In the "for whatever it is worth" category, here is the requirement listed in the VCCA 2007 judging manual:
"Owners are required to have an operational fire extinguisher, which is inspected at the Field Entrance Check. The fire extinguisher must meet current ANSI/UL standards and be rated for a minimum 5 B-C classification. It must pass a pressure check or have a gauge reading in the acceptable range and all seals in tact. The fire extinguisher is to be placed on the passenger side floor of the vehicle while it is on the judging field. No vehicle will be allowed on to the judging field, or be eligible for judging, with out an approved fire extinguisher."
Mike