Contamination

The potable water supply should be protected from contamination from non-potable liquids, solids and gases introduced into the potable water supply through cross-connections and any other piping connections to the system. Back#ow preventers should be installed accordingly.

Throughout history, there have been numerous occurrences of sickness and disease caused by an unprotected water supply. It is important at all times to maintain a safe-for-drinking quality of the potable water supply at all actual and potential connections and outlets. Understanding how

Residential Plumbing Overview 56 back#ow can occur and how to prevent it are necessary for protecting the water supply.

Backflow

Back#ow is the reverse #ow of the intended direction of the #ow of potable water distribution piping. There are two conditions that cause back#ow: back-siphonage and back-pressure. Back- siphonage is the back#ow of water caused by system pressure falling below atmospheric pressure. Back-pressure is pressure created in a non-potable system in excess of the water supply mains, causing back#ow.

All water supply lines and “ttings for every plumbing “xture should be installed in a way that prevents back#ow. All potable water outlets and openings should be protected against back#ow, including faucets, hose bibbs, plumbing “xtures and plumbing appliances. All appliances, water “lters, tanks, softeners, treatment systems, and other devices that connect to the water supply system should be protected against back#ow and contamination of the water system. Back#ow preventers should be readily accessible.

Back#ow can be prevented by one of four ways:

1. an air gap:
2. a back#ow preventer with an intermediate atmospheric vent; 3. a vacuum breaker; or

4. a reduced pressure-principle back#ow preventer.

A boiler should be protected from back#ow. Because boilers are pressurized, back#ow can be
caused by back-pressure. If the pressure of the potable water supply drops below the boiler pressure, back#ow can occur.

Automatic “re sprinkler systems connected to the potable water supply need to protect the water supply from back#ow by a double check valve.

The potable water supply to a lawn irrigation system should be protected against back#ow.

Cross-connections between a private water source (including a well, spring or surface source) and a public potable water source are not permitted. In a dwelling where more than one water supply system is installed, each system should be identi”ed by color marking or metal tags, including the contents of the piping system, with arrows indicating the direction of #ow.

Air Gaps

An air gap in a drainage system is the unobstructed vertical distance of free space between the outlet of the waste pipe and the #ood-level rim of the receptacle into which the waste pipe is discharging.

As an example, in a commercial restaurant, the air gap would be between the drainpipe of a salad bar and the #oor sink or tub drain.

An air gap in a water distribution system is the unobstructed vertical distance of free space between the lowest opening from any pipe supplying water to a receptacle (such as a sink or tub) and the #ood-level rim of the receptacle. This type of air gap is commonly checked by residential property inspectors while examining the bathroom sink and the laundry tub. What you want to see is that the end of the supply “xture is above the #ood-level rim of the sink or tub.

An air gap is not a device and has no moving parts. An air gap is the most eective and dependable method of preventing back#ow. The potable water opening or outlet is terminated at an elevation

Potable Water 57 above the level of the source of contamination.

The minimum air gap should be measured from the lowest end of a water supply outlet to the #ood-level rim of the “xture into which such potable water outlet discharges. The minimum air gap should be twice the diameter of the eective opening of the outlet.

Condensate Drain Connections

Condensate drains from air conditioner coils, condensing furnaces, and heat-recovery ventilators should not drain directly into a DWV pipe. An indirect drain using an air gap should be installed. In some locations, the direct connection of a condensate drain line into a stack is not permitted, even with a trap. The potential danger is that sewer gases may enter the house through the condensate drain line. It is not a cross-connection problem, but it is unsafe and unhealthy.

Solar Energy

The use of solar energy should not compromise the requirements regarding cross-contamination or the protection of the quality of the potable water supply. There are two basic types of solar heating systems: direct and indirect.

In a direct-connection system, the heat-transfer #uid is potable water, so the system has potential safety problems that must be addressed with regard to design, inspection and maintenance. Direct-connection systems are typically limited to solar water-heating systems where the potable water is directly heated by the solar collectors and circulated through the water supply system.

In an indirect-connection system, a freeze-protected, heat-transfer #uid is circulated through a closed loop to a heat exchanger. The heat is then transferred indirectly to the potable water supply of the dwelling.

System components containing #uids should be protected with pressure and temperature-relief valves. Expansion tanks in solar energy systems should be installed in closed #uid loops that contain heat-transfer #uid.

Solar energy collectors, controls, dampers, fans, blowers and pumps should be accessible for inspection, maintenance, repair and replacement. Where mounted on or above the roof coverings, the collectors and supporting structure should be constructed of non-combustible materials or “re retardant-treated wood equivalent to that required for the roof construction.

Water Service Pipe

The water service pipe moves the water from the source to the dwelling. It is typically underground. In areas having a winter-design temperature of 32° F (0° C) or lower, a water pipe should not be installed outside of a building, in exterior walls, in attics, in crawlspaces, or in any other place subjected to freezing temperatures unless adequately protected from freezing by insulation or heat, or both.

A water service pipe installed outside or underground must be at least 12 inches below grade or 6

Residential Plumbing Overview 58 inches below the frost-line depth, whichever is greater. This minimum coverage protects the pipe

against freezing, as well as from exterior damage.

The minimum diameter of the water service pipe is *-inches, based on the nominal pipe size of the material. Hence, a *-inch cross-linked polyethylene (PEX) plastic pipe has a dierent inside diameter than a *-inch galvanized steel pipe. There are 19 dierent types of piping materials that can be used as a water service pipe.

With few exceptions, the water service pipe and the dwelling’s sewer pipe should be separated by 5 feet of undisturbed or compacted earth. The separation is intended to reduce the possibility of the sewer contaminating the potable water supply. Contamination can occur when there’s a leak in the building’s sewer located near the water service pipe. The soil around it can become contaminated. If the water service pipe has a break in it, then contamination could occur. The water service pipe should not be located in, under or above cesspools, septic tanks, septic drainage “elds or seepage pits.

Pipe Material for the Water Service Pipe

An inspector may discover all types of pipe material for the water service pipe, including copper, galvanized steel, lead, PVC plastic, CPV plastic, polyethylene (PE) plastic, polybutylene plastic, cast iron, asbestos cement, and brass. Copper is the most common water service pipe material, and has been used since the 1930s. Galvanized steel was common until the 1950s; the pipes rust inside and out. Lead has not been used for water service piping since around 1950; lead contaminates potability. PVC water service pipe is typically blue or white, and has been used since the 1960s.

PE Plastic Pipe and Tubing

Polyethylene is an inert polyole”n material. It is resistant to chemical reaction, making joining using solvent cement not possible. PE pipe for use as water service pipe is blue or black. Orange PE pipe is used for gas installations. PE cannot be used for hot water distribution systems.

PVC Plastic Pipe

PVC water service pipe is dierent than PVC drainage pipe, although both are white.

Water Distribution Pipe Material

Not all water service pipe material can be used for water distribution. For example, PVC pipe is not usable for water distribution because it cannot tolerate hot water temperatures. Therefore, water service piping materials that are not certi”ed for water distribution should terminate at or before the full-open valve located at the entrance to the dwelling. CPVC and PEX are permitted for both water service and water distribution and, therefore, a termination and a change in pipe material would not be required.

Copper or Copper-Alloy Tubing

Copper tubing is available in Type K, L and M, which indicate wall thickness. Type K is the thickest and typically used for underground water service. Type M is the thinnest and most commonly used in water distribution systems. Type L is high-quality. Types of copper tubing are identi”ed with color markings on the tubing: Type K is green; Type L is blue; and Type M is red. Copper pipe is soldered, but #are connections and compression “ttings can also be used.

Potable Water 59 Some plumbers prefer not to use compression “ttings because they sometimes leak at the

connection.

Inspectors should closely inspect these under-sink connections, since movement of piping is very likely. Recommend to clients that they periodically monitor these connections for leaks.

CPVC Plastic Pipe

CPVC is chlorinated polyvinyl chloride. It is typically ivory-colored, and it is suitable for both hot and cold water systems. It has been used since the 1960s. CPVC is solvent-welded.

Galvanized Steel Pipe

A wide variety of pipe is classi”ed as galvanized steel pipe. It is available in dierent wall thicknesses: Schedule 40, 80 and 160. Galvanized steel pipe is sometimes called wrought-iron pipe, but wrought-iron pipe has not been manufactured in the U.S. since the 1950s. Galvanized steel pipe rusts through from the inside.

PB Plastic Pipe and Tubing

PB pipe has been the subject of much attention because of the manufacturer’s settlement of a multimillion-dollar lawsuit. The manufacturer has not admitted that it’s defective but agreed to the class-action settlement. It has been assumed that oxidants in public water supply systems, such as chlorine, react with the polybutylene piping and “ttings. This reaction causes them to scale, #ake and become brittle. Micro-fractures are created as a result, and the structural integrity of the pipe is compromised. If the pipe system becomes weak, it may fail without warning and cause major damage to the building and personal property.

PB pipe will no longer be manufactured and will no longer be available when current supplies run out. Polybutylene pipe can often be identi”ed by its gray color. However, it was also made in white, blue, black and ivory. One of the easiest ways to identify this pipe is to locate the “PB” lettering on the printed label. PB pipe is typically blue or gray. Blue usually indicates that the pipe is intended for underground water-main service use only. Gray indicates that the pipe can be used for water-main service and for interior water distribution inside the house. Home inspectors should not rely only on the color to identify the material.

The designation “PB 2110” indicates the quality of the material. The material must be of Type 2, Category 1 polybutylene, which is identi”ed as PB 21. “Type 2” indicates density, and “Category 1” indicates extrusion #ow rate. The last two digits (“10”) indicate the hydrostatic design stress of 1,000 psi (6,895 kPa).

Cross-Linked PEX Plastic Tubing

PEX is polyethylene cross-linked plastic tubing. The cross-linked structure prevents the pipe from rupturing over a wide range of temperatures and pressures. PEX is resistant to solvents and cannot be joined by solvent cementing. PEX is #exible and can be bent. PEX can be hot-bent with a hot-air gun. The minimum hot-bending radius is 2 times the outside diameter. PEX can be cold-bent, too (at room temperature), to a minimum radius of six times the outside diameter.

Water Pressure Regulator

The minimum static pressure at the dwelling entrance for either public or private water service (as determined by the local water authority) should be 40 psi (276 kPa). The maximum static pressure

Residential Plumbing Overview 60

should be 80 psi (552 kPa).

When the pressure from the public water main or private well exceeds 80 psi, a pressure-reducing valve or regulator should be installed at the point where the water service pipe enters the dwelling. The pressure regulator should be installed immediately downstream of the main shut-o valve. To allow a continuous #ow of water to the dwelling, the water pressure-reducing valve is designed to remain in an open position if the component fails.

All water pressure-reducing valves should be designed to allow repair and removal of parts without requiring the removal of the valve from the water supply pipe, or breaking the pipeline. The strainer for the valve must also be available for inspection and periodic maintenance without removing the valve or breaking the pipeline.

Water Pressure, Friction and Other Performance Factors

The amount of water supply at a “xture depends on a few factors, including:

• pipe size;
• pipe friction;
• changes in direction of the pipe; • pressure; and
• elevation.

Pressure is one of the key variables in a water supply system. Pressure should be adequate to overcome pressure losses that occur in the system from friction and elevation. All of the plumbing “xtures should operate properly with adequate pressure.

Pipe friction can cause pressure loss. Pressure loss is made when water particles rub against the inside of the water pipe (friction), or when there are changes in the direction of the water #ow (friction).

