ADOPTS WITH AMENDMENTS:

International Residential Code 2015 (IRC 2015)

Part I — Administrative

Part II — Definitions

Part III — Building Planning and Construction

Part IV — Energy Conservation

Part V — Mechanical

Part VI — Fuel Gas

Part VII — Plumbing

Part VIII — Electrical

Part IX — Referenced Standards

Heads up: There are no amended sections in this chapter.

Chapter 31 Vents

AMENDMENT
This section has been amended at the state or city level.
The text of this chapter is extracted from the 2018 edition of the North Carolina Plumbing Code and has been modified where necessary to conform to the scope of application of the North Carolina Residential Code for One- and Two-Family Dwellings. The section numbers appearing in parentheses after each section number are the section numbers of the corresponding text in the North Carolina Plumbing Code.

P3101.1 (901.1) General

AMENDMENT
This section has been amended at the state or city level.
This chapter shall govern the selection and installation of piping, tubing and fittings for vent systems. This chapter shall control the minimum diameter of vent pipes, circuit vents, branch vents and individual vents, and the size and length of vents and various aspects of vent stacks and stack vents. Additionally, this chapter regulates vent grades and connections, height above fixtures and relief vents for stacks and fixture traps, and the venting of sumps and sewers.

P3101.2 (901.2) Trap Seal Protection

AMENDMENT
This section has been amended at the state or city level.
The plumbing system shall be provided with a system of vent piping that will allow the admission or emission of air so that the liquid seal of any fixture trap shall not be subjected to a pressure differential of more than 1 inch of water column (249 Pa).

P3101.2.1 (901.2.1) Venting Required

AMENDMENT
This section has been amended at the state or city level.
Every trap and trapped fixture shall be vented in accordance with one of the venting methods specified in this chapter. All fixtures discharging downstream from a water closet shall be individually vented except as provided in Section P3110.

P3101.3 (901.4) Use Limitations

AMENDMENT
This section has been amended at the state or city level.
The plumbing vent system shall not be used for purposes other than the venting of the plumbing system.

P3101.4 Extension Outside a Structure

AMENDMENT
This section has been amended at the state or city level.

P3101.5 (309.2) Flood Resistance

AMENDMENT
This section has been amended at the state or city level.
In flood hazard areas as established by Table R301.2(1), vents shall be located at or above the elevation required in Section R322.1 (flood hazard areas including A Zones) or R322.2 (coastal high-hazard areas including V Zones). The plumbing systems, pipes and fixtures shall not be mounted on or penetrate through walls intended to break away under flood loads.

P3101.6 (901.5) Tests

AMENDMENT
This section has been amended at the state or city level.
The vent system shall be tested in accordance with Section P2503.5.

P3101.7 (902.1) Materials

AMENDMENT
This section has been amended at the state or city level.
The materials and methods utilized for the construction and installation of venting systems shall comply with the applicable provisions of Section P2906.

P3101.7.1 (902.2) Sheet Copper

AMENDMENT
This section has been amended at the state or city level.
Sheet copper for vent pipe flashings shall conform to ASTM B152 and shall weigh not less than 8 ounces per square foot (2.5 kg/m2).

P3101.7.2 (902.3) Sheet Lead

AMENDMENT
This section has been amended at the state or city level.
Sheet lead for vent pipe flashings shall weigh not less than 3 pounds per square foot (15 kg/m2) for field-constructed flashings and not less than 21/2 pounds per square foot (12 kg/m2) for prefabricated flashings.

P3102.1 Required Vent Extension

AMENDMENT
This section has been amended at the state or city level.

P3102.1 (904.1) Stack Required

AMENDMENT
This section has been amended at the state or city level.
Every building in which plumbing is installed shall have at least one stack the size of which is not less than one-half of the required diameter of the building drain, and not less than 2 inches (51 mm) in diameter. Such stack shall run undiminished in size and as directly as possible from the building drain through to the open air or to a vent header that extends to the open air.

P3102.1.1 (904.1.1) Connection to Drainage System

AMENDMENT
This section has been amended at the state or city level.
A vent stack shall connect to the building drain or to the base of a drainage stack in accordance with Section P3005.5. A stack vent shall be an extension of the drainage stack. For townhouses and one- and two-family dwellings, the main vent shall connect to the building drain, building stack or branch thereof not less than 3 inches (76 mm) in size.
The required vent shall be a dry vent that connects to the building drain or an extension of a drain that connects to the building drain. Such vent shall not be an island fixture vent as permitted by Section P3112.
The required vent shall be sized in accordance with Section P3113.1 based on the required size of the building drain.

