The big advantage of wet pipe systems is not just the delay waiting for water at the nozzle as air, compressed by the water, blows off. It is all the junk in the system clogs up the nozzle. This can be so extensive that flow almost stops. Having a Dodge Charger Hotwheel in your nozzle, backed up by cigarette butts does not make your spray pattern more effective.
Or the system may open to the atmosphere somewhere. Wet systems leak right away when compromised. So how far does the hose team advance the dry hose line towards the fire before they charge it? How much confidence do they have that a decent, protective, hose stream is about to derive? Best Bruce Verhei > On Aug 30, 2017, at 09:45, Steve Leyton <[email protected]> wrote: > > From my perspective, the intent of the building code allowance for dry > standpipes is to accommodate a broad range of exposures to freezing. It > would be silly to run wet pipe through an area subject to freezing in order > to supply a single floor’s hose connections, and you’d have to valve the roof > manifold(s) to hold back water from exposure as well. Since I don’t live in > a place that’s subject to freezing, I’ve never personally had to address this > condition, but if I did I’d run a manual dry all the way. > > The foregoing is my opinion only and is not intended to represent the NFPA 14 > Technical Committee, nor serve as an interpretation of the standard. > > Steve Leyton > Protection Design & Consulting > San Diego, CA > > > > > From: Sprinklerforum [mailto:[email protected]] > On Behalf Of [email protected] > Sent: Wednesday, August 30, 2017 6:16 AM > To: [email protected] > Subject: Standpipe question > > (3) sty sprinklered building > 1st and 2nd floor are un-heated parking garage > 3rd floor is office > > I'm not sure if a manual dry can still be used if top floor is heated > IBC 905.8 permits dry stdp in areas subject to freezing in accordance with > nfpa 14 > NFPa 14 , 2003 5.4.1.4 says CL I systems shall be wet except where subject > to freezing > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
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