9-4.4.4 Excerpt from the LIFE SAFETY CODE HANDBOOK
All fuel tank openings shall be locked and sealed in an approved manner to prevent the escape of vapors. Fuel tanks shall not be more than one-half full or contain more than 10 gallons (37.9L) of fuel, whichever is less.
It is important that fuel tank openings be locked to prevent tampering and accessibility to fuel. It is also important that the tank openings be taped to prevent the escape of flammable vapors. Given that the vehicle is locked, sealed, and ignition sources are eliminated, to avoid excessive quantities of fuel in the exhibition hall.
At least one battery cable shall be removed from the batteries used to start the vehicle engine. The disconnected battery cable shall then be taped.
It is important that at least one of the battery cables be removed from each battery. Many vehicles have more than one battery. The intent is to eliminate the possibility of a spark from a battery that might ignite fuel or surrounding combustibles. Battery cable connectors should be thoroughly taped after they have been removed.
Batteries used to power auxiliary equipment shall be permitted to be kept in service.
This provision allows batteries that cannot be used to start the vehicle to remain in service. These present no more ignition hazard than does providing house electrical power to the item in storage.
Fueling and defueling of vehicles shall be prohibited.
Fueling and defueling in and around the exhibit hall is extremely dangerous.