P3102.4 (904.3) Stack Vent Termination

AMENDMENT
This section has been amended at the state or city level.
Stack vents shall terminate outdoors to the open air or to a stack-type air admittance valve in accordance with Section P3114.

P3102.5 (904.5) Stack Vent Headers

AMENDMENT
This section has been amended at the state or city level.
Stack vents connected into a common vent header at the top of the stacks and extending to the open air at one point shall be sized in accordance with the requirements of Section P3113.1. The number of fixture units shall be the sum of all fixture units on all stacks connected thereto, and the developed length shall be the longest vent length from the intersection at the base of the most distant stack to the vent terminal in the open air, as a direct extension of one stack.

P3103.1 (903.1) Roof Extension

AMENDMENT
This section has been amended at the state or city level.
Open vent pipes that extend through a roof shall be terminated not less than 6 inches (152 mm) above the roof or 6 inches (152 mm) above the anticipated snow accumulation, whichever is greater. Where a roof is to be used for assembly, as a promenade, observation deck or sunbathing deck or for similar purposes, open vent pipes shall terminate not less than 7 feet (2134 mm) above the roof.

P3103.2 Frost Closure

AMENDMENT
This section has been amended at the state or city level.

P3103.3 (903.3) Flashings and Sealing

AMENDMENT
This section has been amended at the state or city level.
The juncture of each vent pipe with the roof line shall be made water tight by an approved flashing. Vent extensions in walls and soffits shall be made weather tight by caulking.

P3103.4 (903.4) Prohibited Use

AMENDMENT
This section has been amended at the state or city level.
Vent terminals shall not be used as a flag pole or to support flag poles, television aerials or similar items, except when the piping has been anchored in an approved manner.

P3103.5 (903.5) Location of Vent Terminal

AMENDMENT
This section has been amended at the state or city level.
An open vent terminal from a drainage system shall not be located directly beneath any door, openable window, or other air intake opening of the building or of an adjacent building or property line, and any such vent terminal shall not be within 10 feet (3048 mm) horizontally of such an opening unless it is 2 feet (610 mm) or more above the top of such opening.

P3103.6 (903.6) Extension Through the Wall

AMENDMENT
This section has been amended at the state or city level.
Vent terminals extending through the wall shall terminate not less than 10 feet (3048 mm) from the lot line and 10 feet (3048 mm) above the highest adjacent grade within 10 feet (3048 mm) horizontally of the vent terminal. Vent terminals shall not terminate under the overhang of a structure with soffit vents. Side wall vent terminals shall be protected to prevent birds or rodents from entering or blocking the vent opening.

Section P3104 (905) Vent Connections and Grades

AMENDMENT
This section has been amended at the state or city level.

P3104.1 (905.1) Connection

AMENDMENT
This section has been amended at the state or city level.
Individual branch and circuit vents shall connect to a vent stack, stack vent or extend to the open air.

Exception: Individual, branch and circuit vents shall be permitted to terminate at an air admittance valve in accordance with Section P3114.

P3104.2 (905.2) Grade

AMENDMENT
This section has been amended at the state or city level.
Vent and branch vent pipes shall be graded, connected and supported to allow moisture and condensate to drain back to the soil or waste pipe by gravity.

P3104.3 (905.3) Vent Connection to Drainage System

AMENDMENT
This section has been amended at the state or city level.
A dry vent connecting to a horizontal drain shall connect above the centerline of the horizontal drain pipe.

P3104.4 (905.4) Vertical Rise of Vent

AMENDMENT
This section has been amended at the state or city level.
A dry vent shall rise vertically to not less than 6 inches (152 mm) above the flood level rim of the highest trap or trapped fixture being vented.

Exceptions:
  1. Vents for interceptors located outdoors.
  2. When vents for interceptors are not located near an adjacent wall, the vent must rise 6 inches (152 mm) vertically before turning horizontally and continuing to the nearest wall. For cleaning purposes, a cleanout of the same size as the vent shall be installed.

P3104.5 (905.5) Height Above Fixtures

AMENDMENT
This section has been amended at the state or city level.
A connection between a vent pipe and a vent stack or stack vent shall be made not less than 6 inches (152 mm) above the flood level rim of the highest fixture served by the vent. Horizontal vent pipes forming branch vents shall be not less than 6 inches (152 mm) above the flood level rim of the highest fixture served.

