Piping, Valves and Control Valves

Piping, Valves and Control Valves

Reference text for the piping, valves and control valves area. Every rule below is written from the

printed line of the 2024 International Plumbing Code (IPC 2024) that carries it, and each rule names

the section it comes from. Where the printed line does not state a value, no value is stated here.

The material comes from the water-supply chapter (materials, joints, valves, design criteria and

installation) and from the drainage-side provisions that govern the same hardware when it is installed

in a sanitary drainage system, together with the fixtures-and-fittings chapter for faucets, fixture

fittings, mixing valves and control devices.

1. Scope of the water supply provisions (Chapter 6)

The chapter governs the materials, design and installation of water supply systems, both hot and cold,

for use in connection with human occupancy and habitation, and governs the installation of individual

water supply systems (IPC 2024, 601.1).

Solar energy systems used to heat potable water, or using an independent medium to heat potable water,

must comply with the applicable requirements of the code, and their use may not compromise the

cross-connection or potable-supply protection requirements (IPC 2024, 601.2). Existing metallic water

service piping used for electrical grounding may not be replaced with nonmetallic pipe or tubing until

another approved means of grounding is provided (IPC 2024, 601.3). The potable water distribution

system is tested in accordance with the code's water distribution test section (IPC 2024, 601.4), and

where a pressure piping system is rehabilitated with an epoxy lining system, that lining system must

comply with ASTM F2831 (IPC 2024, 601.5).

2. Pipe for the water service and for water distribution

Water service pipe must conform to NSF 61 and to one of the standards listed in Table 605.3. Water

service pipe or tubing installed underground and outside the structure must have a working pressure

rating of not less than 160 psi (1100 kPa) at 73.4 °F (23 °C); where the water pressure exceeds

160 psi (1100 kPa), the piping material must have a working pressure rating not less than the highest

available pressure. Water service piping materials that are not third-party certified for water

distribution must terminate at or before the full-open valve located at the entrance to the structure,

and ductile iron water service piping must be cement mortar lined in accordance with AWWA

C104/A21.4 (IPC 2024, 605.3).

The materials Table 605.3 lists, with the standards the code pairs with each, are ABS plastic pipe,

CPVC plastic pipe, CPVC/AL/CPVC, copper or copper-alloy pipe, copper or copper-alloy tubing (Type K,

WK, L, WL, M or WM), PEX plastic pipe and tubing, PEX-AL-PEX pipe, PEX-AL-HDPE, ductile iron water

pipe, galvanized steel pipe, PE plastic pipe, PE plastic tubing, PE-AL-PE pipe, PE-RT plastic tubing,

PP plastic pipe or tubing, PVC plastic pipe, stainless steel pipe (Type 304/304L and Type 316/316L),

and stainless steel tubing (Type 304/304L and Type 316/316L) (IPC 2024, Table 605.3).

Water distribution pipe and tubing must conform to NSF 61 and to one of the standards listed in Table

605.4, and hot water distribution pipe and tubing must have a pressure rating of not less than 100 psi

(690 kPa) at 180 °F (82 °C) (IPC 2024, 605.4). Table 605.4 carries CPVC pipe and tubing, CPVC/AL/CPVC,

copper or copper-alloy pipe, copper or copper-alloy tubing of the types listed above, PEX plastic

tubing, PEX-AL-PEX pipe, PEX-AL-HDPE, ductile iron pipe, galvanized steel pipe, PE-AL-PE composite

pipe, PE-RT plastic tubing, PP plastic pipe or tubing, and stainless steel pipe and tubing in Types

304/304L and 316/316L (IPC 2024, Table 605.4).

Two conditions decide whether a material may be buried at all. Installing a water service or water

distribution pipe is prohibited in soil and ground water contaminated with solvents, fuels, organic

compounds or other detrimental materials that cause permeation, corrosion, degradation or structural

failure of the piping material. Where detrimental conditions are suspected, a chemical analysis of the

soil and ground water is required to determine whether the material is acceptable for that

installation, and where detrimental conditions exist, approved alternative materials or routing must

be used (IPC 2024, 605.1).