Potable Water 61 The amount of pressure loss caused by friction is aected by:

• the velocity of the water;
• the roughness of the water;
• the developed length of the pipe; and • the diameter of the pipe.

As the pipe diameter increases, the eects of friction decrease. The bigger the pipe, the better. As velocity, roughness and pipe length increase, the eects of friction increase. Fittings can cause a greater loss of pressure than the pipe itself.

Friction caused by equipment, such as back#ow preventers, check valves, water meters, strainers, “lters, tankless water heaters and softeners, can also cause pressure loss.

Velocity

With an increase in velocity comes an increase in friction, and the abrasive and erosive eects
of water are subsequently increased. The water supply system’s velocity must be high enough to minimize the potential for suspended materials from depositing, as well as to avoid the destructive eects of erosion-corrosion, cavitation and pressure surges.

The maximum velocity in the water supply pipe is 8 feet per second (2.4 m/s).

Roughness

A scale or buildup on the inner walls of the water supply pipe can form when the supplied water contains dissolved mineral salts, such as sulfates, bicarbonates, chlorides of calcium, sodium and magnesium. Caking can aect the capacity of a pipe over time. Because higher temperatures of water increase the solubility of minerals, caking occurs more rapidly in hot water distribution pipes. Dierent levels of pH can accelerate the eects of caking and corrosion.

Changes in Direction

Pressure loss also happens when the direction of water #ow changes. Cavitation is caused by sharp changes in the direction of the water #ow at high velocities. In a change of direction, vapor bubbles form (boiling occurs) and then collapse (or condense). The noise of popping sounds is produced inside the pipe.

“Water hammer” is a term used to describe noise produced by a destructive force known as hydraulic shock. Water hammer develops in a piping system when an instantaneous change in
the velocity of #owing water occurs, or when water #owing at a given velocity is stopped abruptly. Water hammer can occur without audible sounds. A quick closure of a valve, for example, creates some form of shock, with or without noise. The shock wave is accompanied by a pressure surge that can expand the wall of the pipe. The velocity of the #owing water, the rate at which the water #ow is stopped, and the diameter and material of the pipe aect the intensity of water hammer. To prevent adverse eects from water hammer, the standard requires that the intensity of the water hammer be controlled with water-hammer arrestors, installed according to the manufacturer’s recommendations. Many water-hammer arrestors are now permanently charged and factory-sealed, and require no maintenance and, therefore, need no access.

Residential Plumbing Overview 62

Elevation

The dierence in elevation between the water supply source and the highest water supply “xture results in an increase or decrease in available pressure. There’s typically a loss in pressure because the water supply is usually located below the outlet “xture. The loss is the result of the pressure required to overcome the weight of the water in order to deliver water to the “xture.

To push water up from the basement through the “rst #oor to the showerhead in the second-#oor master bathroom, there may be about 25 vertical feet to overcome. There would be a pressure loss of between 10 and 11 psi (pounds per square inch) or 69 to 76 kPa (kilopascals). If the static pressure at the basement were 60 psi (413 kPa), the static pressure at the master bedroom would be 49 psi (337 kPa).

Static pressure is the pressure exerted by the water on the interior walls of the water supply pipe when no water is #owing. It is how hard the water is being pushed.

Water Pressure Defects

In order to get the most meaningful results in relation to inspecting the water pressure, it is
good practice to inspect the plumbing “xtures at the highest point in the house. And then move downwards to the lowest level of the building while running water at each “xture for a minute or two. Do not let water run at any “xture without close observation. Do not let water run unattended at any “xture.

Many inspectors will run all of the “xtures in one bathroom at the same time and observe their performance. It is helpful to demonstrate to clients how the shower performs when multiple “xtures are running simultaneously. Clients will be able to determine for themselves whether the performance is acceptable or not. When it is not acceptable, inspectors typically call for correction and further investigation by a professional.

Undersized Piping

In some old houses, the supply pipe diameter may be as small as +-inch, while *-inch is considered the minimum diameter.

Steel Piping

Galvanized steel piping rusts from the inside out. Eventually, the pipe will leak. The water pressure drops because the rough surface inside the pipe creates friction loss. The accumulation of rust on the inside of the pipe restricts the #ow. The eective diameter of the pipe is reduced.

Pipe Length

Pressure loss is relative to the length of the pipe. The longer the pipe, the greater the pressure loss due to friction as the water #ows through the pipe. If we wanted to move 3 gallons of water per minute through 100 feet of -inch-diameter pipe, there would be a pressure drop of about 7 psi.

Potable Water 63

Elevation

Dwellings built far above street level may have low water pressure and water #ow. Pressure drops as water is pushed up vertically.

Dirt

Sometimes there are particles in the water supply, and a reduction in the water #ow at the “xture is observed. Often, a simple cleaning of the screen at the lavatory outlet is all that is required.

Water Consumption

There are maximum water consumption #ow rates and quantities for all plumbing “xtures and “xture “ttings. The intention of the maximum rates and quantities is to conserve water resources by limiting the consumption and #ow rates of plumbing “xtures and outlets.

Maximum Flow and Consumption Rates for Plumbing Fixtures and Fittings
Fixture or Fixture Fitting	Maximum Flow Rate or Quantity
lavatory, private	2.2 gpm at 60 psi
showerhead (or hand-held shower spray)	2.5 gpm at 80 psi
sink faucet	2.2 gpm at 60 psi
urinal	1 gallon per #ush cycle (3.785 L)
water closet (toilet)	1.6 gallons per #ushing cycle

Federal law mandates that sink faucets have a maximum #ow rate of 2.2 gpm at 60 psi, and that water closets (toilets) limit their consumption to 1.6 gallons per #ushing cycle. There are few exceptions.

Size of Water Supply Pipe to Fixture

The minimum sizes for “xture supply pipes are given in the following table. Fixture pipe sizes in traditional plumbing trade-sizing designations correspond to the internal diameter of the pipe. Each pipe size number is the minimum size permitted for the supply pipe from the point of source to the “xture. But in the last 30 inches, the pipe can be reduced in size. This is common when connecting faucets to sink supply lines. A #exible water connector installed between the supply pipe and the

Residential Plumbing Overview 64 “xture may reduce the size. Flexible connectors are considered “xture “ttings.

Minimum Size of Fixture Water Supply Pipes
bidet, lavatory, #ush-tank water closet, #ushometer water closet	3/8-inch
dishwasher, hose bibb, kitchen sink, laundry, single- head shower,* bathtub, one-piece water closet	1/2-inch
#ush-valve urinal	3/4-inch
#ush-valve water closet	1 inch
* Can be reduced if it is an individual distribution pipe served by a manifold

Thermal Expansion Control

In the connection of a water distribution system to water-heating appliances, there is the potential for the migration of heated water into the water distribution piping. In a typical water distribution system, the water will expand into the public water service. If the expansion of water is not accommodated in the system, dangerously high pressures can develop that can cause damage to piping, components, and the water heater itself.

For water system sizes up to and including 2 inches, a device for controlling pressure should be installed where the pressure on the downstream side of
a pressure-reducing valve exceeds the pressure- reducing valve setting. This is because of thermal expansion. Where a back#ow-prevention device, check valve, or other device is installed on a water supply system using storage water heating equipment (such that thermal expansion causes an increase in pressure), a device for controlling pressure should be installed. This device can be an expansion tank with a #exible diaphragm inside it.

Potable Water 65 Gridded and Parallel Water Distribution

Gridded and parallel water distributions systems use individual supply pipes that extend to each “xture from a central supply point. The central point is a manifold to which the individual supply pipes connect. These systems have advantages over the traditional branch distribution system. Individual shut-o valves installed at the manifold should be identi”ed as to the “xture being supplied, since the control function of valves at the manifold would not be apparent.

Lead Content of Pipes and Fittings

The EPA enacted a ban on lead solder in June 1986. It also limited the lead content of pipes and “ttings to a maximum of 8%. The limitation also applies to the various qualities of brass used in producing faucets, “ttings and valves. The amount of lead in brass pipe is less than 1%.

Water Distribution Pipe

Pipe used for water distribution is required to conform to NSF 61 standards. Pipe used for distribution of hot water must be capable of withstanding high temperatures. All hot-water- distribution pipe and tubing must have a minimum pressure rating of 100 psi at 180° F (689 kPa at 82° C). The maximum temperature of a hot water distribution system is 180° F (82° C). CPVC, PEX and PB plastic pipe are often identi”ed as rated for 180° F at 100 psi (82° C at 690 kPa). These pipes can actually withstand temperatures in excess of 212° F (100° C).

Solvent-Cement Joint

A solvent-cement joint is a homogeneous chemical bond between a pipe and “tting. The bond is accomplished when the chemical composition of both joining surfaces is the same. If the materials are dierent, the joint will not form a proper chemical bond. Solvent-cementing between ABS and PVC pipe is prohibited. This prohibition extends to solvent-cementing between PVC and CPVC, and between CPVC and ABS, as well. The dierence between ABS, CPVC and PVC solvent-cement joints is based on the type of solvent cement, and the fact that CPVC and PVC joints must “rst be primed. There are few exceptions to the rule of using a primer for CPVC. Failure to use a primer will result in a failed joint and may aect the manufacturer’s warranty. Solvent cement for CPVC is orange in color, indicating that the appropriate solvent cement has been used.

Solder Joint

A soldered joint is the most common method of joining copper pipe and tubing. The copper pipe must be cut square. All cut tube ends of copper pipe should be reamed to the full inside diameter of the tube end to remove the burr. All joint surfaces should be cleaned.

A #ux should be applied before soldering. Flux is a chemically active material that removes and excludes oxides from the joint area during the heating process, and allows the melted solder to spread out on the joining surfaces. The joining of water supply piping should be made with lead-free solder and #uxes. “Lead-free” means a chemical composition equal to or less than 0.2% lead content.

Lead-bearing solder can sometimes be visually identi”ed because the solder tends to darken over time. The solder will #ow by capillary action toward the heat. Heat causes the copper atoms to move farther apart from each other, and the solder atoms enter the spaces between the copper atoms, creating a strong bond when solidi”ed.

Residential Plumbing Overview 66

Galvanic Joint

When copper pipe is joined with galvanized steel pipe, protection against the galvanic corrosion is needed. Galvanic corrosion occurs when two dierent metals come into contact in the presence of an electrolyte, such as water. The more reactive metal at a joint is called the anode (galvanized steel pipe), and the less reactive metal is called the cathode (copper pipe). Two methods of protecting against galvanic corrosion are by using dielectric “ttings and brass “ttings.

Valves Full-Open Valves

Full-open valves are shut-o valves that, in the full-open position, have a straight-through #ow passageway. But, unlike shut-o valves and stops, full-open valves add little resistance to #ow and have little eect on supply pressure. Full-open valves are referred to as water-service valves.

The valves at the street curb, which are called curb valves or corporation cocks, are installed by the water utility company and are usually a lubricated rotor or plug-type valve.

The building entrance valve, or the main water valve, is usually installed before the water meter, when the meter is to be located inside the dwelling. It is usually a ball or gate valve. Valves installed on either side of the meter allow the meter to be removed and replaced without having to drain the distribution system.

Shut-Off Valves

A shut-o valve is dierent from a full-open valve. There is a pressure drop through a shut-o valve. There is little friction loss through a full-open valve. Shut-o valves are commonly referred to as stops, and include globe valves, straight stops and angle stops. One can replace a shut-o valve with a full-open valve, but not vice versa.