P3104.6 (905.6) Vent for Future Fixtures

AMENDMENT
This section has been amended at the state or city level.
Where the drainage piping has been roughed-in for future fixtures, a rough-in connection for a vent, not less than one-half the diameter of the drain, shall be installed. The vent rough-in shall connect to the vent system or shall be vented by other means as provided in this chapter. The connection shall be identified to indicate that the connection is a vent.

P3105.1 (909.1) Distance of Trap From Vent

AMENDMENT
This section has been amended at the state or city level.
Each fixture trap shall have a protecting vent located so that the slope and the developed length in the fixture drain from the trap weir to the vent fitting are within the requirements set forth in Table P3105.1.

Exception: The developed length of the fixture drain from the trap weir to the vent fitting for self-siphoning fixtures, such as water closets, shall not be limited.

TABLE P3105.1
MAXIMUM DISTANCE OF FIXTURE TRAP FROM VENT
SIZE OF TRAP
(inches)
SLOPE
(inch per foot)
DISTANCE FROM
TRAP (feet)
11/4 1/4 5
11/2 1/4 6
2 1/4 8
3 1/8 12
4 1/8 16

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 inch per foot = 83.3 mm/m.

P3105.2 (909.2) Fixture Drains

AMENDMENT
This section has been amended at the state or city level.
The total fall in a fixture drain resulting from pipe slope shall not exceed one pipe diameter, nor shall the vent pipe connection to a fixture drain, except for water closets, be below the weir of the trap.

P3105.3 (909.3) Crown Vent Prohibited

AMENDMENT
This section has been amended at the state or city level.
A vent shall not be installed within two pipe diameters of the trap weir.

Section P3106 (910) Individual Vent

AMENDMENT
This section has been amended at the state or city level.

P3106.1 (910.1) Individual Vent Permitted

AMENDMENT
This section has been amended at the state or city level.
Each trap and trapped fixture shall be permitted to be provided with an individual vent. The individual vent shall connect to the fixture drain of the trap or trapped fixture being vented.

P3107.1 (911.1) Individual Vent as Common Vent

AMENDMENT
This section has been amended at the state or city level.
An individual vent shall be permitted to vent two traps or trapped fixtures as a common vent. The traps or trapped fixtures being common vented shall be located on the same floor level.

P3107.2 (911.2) Connection at the Same Level

AMENDMENT
This section has been amended at the state or city level.
Where the fixture drains being common vented connect at the same level, the vent connection shall be at the interconnection of the fixture drains.

P3107.3 Connection at Different Levels

AMENDMENT
This section has been amended at the state or city level.
Where the fixture drains connect at different levels, the vent shall connect as a vertical extension of the vertical drain. The vertical drain pipe connecting the two fixture drains shall be considered the vent for the lower fixture drain, and shall be sized in accordance with Table P3107.3. The upper fixture shall not be a water closet or clothes washer.

TABLE P3107.3
COMMON VENT SIZES
PIPE SIZE
(inches)
MAXIMUM DISCHARGE FROM
UPPER FIXTURE DRAIN (d.f.u.)
11/2 1
2 4
21/2 to 3 6

For SI: 1 inch = 25.4 mm.

P3108.1 (912.1) Horizontal Wet Vent Permitted

AMENDMENT
This section has been amended at the state or city level.
Any combination of fixtures located on the same floor level shall be permitted to be vented by a wet vent. The wet vent shall be considered the vent for the fixtures and shall extend from the connection of the dry vent along the direction of the flow in the drain pipe to the most downstream fixture drain connection. Each fixture drain shall connect horizontally to the horizontal branch being wet vented or shall have a dry vent. Each wet-vented fixture drain shall connect independently to the horizontal wet vent. A residential clothes washer drain line shall not be used as a wet vent.

P3108.2 (912.2) Dry Vent Connection

AMENDMENT
This section has been amended at the state or city level.
The required dry-vent connection for wet-vented systems shall comply with Sections P3108.2.1 and P3108.2.2.

P3108.2.1 (912.2.1) Horizontal Wet Vent

AMENDMENT
This section has been amended at the state or city level.
The dry-vent connection for a horizontal wet-vent system shall be an individual vent or a common vent for any fixture, except an emergency floor drain. Where the dry vent connects to a water closet fixture drain, the drain shall connect horizontally to the horizontal wet vent system.