Lead content is a separate test on the same parts. Pipe and pipe fittings, including valves and

faucets, used in the water supply system may have not more than 8 percent lead content (IPC 2024,

605.2). Pipe, pipe fittings, joints, valves, faucets and fixture fittings used to supply water for

drinking or cooking must comply with NSF 372 and have a weighted average lead content of 0.25 percent

or less (IPC 2024, 605.2.1).

3. Fittings, nipples and flexible connectors

Pipe fittings must be approved for installation with the piping material installed and must comply

with the applicable standards listed in Table 605.5; fittings used in water supply systems must also

comply with NSF 61, and ductile and gray iron pipe and fittings used in water service piping systems

must be cement mortar lined in accordance with AWWA C104/A21.4 (IPC 2024, 605.5). Table 605.5 covers

fittings for ABS, cast iron, CPVC, copper or copper alloy, PEX-AL-HDPE, PEX tubing, PE-RT tubing, gray

and ductile iron, insert fittings for PE-AL-PE and PEX-AL-PEX, malleable iron, metal (copper alloy)

insert fittings for PE-AL-PE and PEX-AL-PEX, PE pipe, PP pipe or tubing, PVC plastic, stainless steel

in Type 304/304L and Type 316/316L, and steel (IPC 2024, Table 605.5).

A mechanically formed tee fitting is regulated in its own subsection: mechanically extracted outlets

must have a height not less than three times the thickness of the branch tube wall (IPC 2024, 605.5.1).

The branch tube may not restrict the flow in the run tube, a dimple serving as a depth stop must be

formed in the branch tube so that penetration into the collar is of the correct depth, a second dimple

must be placed 1/4 inch (6.4 mm) above the first so that the depth can be inspected, and the dimples

must be aligned with the tube run (IPC 2024, 605.5.1.1). A mechanically formed tee fitting is brazed

in accordance with the code's copper brazed joint provision (IPC 2024, 605.5.1.2).

Flexible water connectors exposed to continuous pressure must conform to ASME A112.18.6/CSA B125.6, and

access must be provided to all flexible water connectors (IPC 2024, 605.6). Manufactured pipe nipples

must conform to one of the standards listed in Table 605.8 — copper, copper alloy and chromium-plated

nipples to ASTM B687, and steel nipples to ASTM A733 (IPC 2024, 605.8).

4. Prohibited joints in the water supply system

The following types of joints and connections are prohibited in the water supply system: cement or

concrete joints; joints made with fittings not approved for the specific installation; solvent-cement

joints between different types of plastic pipe; and saddle-type fittings (IPC 2024, 605.9). The list is

short and each item is a joint type that cannot be inspected to the standard the chapter expects — the

saddle fitting is prohibited as a connection on a pipe, not merely discouraged.

5. Valves: material, standard and compatibility

Valves must be compatible with the type of piping material installed in the system, and must conform to

one of the standards listed in Table 605.7 or be approved; valves intended to supply drinking water

must meet the requirements of NSF 61 (IPC 2024, 605.7). Table 605.7 lists the standards by valve

material: CPVC plastic, copper or copper alloy, PEX plastic, gray iron and ductile iron, PP plastic,

PVC plastic, and stainless steel in Type 304/304L and Type 316/316L (IPC 2024, Table 605.7).

A dual check-valve-type backflow preventer installed on the water supply system must comply with ASSE

1024 or CSA B64.6 (IPC 2024, 605.3.1).

6. Where full-open valves are required

Full-open valves must be installed in the following locations (IPC 2024, 606.1):

2.1 In multiple-tenant buildings three stories or less in height, where a common water supply piping

system is installed to supply other than one- and two-family dwellings, a main shutoff valve must be

provided for each tenant.

occupancies that are two stories or less in height and in one- and two-family residential

occupancies.

occupancies.

fixture equipped with individual stops.

7. Where shutoff valves are required

Shutoff valves must be installed in the following locations (IPC 2024, 606.2):

two-family residential occupancies, and other than in individual dwelling or sleeping units that

are provided with unit shutoff valves in hotels, motels, boarding houses and similar occupancies.

