Hi Jim, I have no idea what Forrest your so called “plumber” crawled out from BUT normally a FAI (fresh air inlet) is half the size of the building house drain and 3″ minimum.
Under no circumstances should any vent terminate under an opening that would allow the carcinogenic foul fumes from re-entering a building.
There are not only height requirements for venting But horizontal distances also that must be taken into consideration.
You see Jim, “sewer gases” can contain hydrogen sulfide which is a flammable poisonous gas that has an odor suggestive of rotten eggs and is found esp. in many mineral waters and in putrefying matter, and of course
Methane which is a colorless odorless flammable gaseous hydrocarbon that is a product of decomposition of organic matter.
Then there are airborne bacteria like hepatitis an acute usu. benign hepatitis caused by an RNA virus that does not persist in the blood serum, and is transmitted esp. in food and water contaminated with infected fecal matter, SEWERS huh?
There are a host of other great cancer causing things that hibernate in sewers, BUT I think you have a good idea why PROPER venting is so very important.
And here you thought us plumbers only protected the health of the world with a plunger, huh?
Want to know about more of the dangers lurking in vent and sewer lines please feel free to E mail me.
Have a good day!
[Edited by John Aldrich on 05 September 2001]