The State of Michigan offers general industry safety standards regarding portable fire extinguishers covering classification, installation, testing, and maintenance requirements. How many fire extinguishers your location needs depends on factors like the size and layout of rooms. The NFPA standard calls for all extinguishers to be easily accessible, with no more than 75 feet between pieces of equipment. No matter the size of a space or building, experts recommend a minimum of two fire extinguishers per floor.