Shut-o valves should be installed:

1. on the water supply pipe to each plumbing “xture, other than showers and bathtubs; 2. on the water supply pipe to each sillcock; and
3. on the water supply pipe to each appliance or mechanical equipment.

Showers and bathtubs typically do not have shut-o valves because they would not be accessible for maintenance. Sillcocks can be damaged, vandalized, abused, and prone to freezing (even when the hose bibb is frost-proof ). Without valves at the previously mentioned locations, the main water shut- o valve in the dwelling would have to be shut o for long periods of time until repairs are made.

Access to all shut-o and full-open valves is required. Water service valves and valves for hose bibbs should be identi”ed or should have an identi”cation tag. All other valves should be identi”ed if the valve’s purpose is not obvious, or if the “xture, appliance or equipment served by the valve is not readily visible. Identi”cation is helpful and sometimes critical in certain situations.

Stop and Waste Valves

Many shut-o valves are stop and waste valves. At these valves, there is a small bleed or drain outlet on the downstream side of the valve. The purpose of this valve is to drain all the water out of the piping.

Potable Water 67

Globe, Ball and Gate Valves

Globe valves tend to be restrictive, but can be used to control water #ow.

Ball valves are less restrictive to #ow than other valves. The handle clearly indicates whether the valve is open or closed. Ball valves do not control water #ow.

Gate valves are meant to be fully open or closed. Since the seal is metal-to-metal, corrosion can cause these valves to fail.

Valve Defects

Home inspectors are not required to operate all the valves in a dwelling. Old valves have brittle packing washers that will crack and cause the valve to leak. Common problems with valves include leaking valves, missing valves, inaccessible valves, damaged or missing handles, or rusted or partially closed valves.

Hot Water

Hot water is de”ned as water of a temperature of 110° F (43° C) or hotter. Tempered water ranges from 85° F to 110° F (29° C to 43° C), and the device supplying the tempered water must limit the temperature to 110° F (43° C).

If the distribution piping distance between the hot water source and any “xture is greater than 100 feet, then the hot water supply system should have a method of maintaining the temperature of the water. Otherwise, water is wasted at the point of use while the user is waiting for the desired temperature to be reached. Pipe insulation is not required on all hot water distribution pipes, but insulation of the hot water distribution pipes on a return circulation system should be installed.

Residential Plumbing Overview 68

Quiz #6

1. T/F: A shut-o valve is the same as a full-open valve.

True False

2. T/F: The U.S. Environmental Protection Agency’s (EPA’s) Oce of Drinking Water controls the quality requirements for water to be classi”ed as potable.

True False

3. A well casing should extend above the ground surface ______ inches.

24 to 48 1 to 3
6 to 12 36 to 48

4. There are _____ wells (more than 25 feet deep) and _____ wells (25 feet or less).

deep….. shallow drilled….. irrigated shallow….. deep deep….. wide

5. All water supply lines and “ttings for every plumbing “xture should be installed in way that prevents ____________.

backflow
indirect venting
friction
defective pressure reduction
inadequate clearance to combustibles

6. A(n) ___________ is the most eective and dependable method of preventing back#ow.

air gap
mechanical device with moving parts ball valve
tee

7. The minimum diameter of a water service pipe is typically ________.

1/2-inch
3/4-inch
1-3/4 inches

Potable Water 69 8. Type K copper tubing is the ________ and typically used for underground water service.

kilo flow pipe Kpa/1,000 value thinnest
thickest

9. In order to get the most meaningful results, it is good practice to inspect the plumbing “xtures at the _______ point in the house.

lowest
most used highest

10. Dwellings built far above street level may have _____ water pressure and water #ow. Pressure ______ as water is pushed up vertically.

high…..drops low…..drops
low…..increases great…..builds

11. T/F: Solvent-cementing between ABS and PVC pipe is prohibited.

True False

Answer Key is on page 115.

Residential Plumbing Overview 70

Sanitary Drainage
General Comments and Testing Standards

Modern plumbing, including proper sanitary drainage, is one of the reasons that diseases such as typhoid fever, cholera and dysentery have been eliminated. Modern plumbing has improved human health and longevity.

The drainage, waste and vent (DWV) system consists of all piping for conveying wastes from:

• plumbing “xtures and appliances, including “xture traps;
• above-ground drainage piping;
• below-ground drainage piping within the building (building drain); • below- and above-ground venting systems; and
• piping to the public sewer or private septic system.

Testing Rough-In DWV

When a home is under construction and the plumbing rough-in work has been completed, all plumbing and drainage work is typically tested by the installer to verify that it is leak-free. The drain, waste and vent (DWV) system of the dwelling should be tested with water, not air. Air cannot be used for testing plastic DWV piping systems. A water test allows for the identi”cation and repair of any plumbing defects before the system is covered up and concealed.

According to 2018 International Residential Code (IRC) Section P2503.5.1, Rough Plumbing, each section of the DWV system must be tested, except for the top 5 feet of the DWV system. Each section should be tested with at least a 5-foot head of water for a period of 15 minutes. This means that a section of pipe should be “lled with water to a point not less than 5 feet above the highest “tting in that section. The system must be leak-free everywhere along the entire length of plastic DWV piping.

The 2018 IRC allows an alternative test. An air-pressure test of the DWV system is the alternative exception, but the DWV piping must not be made of plastic. Air testing cannot be used for testing plastic piping systems. If this exception is used, the non-plastic DVW pipe system must hold 5 psi (34 kPa) pressure throughout for a period of at least 15 minutes without introducing additional
air. Testing DWV systems with air is much more dangerous than testing with water because of the energy that is released if the system fails or ruptures; it can be tremendous and explosive. And increasing the test pressure beyond the material’s safety limits poses a hazard.

The design and installation of a DWV system in a dwelling should function reliably, should not be under- sized or over-sized, and should be constructed of materials, “ttings, and connections listed and approved.

Trenching

Trenches should have solid and continuous load-bearing support at the bottom of the trench, forming a bed for the pipe. Rocks or blocks at any point should not support piping. Detrimental forces induced from pressure points are placed on the piping when the pipe is resting on this type of material.

Pipe is protected from damage by proper back-“lling. Back-“lling is done in 6-inch layers, with each layer being tamped into place. The material used for back”ll must be evenly distributed to avoid pipe movement. Large rocks and chunks of dirt should not be located within 12 inches of the pipe.

Sanitary Drainage 71

Separate Sewers

The combining of sewers (prior
to connection to the public sewer system) that serve dierent buildings under dierent ownership is not permitted. The exception is if the sewers from dierent buildings on the same lot or parcel of land are combined and each building is under the same ownership.

Sewage Treatment

Sewage should not discharge on the ground surface, into the ground, or into any waterway unless it has been “rst rendered innocuous through an approved form of treatment. The discharge of untreated waste and sewage from a DWV system is an environmental and human health hazard. The local code ocial, state health department, or the EPA should approve the form of treatment.

Sanitary Drainage Pipe Material

Materials used in a DWV system should be approved by ASTM or CSA standards. Pipe materials are listed in the table that follows.

Sanitary Drainage Pipe Materials
Material	Above-ground, inside dwelling	Underground, inside dwelling	Underground, outside dwelling
abcrylonitrile butadiene styrene (ABS) plastic pipe (Schedule 40)	permitted	permitted	permitted
asbestos-cement pipe (not commonly used)	not permitted	permitted	permitted
cast-iron pipe (no hub)	permitted	permitted	permitted
concrete pipe	not permitted	not permitted	permitted
copper or copper-alloy pipe	permitted	permitted	permitted
galvanized steel pipe	permitted 6 inches above ground	not permitted	not permitted

Residential Plumbing Overview 72

Sanitary Drainage Pipe Materials
Material	Above-ground, inside dwelling	Underground, inside dwelling	Underground, outside dwelling
polyethylene (PE) plastic pipe	not permitted	not permitted	permitted
polyvinyl chloride (PVC) plastic pipe (Schedule 40)	permitted	permitted	permitted
stainless steel drainage pipe	permitted	permitted	permitted
vitri”ed clay pipe	not permitted	not permitted	permitted

Slope of Drainage Pipe

The minimum velocity in a horizontal drainpipe is 2 feet per second (0.61 m/s). This is called the scouring velocity. The velocity is intended to keep solids in suspension. If the velocity is too low, the solids will tend to drop out of suspension and stop on the pipe bottom. This will lead to blockages and stoppages. Minimum slopes of horizontal drainpipes are listed in the following table.

Slope of Horizontal Drainage Pipe
Size (in inches)	Minimum Slope (inch per foot)
2 or less	1/4
3 to 6	1/8
8 or larger	1/16

Change in Drainpipe Size

The size of the drainage pipe cannot be reduced in the direction of the drainage #ow. A reduction will create an obstruction of the #ow, resulting in blockage or stoppage.

Sanitary Drainage 73

Breakage and Corrosion of Pipes

Pipes passing through or under walls should be protected from breakage. Sheathing or wrapping should allow for expansion and contraction of the pipes to prevent any rubbing action. The minimum wall thickness for the material is 0.025 inches.

Any pipe installed within or under a footing or foundation wall must be protected from any transferred load from the footing or wall. A relieving arch or pipe sleeve may be installed. When a sleeve is used, it should be sized so that it is two pipe sizes larger than the penetration pipe. This space allows for movement of the pipe. Ring-like spaces between sleeves and pipes need to be “lled or tightly caulked. Pay special attention to where the pipe penetrates through

a “re-resistant assembly. A listed “re-stop system may be needed. The purpose of this is to structurally protect the pipe so that it will not be subjected to undue stresses that may cause the pipe to break.

Pipes located in concealed spaces within the interior of the dwelling should be protected from breakage if installed through holes or notches in studs, joists, and similar framing components. Where the hole or notch is less than 1 inches from the nearest member’s edge, steel protective shield plates are required.

Pipes made of brass, copper, cast iron and steel are subject to corrosion when exposed to the lime and acidity of concrete, cinder, soil/dirt, and other corrosive materials. A sheathing, coating or wrapping (or other means) is needed around such pipes. Typical protective materials include coal-tar wrappers with paper, epoxy or plastic coatings.

Fittings

Fittings should be approved and compatible with the type of piping used, and should be of a sanitary or DWV design for drainage and venting. The design of a drainage system is based on uniform
#ow in the drainage piping. Particular “ttings have been designed with patterns providing the least resistance to #ow. Drainage “ttings should maintain a grade of one-quarter unit vertical in 12 units horizontal (2% slope).

Prohibited Joints

The following joints and connections are not permitted:

1. cement or concrete joints;
2. mastic or hot-pour bituminous joints; 3. joints made with unapproved “ttings;

4. joints between dierent diameters of pipes made with elastomeric rolling O-rings; 5. joints between dierent types of plastic pipes made with solvent cement; or
6. saddle-type “ttings.

Residential Plumbing Overview 74

Cement and concrete are in#exible. Bituminous material is unreliable and not permanent. An O-ring has no resistance and can be pushed out of the joint. The joint between dierent types of plastic made with solvent cement is not reliable because the chemical composition of the joint will not be homogeneous. Solvent-cementing is not permitted between ABS and PVC, between PVC and CPVC, or between ABS and CPVC. Saddle “ttings may move out of alignment.

Cleanouts

All cleanouts should be accessible or reachable without having to remove a permanent portion of the structure. Cleanouts are designed to make the interior of a drainage system accessible for clearing stoppages without inconvenience, dismantling wall or ceiling “nishes, or disturbing the sanitary drainage system.

