8.5.2.1.1 of the 2016 edition of NFPA 13 covers how to determine the area covered by a sprinkler. This seems to be pretty straightforward, but I’ve noticed some strange wording. Consider a building with exposed structure and some beams that are deep enough to be obstructions, 36” as an one example.
For spacing between branch lines, the standard says “Determine perpendicular distance to the sprinkler on the adjacent branch line (or to a wall or obstruction in the case of the last branch line) ...” I understand the reference to last branch line when referring to a wall, but not with respect to an obstruction. Similar language exists for spacing along the line. Is this just poor wording, or is it really the intent not to allow measurement to an obstruction if not the end line or sprinkler? I have a case where a deep beam requires an additional line. The designer has spaced heads closer together on the line that is further from the beam, so calculating head spacing times twice the distance to the beam results in an area of less than 100 sq ft (this is extra hazard). However, if the intent is to use the distance to the next line (and ignore the beam) then the area is over 100 sq ft. I think the layout meets the intent, but am interested in other opinions. Sent from my iPad Christopher H. Born, P.E. Director, Fire Protection Engineering|Principal Clark Nexsen 4525 Main Street, Suite 1400 Virginia Beach, VA 23462 (757) 455-5800 (757) 961-7933 (direct) (757) 644-8581(mobile) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.firesprinkler.org/private.cgi/sprinklerforum-firesprinkler.org/attachments/20180308/c689782f/attachment.html> _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
