Imagine a hanger 11" from the last elbow of 1" steel pipe. From the elbow (end of branchline?), there is a return bend with a horizontal piece of pipe 9" in length piped to a pendent sprinkler (end of branchline or armover?). Is an additional hanger required in the 20" of pipe mentioned? Below are the two references from the 2010 edition of NFPA 13 that are applicable. The scenario above meets each reference when dealt with separately. The concern is that code appears to want a hanger within 12" of an end of line pendent but wording has left a loophole. Thoughts??
9.2.3.4.4 Unsupported Length with Maximum Pressure Exceeding 100 psi (6.9 bar) and a Branch Line Above a Ceiling Supplying Sprinklers in a Pendent Position Below the Ceiling. 9.2.3.4.4.1 Where the maximum static or flowing pressure, whichever is greater at the sprinkler, applied other than through the fire department connection, exceeds 100 psi (6.9 bar) and a branch line above a ceiling supplies sprinklers in a pendent position below the ceiling, the hanger assembly supporting the pipe supplying an end sprinkler in a pendent position shall be of a type that prevents upward movement of the pipe. 9.2.3.4.4.2 The unsupported length between the end sprinkler in a pendent position or drop nipple and the last hanger on the branch line shall not be greater than 12 in. (305 mm) for steel pipe or 6 in. (152 mm) for copper pipe. 9.2.3.5.2 Unsupported Armover Length with Maximum Pressure Exceeding 100 psi (6.9 bar) and a Branch Line Above a Ceiling Supplying Sprinklers in a Pendent Position Below the Ceiling. 9.2.3.5.2.1 Where the maximum static or flowing pressure, whichever is greater at the sprinkler, applied other than through the fire department connection, exceeds 100 psi (6.9 bar) and a branch line above a ceiling supplies sprinklers in a pendent position below the ceiling, the cumulative horizontal length of an unsupported armover to a sprinkler or sprinkler drop shall not exceed 12 in. (305 mm) for steel pipe and 6 in. (152 mm) for copper tube. Duane Johnson, PE Program Manager Division of the Fire Marshal (Support Contractor) Office of Research Services National Institutes of Health 301-496-0487 "Protecting Science - One Sprinkler at a Time" -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://fireball.firesprinkler.org/mailman/private/sprinklerforum/attachments/20120918/f1389317/attachment.html> _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
