Jimmy, Attic design has been a real pain in the backside ever since NFPA 13 created the special criteria. I'm not ragging on the new criteria - changes were needed because the standard spacing rules didn't adequately protect typical attic spaces. But none the less, the new criteria can make you pull your hair out.
The short answer: in some attic spaces (particularly narrow spaces with multiple slopes), you can't follow all the criteria. You and the AHJ are forced to make an engineering judgment call as to what criteria to meet and what criteria to let slide. And, no, 'attic sprinklers' aren't the magic bullet if the space isn't framed per the sprinklers listing. The longer answer and a bit of a soapbox: Did I say engineering judgment call? It's a good thing all us designers (ops, a politically incorrect term) and AHJ's are PE's. Otherwise we wouldn't be allowed to make an engineering judgment call. Unfortunately, we don't have a choice so we do the best we can - just don't let your insurance company know. Personally, I place a higher priority on the location and spacing of sprinklers that are away from the eave, and a lower priority on the location & spacing of sprinklers near the eave. I'd love to submit a proposal for the next 13 revision, but I really don't know how to fix it. I can envision an attic design criteria ballooning from 4 paragraphs (07 edition) to a dozen or so. Making it more complicated is not the answer, but forcing designers (with greatly varying degrees of engineering aptitude) to make an engineering judgment call isn't the answer either. Ed Kramer Littleton, CO > Good Monday morning (at least out west) to all. I have a question I'd > like > to pose. It is both practical and somewhat hypothetical. This sort of > relates to a question from the other day, and I didn't really catch the > general consensus of the group. Anyway, on to the predicament. In an > attic > space, or open wood truss space, with a pitch of 4 in 12 or greater, > 8.6.4.1.4.3, dictates a minimum of six feet from the eave, measured > along > the slope. What do you do when you have a hip at one end of the > building? > For example, I have a project where to maintain the six feet from the > eave, > I must be 5'-8.25" from the eave, measured horizontally. This distance > leaves me 8'-5" from the corner of the building before crossing the hip, > and > being under a different slope. What about this uncovered area? Do you > violate the rule with one sprinkler and pitch it to cover both areas? > Do > you violate the rule with two heads and install a baffle? Does NFPA > have > any recommendations? Do the experienced designers have any > recommendations? > Hopefully I explained this all well enough for everyone to understand. > I > would be more than happy to send a .pdf to anyone interested in > contacting > me off-line. > > > > Thanks, > > > > Jimmy Waite > > Burtell Fire Protection, Inc. > > [EMAIL PROTECTED] > > (406) 652-7697 _______________________________________________ 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)
