Which hazard occupancy is associated with moderate fire risk areas and a maximum of 400 ft²?

Which hazard occupancy is associated with moderate fire risk areas and a maximum of 400 ft²?

• A. Light hazard occupancy
• B. Ordinary hazard occupancy
• C. Concealed sprinklers
• D. Water meters

Answer: (B)

In NFPA 13R for low-rise residential systems, spaces are classified by fire risk: light hazard for lower-risk areas with smaller sprinkler coverage, and ordinary hazard for moderate-risk areas. Ordinary hazard is the classification used for areas with a typical residential fire load, where a design approach allows about 400 ft² per sprinkler head. This matches the scenario described—moderate fire risk areas with a maximum of 400 ft² per sprinkler—so the best choice is ordinary hazard occupancy. Concealed sprinklers are a sprinkler type, not an occupancy classification, and water meters are not a hazard occupancy category.

In NFPA 13R for low-rise residential systems, spaces are classified by fire risk: light hazard for lower-risk areas with smaller sprinkler coverage, and ordinary hazard for moderate-risk areas. Ordinary hazard is the classification used for areas with a typical residential fire load, where a design approach allows about 400 ft² per sprinkler head. This matches the scenario described—moderate fire risk areas with a maximum of 400 ft² per sprinkler—so the best choice is ordinary hazard occupancy.

Concealed sprinklers are a sprinkler type, not an occupancy classification, and water meters are not a hazard occupancy category.