What are the requirements for fire retardant system in a warehouse?

OSHA says employers shall assure that sprinklers are spaced to provide a maximum protection area per sprinkler, a minimum of interference to the discharge pattern by building or structural members or building contents and suitable sensitivity to possible fire hazards. The minimum vertical clearance between sprinklers and material below shall be 18 inches.

Materials, racks, products, etc., must be spaced from the sprinkler head to provide an 18-inch spray pattern clearance.

Section 1910.159 states there are two basic types of sprinkler system design. Pipe schedule designed systems are based on pipe schedule tables developed to protect hazards with standard sized pipe, number of sprinklers, and pipe lengths. Hydraulic designed systems are based on an engineered design of pipe size which will produce a given water density or flow rate at any particular point in the system. Either design can be used to comply with this standard.

The National Fire Protection Association’s Standard (NFPA) No. 13, “Automatic Sprinkler Systems,” contains the tables needed to design and install either type of system. Minimum water supplies, densities, and pipe sizes are given for all types of occupancies. Your employer can also check with a reputable fire protection engineering consultant or sprinkler design company when evaluating existing systems or designing a new installation for your facility. Pipes must be placed according to NFPA requirements above and depends on the total design of the system. Generally, they can’t be placed in the food/product racks.

Per NFPA No. 13, the minimum pressure at the sprinkler head is 7 psi. For fire retardant systems, this is called a fixed extinguishing system OSHA’s standards.