Re: propane clearances for regs. different than for tanks
Ok, here it is out of a 2001 edition of NFPA 58:
3.2.12.5 "The point of discharge from the required pressure relief device on regulating equipment installed outside of buildings in fixed piping systems shall be located not less than 3 ft horizontally away from any building opening below the level of such discharge, and not beneath any building unless this space is well ventilated to the outside and is no enclosed more than 50 percent of its perimeter. The point of discharge shall also be located not less than 5ft. in any direction away from any source of ignition, openings into direct vent (sealed combustion system) appliances, or mechanical ventilation air intakes. Where a vent line is used to comply with the point of discharge requirements, it shall comply with 3.2.12.6(a) and (c)."
The other 3ft versus 10 foot clearances for DOT cylinders versus ASME containers has to do with the point of transfer and exposures (fill cap). Therefore, such clearances are not to the edge of the tank but the fill cap inside the bonnet.
HTH,
Bob