8. Access to valves, and valve identification

Access must be provided to all full-open valves and shutoff valves (IPC 2024, 606.3). Service and hose

bibb valves must be identified, and other valves installed in locations that are not adjacent to the

fixture or appliance they serve must be identified so as to indicate the fixture or appliance served

(IPC 2024, 606.4). The identification rule is what makes the access rule usable: a valve behind an

access panel still has to say what it isolates.

9. Design criteria and required capacity

The design of the water distribution system must conform to accepted engineering practice, and the

methods used to determine pipe sizes must be approved (IPC 2024, 604.1). At the points of

interconnection between the hot and cold water supply piping systems and the individual fixtures,

appliances or devices, provisions must be made to prevent flow between the piping systems (IPC 2024,

604.2).

The system must be designed, and pipe sizes selected, so that under conditions of peak demand the

capacities at the fixture supply pipe outlets are not less than Table 604.3 shows; for fixtures and

appliances not listed in the table, the minimum flow rate and flow pressure follow the manufacturer's

installation instructions (IPC 2024, 604.3). Table 604.3 pairs each fixture supply outlet with a flow

rate in gallons per minute and a flow pressure in psi — among them bathtubs, bidets and showers with

balanced-pressure, thermostatic or combination mixing valves at 20 psi, combination fixtures, laundry

trays and sinks at 8 psi, urinals supplied by a valve at 25 psi, and water closets by type of flush

(IPC 2024, Table 604.3).

Maximum flow and consumption is a separate ceiling on the same fixtures and fixture fittings (IPC 2024,

604.4), with exceptions for blowout design water closets having a water consumption not greater than

3 1/2 gallons (13 L) per flushing cycle, vegetable sprays, clinical sinks having a water consumption

not greater than 4 1/2 gallons (17 L) per flushing cycle, service sinks, and emergency showers

(IPC 2024, 604.4). Table 604.4 prints the ceilings: private lavatories 2.2 gpm at 60 psi, public

lavatories 0.25 gallon per metering cycle where metering and 0.5 gpm at 60 psi otherwise, shower heads

2.0 gpm at 80 psi, sink faucets 2.2 gpm at 60 psi, urinals 1.0 gallon per flushing cycle, and water

closets 1.6 gallons per flushing cycle (IPC 2024, Table 604.4).

Where street water main pressures fluctuate, the building water distribution system must be designed

for the minimum pressure available (IPC 2024, 604.6).

10. Size of the fixture supply

The minimum size of a fixture supply pipe is as shown in Table 604.5, and the fixture supply pipe must

terminate not more than 30 inches (762 mm) from the point of connection to the fixture. A reduced-size

flexible water connector installed between the supply pipe and the fixture must be of an approved type,

and the supply pipe must extend to the floor or wall adjacent to the fixture. The minimum size of

individual distribution lines used in gridded or parallel water distribution systems is likewise shown

in Table 604.5 (IPC 2024, 604.5).

Table 604.5 gives the minimum pipe size per fixture — for example 3/8 inch for bidets, drinking

fountains, lavatories, water closets with a flush tank or a flushometer tank, 1/2 inch for bathtubs,

domestic dishwashers, hose bibbs, kitchen sinks, laundry trays, single-head showers, service sinks,

urinals with a flush tank and one-piece water closets, 3/4 inch for flushing rim sinks and urinals

with a flushometer valve, and 1 inch for water closets with a flushometer valve. Its footnote allows a

manifold-supplied individual distribution line in a parallel water distribution system to be one

nominal tube size smaller than the listed size where the developed length of the distribution line is

50 feet or less and the available pressure at the meter is 35 psi or greater (IPC 2024, Table 604.5).

11. Pressure: reducing valves, boosters and water hammer

Wherever water pressure from the street main or other source of supply is insufficient to provide the

flow pressures Table 604.3 requires at fixture outlets, a water pressure booster system conforming to

the code's booster provisions must be installed on the building water supply system (IPC 2024, 604.7).

A water pressure-reducing valve or regulator is required in the other direction: where water pressure

within a building exceeds 80 psi (552 kPa) static, an approved water pressure-reducing valve

conforming to ASSE 1003 or CSA B356 with strainer must be installed to reduce the pressure in the

building water distribution piping to not greater than 80 psi (552 kPa) static (IPC 2024, 604.8).