Cleanout plugs are very common. They are usually located at changes in direction in a drain
line and at the bottom of stacks. Cleanouts should be installed to open and allow cleaning in the direction of the #ow of the drainage pipe, or at right angles thereto. They must be water-tight and gas-tight. A cleanout plug can be made of brass or plastic. A cleanout plug should have a raised square or a counter-sunk square head where a trip hazard may exist. The square shape minimizes the possibility of stripping the plug during removal.

Drainage pipe cleanouts should be installed not more than 100 feet apart in horizontal drainage lines, as measured from the upstream entrance of the cleanout.

A cleanout should not be covered with cement, plaster or other “nish material. Where it is necessary for a cleanout to be concealed, an approved type of cover plate or access door should be provided. The minimum clearance in front of cleanouts is 18 inches on pipes 3 inches and larger, and 12 inches on smaller pipes.

Cleanouts should be installed at each change in direction greater than 45 degrees in the building sewer, building drain, and horizontal waste or soil line. A cleanout is not required for each and every change in direction. If a 90-degree change in direction is made with a single “tting, then
a cleanout is needed. If the same change in direction is made with two bends, a cleanout is not required because rodding equipment should be able to easily pass through “ttings having a change in direction of 45 degrees or less.

A cleanout cannot be removed in order to install a new “xture or additional drainage piping. A cleanout “tting is commonly removed to allow a new connection; however, a substitute cleanout must be installed in the same capacity as the original cleanout that was removed. For this reason, many cleanout “ttings have only a few threads and are unable to securely receive a threaded pipe or male adapter.

Cleanouts in the “nished #oor are often improperly converted into #oor drains. Such an opening would not have a water trap, and sewer gases would enter the dwelling’s interior.

With few exceptions, cleanouts should be the same size as the pipe they serve, up to 4 inches. For pipes larger than 4 inches, the cleanout size should be at least 4 inches.

Drainage System Sumps and Ejectors

Where the drainage system cannot drain by gravity to the sewer, an automatic pump or ejector
can be used to discharge the soil and waste. The cover for the pump should be tightly sealed (gas- tight). Other than pneumatic ejectors, sumps should be vented with a minimum 1-inch diameter vent pipe. Pumps use mechanical methods to discharge, and pneumatic ejectors use air pressure. Grinder pumps and ejectors pulverize solids to a near-liquid state and pump the slurry to the

Sanitary Drainage 75

drainage system.

The capacity of the sump should not exceed one-half of a day’s (12 hours’) discharge load from the piping system connected to the sump under normal use. The retention period should be short
to prevent the pump from acting like a septic tank. The minimum capacity of the sump must be such that the pump operates for at least 15 seconds per pumping cycle to prevent short-cycling and overuse of the equipment. The level of the euent in the pit should not rise within 2 inches of the gravity drainage pipe entering the pit.

The sump pit should not be less than 18 inches in diameter or 24 inches deep. The pit should be accessible. All drainage to the pit should #ow by gravity only. The pit bottom should be solid and should provide stable support for the pump. The pit’s cover should be able to structurally support anticipated weight loads in that area of use.

The discharge pipe should have a check valve installed to prevent previously pumped discharge from returning to the pump. A full-open valve should be installed on the discharge side of the check valve. This valve is used to prevent waste and gases from coming back toward the pump when maintenance or repair is performed on the check valve or the pump/ejector unit. The valves must be accessible.

Residential Plumbing Overview 76

Quiz #7

1. The joint between dierent types of plastic made with solvent cement will not be reliable because the chemical composition of the joint will not ____________.

be homogeneous
have chemical dissimilarity be chemically porous

2. The square shape of a cleanout ________ the possibility of stripping the plug during removal.

minimizes increases eliminates

3. T/F: It is permitted, in certain situations, to discharge untreated sewage or wastewater on the ground surface.

True False

4. T/F: Rocks or blocks at any point could support drainage piping inside a trench.

True False

5. Particular drainage “ttings have been designed with patterns providing ________ resistance to #ow.

the greatest the least
a frictional

6. The minimum slope of a horizontal drainpipe that is sized between 3 and 6 inches is _______.

1/8-inch per foot 3/16-inch per foot 1/16-inch per foot 1 inch per foot

7. The drain, waste and vent (DWV) system of the dwelling should be tested with a minimum _______ head of water for 15 minutes.

10-foot 100-foot 1-foot

Sanitary Drainage 77 8. Drainage pipe cleanouts should be installed not more than _________ apart in horizontal

drainage lines measured from the upstream entrance of the cleanout.

10 feet 150 feet 100 feet

9. T/F: A cleanout is required for each and every change in direction of the sewer drainage pipe.

True False

10. The sump pit should not be less than ____ inches in diameter and ____ inches deep.

24…..18 24…..36 18…..24

11. The discharge pipe on a sump pump should have a _________ installed to prevent previously pumped discharge from returning to the pump.

check valve
drain hole
smooth-walled pipe wye fitting
float-ball valve

Answer Key is on page 115.

Vents
Drain Waste Vent Basics

Residential Plumbing Overview 78

Every trap and trap “xture should be vented. The purpose of venting is to protect the trap seal of each trap. The vent system reduces pressure dierences in the drainage system. Venting protects the trap seals from positive pressures and siphonage. Every dwelling should have at least one vent pipe that extends to the exterior.

The minimum size of any vent is half of the required size of the drainpipe, but not less than 1 inches. All vent and branch vent pipes should be sloped and connected in order to drain back to the drainage pipe via gravity.

The most common way of venting is to install a separate or individual vent for each trap or trapped “xture that is then connected to the dwelling’s main venting system. The other methods of venting include common venting, wet-venting, waste- stack venting, circuit venting, combination drain-and-vent, and island-“xture venting.

A common vent is one vent that serves more than one
“xture, functioning as an individual vent for each
“xture. Wet-venting is venting single or double
bathroom groups or combinations thereof, where one
vent pipe may serve all the “xtures connected to the
wet vent. Waste-stack venting is venting individual
“xtures through a drainage stack, and the oversized
stack functions as the vent. Circuit venting is venting
up to eight “xtures with a single vent pipe. A
combination drain-and-vent system is restricted to #oor
drains, sinks and lavatories, and relies on the oversized
drainpipe. Island-“xture venting has a vent installed
below the #ood-level rim of the “xture before rising to connect to another vent.

Air Valves

Individual, branch and circuit vents are permitted to terminate with a connection to an individual or branch-type air-admittance valve. Stack vents and vent stacks should be permitted to terminate to stack-type air-admittance valves. Access should be provided to all air-admittance valves. The air-admittance valve should be rated according to the size of the vent to which it is connected.

Vents 79

Vent Distances

The table below lists the maximum distance of a “xture trap from a vent, according to size of the trap and the slope of the drainage pipe. The developed length of the “xture drain from the trap weir to the vent “tting for self-siphoning “xtures, such as water closets, is not limited.

Maximum Distance of Fixture Trap from Vent
Size of Trap (in inches)	Slope (in inches per foot)	Distance from Trap (in feet)
1	1/4	5
1	1/4	6
2	1/4	8
3	1/8	12
4	1/8	16

Vent Terminations

The vent system for a dwelling should have at least one vent pipe that extends outdoors to the open air. The vent should be a dry vent that connects the building drain and extends to the outdoors. A vent stack or stack vent may terminate outdoors or to a stack- type air admittance valve.

Here are some important terms and de”nitions related to dierent types of vents:

The stack is a general term used to refer to any vertical line of soil, waste or vent pipe that extends through at least one story of a building.
The stack vent is provided

Residential Plumbing Overview 80

for the waste stack. The stack vent is the extension of a soil or waste stack above the highest horizontal drain that is connected to the stack. This is the pipe that is visible in the attic and from the roof surface. The diameter size of the stack vent must not be smaller to that of the waste stack.

The vent stack is the vertical vent pipe installed primarily for providing air circulation to and from any part of the drainage system, which is the piping in a home that carries away sewage or other liquid waste.
A local vent stack is the vertical pipe into which other pipe connections are made from the “xture side of traps. Vapor or foul air is removed from the “xture through the local vent stack.
The building drain is the lowest pipe of a drainage system into which drains the soil, waste and other drainage pipes from inside, and it extends at least 30 inches beyond the exterior building walls. This is extended into the building sewer.
The building sewer is the piping that extends from the end of the building drain and connects to the public sewer, private sewer, or individual sewage system. Vent Termination at Roof The vent pipe that passes through the roof should end at least 6 inches above it to protect the end of the vent pipe from being blocked by snow, and to allow a sucient length of pipe for proper roof #ashing. Where the roof area can be occupied, the vent should extend at least 7 feet above the roof to prevent noxious sewer gases from harming people. Frost Closure In cold climates, vent pipes installed at the dwelling’s exterior should be protected against freezing by insulation, heat, or both. A vent pipe located outside a home increases the likelihood of frost closure. To prevent frost buildup on the pipe’s interior, it should be protected. If insulated well enough, the heat of the vent gases and vapors may be relied upon to prevent frost from developing. The possibility of frost closure occurs in cold climates having a winter outdoor 97.5% design temperatures of 0° F (-18° C) or below; therefore, a minimum 3-inch-diameter vent will be needed. A vent pipe of 3 inches or larger will likely not completely close up with frost. The 97.5% design temperature means that if the outdoor winter design temperature is 20° F (-7° C), the temperature during the winter is 20° or higher 97.5% of the time. For example, Pueblo, Colorado, has a winter 97.5% design temperature of 0° F (-18° C) and will require a vent pipe at least 3 inches in diameter. Appendix D of the International Plumbing Code includes a table for dierent areas of the United States. Vent Terminal Location The opening of a vent terminal should be located away from any air-intake opening to prevent
sewer gases from entering the dwelling. It should not be located directly beneath any door, openable window, or other air-intake opening of the dwelling, or any adjacent dwelling. Any such vent terminal should be at least 10 feet away horizontally from such an opening, unless it is at least 2 feet above the top of the opening. Vent terminals extending through the wall should terminate at least 10 feet from the lot line and 10 feet above ground level. They should not end under a sot overhang. A side-wall vent should have a screen or protection over the opening to prevent birds from building nests in them and rodents from entering the drainage system.

Quiz #8

1. The vent pipe that passes through a roof should end at least _________ above the roof.

6 inches 3 inches 12 inches

2. A dwelling should have at least ____ vent pipe(s) that extend(s) to the outdoor air.

one two three four

3. For homes located in cold climates, their _______ should be protected against freezing by insulation, heat, or both.

vent pipes or vent stacks chimney vents
pressure-relief valves

Answer Key is on page 116.

Vents 81

Traps
Traps: The Basics

Residential Plumbing Overview 82

A trap is designed to keep sewer gases and airborne bacteria from escaping the drainage system and entering the dwelling. Each plumbing “xture should be separately trapped by a water-seal trap, except as otherwise permitted by the plumbing standard. Fixtures such as water closets and urinals that have integral traps do not require an additional trap.

The vertical distance from the “xture outlet to the trap weir should not exceed 24 inches. The vertical distance controls the drainage-#ow velocity. If the trap has an excessively long vertical separation from the “xture, the velocity of the #ow at the trap inlet can create siphoning.

The horizontal distance should not exceed 30 inches, as measured from the centerline of the “xture outlet to the centerline of the inlet of the trap. The horizontal distance from a “xture to the trap limits the amount of bacterial growth and odor. It is desirable to locate the trap as close as possible to the “xture. A “xture should not be double- trapped.

Standpipes should be individually trapped. Standpipes for washing machines and similar appliances are required to be a minimum of 18 inches and a maximum of 42 inches high above the trap. Access to all standpipes should be provided for cleaning and rodding.

