The epa and other guidelines somewhat follow the standard codes for plumbing vent pipes which generally are vented above the buildings roof.
Roof vent clearances.
1 0 foot above the roof surface 1 7 12 to 8 12.
To a height of only 2 in.
In all areas exhaust vents should be at least 1 foot above roof surface.
Roof pitch rise run in inches.
The vent opening must communicate with outside air over an area no less than the area of the vent pipe measured on the inside.
New york state just raised plumbing vent pipe code from 12 inches to 18 inches above the roof and at least 10 feet horizontal distance from any opening to the building i e.
Table of rooftop chimney clearances for metal b vent chimneys flues.
The 2 10 rule states that combustion vents should terminate at least 2 feet above any part of the roof within 10 feet.
2 5 feet above the roof surface.
The quench vent should be a minimum of 5 m above walking surfaces.
The exit point for the quench vent pipe should be located away from operable windows and air inlets.
Window or fresh air intake.
Minimum height above the roof surface 1 flat to 7 12.
Vegetation must not be allowed to grow within 3 feet of an exhaust vent.
Exhaust vents must be protected against rain and equipped with back flow prevention features e g flap dampers.
2 0 feet above the roof surface.
1 5 feet above the roof surface.