Service lines to sill cocks and outside hydrants, and main supply risers where pressure from the mains

is reduced to 80 psi (552 kPa) or less at individual fixtures, are excepted (IPC 2024, 604.8).

The reducing valve must be designed to remain open to permit uninterrupted water flow in case of valve

failure (IPC 2024, 604.8.1), and water pressure-reducing valves, regulators and strainers must be

constructed and installed so that parts can be repaired or removed without breaking a pipeline or

removing the valve and strainer from the pipeline (IPC 2024, 604.8.2).

Water hammer is controlled by velocity and by hardware: the flow velocity of the water distribution

system must be controlled to reduce the possibility of water hammer, a water-hammer arrestor must be

installed where quick-closing valves are used, arrestors must be installed in accordance with the

manufacturer's instructions, and they must conform to ASSE 1010 (IPC 2024, 604.9).

12. Manifolds and individual pressure balancing valves

Hot water and cold water manifolds installed with gridded or parallel connected individual distribution

lines to each fixture or fixture fitting must be designed in accordance with the manifold provisions

(IPC 2024, 604.10).

Hot water and cold water manifolds must be sized in accordance with Table 604.10.1, where the total

gallons per minute is the demand of all outlets supplied (IPC 2024, 604.10.1). Table 604.10.1 gives,

for nominal internal diameters from 1/2 inch to 1 1/2 inches, the maximum demand at a velocity of

4 feet per second and at a velocity of 8 feet per second — 1/2 inch: 2 and 5 gpm; 3/4 inch: 6 and

11 gpm; 1 inch: 10 and 20 gpm; 1 1/4 inch: 15 and 31 gpm; 1 1/2 inch: 22 and 44 gpm (IPC 2024, Table

604.10.1).

Individual fixture shutoff valves installed at the manifold must be identified as to the fixture being

supplied (IPC 2024, 604.10.2), and access must be provided to manifolds with integral factory- or

field-installed valves (IPC 2024, 604.10.3).

Where individual pressure balancing in-line valves for individual fixture fittings are installed, they

must comply with ASSE 1066 and be installed in a location with access, and they may not be used alone

as a substitute for the balanced pressure, thermostatic or combination shower valves the

fixtures chapter requires (IPC 2024, 604.11).

13. Water pressure booster systems and tanks

Water pressure booster systems are provided as the code's booster provisions direct (IPC 2024, 606.5).

Where the water pressure in the public water main or individual water supply system is insufficient to

supply the minimum pressures and quantities the code specifies, the supply must be supplemented by an

elevated water tank, a hydropneumatic pressure booster system, or a water pressure booster pump

installed in accordance with the low-pressure cutoff provision (IPC 2024, 606.5.1).

Water supply tanks must be supported in accordance with the International Building Code (IPC 2024,

606.5.2) and covered to keep out unauthorized persons, dirt and vermin; the covers of gravity tanks

must be vented with a return bend vent pipe whose area is not less than the area of the down-feed riser

pipe, screened with a corrosion-resistant screen of not less than 16 by 20 mesh per inch (630 by 787

mesh per m) (IPC 2024, 606.5.3).

A gravity or suction water supply tank must have an overflow with a diameter not less than Table 606.5.4

shows. The overflow outlet must discharge at a point not less than 6 inches (152 mm) above the roof or

roof drain, floor or floor drain, or over an open water-supplied fixture; it must be covered with a

corrosion-resistant screen of not less than 16 by 20 mesh per inch (630 by 787 mesh per m) and by

1/4-inch (6.4 mm) hardware cloth, or terminate in a horizontal angle seat check valve; and drainage

from overflow pipes must be directed so as not to freeze on roof walks (IPC 2024, 606.5.4). Table

606.5.4 sizes the overflow pipe against the maximum capacity of the water supply line to the tank,

from 2 inches where that capacity is 0 to 50 gpm up to 8 inches where it is over 1,000 gpm (IPC 2024,

Table 606.5.4).