Minimum Trap Size

Fixtures and their minimum trap sizes are listed in the following table. Note that a 1-inch drain is the minimum acceptable size to permit proper, open #ow in a pipe for sanitary drainage. The minimum trap size is based on this pipe size.

Traps 83

Drainage Fixture and Minimum Trap Size
automatic clothes washer (residential)	2 inches
bathtub (with or without overhead shower or whirlpool attachment)	1 inches
bidet	1 inches
clothes washer standpipe	2 inches
dishwashing machine (residential)	1 inches
#oor drain	2 inches
kitchen sink (with or without food waste grinder and/or dishwasher, one or two traps)	1 inches
laundry tub/tray (one or more compartments)	1 inches
lavatory	1 inches
shower (based on total #ow rate through showerheads and body sprayers) !ow rate: • 5.7 gpm and less • more than 5.7 gpm, up to 12.3 gpm • more than 12.3 gpm, up to 25.8 gpm • more than 25.8 gpm, up to 55.6 gpm	• 1 inches • 2 inches • 3 inches • 4 inches
water closet (residential) (1.6 gallons per #ush or greater)	trap size consistent with “xture outlet size

Residential Plumbing Overview 84

Trap Seal

A water seal of 2 inches is standard for most traps. Each “xture trap should have a liquid seal of
at least 2 inches and, at most, 4 inches or deeper for specially designed “xtures. Traps that do not periodically receive waste discharge will evaporate their seal. Fixtures such as #oor drains typically have trap seals that lose their water by evaporation and, therefore, should be provided with seal primers. A trap seal primer will be either water supply-fed or of a drainage type.

Protecting the Trap Seal

Traps that do not periodically receive waste discharge will evaporate their seal. Fixtures such as #oor drains typically have trap seals that lose their water by evaporation. The trap seals should be protected from evaporation by one of the following methods:

A potable water-supplied trap seal primer. The discharge pipe from the primer should connect to the trap above the trap seal on the inlet side.
Reclaimed or gray water-supplied seal primer valve. The discharge pipe from the primer should connect to the trap above the trap seal on the inlet side.
Waste water-supplied trap primer device. The discharge pipe from the primer should connect to the trap above the trap seal on the inlet side.
Barrier-type trap seal protection device. The device is installed according to the manufacturer’s recommendation. Prohibited Traps There are traps that impede drainage #ow by moving parts, design #aws, #ow pattern, or the ability to lose a trap seal. The following types of traps are not permitted:

traps that depend on moving parts;
bell traps;
crown-vented traps;
traps not integral with a “xture and that depend on interior partitions for the seal (except for those traps constructed of an approved material that is resistant to corrosion and degradation);
S-traps; and
drum traps (except when used for intercepting solids and chemical waste). Trap Cleanout A cleanout plug or removable trap section should be installed on traps located below laundry tubs, sinks and washbasins used for cleaning.

Trap Defects

Inspectors should check for traps under each “xture. Toilets never have traps. Leaks at traps are common due to loose connections and damaged pipes. In cold climates, check for traps that are subject to freezing. A common defect results when an unquali”ed person has unsuccessfully tried to repair a trap. Check for staining, water damage, and buckets. Many old tailpieces and traps are made of soft brass with chrome or nickel plating. They are sometimes so thin that a gentle touch will cause them to break into pieces.

Traps 85

Residential Plumbing Overview 86

Quiz #9

1. Standpipes for washing machines and similar appliances are required to be a minimum of ___ inches high above the trap.

4 inches 18 inches 2 feet

2. Each “xture trap should have a liquid seal of at least _________ and, at most, 4 inches or deeper for specially designed “xtures.

1/2-inch 1 inch 2 inches

3. ________ traps are not permitted because they impede drainage #ow.

T-
Bubble S-

4. Many old tailpieces and traps are made of soft brass with chrome or nickel plating and are sometimes so thin that a gentle touch will cause them to ____________.

make noises
stain your fingers break into pieces

Answer Key is on page 116.

Protection 87

Protection
Protection Against Pipe Damage

It is critical that piping that passes through holes and notches in joists, studs, rafters and other structural members in concealed locations less than 1 inches from the nearest edge of the member be protected from damage that can typically be caused by wallboard fasteners and/or wood structural panels. Shield plates are to be utilized. They should be at least 1/16-inch thick and made of steel. They should cover the area of the pipe where the member is notched or bored, and should extend a minimum of 2 inches above the sole plates and below the top plates.

For fuel-gas piping, the plate should extend a minimum of 4 inches above sole plates, below top plates, and to each side of a stud, joist or rafter.

Fuel piping must not be installed in any solid concrete or masonry #oor construction. The potential for pipe damage caused by settlement of the slab or the corrosive action of the #oor material makes it crucial that the gas piping be installed in channels or casings, or have similar protection.

Plumbing Support
The Fundamentals of Plumbing Support

Piping should be supported to ensure alignment and to prevent sagging. Piping in the ground should be laid on a proper bed. Piping above ground should be supported with hooks, straps, bands, brackets and/or hangers suitable for the size of the piping, of adequate strength and quality, and located at intervals so as to prevent sagging, damage and vibration. Other piping should not support piping. Piping should not put strain upon connected equipment or appliances.

Hangers and strapping should be of approved material that will not promote galvanic reaction.

Rigid-support sway-bracing should be

installed at changes in direction greater than 45 degrees for pipe sizes 4 inches and larger. Piping should be supported at distances not to

exceed those in the table to follow. For large pipes, hangers alone may not be sucient to resist the forces created by water movement inside the pipes, so rigid bracing may be needed. Vertical piping typically needs support only at each story height.

Residential Plumbing Overview 88

Piping Support
Material	Maximum Horizontal Spacing (in feet)	Maximum Vertical Spacing (in feet)
ABS pipe	4	10
aluminum tubing	10	15
brass pipe	10	10
cast-iron pipe	5	15
copper and copper-alloy pipe	12	10
copper and copper-alloy tubing (1-inch diameter and smaller)	6	10
copper and copper-alloy tubing (1-inch diameter and larger)	10	10
cross-linked polyethylene (PEX) pipe	2.67	10
cross-linked polyethylene/ aluminum/cross-linked polyethylene (PEX-AL-PEX) pipe	2.67	4
CPVC pipe and tubing (1 inch and smaller)	3	10
CPVC pipe and tubing (1 inches and larger)	4	10
lead pipe	continuous	4

Protection 89

Piping Support
Material	Maximum Horizontal Spacing (in feet)	Maximum Vertical Spacing (in feet)
PB pipe and tubing	2.67	4
polyethylene/aluminum/ polyethylene (PE-AL-PE) pipe	2.67	4
polypropylene (PP) pipe and tubing (1 inch and smaller)	2.67	10
polypropylene (PP) pipe and tubing (1 inches and larger)	4	10
PVC pipe	4	10
stainless steel pipe	10	10
steel pipe	12	15

Residential Plumbing Overview 90

Quiz #10

1. Hangers and strapping should be of approved material that will not promote ________ reaction.

seismic galvanic inert

2. The maximum horizontal spacing for PVC drainage pipe is _____ feet.

8 2 4

3. The maximum horizontal spacing for supporting cast-iron pipe is _____ feet.

15 5 2

Answer Key is on page 116.

Storm Drainage Storm Drainage Basics

Storm Drainage 91

Storm drainage is the system of collecting and transporting away from a dwelling the rainwater, groundwater, and storm water typically associated with rainfall. Connection of #oor drains to the storm drainage system is not permitted. Storm water, rainwater and groundwater should not be drained into a sewer system. The rainwater should drain to an acceptable point of disposal, such as a retention basin, river, stream, pond, public storm sewer system, or to the surrounding land if it does not adversely aect the building.

The ground surface of the lot should be graded so as to drain surface water away from foundation walls. The grade should be dropped a minimum of 6 inches within the “rst 10 feet. Where the site does not allow for the necessary fall away from the structure, drains or swales could be used.

Gutters and downspouts, or other means, should prevent rainwater from washing soil away from the dwelling’s foundation or building up around

and increasing groundwater pressure on basement walls. The size of the drainage pipe should not be reduced in the direction of #ow.

Residential Plumbing Overview 92

Quiz #11

1. Storm water, rainwater or groundwater should not be drained into a ________.

hole in the ground
drainpipe
outdoor drainage grate lake
sewer system

2. The ground surface of the lot should be graded so as to drain surface water away from foundation walls. The grade should be dropped a minimum of _____ inches within the “rst 10 feet.

10 18 24 6

Answer Key is on page 116.

Dryer Systems 93

Dryer Systems
Dryer Exhaust Systems: The Basics

Clothes dryer exhausts emit exhaust air that is laden
with moisture and lint. The air must be vented to the outside. It should not discharge into an attic, crawlspace or attached garage because wood structural members could be adversely aected by excessive moisture, and the accumulation of lint could pose a “re hazard.

Length

The maximum length of a clothes dryer exhaust duct should not exceed 35 feet from the dryer’s location to the wall or roof termination. The maximum length is reduced by 2 feet for each 45-degree bend, and 5 feet for each 90-degree bend. The maximum length does not include the transition duct. There are some exceptions to this rule, including powered-fan exhaust systems for dryers.

Short, straight, horizontal duct runs are the most ecient. The size and maximum length of the exhaust duct shall be determined by the dryer manufacturer’s installation instructions and must comply with local building codes.

One best practice is a duct length of no more than 35 feet from the connection to the transition duct to the outlet terminal (the exhaust termination point). This maximum length is reduced by the types of exhaust duct “ttings. The 2018 IRC M1502.4.5.1 describes those reductions as follows:

Dryer Exhaust Duct Fitting Type	Equivalent Length
4-inch radius, mitered 45-degree elbow	2.5 feet
4-inch radius, mitered 90-degree elbow	5 feet

The maximum length of the exhaust duct does not include the transition duct.

Terminations

The duct termination should be “tted with a closeable gravity or automatic damper (a backdraft damper).

Exhaust outlets should be equipped with backdraft dampers to prevent cold air, rain, snow, rodents and vermin from entering the vent. Screens are not permitted at the duct termination because they can trap lint and debris, which can prevent proper venting and pose a “re hazard. The damper should be periodically checked for proper operation, as well as debris and material behind it

from nesting birds. The dryer exhaust should terminate not less than 3 feet in any direction from openings into the building, including operable windows, doors and air intakes.

Residential Plumbing Overview 94

The exhaust duct should terminate outside the home at least 3
feet from any opening, and
at least 10 feet from an air conditioner or heat pump condenser.

Connections

Ducts should be sealed
and mechanically fastened.
Ducts should not be joined,
connected or installed with
sheet-metal screws or other
fasteners that will obstruct
air#ow. The fasteners must
not protrude into the inside
of the duct more than 1/8-
inch. The ducts should be
joined with clamps or foil
tape. Screws or similar
fasteners that can protrude into the inside of the duct and catch lint must not be used. Ducts should not extend into or through ducts or plenums. The exhaust duct should be a minimum of 4 inches in diameter. Transition ducts should not be concealed within construction materials.

Fuel 95

Fuel
Oil Storage Tanks

Tanks should be listed and labeled, and conform to standards for underground and above-ground tanks. The maximum amount of fuel oil stored above ground or inside a dwelling is limited to 660 gallons (2,498 L). The cross-connection of two tanks is permitted if the total aggregate capacity does not exceed 660 gallons. Gravity #ow from one tank to another is permitted, provided that the two tanks are on the same horizontal plane.

