Fixture Drain Requirements


Every fixture must have a trap. The purpose of a fixture trap is to stop sewer gas from entering the living space of a building.


7.2.3.1. (1) (a):

"every trap shall have a trap seal depth of at least 38 mm".


bloody_trap.png


7.4.9.3.(1) Except as provided in Sentence (2) the size of every fixture outlet pipe shall conform to Table 7.4.9.3..


Fixture outlet pipe = fixture trap size = fixture drain size.

Developed length of a fixture drain




Developed length means the length along the center of pipe and the fittings


Requirements:


  • The developed length of fixture drain between the trap weir and its vent
  1. Min 2 fixture drain diameter,
  2. max 1500 mm
  • The minimum slope of the fixture drain
  • 1:50 or 1/4" per foot fall for fixture drains of 3" and less
  • The total fall of the fixture drain


7.4.8.1.

  1. Every drainage pipe that has a size of 3" or less, and every drain shall have a downward slope in the direction of flow of at least 1 in 50. (See Appendix A.)
  2. Sentence (1) does not apply to a force main.


7.4.9.1.(1)

No soil or waste pipe that is of minimum size required by this Code for the purpose for which it is installed shall be so connected as to drain to other drainage pipe of lesser size.


  1. From P-trap: one fixture drain diameter ,
  2. if Y and 45o elbow is used to connect a fixture drain to its vent, between Y and 45o elbow there should be a nipple of 1 1/2" long:








  • Total change of direction between a trap and its vent


  1. P-trap 1350 :


  1. S-(siphonic trap) 2250 :