NFPA496: This is a purge and pressurize standard that I have only ever seen applied to electrical cabinets located in Class 1 Div 2/Zone2 areas; and MCC or control rooms located within a Class 1 Div2/Zone 2 building.Has anyone ever applied this code to a large clear span (no separate rooms, just one large open space) natural gas compressor building (the entire building)? With such large leakage potential and high natural gas pressures (800psi +) this does not seem a reasonable place to use general area class electrical equipment (even with a purge pressurize system. I have a client requesting this and we normally ALWAYS use the ventilating air dilution method (NOT purge and pressurize) to reduce area class on the inside of the building from Class 1 Div 1 to Class 1 Div 2. However, from a cursory reading of the std, I do not see anything that would prevent it (short interp doc attached). Any guidance you have would be helpful. Thanks.