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 centerline 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 P2706.1.2. Fixtures shall not be double trapped.
Trap sizes for plumbing fixtures shall be as indicated in Table P3201.7. Where the tailpiece of a plumbing fixture is larger than that indicated in Table P3201.7, the trap size shall be the same nominal size as the fixture tailpiece. A trap shall not be larger than the drainage pipe into which the trap discharges.
|PLUMBING FIXTURE||TRAP SIZE MINIMUM (inches)|
|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 food waste disposer)||11/2|
|Laundry tub (one or more compartments)||11/2|
|Shower (based on the total flow rate through showerheads and bodysprays)|
|5.7 gpm and less||11/2|
|More than 5.7 gpm up to 12.3 gpm||2|
|More than 12.3 gpm up to 25.8 gpm||3|
|More than 25.8 gpm up to 55.6 gpm||4|
For SI: 1 inch = 25.4 mm, 1 gallon per minute = 3.785 L/m.