CODES

ADOPTS WITH AMENDMENTS:

International Residential Code 2015 (IRC 2015)

Part I ‒ Administrative

Chapter 1 Scope and Administration

Part II ‒ Definitions

Chapter 2 Definitions

Part III ‒ Building Planning and Construction

Chapter 3 Building Planning

Chapter 4 Foundations

Chapter 5 Floors

Chapter 6 Wall Construction

Chapter 7 Wall Covering

Chapter 8 Roof-Ceiling Construction

Chapter 9 Roof Assemblies

Chapter 10 Chimneys and Fireplaces

Part IV ‒ Energy Conservation

Chapter 11 [RE] Energy Efficiency

Part V ‒ Mechanical

Chapter 12 Mechanical Administration

Chapter 13 General Mechanical System Requirements

Chapter 14 Heating and Cooling Equipment and Appliances

Chapter 15 Exhaust Systems

Chapter 16 Duct Systems

Chapter 17 Combustion Air

Chapter 18 Chimneys and Vents

Chapter 19 Special Appliances, Equipment and Systems

Chapter 20 Boilers and Water Heaters

Chapter 21 Hydronic Piping

Chapter 22 Special Fuel oil Piping and Storage Systems

Chapter 23 Solar Thermal Energy Systems

Part VI ‒ Fuel Gas

Chapter 24 Fuel Gas

Part VII ‒ Plumbing

Chapter 25 Plumbing Administration

Chapter 26 General Plumbing Requirements

Chapter 27 Plumbing Fixtures

Chapter 28 Water Heaters

Chapter 29 Water Supply and Distribution

Chapter 30 Sanitary Drainage

Chapter 31 Vents

Chapter 32 Traps

Chapter 33 Storm Drainage

Part VIII ‒ Electrical

Chapter 34 General Requirements

Chapter 34 GENERAL REQUIREMENTS

Chapter 35 Electrical Definitions

Chapter 35 ELECTRICAL DEFINITIONS

Chapter 36 Services

Chapter 36 SERVICES

Chapter 37 Branch Circuit and Feeder Requirements

Chapter 37 BRANCH CIRCUIT AND FEEDER REQUIREMENTS

Chapter 38 Wiring Methods

Chapter 38 WIRING METHODS

Chapter 39 Power and Lighting Distribution

Chapter 39 POWER AND LIGHTING DISTRIBUTION

Chapter 40 Devices and Luminaires

Chapter 40 DEVICES AND LUMINAIRES

Chapter 41 Appliance Installation

Chapter 41 APPLIANCE INSTALLATION

Chapter 42 Swimming Pools

Chapter 42 SWIMMING POOLS

Chapter 43 Class 2 Remote-Control, Signaling and Power-Limited Circuits

Chapter 43 CLASS 2 REMOTE-CONTROL, SIGNALING AND POWER-LIMITED CIRCUITS

Part IX ‒ Referenced Standards

Chapter 44 Referenced Standards

Chapter 45 HIGH WIND ZONES

Chapter 46 COASTAL AND FLOOD PLAIN CONSTRUCTION STANDARDS

Appendix A Sizing and Capacities of Gas Piping

Appendix B Sizing of Venting Systems Serving Appliances Equipped With Draft Hoods, Category I Appliances, and Appliances Listed for Use With Type B Vents

Appendix C Exit Terminals of Mechanical Draft and Direct-Vent Venting Systems

Appendix D Recommended Procedure for Safety Inspection of an Existing Appliance Installation

Appendix E Manufactured Housing Used as Dwellings

Appendix E (E-1 THROUGH E-4)
RESIDENTIAL REQUIREMENTS FOR ENERGY CONSERVATION

Appendix F Radon Control Methods

Appendix G Piping Standards for Various Applications

Appendix H Patio Covers

Appendix I Private Sewage Disposal

Appendix J Existing Buildings and Structures

Appendix J EXISTING BUILDINGS AND STRUCTURES

Appendix K Sound Transmission

Appendix L Permit Fees

Appendix M HOME DAY CARE—R-3 OCCUPANCY

Appendix M WOOD DECKS

Appendix N Venting Methods

Appendix O Automatic Vehicular Gates

Appendix O FOAM PLASTIC DIAGRAMS

Appendix P Sizing of Water Piping System

Appendix Q Reserved

Appendix Q DISCONTINUOUS FOOTINGS

Appendix R Light Straw-Clay Construction

Appendix S Strawbale Construction

Appendix T Recommended Procedure for Worst-Case Testing of Atmospheric Venting Systems Under N1102.4 or N1105 Conditions ≤ 5ACH50

Appendix U SOLAR-READY PROVISIONS—DETACHED ONE- AND TWO-FAMILY DWELLINGS, MULTIPLE SINGLE- FAMILY DWELLINGS (TOWNHOUSES)

Appendix V SWIMMING POOLS, SPAS AND HOT TUBS

Appendix W BASIC LOAD ESTIMATING

Chapter 31 Vents

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
User note: Code change proposals to this chapter will be considered by the IRC ‒ Plumbing and Mechanical Code Development Committee during the 2015 (Group A) Code Development Cycle. 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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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 P3107.

