14-06 Tub vent

Question: 05-17Code Section: 7Date: 5 February 2014OBC 2012 Reference:

Question Submitted:

1) If a building is under construction and I install a 2″ trap on a fixture, would I be able to run this trap arm 2.4 M?

2) If I am stack venting and increase a bath tub trap to 2″ in order to extend the trap arm length so that I can avoid separately venting it,  would the load still be 1.5 fu’s or 3 fu’s?


1) Yes: as per Table, the maximum trap arm length for a 2” trap, installed at a 1 in 50 minimum slope, is 2.4m.

2) 1.5 fixture units should be assigned to the bathtub as it is a listed fixture according to Table