Overview of Combination Standpipe – Minimum Size
Section 7.6.2 of the 2016 edition of NFPA 14 states that the minimum size for a standpipe that is part of a combined system in a partially sprinklered building is 6-inches. Does this mean that a 4-inch standpipe is acceptable for a hydraulically designed combination sprinkler/standpipe system in a fully sprinklered building? Yes, a 4-in. minimum standpipe pipe is acceptable in fully protected buildings. Section 7.6.2 would not apply to buildings protected throughout by an automatic fire sprinkler system. Minimum standpipe pipe size is 4 in. as stated in Section 7.6.1, and all standpipes that are part of a combined system in partially sprinklered buildings must have a minimum 6 in. Further, Section 7.6.2.1 allows buildings protected throughout by an approved automatic sprinkler system in accordance with NFPA 13 or NFPA 13R to have a minimum standpipe size of be 4 in. for systems hydraulically designed in accordance with 7.8.1. The technical committee attempted to ...