vent pipe

There are additional concerns than getting the liquid down the drain. First, keeping flammable/noxious gases from getting into the house.

It is done in cases where a roof terminal would be objectionable or impractical.

But there are conditions to be met regarding clearance from openings, air intakes, etc. Needs to be equipped with U-bend and/or screens to prevent nesting or foreign objects.

Local authority no doubt has specific rules.

Jim

on 8/14/2007 9:58 AM franz frippl said the following:

The vent is open directly to the sewer system. There are no traps in the vent system. Do you want sewer gases, and their smells, closer to the ground, or wafting through open windows near the vent, or through the soffit vents into the attic? The idea is to exhaust them as far away as possible from living areas.

Depends on your local code.

IIRC, UPC says all vents must go through the roof, IRC says the main vent needs to go through the roof, others can go through the wall under certain restrictions -- setbacks from property lines and highest grade, not under vented soffit, etc.

One important concern is where fumes coming out of the vent might go. Your sewer burps a bunch of methane, or some idiot pours gas down a drain -- do the fumes coming up your sewer main vent to open air, or waft into your attic, or into your furnace intake, or....

If you live in an area where it often gets cold you could end up with a blocked system. It is (was) not uncommon in Great Britain