Chris, point well made and well taken. To rephrase my earlier post, if a 3000 sf DA is required for SS sprinklers, I can think of no justification not to require it for residential sprinklers. On the other hand, if the 3000 sf DA is overkill for SS sprinks, then it's probably overkill for residentials as well. Regardless, I think both types of sprinklers should be treated the same in regards to the increased DA.
Given the right conditions, a given building with dwelling units could be protected using SS sprinks with a DA of 3000 sf. The same building could be protected using residentials while calcing 4 sprinks. 3000 sf may be overkill, but calcing 4 sprinks just doesn't equate to property protection to me. Maybe something in the middle is reasonable - say 1500 sf w/reduction for low ceiling ht. Thinking out loud, Ed Kramer Littleton, CO > The only point you didn't take into consideration is the 3000sf has no > correlation to property protection. As I understand it, it was a WAG > years > ago before the current emphasis on testing and data to make changes. > There > is no experience or testing that I have heard of that justifies this > requirement. Seems to me there was a time in the mid 90's where some > lobbied to take it away. Of course they didn't have data or testing to > show > it served little value either so it remains. > > Let's face it for the most part we are talking about fire above a > ceiling > above the sprinklers, right. Sprinklers don't spray up very well > especially > through ceilings these days. > > I was involved in a fire of this nature in a sprinklered building. My > notes > from the day: > > Occupant cutting away old pipes with torch. Noted a small hot > spot/fire in the fiber board ceiling. Occupant sprayed water on area. > 14 hours later passer by noted smoke coming from roof. Fire all above > ceiling in joist space where no sprinklers are required nor present. > About 10 heads operated through the course of the fire. 4 in the > immediate area of the origin. The others in a sporadic fashion. > Sprinkler monitoring had been turned off for quite some time. > > To gain control of the fire we had to shut the system off. It was > rather > problematic to work through the ceiling while in the down pour of > sprinkler > water. Granted this was a poor example in that there was not much to > burn > on the floor. But either way there wasn't much drop down even had there > been stuff on the floor. As I saw it the only value of the sprinklers > was > heat detector with water (vs. electrons) as the signal transfer medium > based > fire alarm system. Go look for that in NFPA 72. I'm convinced had the > monitoring been present even with combustibles below this would have > been a > 1 or 2 head fire and we'd still have shut off the sprinklers to get at > it. > > > Chris Cahill, P.E. > Fire Protection Engineer > Sentry Fire Protection, Inc. > > 763-658-4483 > 763-658-4921 fax > > Email: [EMAIL PROTECTED] > > Mail: P.O. Box 69 > Waverly, MN 55390 > > Location: 4439 Hwy 12 SW > Waverly, MN 55390 > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Ed Kramer > Sent: Friday, April 18, 2008 11:30 AM > To: [email protected] > Subject: RE: NFPA 13 Building with residential heads > > I'll chime in with my opinion. > > Does 13 REQUIRE the 3,000 sf DA? The section that requires the 3,000 sf > DA > [11.2.3.1.4(3)] is part of section 11.2 "Occupancy Hazard Fire Control > Approach". Residential sprinkler design is a separate section (11.3.1) > and > is not subject to the requirements of section 11.2. > > SHOULD 13 require the 3,000 sf DA? The underlying premise of 13 is > property > protection. Allowing residential sprinklers to be used in dwelling > units > adds to the life safety aspect of the system, but its' still primarily a > property protection system. For that reason, I can't believe it's the > INTENT of 13 to not require the 3,000 sf DA. Property protection is > property protection, whether the sprinkler used is a SSP or residential. > That's the exact reason why a .10 gpm/sf density is required when using > residential sprinklers. So even though I don't think the 3,000 sf DA is > required, I think it should be. > > Exit soapbox, stage right. > Ed Kramer > Littleton, CO > > > > NFPA 13 (07ed) > > > > I am designing a sprinkler system for a Hotel that falls under NFPA > 13. > > The floors containing the residential units have a combustible > concealed > > space > > that does not require sprinklers (8.15.1.2.6) but does not qualify for > > the 3000 sq ft > > exemption of 11.2.3.1.4 (4) for unsprinklered combustible concealed > > spaces. > > If I am using residential sprinklers, are they exempt from this rule > > because they are > > a specific application sprinkler and not an area/density or room > design > > method? > > Thanks, > > Dewayne > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > To Unsubscribe, send an email to:Sprinklerforum- > [EMAIL PROTECTED] > (Put the word unsubscribe in the subject field) > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > To Unsubscribe, send an email to:Sprinklerforum- > [EMAIL PROTECTED] > (Put the word unsubscribe in the subject field) _______________________________________________ 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)
