How are the different classifications of hazard of occupancies and contents used?

by Nils Deacon, Manager, Inspections and Rating Services

Various NFPA Standards and Codes use occupancy and contents hazard classifications to determine the amount of fire protection to be provided in a building. This would include if an automatic sprinkler system is needed and if so, the specific design of the sprinkler system to be installed in a building.

For example, NFPA 13, the sprinkler standard, has different area of coverage requirements for the occupancy classifications. One sprinkler riser is permitted for Light and Ordinary Hazard occupancies to cover up to 52,000 square feet of area. Extra Hazard occupancies would allow one riser to cover no more than 40,000 square feet of area. Among other factors, this would affect the cost to install the sprinkler system.

NFPA 101, the Life Safety Code, breaks down occupancy types to include Assembly, Educational, Residential, and Mercantile. Safety features including the number of means of egress, exit signs, and size of exits as determined by the occupancy type.

DISCLAIMER: This information reflects the interpretation of MSO, Inc. with regard to NFPA Standards and Codes. It does not represent NFPA’s official position on the items discussed.

Typical mercantile occupancy – Ordinary Hazard.