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 shall be permitted to be used on the trap inlet, trap outlet, or within the trap seal. Slip joints shall be accessible.
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.
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.
|PLUMBING FIXTURE||TRAP SIZE |
|Bathtub (with or without shower head and/or whirlpool attachments)||11/2|
|Clothes washer standpipe||2|
|Dishwasher (on separate trap)||11/2|
|Kitchen sink (one or two traps, with or |
without dishwasher and garbage grinder)
|Laundry tub (one or more compartments)||11/2|
|Shower (based on the total flow rate through showerheads and bodysprays) |
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.