NFPA 20: More key factors to consider
Double-wall fuel tanks: Language to clarify that a dike is not required for double-wall diesel oil fuel tanks for fire pumps was added to the 2013 edition of NFPA 20. It should be noted that NFPA 20 does not refer to NFPA 30: Flammable and Combustible Liquids Code, and therefore the requirement in NFPA 30 that requires all pipe into a double-wall fuel tank to be through the top of the tank does not apply to NFPA 20. NFPA 20 requires the diesel fuel line near the bottom of the tank to provide gravity feed to the diesel engine.
Elbows, tees in pump suction piping: While the requirement that the distance between the flanges of the pump suction intake and an elbow or tee must be greater than 10 times the suction pipe for elbows and tees that have a centerline plane parallel to a horizontal split-case pump shaft was not changed, the figures in the appendix demonstrating proper installation were clarified. See Figure 6 for an example of an elbow incorrectly installed with a centerline plane parallel to the horizontal split-case pump shaft.
Equipment access: Fire pump rooms that are not directly accessible from the outside must be accessible through an enclosed passageway from an enclosed stairway or exterior exit having a fire-resistance rating not less than the fire-resistance rating of the fire pump room.
Reliability measurement: The ongoing debate over what makes a “reliable” electrical source for fire pumps was not resolved and will continue to be studied for the next cycle.
Gayle Pennel is a project manager with Aon Fire Protection Engineering. His expertise lies in fire protection systems and water supplies. He is currently chairman of the NFPA 20 committee and serves on the NFPA 25 committee. He has designed fire protection systems for super high-rise and large exhibition centers, as well as industrial sites. Pennel has consulted on pressure surge, corrosion, and other fire protection failure issues and has successfully presented fire protection design alternatives to state and local authorities.