IFGC 503.6.6 on gas vent terminations
804.3.3 of the IMC deals with power venting kept 10ft from lot lines. If this applied to all vents, there would be no way to heat townhomes with combustion appliances.
As for fresh air intakes, if within 10 feet horizontally, the vent discharge must be at least 3ft above the inlet. IFGC503.8
Keep the fire inside the fireplace.
You don't have to keep the vents 10' apart, just 10' from fresh air intakes or property lines. I always run my vents up through pate pipe curbs together for termination on condos or townhomes.
mechanical code book
Normally the BW vent change to B vent once it enters the attic. So you would use the same code that applies to b vent. Slop of the rood decides how tall the vent pipe should be. As long as this is a cat. 1 appliance.
Flat roof to 7/12 pictch 1 foot min. from the tabel I am using.
Not the chimney codes that are stated above.
Nice call, Hearthman...
Its a common mistake - is it a chimney? Or is it a manufactured vent? Like you say, its a vent, and the regulations are different.
Just to be the devil's advocate, for those thinking "taller is better...", doesn't ANY excess height (over and above the required by code) in a cold climate contribute to reduced exhaust gas temps? Aren't we looking for preventing the gases from condensing, and that moisture running back down the B-vent?
Ever seen that condition? Many times here.....