P3101.3 (901.4) Use Limitations

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
In climates where the 97.5-percent value for outside design temperature is 0°F (-18°C) or less (ASHRAE 97.5-percent column, winter, see Chapter 3), vent pipes installed on the exterior of the structure shall be protected against freezing by insulation, heat or both. Vent terminals shall be protected from frost closure in accordance with Section P3103.2.

P3101.5 (309.2) Flood Resistance

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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 212 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. Amendments are shown in green text.
The vent system serving each building drain shall have not less than one vent pipe that extends to the outdoors.

P3102.1 (904.1) Stack required

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
Where the 97.5-percent value for outside design temperature is 0°F (-18°C) or less, vent extensions through a roof or wall shall be not less than 3 inches (76 mm) in diameter. Any increase in the size of the vent shall be made not less than 1 foot (304.8 mm) inside the thermal envelope of the building.

P3103.3 (903.3) Flashings and Sealing

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
A vent terminal shall not be used for any purpose other than a vent terminal. 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. Amendments are shown in green text.
An open vent terminal from a drainage system shall not be located less than 4 feet (1219 mm) directly beneath any door, openable window, or other air intake opening of the building or of an adjacent building, nor shall or property line, and any such vent terminal shall not be within 10 feet (3048 mm) horizontally of such an opening unless it is not less than 3 feet (914 mm)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. Amendments are shown in green text.
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. Amendments are shown in green text.

P3104.1 (905.1) Connection

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.

P3106.1 (910.1) Individual Vent Permitted

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

P3107.3 Connection at Different Levels

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
Any combination of fixtures within two bathroom groups located on the same floor level shall be permitted to be vented by a horizontal 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. Only the fixtures within the bathroom groups shall connect to the wet-vented horizontal branch drain. Any additional fixtures shall discharge downstream of 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. Amendments are shown in green text.
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. Amendments are shown in green text.
The dry-vent connection for a horizontal wet-vent system shall be an individual vent or a common vent for any bathroom group 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. Not more than one wet-vented fixture drain shall discharge upstream of the dry-vented fixture drain connection.

P3108.2.2 (912.2.2) Vertical Wet Vent

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.

P3109.1 (913.1) Waste Stack Vent Permitted

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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 P3104.5. The stack vent shall be permitted to connect with other stack vents and vent stacks in accordance with Section P3113.3.

P3109.4 (913.4) Waste Stack Size

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.

P3110.1 (914.1) Circuit Vent Permitted

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.

P3111.1 Type of Fixtures

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
A combination waste and vent system shall not serve fixtures other than floor drains, sinks and lavatories. A combination waste and vent system shall not receive the discharge of a food waste disposer.

P3111.2 Installation

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The only vertical pipe of a combination waste and vent system shall be the connection between the fixture drain and the horizontal combination waste and vent pipe. The vertical distance shall be not greater than 8 feet (2438 mm).

P3111.2.1 Slope

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The horizontal combination waste and vent pipe shall have a slope of not greater than 1/2 unit vertical in 12 units horizontal (4-percent slope). The minimum slope shall be in accordance with Section P3005.3.

P3111.2.2 Connection

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The combination waste and vent system shall be provided with a dry vent connected at any point within the system or the system shall connect to a horizontal drain that serves vented fixtures located on the same floor. Combination waste and vent systems connecting to building drains receiving only the discharge from one or more stacks shall be provided with a dry vent. The vent connection to the combination waste and vent pipe shall extend vertically to a point not less than 6 inches (152 mm) above the flood level rim of the highest fixture being vented before offsetting horizontally.

P3111.2.3 Vent Size

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The vent shall be sized for the total fixture unit load in accordance with Section P3113.1.

P3111.2.4 Fixture Branch or Drain

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The fixture branch or fixture drain shall connect to the combination waste and vent within a distance specified in Table P3105.1. The combination waste and vent pipe shall be considered the vent for the fixture.

P3111.3 Size

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The size of a combination drain and vent pipe shall be not less than that specified in Table 3111.3. The horizontal length of a combination drain and vent system shall be unlimited.

TABLE P3111.3 SIZE OF COMBINATION WASTE AND VENT PIPE

DIAMETER PIPE
(inches)
MAXIMUM NUMBER OF FIXTURE UNITS (d.f.u.)
Connecting to a
horizontal branch
or stack
Connecting to a
building drain or
building subdrain
2 3 4
21/2 6 26
3 12 31
4 20 50

For SI: 1 inch = 25.4 mm.

Section P3112 (916) Island Fixture Venting

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.

P3112.1 (916.1) Limitation

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.

P3114.1 (918.1) General

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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. Amendments are shown in green text.
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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