Inside and Outside

Tanks for use inside dwellings should be
sized to permit installation and removal
as whole units. Any tank larger than 10 gallons (38 L) should be at least 5 feet from any “re or #ame of any fuel-burning appliance.

Tanks located outside and above ground should be at least 5 feet away from an adjoining property line. Tanks located outdoors should be protected from the weather and from physical damage. Tanks should have a fuel-level gauge, but glass gauges should not be used. In areas prone to #ooding, tanks should be installed at or above the #ood elevation, or should be anchored to prevent #oatation, collapse or lateral movement under #ood conditions.

Oil Tank Supply

Exterior above-ground “ll and vent piping should be removed when tanks are abandoned or removed. Fill piping should terminate outside of the dwelling at a point at least 2 feet away from any building opening at the same or a lower level. Supply piping should not be smaller than 3/8- inch pipe, or 3/8-inch outside-diameter tubing, and the copper tubing should be at least Type L in thickness.

Oil Tank Vents

Vent piping should not be smaller than 1-inch pipe. Vent piping should slope toward the tank. The lower end of the vent pipe should enter through the top of the tank. Vent piping should terminate outside of dwellings at a point not less than 2 feet measured vertically and horizontally from any dwelling’s opening.

Oil Supply Lines

Oil supply lines move the oil from the storage tank to the burner at the equipment or appliance. They are typically made of 3/8-inch copper tubing. If the copper supply oil line passes through a concrete #oor or wall, then provision should be made for lateral thermal expansion and movement of the pipe. In general, the oil supply piping should be installed in a manner that avoids placing

Residential Plumbing Overview 96

stress on the piping and accommodates the expansion and contraction of the piping system and building materials. This may be accomplished with a plastic or rubber sleeve. Buried piping should be protected by corrosion-resistant coatings, special alloys, or “berglass-reinforced plastic. Refer
to your local plumbing code for speci”c requirements. An oil “lter and a shut-o valve should be installed on the supply line coming from the oil storage tank.

Oil Tank Defects

Common problems include
leaks at the oil tank, strong odors, improperly supported legs, rust and corrosion damage at the tank legs, missing caps at the pipes, a damaged gauge, and/or excessive rust and corrosion on the tank. An oil “lter may be missing, leaking or dirty.

Underground Fuel-Gas Piping

Underground piping for fuel
gas should be at least 12 inches
below the “nish grade. A minimum of 8 inches is required for individual lines to outdoor lights, grills, and other appliances. Metallic pipe and tubing exposed to corrosive elements, such as soil or moisture, should be protected in an approved manner.

Support for Fuel-Gas Piping

Fuel-gas piping should be supported at intervals not exceeding the spacing listed in the table that follows.

Support for Fuel-Gas Piping
Nominal Size of Steel Pipe (in inches)	Spacing of Supports (in feet)	Nominal Size of Smooth-Wall Tubing (in inches, per outside diameter)	Spacing of Supports (in feet)
1/2	6	1/2	4
3/4 or 1	8	5/8 or 3/4	6
1 or larger	10	7/8	8

Fuel 97

Support for Fuel-Gas Piping
Nominal Size of Steel Pipe (in inches)	Spacing of Supports (in feet)	Nominal Size of Smooth-Wall Tubing (in inches, per outside diameter)	Spacing of Supports (in feet)
1 or larger (vertical)	at every #oor level	1 or larger (vertical)	at every #oor level

Fuel-Gas Sediment Traps

Most fuel-gas appliance manufacturers require the installation of a sediment trap. Sediment traps prevent debris from entering the gas controls and causing hazardous malfunctions. A sediment trap should be installed downstream of the equipment’s shut-o
valve as close as possible to the inlet of the equipment/

appliance. Sediment traps cause the gas #ow to change direction 90 degrees at the sediment-collection point. The solids and contaminants in the fuel will drop out of the gas #ow at the collection point. The sediment trap could be constructed as a T-“tting with a capped nipple at the bottom of the opening of the run of the tee.

Fuel-Gas Pressure Regulators

A line pressure regulator should be installed where the appliance is designed to operate at a lower pressure than the

Fuel Connectors

Residential Plumbing Overview 98

supply pressure. Access should be provided to all pressure regulators. They should be protected from physical damage. Pressure regulators that require vents should be vented directly to the outdoor air.

Shut-Off Valves for Fuel-Gas Appliances

Each piece of equipment and appliance should be provided with a shut-o valve that is separate from the appliance to permit maintenance, repair, replacement and temporary disconnection. The shut-o valve should be adjacent to the appliance, no farther away than 6 feet, conspicuously located, and within reach.

Shut-o valves should not be located in concealed locations, and should have access provided. They should be easily located and operated in the event of an emergency. For example, a gas shut-o valve for an appliance on the “rst #oor should not be located in the basement. There is an exception for decorative appliances.

A shut-o valve should be installed ahead of any #exible (semi-rigid) appliance fuel connector. It should not be less than the nominal size of the connector.

Gas outlets that do not connect to appliances should be capped gas-tight in case the shut-o valve opens or fails.

Every gas meter should be equipped with a shut-o valve located on the supply side of the meter.

Flexible (semi-rigid) appliance fuel connectors are typically used with cooking ranges and clothes dryers where the gas connection is located behind the appliance. Some degree of #exibility is needed to facilitate the hook-up of the appliance. Flexible connectors are usually made of brass or stainless steel. They should be labeled with tags of metal rings placed over the tubing.

Connectors should have an overall maximum length of 3 feet, except for range and clothes dryer connections, which should not exceed 6 feet in length. Only one connector should be used for each individual appliance. Connectors should not be concealed within or passed through walls, #oors, partitions, ceilings or appliance housings, with the exception of “replace inserts.

Protection from damage: Connectors and tubing shall be installed so as to be protected against physical damage.

Prohibited locations and penetrations: Connectors shall not be concealed within or extended through walls, #oors, partitions, ceilings or appliance housings.

Shut-o valve: A shut-o valve not less than the nominal size of the connector shall be installed ahead of the connector.

Equipment shut-o valve: Each appliance shall be provided with a shut-o valve separate from the appliance. The shut-o valve shall be located in the same room as the appliance, not farther than 6 feet from the appliance, and shall be installed upstream from the union, connector, or quick disconnect device it serves. Such shut-o valve shall be provided with access.

Fuel 99 Certain Older Gas Connectors May Be Dangerous

Gas connectors are corrugated metal tubes used to connect gas appliances in the home to fuel- gas supply pipes. Some older brass connectors can come apart, causing “res and explosions and resulting in deaths and injuries.

These older brass connectors have a serious #aw in how their tubing is joined to their end pieces. Over time, the end pieces can separate from the tubing and cause a serious gas leak, explosion, or “re. These dangerous uncoated brass connectors have not been made for more than 30 years, but many of them are still in use. The older these connectors get, the greater the possibility of failure.

Although not all uncoated connectors have this #aw, it is very dicult to tell which ones do. Therefore, any uncoated brass connector should be replaced immediately with either a new plastic- coated brass connector or a new stainless steel connector. Connectors can wear out from too much moving, bending, or corrosion. Connectors should always be replaced whenever the appliance is replaced or moved from its location.

WARNING

Only a quali”ed professional should check the connector and replace it, if needed.

Moving the appliance even slightly, whether to clean behind it or to inspect its gas connector, can cause the complete failure of one of these older weakened connectors, possibly resulting in a deadly “re or explosion.

Do not move the appliance to check the connector. If you smell gas and suspect a gas leak:

• Leave the house immediately.
• Do not use your phone.
• Call your gas supplier or dial 911 for assistance from a neighbor’s house. • Do not light any matches.
• Do not turn on any lights.
• Do not switch on anything electrical.

Fuel-Gas Venting Systems

Connectors should be used to connect an appliance and equipment to the vertical chimney or vent, except where the chimney or vent is attached directly to the appliance. The vent connector should be as short as practical, and the appliance should be located as close as practical to the chimney or vent.

All vent pipes should be listed and labeled. The type and size of the vent for each fuel-gas appliance are dictated by the appliance manufacturer’s installation instructions. The design and installation instructions presented by the vent manufacturer should be followed when designing a vent system. Various types of vents are listed in the building standard, along with the corresponding types of appliances that can be served by the vent, which include, but are not limited to:

• Type B gas vents;
• single-wall metal pipes;
• Type L plastic vents for Category IV appliances; and

Residential Plumbing Overview 100

• Type BW vents.

Where two or more vent connectors enter a common gas vent, chimney #ue, or single-wall metal pipe, the smaller connector should enter at the highest level consistent with the available head room or clearance to combustible materials. Vent connectors serving Category I appliances (those with a natural draft and no condensate produced) should not be connected to any portion of a mechanical draft system operating under positive static pressure, such as those serving Category III and IV appliances (those with a draft-inducer fan and producing condensate).

Vent connectors should be installed without dips or sags and should slope upward toward the vent or chimney at least a -inch per foot. There’s an exception for mechanical draft systems.

Insulation Shields

Insulation shields should be installed in attics to prevent the insulation from coming into contact with chimneys. The attic shield creates air space between the chimney and the insulation material. Where vents pass through insulated assemblies, an insulation shield constructed of not less than 26-gauge sheet metal should be installed to provide clearance between the vent and the insulation material. Where vents pass through attic space, the shield should terminate not less than 2 inches above the insulation materials, and should be secured in place to prevent displacement.

Factory-Built Chimneys Serving Fuel Gas

A factory-built chimney should be installed according to the manufacturer’s instructions. All pre- fabricated chimneys must have a label from an approved agency. The label should state the type of appliance with which the chimney was tested for use, a reference to the manufacturer’s instructions, and the minimum clearances to combustibles. The manufacturer’s instructions should contain every aspect of the installation of the chimney, including component assembly, clearances, supports, terminations, “re-blocking or “re stops, and connections.

Termination

Chimneys for residential or low-heat appliances must extend 3 feet above the highest point where the chimney passes through the roof. They must also extend at least 2 feet higher than any portion of the building within a horizontal distance of 10 feet.

Chimney Connections

Connector vent pipes should connect to a masonry chimney #ue at a point not less than 12 inches above the lowest portion of the interior of the chimney #ue. Abandoned inlet openings in chimneys and vents should be closed by an approved method.

Fuel-Gas Vent Terminations

The type of venting materials used for fuel-gas vent terminations depends on the operating characteristics of the appliance being vented. Appliances can be characterized with respect to:

• positive or negative pressure within the venting system; and
• whether or not the appliance generates gases that condense in the venting system.

Regardless, all appliances must be connected to venting systems. The venting system must never extend into or pass through any fabricated air duct or furnace plenum. It must convey an adequate,

Fuel 101 positive #ow of #ue or vent gases directly to the outdoors.

Mechanical Draft Systems

Mechanical draft systems must be installed according to the manufacturer’s recommendations and installation instructions.

The appliance can be mechanically drafted by either forced- or induced-draft methods.

Forced-draft systems and all portions of induced-draft systems must be under positive pressure during operation and must not leak into the building.

Natural-draft appliances must not have their vent connectors connected to any portion of a mechanical daft system that is operating under positive pressure.

The vent termination of a mechanical draft system must be at least 7 feet above ground level, and at least 3 feet above any forced-air inlet located within 10 feet. There are exceptions to this rule: The mechanical draft venting system can terminate at least 4 feet below, 4 feet horizontally from, or 1 foot above any door, operable window, or gravity air inlet into any building. The vent termination must be at least 1 foot above ground level.