The other tank provisions fix what the controls must do. A low-pressure cutoff must be installed on

all booster pumps in a water pressure booster system to prevent the creation of a vacuum or negative

pressure on the suction side of the pump when a positive pressure of 10 psi (68.94 kPa) or less occurs

on that suction side (IPC 2024, 606.5.5). Potable water inlets to gravity tanks must be controlled by a

fill valve or other automatic supply valve installed so as to prevent the tank from overflowing, and

the inlet must terminate so as to provide an air gap not less than 4 inches (102 mm) above the

overflow (IPC 2024, 606.5.6). A drain pipe with a valve must be provided at the lowest point of each

tank to permit emptying, discharging as required for overflow pipes and not smaller than Table 606.5.7

specifies — from 1 inch for a tank capacity up to 750 gallons to 4 inches for a capacity over 7,500

gallons (IPC 2024, 606.5.7 and Table 606.5.7).

Potable water gravity tanks and the manholes of potable water pressure tanks may not be located

directly under any soil or waste piping or any other source of contamination (IPC 2024, 606.5.8).

Water pressure tanks must have a vacuum relief valve at the top of the tank that will operate up to a

maximum water pressure of 200 psi (1380 kPa) and up to a maximum temperature of 200 °F (93 °C), sized

not less than 1/2 inch (12.7 mm); the requirement does not apply to pressurized captive air

diaphragm/bladder tanks (IPC 2024, 606.5.9). Every pressure tank in a hydropneumatic pressure booster

system must be protected with a pressure relief valve set at a maximum pressure equal to the rating of

the tank, installed on the supply pipe to the tank or on the tank, and discharging by gravity to a

safe place of disposal (IPC 2024, 606.5.10).

14. Testing the system as it is completed

Upon completion of a section of, or the entire, water supply system, the system or the completed

portion must be tested in accordance with the code's test provisions (IPC 2024, 606.6). The potable

water distribution system is tested under the same test section the chapter's general provision points

to (IPC 2024, 601.4).

15. Faucets and fixture fittings

Faucets and fixture fittings must conform to ASME A112.18.1/CSA B125.1; faucets and fixture fittings

that supply drinking water for human ingestion must conform to the requirements of NSF 61, Section 9;

and flexible water connectors exposed to continuous pressure must conform to the flexible connector

section (IPC 2024, 412.1).

Faucets and supply fittings must conform to the water consumption requirements of the maximum flow

provision (IPC 2024, 412.1.1), and waste fittings must conform to ASME A112.18.2/CSA B125.2, ASTM F409

or one of the standards listed in the tables for aboveground drainage and vent pipe and fittings

(IPC 2024, 412.1.2).

Hand-held showers must conform to ASME A112.18.1/CSA B125.1 and must provide backflow protection in

accordance with that standard, or be protected against backflow by a device complying with ASME

A112.18.3 or ASSE 1014 (IPC 2024, 412.2).

Individual shower valves — and tub-shower combination valves — must be balanced-pressure, thermostatic

or combination balanced-pressure/thermostatic valves conforming to ASSE 1016/ASME A112.1016/CSA

B125.16 or ASME A112.18.1/CSA B125.1, must be installed at the point of use, and must be rated for the

flow rate of the installed shower head. They must be equipped with a means to limit the maximum

setting of the valve to 120 °F (49 °C), field adjusted in accordance with the manufacturer's

instructions to provide water at a temperature not exceeding 120 °F (49 °C); in-line thermostatic

valves may not be used for compliance with the section (IPC 2024, 412.3).

Multiple (gang) showers supplied with a single tempered water supply pipe must have that supply

controlled by an approved automatic temperature control mixing valve conforming to ASSE 1069 or CSA

B125.3, or each shower head must be individually controlled by a balanced-pressure, thermostatic or

combination valve conforming to the shower-valve standards and installed at the point of use. Where a

shower head is individually controlled, the control valves must be rated for the flow rate of the

installed shower head, and the valves must carry the same 120 °F (49 °C) limiting means and field

adjustment. Access must be provided to an ASSE 1069 or CSA B125.3 valve (IPC 2024, 412.4).

