While I agree with all of you, if the space is only 25' end to end why not just stick 2 HSW sprinklers in it and move on. If the situation occurs 100 times in a building try talking sense to the AHJ, but if it's only once, life's too short.
Thom McMahon, SET Firetech, Inc. 2560 Copper Ridge Dr P.O. Box 882136 Steamboat Springs, CO 80488 Tel: 970-879-7952 Fax: 970-879-7926 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Roland Huggins Sent: Tuesday, August 26, 2008 3:35 PM To: [email protected] Subject: Re: small ceiling pockets I concur with Mark (and not just because we PE's must stick together) The original proposal was a 12 ft deep pocket. Considering that is basically the height of a story, the committee felt it appropriate to assign a lower value. I would first approach allowing a small increase in height based on the modeling (see out web site for a copy of the report) and the very small volume. Our position has been that ceiling pockets or even openings in a drop ceiling that are narrow and along a wall are not a problem. We have arbitrary picked 12 inches as a maximum width until we do some modeling. I picked this because other than a curtain fire, the center line of the fire plume is not directly against the wall. With it being in the center of the fuel package, even a small chair at 2 ft wide will be at 12 inches form the wall. AS such, a adequate amount of the heat will be captured by the lower ceiling. Naturally discuss this with the AHJ since it has not yet been addressed by the 13 committee. Additionally, as a member of the technical committee i need to say, this is not to be considered a formal interpretation by NFPA or any of its technical committees. Roland On Aug 26, 2008, at 12:01 PM, Mark Sornsin wrote: > I am going to go out on a limb and say "No" this should not require > sprinklers within. Unfortunately, there is nothing absolute to back > me up, at least in NFPA 13. > > I would argue that the ceiling jet from a fire is not going to > 'notice' such a narrow gap. Also, whatever amount of heat manages to > 'escape' into this void space will quickly fill it, due to its > miniscule volume. So I guess I would try to use reason and note that > the ceiling pocket rules of NFPA 13 allow a volume of up to 1,000 > cu. ft. this volume is less than 10% of that. > > But I think the small width of the gap is the bigger reason it won't > affect the activation of the ceiling sprinklers. > > Those in the know may now feel free to rip apart my argument. > > Mark A. Sornsin, PE > Fire Protection Engineer > Ulteig Engineers, Inc. > Fargo, ND > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.138 / Virus Database: 270.6.9/1635 - Release Date: 8/26/2008 7:29 AM _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