P3108.2.2 (912.2.2) Vertical Wet Vent

AMENDMENT
This section has been amended at the state or city level.
The dry-vent connection for a vertical wet-vent system shall be an individual vent or common vent for the most upstream fixture drain.

P3108.3 (912.3) Size

AMENDMENT
This section has been amended at the state or city level.
Horizontal and vertical wet vents shall be not less than the size as specified in Table P3108.3, based on the fixture unit discharge to the wet vent. The dry vent serving the wet vent shall be sized based on the largest required diameter of pipe within the wet-vent system served by the dry vent.

TABLE P3108.3
WET VENT SIZE
WET VENT PIPE SIZE
(inches)
FIXTURE UNIT LOAD
(d.f.u.)
11/2 1
2 4
21/2 6
3 12
4 32

For SI: 1 inch = 25.4 mm.

P3108.4 (912.1.1) Vertical Wet Vent Permitted

AMENDMENT
This section has been amended at the state or city level.
A combination of fixtures located on the same floor level shall be permitted to be vented by a vertical wet vent. The vertical wet vent shall be considered the vent for the fixtures and shall extend from the connection of the dry vent down to the lowest fixture drain connection. Each wet-vented fixture shall connect independently to the vertical wet vent. All water closet drains shall connect at the same elevation. Other fixture drains shall connect above or at the same elevation as the water closet fixture drains. The dry vent connection to the vertical wet vent shall be an individual or common vent serving one or two fixtures.

Section P3109 (913) Waste Stack Vent

AMENDMENT
This section has been amended at the state or city level.

P3109.1 (913.1) Waste Stack Vent Permitted

AMENDMENT
This section has been amended at the state or city level.
A waste stack shall be considered a vent for all of the fixtures discharging to the stack where installed in accordance with the requirements of this section.

P3109.2 (913.2) Stack Installation

AMENDMENT
This section has been amended at the state or city level.
The waste stack shall be vertical, and both horizontal and vertical offsets shall be prohibited between the lowest fixture drain connection and the highest fixture drain connection to the stack. Every fixture drain shall connect separately to the waste stack. The stack shall not receive the discharge of water closets or urinals.

P3109.3 (913.3) Stack Vent

AMENDMENT
This section has been amended at the state or city level.
A stack vent shall be installed for the waste stack. The size of the stack vent shall be not less than the size of the waste stack. Offsets shall be permitted in the stack vent and shall be located not less than 6 inches (152 mm) above the flood level of the highest fixture, and shall be in accordance with Section P3104.2. The stack vent shall be permitted to connect with other stack vents and vent stacks in accordance with Section P3102.5.

P3109.4 (913.4) Waste Stack Size

AMENDMENT
This section has been amended at the state or city level.
The waste stack shall be sized based on the total discharge to the stack and the discharge within a branch interval in accordance with Table P3109.4. The waste stack shall be the same size throughout the length of the waste stack.

TABLE P3109.4
WASTE STACK VENT SIZE
STACK SIZE
(inches)
MAXIMUM NUMBER OF FIXTURE UNITS (d.f.u.)
Total discharge into
one branch interval
Total discharge
for stack
11/2 1 2
2 2 4
21/2 No limit 8
3 No limit 24
4 No limit 50

For SI: 1 inch = 25.4 mm.

Section P3110 (914) Circuit Venting

AMENDMENT
This section has been amended at the state or city level.

P3110.1 (914.1) Circuit Vent Permitted

AMENDMENT
This section has been amended at the state or city level.
Not greater than eight fixtures connected to a horizontal branch drain shall be permitted to be circuit vented. Each fixture drain shall connect horizontally to the horizontal branch being circuit vented. The horizontal branch drain shall be classified as a vent from the most downstream fixture drain connection to the most upstream fixture drain connection to the horizontal branch.

P3110.1.1 (914.1.1) Multiple Circuit-Vented Branches

AMENDMENT
This section has been amended at the state or city level.
Circuit-vented horizontal branch drains are permitted to be connected together. Each group of a maximum of eight fixtures shall be considered a separate circuit vent and shall conform to the requirements of this section.