Bathtub and whirlpool bathtub valves must have, or be supplied by, a water-temperature-limiting device

conforming to ASSE 1070/ASME A112.1070/CSA B125.70, or a water heater complying with ASSE 1082 or ASSE

1084, except where the valves are combination tub/shower valves under the shower-valve section. The

device must carry a means to limit the maximum setting to 120 °F (49 °C) and, where adjustable, be

field adjusted in accordance with the manufacturer's instructions to provide hot water not exceeding

120 °F (49 °C), and access must be provided to devices conforming to ASSE 1070/ASME A112.1070/CSA

B125.70 — access not being required for nonadjustable devices of that standard that are integral with

a fixture fitting, provided the fixture fitting itself can be accessed for replacement (IPC 2024,

412.5).

Faucets and fixture fittings with hose-connected outlets must conform to ASME A112.18.3 or ASME

A112.18.1/CSA B125.1 (IPC 2024, 412.6).

Temperature-actuated, flow-reduction devices installed for individual fixture fittings must conform to

ASSE 1062, and such a device is an approved method for limiting the water temperature to not greater

than 120 °F (49 °C) at the outlet of a faucet or fixture fitting. Such devices may not be used alone as

a substitute for the balanced-pressure, thermostatic or combination shower valves required for shower

valves, nor as a substitute for bathtub or whirlpool tub water-temperature-limiting valves (IPC 2024,

412.7).

Deck-mounted bath/shower transfer valves containing an integral atmospheric vacuum breaker must

conform to ASME A112.18.1/CSA B125.1 (IPC 2024, 412.8). Personal hygiene devices integral to water

closets or water closet seats must conform to ASME A112.4.2/CSA B45.16 (IPC 2024, 412.9).

Head shampoo sink faucets must be supplied with hot water limited to not more than 120 °F (49 °C), and

each faucet must have integral check valves to prevent crossover flow between the hot and cold water

supply connections. The means for regulating the maximum temperature must be one of a limiting device

conforming to ASSE 1070/ASME A112.1070/CSA B125.70, a water heater conforming to ASSE 1082 or ASSE

1084, or a temperature-actuated, flow-reduction device conforming to ASSE 1062 (IPC 2024, 412.10).

Prerinse spray valves for commercial food service must conform to ASME A112.18.1/CSA B125.1 (IPC 2024,

412.11), and electrically heated or cooled water dispensers must comply with ASSE 1023 (IPC 2024,

412.12).

16. Temperature control devices and valves

Temperature-actuated mixing valves installed to reduce water temperatures to defined limits must comply

with ASSE 1017, and such valves must be installed at the hot water source (IPC 2024, 613.1). The

location matters as much as the standard: the device is a control on the source, not a correction

applied somewhere downstream in the distribution.

17. Drinking water treatment units

Point-of-use reverse osmosis drinking water treatment units must comply with CSA B483.1 or NSF 58, and

drinking water treatment units must meet the requirements of CSA B483.1, NSF 42, NSF 44, NSF 53 or NSF

62 (IPC 2024, 611.1). The discharge from a reverse osmosis drinking water treatment unit must enter the

drainage system through an air gap or an air gap device meeting the requirements of CSA B483.1 or NSF

58 (IPC 2024, 611.2). The tubing to and from drinking water treatment units must be of a size and

material recommended by the manufacturer and must comply with NSF 14, NSF 42, NSF 44, NSF 53, NSF 58

or NSF 61 (IPC 2024, 611.3).

18. Solar systems

The construction, installation, alteration and repair of systems, equipment and appliances intended to

use solar energy for space heating or cooling, domestic hot water heating, swimming pool heating or

process heating must be in accordance with the International Mechanical Code (IPC 2024, 612.1).

19. Backflow preventers as installed hardware

The assemblies and devices that protect the potable supply are also piping components, and the

installation rules that apply to them are the ones an installer of valves and controls works to. Means

of protection against backflow are provided as Sections 608.14.1 through 608.14.9 direct (IPC 2024,

608.14).

