Since there is no natural gas in this area, the question rarely comes up, however more homeowners are opting for propane powered residential equipment which puts a rather large fuel tank near the building.  I can't find anything in the NEC that regulates proximity of service equipment to these tanks unless Table 515.3 would apply here and the overpressure relief valve would be considered a "vent"?
	
		
			
		
		
	
				
			
				