Minimum distance of wet vent to furnace vent

[TiredinDC]

I can't find any information on how close a plumbing vent (PVC) can be to a metal furnace vent. Reading through my local county code website I can't find any specific information either. The only relevant information I found was a single wall furnace vent requires 6 inches of clearance while a double wall requires 1 inch from combustible materials.

I'm having my roof redone and want to clear up more roof space for future solar installation. Moving them closer together would allow an additional panel to be installed.

 

[Tuttles Revenge]

Any vent that is exhausting only needs to be away from Intake air on the roof. You could potentially consolidate the two exhaust vents and locate the plumbing vent as nearby as practicable.