Reduced pressure principle backflow prevention assemblies must conform to ASSE 1013, AWWA C511, CSA

B64.4 or CSA B64.4.1, and reduced pressure detector assemblies to ASSE 1047; these devices may be

installed where subject to continuous pressure conditions, and the relief opening must discharge by air

gap and be kept from being submerged (IPC 2024, 608.14.2). Backflow preventers with an intermediate

atmospheric vent must conform to ASSE 1012, ASSE 1081 or CSA B64.3, may be installed under continuous

pressure conditions, and have the same relief opening requirement (IPC 2024, 608.14.3). Pressure vacuum

breaker assemblies must comply with ASSE 1020 or CSA B64.1.2 and spill-resistant vacuum breaker

assemblies with ASSE 1056 or CSA B64.1.3; they must be installed with the critical level of the

assembly not less than 12 inches (305 mm) above all downstream piping and outlets, and may not be

installed where spillage could damage the structure (IPC 2024, 608.14.5).

Double check backflow prevention assemblies must conform to ASSE 1015, CSA B64.5, CSA B64.5.1 or AWWA

C510, and double check detector fire protection assemblies to ASSE 1048; they must be capable of

operating under continuous pressure conditions (IPC 2024, 608.14.7). Dual check backflow preventers

must conform to ASSE 1024 or CSA B64.6 (IPC 2024, 608.14.9).

Access must be provided to backflow preventers as the manufacturer's instructions specify (IPC 2024,

608.15), outdoor enclosures for backflow prevention devices must comply with ASSE 1060 (IPC 2024,

608.15.1), and a backflow preventer may not be located in an area subject to freezing except where it

can be removed by means of unions or is protected from freezing by heat, insulation, or both (IPC 2024,

608.15.2). The piping from the relief port or air gap fitting of a backflow preventer must terminate so

as to discharge to an approved indirect waste receptor or to the outdoors where it will not cause

damage or create a nuisance, and the waste receptor and drainage piping must be sized to drain the

maximum discharge flow rate from the relief port as published by the backflow preventer manufacturer

(IPC 2024, 608.15.2.1).

20. Drainage-side joints for the same piping materials

When the same materials are installed on the sanitary drainage side, Chapter 7 governs the joints.

Joints between ABS plastic pipe or fittings comply with the ABS provisions (IPC 2024, 705.2), between

cast-iron pipe or fittings with the cast-iron provisions (IPC 2024, 705.3), between concrete pipe and

fittings with the concrete provision (IPC 2024, 705.4), between copper or copper-alloy pipe or fittings

with the copper pipe provisions (IPC 2024, 705.5), between copper or copper-alloy tubing or fittings

with the copper tubing provisions (IPC 2024, 705.6), between galvanized steel pipe or fittings with the

steel provisions (IPC 2024, 705.8), between lead pipe or fittings with the lead provisions (IPC 2024,

705.9), between PVC plastic pipe or fittings with the PVC provisions (IPC 2024, 705.10), between

polyethylene plastic pipe and fittings with the polyethylene provisions (IPC 2024, 705.12), between

polyolefin plastic pipe and fittings with the polyolefin provisions (IPC 2024, 705.13), between

polyvinylidene fluoride plastic pipe and fittings with the polyvinylidene fluoride provisions (IPC

2024, 705.14), and between polypropylene plastic pipe and fittings with the polypropylene provision,

whose joint must incorporate an elastomeric seal, conform to ASTM D3212 and not be installed above

ground (IPC 2024, 705.15).

Joints between different piping materials in the drainage system must be made with a mechanical joint

conforming to ASTM C1173, ASTM C1460 or ASTM C1461, and connectors and adapters must be approved for

the application and have an elastomeric seal conforming to one of the listed standards, or be made as

the provisions for particular material pairs direct (IPC 2024, 705.16). The particular pairs are copper

pipe or tubing to cast-iron hub pipe (IPC 2024, 705.16.1), copper or copper-alloy pipe or tubing to

galvanized steel pipe (IPC 2024, 705.16.2), cast-iron pipe to galvanized steel pipe (IPC 2024,

705.16.3), plastic pipe or tubing to other piping material (IPC 2024, 705.16.4), lead pipe to other

piping material (IPC 2024, 705.16.5), borosilicate glass to other materials (IPC 2024, 705.16.6), and

stainless steel drainage systems to other materials (IPC 2024, 705.16.7). Joints between glass pipe and

other types of materials must be made with adapters having a TFE seal, and all such joints are

installed in accordance with the manufacturer's instructions (IPC 2024, 705.16).