P3110.2 (914.2) Vent Connection

AMENDMENT
This section has been amended at the state or city level.
The circuit vent connection shall be located between the two most upstream fixture drains. The vent shall connect to the horizontal branch and shall be installed in accordance with Section P3104. The circuit vent pipe shall not receive the discharge of any soil or waste.

P3110.3 (914.3) Slope and Size of Horizontal Branch

AMENDMENT
This section has been amended at the state or city level.
The slope of the vent section of the horizontal branch drain shall be not greater than one unit vertical in 12 units horizontal (8-percent slope). The entire length of the vent section of the horizontal branch drain shall be sized for the total drainage discharge to the branch in accordance with Table P3005.4.1. Drainage discharge dfu values for horizontal fixture branches shall be reduced 50 percent in Table P3005.4.1 for circuit vented fixture branches.

P3110.4 (914.5) Additional Fixtures

AMENDMENT
This section has been amended at the state or city level.
Fixtures, other than the circuit vented fixtures shall be permitted to discharge, to the horizontal branch drain. Such fixtures shall be located on the same floor as the circuit vented fixtures and shall be either individually or common vented.

Section P3111 Combination Waste and Vent System

AMENDMENT
This section has been amended at the state or city level.

P3111.1 Type of Fixtures

AMENDMENT
This section has been amended at the state or city level.

P3111.2 Installation

AMENDMENT
This section has been amended at the state or city level.

P3111.2.1 Slope

AMENDMENT
This section has been amended at the state or city level.

P3111.2.2 Connection

AMENDMENT
This section has been amended at the state or city level.

P3111.2.3 Vent Size

AMENDMENT
This section has been amended at the state or city level.

P3111.2.4 Fixture Branch or Drain

AMENDMENT
This section has been amended at the state or city level.

P3111.3 Size

AMENDMENT
This section has been amended at the state or city level.

Section P3112 (916) Island Fixture Venting

AMENDMENT
This section has been amended at the state or city level.

P3112.1 (916.1) Limitation

AMENDMENT
This section has been amended at the state or city level.
Island fixture venting shall not be permitted for fixtures other than sinks and lavatories. Kitchen sinks with a dishwasher waste connection, a food waste disposer, or both, in combination with the kitchen sink waste, shall be permitted to be vented in accordance with this section.

P3112.2 (916.2) Vent Connection

AMENDMENT
This section has been amended at the state or city level.
The island fixture vent shall connect to the fixture drain as required for an individual or common vent. The vent shall rise vertically to above the drainage outlet of the fixture being vented before offsetting horizontally or vertically downward. The vent or branch vent for multiple island fixture vents shall extend not less than 6 inches (152 mm) above the highest island fixture being vented before connecting to the outside vent terminal.

P3112.3 (916.3) Vent Installation Below the Fixture Flood Level Rim

AMENDMENT
This section has been amended at the state or city level.
The vent located below the flood level rim of the fixture being vented shall be installed as required for drainage piping in accordance with Chapter 30, except for sizing. The vent shall be sized in accordance with Section P3113.1. The lowest point of the island fixture vent shall connect full size to the drainage system. The connection shall be to a vertical drain pipe or to the top half of a horizontal drain pipe. Cleanouts shall be provided in the island fixture vent to permit rodding of all vent piping located below the flood level rim of the fixtures. Rodding in both directions shall be permitted through a cleanout.

P3113.1 (906.1) Size of Vents

AMENDMENT
This section has been amended at the state or city level.
The required diameter of individual vents, branch vents, circuit vents, vent stacks and stack vents shall be not less than one-half the required diameter of the drain served. The required size of the drain shall be determined in accordance with Chapter 30. Vent pipes shall be not less than 11/4 inches (32 mm) in diameter. Vents exceeding 40 feet (12 192 mm) in developed length shall be increased by one nominal pipe size for the entire developed length of the vent pipe.

P3113.2 (906.3) Developed Length

AMENDMENT
This section has been amended at the state or city level.
The developed length of individual, branch, and circuit vents shall be measured from the farthest point of vent connection to the drainage system, to the point of connection to the vent stack, stack vent or termination outside of the building.

P3113.3 (906.4) Branch Vents

AMENDMENT
This section has been amended at the state or city level.
Where branch vents are connected to a common branch vent, the common branch vent shall be sized in accordance with this section, based on the size of the common horizontal drainage branch that is or would be required to serve the total drainage fixture unit (d.f.u.) load being vented.