Residential Plumbing Overview 102

Types of Venting Systems

There are several types of venting systems that can be used, including: plastic piping; special gas vents designed by the manufacturer; and masonry, metal, and factory-built chimneys.

Type of Venting System to Be Used
Appliance	Type of Venting System
• Category I appliances • Appliances with draft hoods • Appliances with Type B vents	• Type B gas vent • Chimney • Single-wall metal pipe • Listed chimney lining for gas venting • Special gas vent listed for the appliance
Listed vent wall furnaces	Type B-W gas vent
Category II appliances	As speci”ed by the manufacturer of the appliance
Category III appliances	As speci”ed by the manufacturer of the appliance
Category IV appliances	As speci”ed by the manufacturer of the appliance
Unlisted appliances	Chimney
Decorative appliances in vented “replaces	Chimney
Direct-vent appliances	As speci”ed by the manufacturer of the appliance
Appliances with integral vents	As speci”ed by the manufacturer of the appliance

Plastic Piping Materials

Plastic piping used for venting appliances must be approved and installed according to the appliance manufacturer’s installation instructions. If a primer is required, it must be of a distinct color.

Fuel 103 Chimney Clearances vs. Fuel-Gas Vent Clearances

It is a common mistake to apply chimney (masonry) termination height requirements (the 3-2-10 Rule) to gas fuel vents, which cause vents to extend above roofs much higher than needed, in most cases. For example, gas vent pipes terminating above roof slopes up to 6:12 need to be only 1 foot high.

Gas vents that are 12 inches or less in size and located at least 8 feet away from a vertical wall or similar structure should terminate above the roof in accordance with the requirements in the table to follow.

Gas Vent Terminations
Roof Slope	Minimum Height in Feet (& in Meters)
#at to 6:12	1 (0.30)
6:12 to 7:12	1 (0.38)
over 7:12 to 8:12	1 (0.46)
over 8:12 to 9:12	2 (0.61)
over 9:12 to 10:12	2 (0.76)
over 10:12 to 11:12	3 (0.99)
over 11:12 to 12:12	4 (1.22)
over 12:12 to 14:12	5 (1.52)
over 14:12 to 16:12	6 (1.83)
over 16:12 to 18:12	7 (2.13)
over 18:12 to 20:12	7 (2.27)
over 20:12 to 21:12	8 (2.244)

Residential Plumbing Overview 104

The table requirements indicate that a greater vent height above the roof is needed as the roof slope approaches being a vertical surface. The greater the roof slope, the greater the eect of the wind hitting the roof’s surface.

Gas vents that are greater than 12 inches in size or that are located less than 8 feet from a vertical wall or similar structure should terminate at least 2 feet above the highest point where they pass through the roof, and not less than 2 feet above any portion of a dwelling within 10 feet horizontally. There are other requirements for direct-vent “replaces, appliances with integral vents, and appliances using mechanical draft fans.

Type B and Type L

Type B and L gas vents must terminate at least 5 feet in vertical height above the highest connected appliance’s draft hood or #ue collar. Type B-W gas vents must terminate at least 12 feet in vertical height above the bottom of the wall furnace. For more information about Type B and L vent pipes, visit www.nachi.org/type-b-l-vent-inspection

Gas vents should extend through the roof #ashing, roof jack or thimble, and terminate with a listed cap or assembly.

Forced-Air Inlet

Gas vents must terminate at least 3 feet above any forced-air inlet located within 10 feet.

Chimney (Masonry) and Fireplace Termination (The 2-10 Rule)

Chimneys should extend at least 2 feet higher than any portion of a building within 10 feet, but not less than 3
feet above the highest point where

the chimney passes through the roof. This is known a the 3-2-10 Rule for Chimneys.

Type L venting systems should terminate with a listed and labeled cap at least 2 feet above the roof and at least

2 feet above any portion of the building within 10 feet. This is known as the 2-2-10 Rule for Type L Vents.

Automatic Dampers

Fuel

105

An automatic #ue damper is an energy-saving device that closes o or restricts an appliance #ue when the appliance is not operating and is in its “o” cycle. It traps residual heat in the heat exchanger after the burners shut o, and prevents the escape of conditioned air up the vent pipe.

An automatic vent damper should be labeled and of a listed type. The installation of an automatic damper

must be in strict accordance with the manufacturer’s installation instructions. A malfunctioning or improperly installed damper could cause malfunction and a discharge of combustion byproducts into the dwelling’s interior.

A manual damper should be used only with a solid fuel-burning appliance, and not with a gas-“red appliance. The user of a solid fuel-burning appliance would be aware of a closed or malfunctioning manual damper because of the smoke. The user of a gas-“red appliance may not know of a partially closed or malfunctioning manual damper, and a hazardous condition would develop.

Residential Plumbing Overview 106

Quiz #12

1. A(n) ________ damper should be used only with a solid fuel-burning appliance, and not with a gas-fired appliance.

4-inch diameter flow-reducing manual
automatic

2. The cross-connection of two oil storage tanks is permitted if the total aggregate capacity does not exceed ____ gallons.

2,000 660 1,220

3. A sediment trap should be installed ________ of the equipment’s shut-o valve and as close as possible to the inlet of the equipment/appliance.

downstream upstream in lieu

4. Where two or more vent connectors enter a common gas vent, chimney #ue, or single-wall metal pipe, the ________ connector should enter at the highest level consistent with the available head room or clearance to combustible materials.

double-walled larger
greatest
smaller

5. Gas vent pipes terminating above roof pitches up to 6:12 need to be _______ high.

at least 10 feet at least 3 feet only 1 foot

Answer Key is on page 116.

Inspection Checklist 107

Inspection Checklist

Plumbing systems in the home cover not just the water supply, waste and vents, but many other areas. Normally, any evaluation of the plumbing also includes other supply piping, such as gas and oil lines.

The following inspection guidelines are excerpted from InterNACHI’s Home Inspection Standards of Practice, reiterated here for the inspector’s review:

3.6. Plumbing
I. The inspector shall inspect:

A. the main water supply shut-o valve;

B. the main fuel supply shut-o valve;

C. the water heating equipment, including the energy source, venting connections, temperature/ pressure-relief (TPR) valves, Watts 210 valves, and seismic bracing;

D. interior water supply, including all “xtures and faucets, by running the water; E. all toilets for proper operation by #ushing;
F. all sinks, tubs and showers for functional drainage;
G. the drain, waste and vent system; and

H. drainage sump pumps with accessible #oats.

II. The inspector shall describe:

A. whether the water supply is public or private based upon observed evidence; B. the location of the main water supply shut-o valve;
C. the location of the main fuel supply shut-o valve;
D. the location of any observed fuel-storage system; and

E. the capacity of the water heating equipment, if labeled.

III. The inspector shall report as in need of correction:

A. de”ciencies in the water supply by viewing the functional #ow in two “xtures operated simultaneously;

B. de”ciencies in the installation of hot and cold water faucets;

C. mechanical drain stops that were missing or did not operate if installed in sinks, lavatories and tubs; and

D. toilets that were damaged, had loose connections to the #oor, were leaking, or had tank components that did not operate.

Most computerized reporting systems include a “eld that identi”es the location of the main water shut-o valve. Some inspectors also physically tag it as a future aid to the home buyer. Caution must be exercised with old shut-o valves, as they can easily leak when they have not been operated in some time. Evaluation of the supply should also include the materials of the supply and waste piping.

Residential Plumbing Overview 108

It should be determined whether the water supply is from a private well or a public supply. Often, an inspector will recommend water testing of private water sources to determine the safety of the supply.

The water heating system must be identi”ed and described, and its visible condition reported on. Special care should be taken to evaluate the TPR valve and discharge line. It is not required to operate the TPR valve, but it needs to be present and should have a proper discharge line and termination. Many regions also require that the tank be strapped due to potential seismic issues.

All toilets should be fully evaluated and the inspection report should re#ect any de”ciencies in water supply, waste service, connection to the #oor, and obvious defects, such as cracked lids. It is common to “nd rotted sub-#ooring adjacent to the toilet due to leakage around the mounting #ange.

The most common procedure used when evaluating plumbing “xtures is to stopper the sinks, run the faucets (noting their operation), then unplug the sink and inspect the waste and its connections for signs of leakage. Water stains in the bottom of cabinetry are a reliable sign of previous or ongoing problems that should be reported on. Fixtures that are slow to drain should also be reported, as it can indicate blockages or poor ventilation in the system.

Inspectors should report on the functional #ow of water through the “xtures. The most common method is to run two or more faucets or “xtures at the same time. Signi”cant drops in #ow at an individual faucet during this test can be a sign of either poor supply pressure or partially clogged piping, which would require further evaluation. Some inspectors use a pressure and #ow meter, but this is not required.

Fuel supply lines and storage devices should also be inspected and described, such as gas lines and their shut-os, oil tanks and their locations (if known), and any propane or LPG tanks.

Any sump pumps, if accessible, should be evaluated and operated during the plumbing inspection, with any de”ciencies noted.

IV. The inspector is not required to:

A. light or ignite pilot #ames.

B. determine the size, temperature, age, life expectancy or adequacy of the water heater.

C. inspect the interior of #ues or chimneys, combustion air systems, water softener or “ltering systems, well pumps or tanks, safety or shut-o valves, #oor drains, lawn sprinkler systems, or “re sprinkler systems.

D. determine the exact #ow rate, volume, pressure, temperature or adequacy of the water supply. E. determine the water quality, potability or reliability of the water supply or source.
F. open sealed plumbing access panels.
G. inspect clothes washing machines or their connections.

H. operate any valve.

I. test shower pans, tub and shower surrounds or enclosures for leakage or functional over#ow protection.

J. evaluate the compliance with conservation, energy or building standards, or the proper design or sizing of any water, waste or venting components, “xtures or piping.

K. determine the eectiveness of anti-siphon, back-#ow prevention or drain-stop devices.

Inspection Checklist 109

L. determine whether there are sucient cleanouts for eective cleaning of drains. M. evaluate fuel storage tanks or supply systems.
N. inspect wastewater treatment systems.
O. inspect water treatment systems or water “lters.

inspect water storage tanks, pressure pumps, or bladder tanks.
evaluate wait time to obtain hot water at “xtures, or perform testing of any kind to water heater elements.
evaluate or determine the adequacy of combustion air.

S. test,operate,openorclosesafetycontrols,manualstopvalvesand/ortemperature/pressure-relief valves.

T. examine ancillary or auxiliary systems or components, such as, but not limited to, those related to solar water heating and hot water circulation.

U. determine the existence or condition of polybutylene, polyethylene, or similar plastic piping. V. inspect or test for gas or fuel leaks, or indications thereof.

As in the case of heating boilers, the inspector is not required to ignite pilot lights, and should never start any system that has been shut down. There are many tales of inspectors who, in an eort to be helpful, have activated a plumbing system, only to have a major #ood on their hands!

While the age and size of a water heater can often be determined from the data plate, it is usually a mistake to guess how well it will meet the future loads placed on it and, especially, how long it is likely to last. There are too many variables that come into play, such as usage, maintenance and water quality. Many inspectors have fallen into the trap of, in eect, warranting a system, only for that system to fail soon after or be shown to be inadequate for new needs.

The inspector can comment and report only on what s/he can see. The inspector is not required to remove any normally “xed access panels. Many plumbing components are hidden in this way and are, therefore, not available for inspection. Bath and shower drains are examples of components that simply cannot be visually inspected. The internal parts of other components, such as the bladder in a pressure tank, are inaccessible and, generally, cannot be evaluated for their condition.

