NICET Special Hazards Level I cheat sheet

Special Hazards Systems

• NFPA 13 densities apply to wet/dry pipe; NFPA 13R and 13D permit reduced densities and omit design areas for certain residential occupancies.

• NFPA 13 design area may be reduced by 25% for quick-response sprinklers in wet systems when ceiling height is 10 ft (3 m) or less, but never below 1,500 sq ft.

• Sloped ceiling design area increases by 30% for slopes exceeding 2/12 up to 4/12, and by 30% per 2 in of slope beyond that, per NFPA 13.

• NFPA 15 water spray systems protect specific hazards (transformers, tanks, gas cylinders); NFPA 16 covers foam-water sprinkler and spray systems.

• NFPA 17A wet chemical systems protect commercial cooking equipment; the appliance must be shut down and fuel supply cut on actuation.

• NFPA 2001 clean agent systems use halocarbon or inert gas agents; design concentration for Class B hazards is set at the agent's flame extinguishment value with a safety factor.

• NFPA 11 foam systems: low-expansion foam for hydrocarbon storage tanks, medium- and high-expansion foam for enclosed spaces and flammable liquid spills.

• NFPA 750 water mist systems are classified by pressure: low (<175 psi), intermediate (175-500 psi), and high (>500 psi).