I'm finding little information on what fittings are allowed for
dry-vents. Drains are understandably restrictive. I need to join
several dry-vents before going out the roof. Must I use Ys to connect
horizontal dry-vents or can I use sanitary Ts or straight Ts? Can I
connect a vertical dry-vent to an overhead horizontal dry-vent with a
sanitary or straight T?

oldee wrote:

I'm finding little information on what fittings are allowed for
dry-vents. Drains are understandably restrictive. I need to join
several dry-vents before going out the roof. Must I use Ys to connect
horizontal dry-vents or can I use sanitary Ts or straight Ts? Can I
connect a vertical dry-vent to an overhead horizontal dry-vent with a
sanitary or straight T?


San TEE's would be preferred in most of these cases as they
provide the built-in slope for condensate drainage.
Where slope is not a factor, plain TEE's can be used.
WYE fittings can be use to advantage where space is limited,
but there is no functional advantage over a San TEE.

Note that the inspector may have his preferences./

Jim