For non direct vent applications that is side wall venting only the required clearance is 7 feet.
Fireplace vent pipe clearance.
See fire clearances single wall metal flues vents for the clearance from combustibles required for flue vent connectors these are not chimneys but rather the flue pipe smoke pipe or stack pipe that connects a heating appliance to a chimney.
This is a bit of an odd measurement and chimney clearance case because the chimney side is actually about 8 away from the roof edge.
Most of the double wall stove pipe allows for 6 clearance from wall combustibles and 8 from ceiling combustibles.
Many think stovepipe can run from the wood stove right up through the ceiling and roof.
In direct vent applications this clearance distance must be in compliance with local building codes the requirements of the fuel gas supplier for the heating appliance in use and the appliance manufacturer s instructions.
The general rule of thumb however is a 1 inch clearance all the way around for vertical vent runs.
The height of the chimney above the roof surface measured at the up slope side of the chimney from the roof surface to the chimney top should be at least three feet the green line in our photo.
This article gives typical clearance distance requirements between the termination cap of a gas fireplace or fireplace insert and other building or site features such as windows doors other mechanical system components air intakes exhausts.