Perhaps you could use this and run a quick calc? I can't imagine a 3" isn't adaquite for 5 heads??? 13,2007
11.2.3.3.6 Where the room design method is used and the area under consideration is a corridor protected by a single row of sprinklers with protected openings in accordance with 11.2.3.3.5, the maximum number of sprinklers that needs to be calculated is five or when extended coverage sprinklers are installed, all sprinklers contained within 75 linear feet (22.9 linear meters) of corridor. 11.2.3.3.7 Where the area under consideration is a corridor protected by a single row of sprinklers with unprotected openings, in a light hazard occupancy, the design area shall include all sprinklers in the corridor to a maximum of five, or when extended coverage sprinklers are installed, all sprinklers within 75 linear feet (22.9 linear meters) of the corridor. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Doug Hicks Sent: Wednesday, January 12, 2011 9:15 AM To: [email protected] Subject: Re: Hydraulic Calcs The dry pipe protects the overhang of a walkway, no attic. the original install is about 20 years old. About 6 years ago, 2 more low hazard buildings were built and the dry pipe system was extended. The 2 new buildings are each protected by a separate wet system. All the fire water comes from the original street connection. The extension increased the protected area about 35-40 %. I assume hydraulic Calcs were done by a licensed person. I tried to type that with a straight face. No increase in pipe sizes were done. I do not know what edition of 13 was used for any of the sprinkler work. I doubt that any water supply information is on file anyplace. So if Calcs are needed, I will have to have a qualified person do that for me. My local AHJ allows do whatever I want. So the decision will be up to the client and his engineer. I will print this out, we have a meeting at 9:00 AM. After the meeting I am sure I will have more questions. -----Original Message----- From: Todd Williams Sent: Wednesday, January 12, 2011 4:06 AM To: [email protected] Subject: Re: Hydraulic Calcs Are you replacing only the 3" pipe or branch lines and heads as well? Was the existing system hydraulically calculated or pipe schedule? How old is the system? Depending on the age of the existing system, new hydraulics could open cans of worms. If it is pipe schedule, the system has probably never been calculated so there is no indication of how the hydraulics looked in the first place. If it has been calculated, was the 30% increase for dry systems, 30% increase for roof slope and the new(er) minimum end head pressures included? If not, you may not have an adequate system, based on current Code. But it may have been fine when it was installed. Is there a compelling reason to bring this attic up to current Code? This probably needs to be hashed out between you, the Owner, Engineer and AHJ. I hope your quote included a provision so you get extra $$ if the pipe sizes increase due to the hydraulics. At 02:10 AM 1/12/2011, you wrote: >I am bidding on removal and replacement of an existing dry pipe system. >This is about 1,000 feet of 3 inch. Part of the specification is >“Contractor shall submit working plans that have been approved by >authorities having jurisdiction, including hydraulic calculations, prior to >starting work.†Is it normal to have new calculations done when just >replacing rusting pipes? If so, where do you draw the line at needing new >calculations? There has been new construction, since the building was >built. Three new low hazard buildings have been built, with a new low >hazard rehabilitation facility going in a block down the street. >_______________________________________________ Sprinklerforum mailing list >[email protected] >http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For >Technical Assistance, send an email to: [email protected] To >Unsubscribe, send an email to:[email protected] (Put >the word unsubscribe in the subject field) Todd G. Williams, PE Fire Protection Design/Consulting Stonington, CT 860.535.2080 www.fpdc.com _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
