I’m pretty sure those initials after your name mean that you can intelligently evaluate the scenario and suggest an appropriate solution.
-Kyle M From: Fpdcdesign <fpdcdes...@gmail.com> Sent: Friday, January 13, 2023 10:26 AM To: Discussion list on issues relating to automatic fire sprinklers <sprinklerforum@lists.firesprinkler.org> Subject: [EXTERNAL] [Sprinklerforum] Another phantom flow question This is one of my least favorite parts of the standard and the one I most disagree with. I have a canopy that has been added to the front of a daycare center. The footprint of the canopy is about 174 sqft. The construction is wood framed and has a peaked roof with about a 8:12 pitch. The canopy is separated from the main building by a brick and block wall (12” thick) with no openings. My plan is to protect it with a small dry pipe system. The system design consists of 1 branch line with sprigs to 3 sprinklers at the peak and arms to 2 dry pendants for below. The branch line connects directly to the DPV. The way this standard is written, I have to multiply the density by the area. The density is 0.1 and the area is 1500 x 1.3(dry system x 1.3(roof slope) for a total of 2535 sqft. The result is that I need 253.5 gpm minimum. My flow for the 3 sprinklers above the ceiling (greatest demand) is 51.5 gpm. Consequently, I have to add in an additional 202 gpm at some point. The standard (2013) states that the connection shall be “at the point of connection of the branch line to the cross main furthest from the source”. The problem in my case is that there is no cross main. So where should I add the flow? Before or after the DPV? This seems like a ridiculous exercise. The rating of the wall between the canopy exceeds the demand duration of the sprinkler systems on either side. This should be treated as a separate fire area which would make crossover unlikely. How increasing the demand flow by 5 times provides significantly better is beyond my comprehension. Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT 860-535-2080<tel:860-535-2080> (ofc) 860-554-7054<tel:860-554-7054> (fax) 860-608-4559<tel:860-608-4559> (cell)
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