Part I ‒ Administration

Chapter 1 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 Energy Efficiency

Part V ‒ Mechanical

Chapter 12 Mechanical Administration

Chapter 13 General Mechanical System Requirements

Chapter 14 Heating and Cooling Equipment

Chapter 15 Exhaust Systems

Chapter 16 Duct Systems

Chapter 17 Combustion Air

Chapter 18 Chimneys and Vents

Chapter 19 Special Fuel-Burning Equipment

Chapter 20 Boilers and Water Heaters

Chapter 21 Hydronic Piping

Chapter 22 Special Piping and Storage Systems

Chapter 23 Solar 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

Part VIII ‒ Electrical

Chapter 33 General Requirements

Chapter 34 Electrical Definitions

Chapter 35 Services

Chapter 36 Branch Circuit and Feeder Requirements

Chapter 37 Wiring Methods

Chapter 38 Power and Lighting Distribution

Chapter 39 Devices and Luminaires

Chapter 40 Appliance Installation

Chapter 41 Swimming Pools

Chapter 42 Class 2 Remote-Control‚ Signaling and Power-Limited Circuits

Part IX ‒ Referenced Standards

Chapter 43 Referenced Standards

Appendix A Sizing and Capacities of Gas Piping

Appendix B Sizing of Venting Systems Serving Appliances Equipped With Draft Hoods

Appendix C Plumbing Sanitary Drainage Fittings

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

Appendix E Manufactured Housing Used as Dwellings

Appendix F Reserved

Appendix G Swimming Pools‚ Spas and Hot Tubs

Appendix H Patio Covers

Appendix I Reserved

Appendix J Existing Buildings and Structures

Appendix K Sound Transmission

Appendix L Reserved

Appendix M Reserved

Appendix N Structural Safety

Appendix O Reserved

Appendix P Reserved

Appendix Q Reserved

Traps shall be of standard design, shall have smooth uniform internal waterways, shall be self-cleaning and shall not have interior partitions except where integral with the fixture. Traps shall be constructed of lead, cast iron, cast or drawn brass or approved plastic. Tubular brass traps shall be not less than No. 20 gage (0.8 mm) thickness. Solid connections, slip joints and couplings are permitted to be used on the trap inlet, trap outlet, or within the trap seal. Slip joints shall be accessible.
Traps shall have a liquid seal not less than 2 inches (51 mm) and not more than 4 inches (102 mm). Traps for floor drains shall be fitted with a trap primer or shall be of the deep seal design.
Traps shall be set level with respect to their water seals and shall be protected from freezing. Trap seals shall be protected from siphonage, aspiration or back pressure by an approved system of venting (see Section P3101).
Building (house) traps shall be prohibited, except where local conditions necessitate such traps as required by the code enforcement official. Building traps may be installed inside or outside the building, and the material shall be consistent with the building sewer pipe. Building traps shall be provided with a cleanout and a relief vent or fresh air intake on the inlet side of the trap. The housetrap shall not be the only plumbing vent to the exterior. The size of the relief vent or fresh air intake shall not be less than one-half the diameter of the drain to which the relief vent or air intake connects. Such relief vent or fresh air intake shall be carried above grade and shall be terminated in a screened outlet located outside the building.
The following types of traps are prohibited:

1. Bell traps.
2. Separate fixture traps with interior partitions, except those lavatory traps made of plastic, stainless steel or other corrosion-resistant material.
3. "S" traps.
4. Drum traps.
5. Trap designs with moving parts.
Each plumbing fixture shall be separately trapped by a water seal trap. The vertical distance from the fixture outlet to the trap weir shall not exceed 24 inches (610 mm) and the horizontal distance shall not exceed 30 inches (762 mm) measured from the center line of the fixture outlet to the centerline of the inlet of the trap. The height of a clothes washer standpipe above a trap shall conform to Section P2706.2. Fixtures shall not be double trapped.


1. Fixtures that have integral traps.
2. A single trap shall be permitted to serve two or three like fixtures limited to kitchen sinks, laundry tubs and lavatories. Such fixtures shall be adjacent to each other and located in the same room with a continuous waste arrangement. The trap shall be installed at the center fixture where three fixtures are installed. Common trapped fixture outlets shall be not more than 30 inches (762 mm) apart.
3. Connection of a laundry tub waste line into a standpipe for the automatic clothes-washer drain is permitted in accordance with Section P2706.2.1.
Fixture trap size shall be sufficient to drain the fixture rapidly and not less than the size indicated in Table P3201.7. A trap shall not be larger than the drainage pipe into which the trap discharges.


Bathtub (with or without shower head
and/or whirlpool attachments)
Bidet 11/4
Clothes washer standpipe 2
Dishwasher (on separate trap) 11/2
Floor drain 2
Kitchen sink (one or two traps, with
or without dishwasher and garbage grinder)
Laundry tub (one or more compartments) 11/2
Lavatory 11/4
Shower (based on the total flow rate
through showerheads and bodysprays)
Flow rate:
  5.7 gpm and less
More than 5.7 gpm up to 12.3 gpm
More than 12.3 gpm up to 25.8 gpm
More than 25.8 gpm up to 55.6 gpm
Water closet Note a

For SI: 1 inch = 25.4 mm.

a. Consult fixture standards for trap dimensions of specific bowls.
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