Evaluation of septic and other sewage systems is, likewise, beyond the capabilities of most inspectors and, in many states, is a separately licensed profession. Inspection of sprinkler systems and irrigation equipment is also not required by these Standards. Finally, water “ltration, water softening and other treatment systems and equipment should be evaluated and serviced by the original installers and manufacturers’ agents.

Checklist for Bathroom Fixtures:

Fully open cold water faucet at lavatory.
Fully open cold water faucet at bathtub. Note any pressure or #ow changes.
Close faucets.
Fully open hot water faucet at lavatory.
Fully open hot water faucet at bathtub. Note any pressure or #ow changes. Note water temperature.
Con”rm that, when facing the “xtures’ handles, the left side controls the hot water.

Residential Plumbing Overview 110

Close drainage stoppers.
Check the traps, waste piping, and water supply valves and pipes.
Engage the showerhead. Note pressure and #ow.
Flush the toilet.
Note pressure and #ow at showerhead.
Close faucets, leaving a few inches of water in the lavatory and bathtub.
Flush toilet and open the drain stoppers of the lavatory and bathtub at the same time. Note drainage and listen for gurgling.
Observe drainage. Note slow or clogged drains.
Don’t leave the water running unattended. Some inspectors will run water in two bathrooms simultaneously.

Inspection Checklist 111

Quiz #13

1. When inspecting toilets, inspectors should check:

attachments
cracks in the bowl waste connections water supply
all of these

2. T/F: Inspectors should #ush all toilets.

True False

3. T/F: All visible wastes, drains and vents should be inspected.

True False

4. Reporting on the inspection of the water heater should include the ___________________.

age of the unit
presence of a TPR valve
size of the unit
identification of any sludge buildup

5. T/F: It is not necessary to report on leaky faucets.

True False

6. T/F: Inspectors should determine whether the water supply is public or private.

True False

7. T/F: Inspectors should identify main water and fuel shut-o valves.

True False

8. Functional water #ow should be evaluated by ______________.

running two faucets simultaneously using a pressure and flow meter
the local utility company only

Residential Plumbing Overview 112 9. When evaluating the water heater, the inspector should report on its ______________.

age
fuel type
total capacity life expectancy

10. Mechanical drain stoppers should be reported as ______________ if missing or if not working properly.

in need of repair a significant defect a structural failure

11. T/F: The plumbing inspection report should include the types of supply piping inspected.

True False

12. T/F: Inspectors are required to operate all plumbing and fuel shut-o valves.

True False

13. T/F: Sump pumps are not included as part of a home inspection.

True False

14. T/F: The inspector must determine the potability of the water supply.

True False

15. T/F: The inspector must guarantee that shower pans and bath wastes are free of leaks.

True False

16. T/F: Evaluating water softeners and puri”ers is part of a home inspection.

True False

Answer Key is on page 117.

Appendix I: Answer Keys 113 Appendix I: Answer Keys

Answer Key for Quiz #1

1. T/F: This is a code-compliance plumbing course. Answer: False

2. “Plumbing” comes from the Latin word meaning “lead.” 3. T/F: Contamination can aect the water’s potability.

Answer: True
Answer Key for Quiz #2

1. The inspector is required to “ush all toilets.
2. T/F: The inspector is required to light or ignite pilot lights.

Answer: False
3. T/F: An inspector is not required to determine whether the water supply is public or private.

Answer: False
4. T/F: The inspector is required to determine the existence of polybutylene plumbing in a home.

Answer: False
Answer Key for Quiz #3

1. The unobstructed vertical distance through the free atmosphere between an outlet and the rim best describes an air gap in the drainage system.

2. Air-admittance valves protect traps from siphonage.
3. The vertical, upper portion above the top-most “xture through which gases and odors escape

the sanitary drainage system, carrying no liquids or solids, best describes a vent stack. 4. A lavatory is a bathroom or washroom sink.

5. A water closet “ange is an anchoring ring secured to the #oor, and a toilet is secured to this ring with bolts.

6. A toilet or commode is referred to in plumbing standards as a water closet.
7. The #ow of liquids in potable water distribution piping in reverse of its intended path caused

by back-siphonage or back-pressure best describes back“ow. 8. Hot water is water at a temperature of 110° F or higher.
9. ABS stands for acrylonitrile butadiene styrene.

Residential Plumbing Overview 114 Answer Key for Quiz #4

1. There should be a space of at least 21 inches in front of the water closet, lavatory or bidet to any wall, “xture or door.

2. Closet bolts are often made of brass because they resist corrosion.
3. The waste from an automatic clothes washer must discharge its water through a(n) air break or air

gap into a standpipe or into a laundry tub.
4. If a standpipe for an automatic clothes washer is used, the standpipe and its trap should be at

least 2 inches in diameter.
5. Plastic bathtubs are made with #re-resistant chemicals in case of accidental exposure to a

plumber’s torch.
6. An exterior window at an exterior wall must be made of safety glazing unless the bottom

exposed edge of the glass is 60 inches or more above the tub #oor surface.
7. Laundry trays made of concrete are no longer permitted because they do not provide a smooth,

impervious, sanitary surface.

8. The shower opening (or access and egress opening) should be at least 22 inches of clear and unobstructed “nish width.

9. If the pump at a whirlpool bathtub is located more than 2 feet from the access opening, the opening is typically at least 18 x 18 inches.

10. Tailpieces are best described as short lengths of pipe attached directly to a “xture by means of a #ange for connection to other piping or traps.

Answer Key for Quiz #5

1. Fuel-“red water heaters may not obtain combustion air from sleeping rooms, bathrooms or toilet rooms.

2. A suitable access opening, passageway and work space is required when a water heater is installed in a(n) attic.

4. T/F: A shut-o switch or disconnect is required on all electric water heaters. Answer: True

5. Temperature/pressure-relief (TPR) valves must be set to discharge at a temperature not higher than 210° F (99° C).

6. The TPR discharge pipe should discharge through a(n) air gap located in the same room as the water heater.

7. A relief-valve pipe terminating into a water leak catch pan is not permitted because the pan is not an indirect waste receptor.

Appendix I: Answer Keys 115

Answer Key for Quiz #6

1. T/F: A shut-o valve is the same as a full-open valve. Answer: False

2. T/F: The U.S. Environmental Protection Agency’s (EPA’s) Oce of Drinking Water controls the quality requirements for water to be classi”ed as potable.
Answer: True

3. The casing should extend above the ground surface 6 to 12 inches.
4. There are deep wells (more than 25 feet deep) and shallow wells (25 feet or less).

5. All water supply lines and “ttings for every plumbing “xture should be installed in way that prevents back“ow.

6. A(n) air gap is the most eective and dependable method of preventing back#ow.

7. The minimum diameter of a water service pipe is typically 3/4-inch.

8. Type K copper tubing is the thickest and typically used for underground water service.

9. In order to get the most meaningful results, it is good practice to inspect the plumbing “xtures at the highest point in the house.

10. Dwellings built far above street level may have low water pressure and water #ow because pressure drops as water is pushed up vertically.

11. T/F: Solvent-cementing between ABS and PVC pipe is prohibited. Answer: True

Answer Key for Quiz #7

1. The joint between dierent types of plastic made with solvent cement will not be reliable because the chemical composition of the joint will not be homogeneous.

2. The square shape of a cleanout minimizes the possibility of stripping the plug during removal.

3. T/F: It is permitted, in certain situations, to discharge untreated sewage or wastewater on the ground surface.
Answer: False

4. T/F: Rocks or blocks at any point could support drainage piping inside a trench. Answer: False

5. Particular drainage “ttings have been designed with patterns providing the least resistance to #ow.

6. The minimum slope of a horizontal drainpipe that is sized between 3 and 6 inches is 1/8-inch per foot.

7. The drain, waste and vent (DWV) system of the dwelling should be tested with a minimum 10-foot head of water for 15 minutes.

8. Drainage pipe cleanouts should be installed not more than 100 feet apart in horizontal drainage lines measured from the upstream entrance of the cleanout.

Residential Plumbing Overview 116 9. T/F: A cleanout is required for each and every change in direction of the sewer drainage pipe.

Answer: False

10. The sump pit should not be less than 18 inches in diameter and 24 inches deep.

11. The discharge pipe on a sump pump should have a check valve installed to prevent previously pumped discharge from returning to the pump.

Answer Key for Quiz #8

1. The vent pipe that passes through a roof should end at least 6 inches above the roof.

2. A dwelling should have at least one vent pipe(s) that extend(s) to the outdoor air.

3. For homes located in cold climates, their vent pipes or vent stacks should be protected against freezing by insulation, heat, or both.

Answer Key for Quiz #9

1. Standpipes for washing machines and similar appliances are required to be a minimum of 18 inches high above the trap.

2. Each “xture trap should have a liquid seal of at least 2 inches and, at most, 4 inches or deeper for specially designed “xtures.

3. S-traps are not permitted because they impede drainage #ow.
4. Many old tailpieces and traps are made of soft brass with chrome or nickel plating and are

sometimes so thin that a gentle touch will cause them to break into pieces. Answer Key for Quiz #10

1. Hangers and strapping should be of approved material that will not promote galvanic reaction. 2. The maximum horizontal spacing for PVC drainage pipe is 4 feet.
3. The maximum horizontal spacing for supporting cast-iron pipe is 5 feet.

Answer Key for Quiz #11

1. Storm water, rainwater or groundwater should not be drained into a sewer system.
2. The ground surface of the lot should be graded so as to drain surface water away from

foundation walls. The grade should be dropped a minimum of 6 inches within the “rst 10 feet. Answer Key for Quiz #12

1. A manual damper should be used only with a solid fuel-burning appliance, and not with a gas- “red appliance.

Appendix I: Answer Keys 117 2. The cross-connection of two oil storage tanks is permitted if the total aggregate capacity does

not exceed 660 gallons.
3. A sediment trap should be installed downstream of the equipment’s shut-o valve and as close

to the inlet of the equipment/appliance as possible.

4. Where two or more vent connectors enter a common gas vent, chimney #ue, or single-wall metal pipe, the smaller connector should enter at the highest level consistent with the available head room or clearance to combustible material.

5. Gas vent pipes terminating above roof pitches up to 6:12 need to be only 1 foot high. Answer Key for Quiz #13

1. When inspecting toilets, inspectors should check all of these. 2. T/F: Inspectors should #ush all toilets.

Answer: True
3. T/F: All visible wastes, drains and vents should be inspected.

Answer: True
4. Reporting on the inspection of the water heater should include the presence of a TPR valve.

5. T/F: It is not necessary to report on leaky faucets. Answer: False

6. T/F: Inspectors should determine whether the water supply is public or private. Answer: True

7. T/F: Inspectors should identify main water and fuel shut-o valves. Answer: True

8. Functional water #ow should be evaluated by running two faucets simultaneously.

9. When evaluating the water heater, the inspector should report on its fuel type.

10. Mechanical drain stoppers should be reported as in need of repair if missing or if not working properly.

11. T/F: The plumbing inspection report should include the types of supply piping inspected. Answer: True

12. T/F: Inspectors are required to operate all plumbing and fuel shut-o valves. Answer: False

13. T/F: Sump pumps are not included as part of a home inspection. Answer: False

14. T/F: The inspector must determine the potability of the water supply. Answer: False

15. T/F: The inspector must guarantee that shower pans and bath wastes are free of leaks. Answer: False

16. T/F: Evaluating water softeners and puri”ers is part of a home inspection. Answer: False

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