Caulking ferrules must be of copper alloy and in accordance with Table 705.18, which gives for pipe

sizes 2, 3 and 4 inches an inside diameter of 2 1/4, 3 1/4 and 4 1/4 inches, a length of 4 1/2 inches,

and minimum weights of 1 pound, 1 pound 12 ounces and 2 pounds 8 ounces (IPC 2024, 705.18 and Table

705.18). Soldering bushings must be of copper or copper alloy and in accordance with Table 705.19,

which gives minimum weights per pipe size from 6 ounces at 1 1/4 inches to 3 pounds 8 ounces at

4 inches (IPC 2024, 705.19 and Table 705.19). Drainage slip joints must comply with the code's slip

joint provision (IPC 2024, 705.17), and O-ring joints for stainless steel drainage systems must be made

with an approved elastomeric seal (IPC 2024, 705.20).

21. Connections between drainage piping and fittings

Connections and changes in direction of the sanitary drainage system must be made with approved

drainage fittings, and connections between drainage piping and fixtures must conform to the code's

fixture connection provisions (IPC 2024, 706.1).

Fittings may not have ledges, shoulders or reductions capable of retarding or obstructing flow in the

piping, and threaded drainage pipe fittings must be of the recessed drainage type; the section does not

apply to tubular waste fittings used to convey vertical flow upstream of the trap seal liquid level of

a fixture trap (IPC 2024, 706.2).

Fittings must be installed so as to guide sewage and waste in the direction of flow, and changes in

direction must be made by fittings installed in accordance with Table 706.3. A change in direction by

combination fittings, side inlets or increasers must be installed in accordance with that table based

on the pattern of flow created by the fitting. Double sanitary tee patterns may not receive the

discharge of back-to-back water closets and fixtures or appliances with pumping action discharge,

except where the horizontal developed length between the outlet of the water closet and the connection

to the double sanitary tee pattern is 18 inches (457 mm) or greater (IPC 2024, 706.3).

Table 706.3 lists, by fitting pattern and by type of change in direction, which patterns are permitted

for a horizontal to vertical, a vertical to horizontal and a horizontal to horizontal change; the

quarter bend and short sweep carry footnotes limiting their use to a 2-inch or smaller fixture drain

and, for the short sweep, to three inches or larger in one of the columns (IPC 2024, Table 706.3).

Heel-inlet quarter bends are an acceptable means of connection, except where the quarter bend serves a

water closet, and a low-heel inlet may not be used as a wet-vented connection. Side-inlet quarter bends

are an acceptable means of connection for drainage, wet venting and stack venting arrangements

(IPC 2024, 706.4).

22. Prohibited joints and connections in the drainage system

The following types of joints and connections are prohibited: cement or concrete joints; mastic or

hot-pour bituminous joints; joints made with fittings not approved for the specific installation;

joints between different diameter pipes made with elastomeric rolling O-rings; solvent-cement joints

between different types of plastic pipe except where the plastic-to-plastic provision allows a single

such joint; and saddle-type fittings (IPC 2024, 707.1).

23. Reading the area: what each control is checked against

carries, and for potable contact where it contacts drinking water (IPC 2024, 605.3, 605.4, 605.5

and 605.7)?

(IPC 2024, 605.9 and 707.1)?

valve at every fixture supply, sill cock and appliance, with access and identification where the

code requires them (IPC 2024, 606.1, 606.2, 606.3 and 606.4)?

design criteria require — reducing pressure above 80 psi static, supplementing an inadequate

supply, limiting outlet temperature, or cutting the pump off at low suction pressure (IPC 2024,

604.7, 604.8, 606.5.5 and 613.1)?

that may be serviced and will not freeze, with its relief discharge able to take the device's

published maximum flow (IPC 2024, 608.14.2, 608.15.2 and 608.15.2.1)?

(IPC 2024, 601.4 and 606.6)?