# Catch basin venting



## luv2plum (May 16, 2012)

Hey all,
Might be a dumb question, but I can't seem to find a definitive answer in the OBC: do you have to vent an interior catch basin, and if so, how do you size the vent? Any job I have worked on, the catch basins never were vented, just got an inverted TY with an end cleanout in the basin. But I was thinking the other day that, these get tied into sanitary drains and could siphon out just like any other trap, theoretically. Also, I've never seen a catch basin primed, although it seems like they should be. 
Sorry to sound like a newbie, just never gave this much thought before.


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## Ptturner91 (Oct 13, 2012)

luv2plum said:


> Hey all, Might be a dumb question, but I can't seem to find a definitive answer in the OBC: do you have to vent an interior catch basin, and if so, how do you size the vent? Any job I have worked on, the catch basins never were vented, just got an inverted TY with an end cleanout in the basin. But I was thinking the other day that, these get tied into sanitary drains and could siphon out just like any other trap, theoretically. Also, I've never seen a catch basin primed, although it seems like they should be. Sorry to sound like a newbie, just never gave this much thought before.


Too be fair, there are not too many catch basins inside

And usually they go to a sanitary pit so not really a danger of sewer gases


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## Fast fry (May 19, 2012)

It's definitely arguable ...... As they are a trap . I just finished a brewery where the print made me have a 2" vent on the inlet side , 2" on the outlet side and a 3" coming straight off the sump . Sump was just picking up 40' of watts dead level trench drains . They usually make us put a backwater check valve on the outlet side of sumps.


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