1. Log in
  2. Sign up

Traps

Traps

This chapter establishes design requirements and approved materials for fixture traps, ensuring they are self-cleaning and have smooth internal waterways.

P3201 — Fixture Traps

P3201.1 Design of traps. 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 approvedplastic. Tubular brass traps shall be not less than No. 20 gage (0.8 mm) thickness. Solid connections, slipjoints and couplings are permitted to be used on the trap inlet, trap outlet, or within the trap seal. Slip joints shall be accessible.

P3201.2 Trap seals and trap seal protection. 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. Trap seal primer valves shall connect to the trap at a point above the level of the trap seal.

P3201.3 Trap setting and protection. 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).

P3201.4 Building traps. Building traps shall not be installed, except in special cases where sewer gases are extremely corrosive or noxious, as directed by the building official.

P3201.5 Prohibited trap designs. The following types of traps are prohibited:

  • Bell traps.
  • Separate fixture traps with interior partitions, except those lavatory traps made of plastic, stainless steel or other corrosion-resistant material.
  • "S" traps.
  • Drum traps.
  • Trap designs with moving parts.

P3201.6 Number of fixtures per trap. 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 ofa clothes washer standpipe above a trap shall conform to Section P2706.2. Fixtures shall not be double trapped.

Exceptions: Fixtures that have integral traps. 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. Connection of a laundry tray waste line into a standpipe for the automatic clothes-washer drain is permitted in accordance with Section P2706.2.1.

Exceptions:

  • Fixtures that have integral traps.
  • 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.
  • Connection of a laundry tray waste line into a standpipe for the automatic clothes-washer drain is permitted in accordance with Section P2706.2.1.

P3201.7 Size of fixture traps. 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.

A table appears here in the adopted code. Refer to the official source for the full table.

Frequently asked questions

What are the fundamental design requirements for plumbing fixture traps?

Fixture traps must be of standard design, have smooth, uniform, self-cleaning internal waterways, and generally avoid internal partitions unless integral with the fixture itself.

What materials are permitted for the construction of plumbing fixture traps?

Approved materials for traps include lead, cast iron, cast or drawn brass, and approved plastic.

Are internal partitions allowed within plumbing traps?

Internal partitions are only allowed in traps if they are an integral part of the fixture itself.

Where verbatim source text is shown, it is reproduced from the code as adopted into law by the jurisdiction, sourced from public.resource.org under the government edicts doctrine (see Georgia v. Public.Resource.Org, Inc., 590 U.S. 255 (2020)). This material reflects enacted law and is provided for reference and educational purposes only. It is not legal advice and may not reflect local amendments or the most recently adopted edition. Always verify requirements with the authority having jurisdiction.