P3113.4 (906.5) Sump Vents

AMENDMENT
This section has been amended at the state or city level.
Sump vent sizes shall be determined in accordance with Sections P3113.4.1 and P3113.4.2.

P3113.4.1 (906.5.1) Sewage Pumps and Sewage Ejectors Other Than Pneumatic

AMENDMENT
This section has been amended at the state or city level.
Drainage piping below sewer level shall be vented in the same manner as that of a gravity system. Building sump vent sizes for sumps with sewage pumps or sewage ejectors, other than pneumatic, shall be determined in accordance with Table P3113.4.1. An open vent terminal from a drainage system shall not be located directly beneath any door, openable window, or other air intake opening of the building or of an adjacent building or property line, and any such vent terminal shall not be within 10 feet (3048 mm) horizontally of such an opening unless it is at least 2 feet (610 mm) above the top of such opening.

TABLE P3113.4.1
SIZE AND LENGTH OF SUMP VENTS
DISCHARGE CAPACITY OF PUMP
(gpm)
MAXIMUM DEVELOPED LENGTH OF VENT (feet)a
Diameter of vent (inches)
11/4 11/2 2 21/2 3
10 No limitb No limit No limit No limit No limit
20 270 No limit No limit No limit No limit
40 72 160 No limit No limit No limit
60 31 75 270 No limit No limit

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon per minute (gpm) = 3.785 L/m.
a. Developed length plus an appropriate allowance for entrance losses and friction caused by fittings, changes in direction and diameter. Suggested allowances shall be obtained from NBS Monograph 31 or other approved sources. An allowance of 50 percent of the developed length shall be assumed if a more precise value is not available.
b. Actual values greater than 500 feet.

P3113.4.2 (906.5.2) Pneumatic Sewage Ejectors

AMENDMENT
This section has been amended at the state or city level.
The air pressure relief pipe from a pneumatic sewage ejector shall be connected to an independent vent stack terminating as required for vent extensions through the roof. The relief pipe shall be sized to relieve air pressure inside the ejector to atmospheric pressure, but shall be not less than 11/4 inches (32 mm) in size.

Section P3114 (918) Air Admittance Valves

AMENDMENT
This section has been amended at the state or city level.

P3114.1 (918.1) General

AMENDMENT
This section has been amended at the state or city level.
Vent systems using air admittance valves shall comply with this section. Individual and branch-type air admittance valves shall conform to ASSE 1051. Stack-type air admittance valves shall conform to ASSE 1050.

P3114.2 (918.2) Installation

AMENDMENT
This section has been amended at the state or city level.
The valves shall be installed in accordance with the requirements of this section and the manufacturer's instructions. Air admittance valves shall be installed after the DWV testing required by Section P2503.5.1 or P2503.5.2 has been performed.

P3114.3 (918.3) Where Permitted

AMENDMENT
This section has been amended at the state or city level.
Individual vents, branch vents, circuit vents and stack vents shall be permitted to terminate with a connection to an air admittance valve. Individual and branch type air admittance valves shall vent only fixtures that are on the same floor level and connect to a horizontal branch drain.

P3114.4 (918.4) Location

AMENDMENT
This section has been amended at the state or city level.
Individual and branch air admittance valves shall be located not less than 4 inches (102 mm) above the horizontal branch drain or fixture drain being vented. Stack-type air admittance valves shall be located not less than 6 inches (152 mm) above the flood level rim of the highest fixture being vented. The air admittance valve shall be located within the maximum developed length permitted for the vent. The air admittance valve shall be installed not less than 6 inches (152 mm) above insulation materials where installed in attics.

P3114.5 (918.5) Access and Ventilation

AMENDMENT
This section has been amended at the state or city level.
Access shall be provided to air admittance valves. Such valves shall be installed in a location that allows air to enter the valve.

P3114.6 (918.6) Size

AMENDMENT
This section has been amended at the state or city level.
The air admittance valve shall be rated for the size of the vent to which the valve is connected.

P3114.7 (918.7) Vent Required

AMENDMENT
This section has been amended at the state or city level.
Within each plumbing system, not less than one stack vent or a vent stack shall extend outdoors to the open air.

P3114.8 (918.8) Prohibited Installations

AMENDMENT
This section has been amended at the state or city level.
Air admittance valves shall not be used to vent sumps or tanks except where the vent system for the sump or tank has been designed by an engineer. Air admittance valves shall not be located in spaces utilized as supply or return air plenums.
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