I work for an EPC company that will be installing some water spray systems to protect some electrical equipment. These systems are to be designed according to NFPA 15, with a design density of 0.5 gpm/sqft. This translates into about 2000 gpm & around 28 nozzles for our systems.
My fire protection consultant has deferred design of the piping supports to my structural consultant. My structural consultant is unwilling to follow the prescriptive design rules for pipe stands in Chapter 6 of NFPA 15, and is specifying very large steel supports based on a structural analysis based on a L/360 deflection criteria.
My questions are
1) Are piping supports for NFPA 15 water spray systems of this scale typically designed prescriptively or using a full structural/FEA analysis?
2) If the latter, what loads typically control the design, and what standards should I direct my structural engineer to for the maximum allowable deflections? Dead load & seismic loads would seem to be dominant, I am less sure about wind load, thrust at fittings, & thrust at nozzles.
My fire protection consultant has deferred design of the piping supports to my structural consultant. My structural consultant is unwilling to follow the prescriptive design rules for pipe stands in Chapter 6 of NFPA 15, and is specifying very large steel supports based on a structural analysis based on a L/360 deflection criteria.
My questions are
1) Are piping supports for NFPA 15 water spray systems of this scale typically designed prescriptively or using a full structural/FEA analysis?
2) If the latter, what loads typically control the design, and what standards should I direct my structural engineer to for the maximum allowable deflections? Dead load & seismic loads would seem to be dominant, I am less sure about wind load, thrust at fittings, & thrust at nozzles.
