How do I know if I have enough fire extinguishers?

The standard rule of thumb is a travel distance of no more than seventy-five feet for class “A” hazards and fifty feet travel distance for class “B” hazards. These are general guidelines and can differ based on many factors. Fire extinguisher spacing is addressed in NFPA 10 (Standard for portable fire extinguishers) section 6.2.1.1.