Sanitary Tee direction for venting

[JimV]

I see in the drawings in this forum that sanitary tees are installed so that air flowing out through the vent takes the "smoother" route. If the venting is primarily to keep a suction from forming and pulling out the trap water, wouldn't it be better to orient the tee so that air being pulled down into the system has the "smoother" route? Thanks for all the great advice.

[HayZee518]

the best route for a drain and vent is a TEE WYE with an Eighth bend elbow. this allows for a straighter transition in direction. any baffle in a vent line really wouldn't matter as far as air flow or suction goes. a sanitary T does have a sort of baffle in it.