ground loop / lightning protection for a CNG bus maintenance facility?

Merry Christmas
Location
VA
Occupation
electrical engineering
Greetings, we are designing a CNG bus maintenance facility where I am specifying a ground loop around the facility as per NFPA 780 7.3.7.1:

"7.3.7.1 A ground ring electrode or ground loop conductor
supplemented by grounding electrodes as identified in 4.13.2
through 4.13.7 shall be provided for structures containing
flammable vapors, flammable gases, or liquids that can give off
flammable vapors."

However, one electrical designer on the design team is stating that the ground loop around the facility is not required. Here is what he is stating, which I think is incorrect:

"No fueling in the building. The only flammable gases are inside a gas tank of a vehicle and therefore no grounding loop is required because a vehicle is not part of the building. This is an additional cost that is not required nor is needed. If there were flammable vapors, gases then it would require by code (1) loop for lightning and (1) loop for grounding".

Any feedback from those who have designed such facilities would be appreciated.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Respectfully, your colleague is not correct. By his reasoning, I could store pallets of 55-gallon drums full of acetone in the building and skip the ground loop conductor, because the drums are not "part of the building".
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The annex information in NFPA 780 says Chapter 7 of that code only applies if there are Class I areas in the building. I don't see this as being a classified area. Chapter 7 is the only place NFPA 780 requires a ground ring as part of the lighting protection system grounding electrode system.
 
Top