Roland, Thanks for your guidance. However, with all respect, I disagree about the mix-up. According to 8.5.7 a sky light is a ceiling pocket, considering the wording "sky lights and similar ceiling pockets". (A sky light is a ceiling pocket, but not every ceiling pocket is a sky light.)
This is how I see it: In the case of the hall in concern we have Standard Upright Spray Sprinklers (chapter 8.6) and sky lights (= ceiling pockets) less than 914 mm deep. Ergo: section 8.6.7 applies and if the 7 conditions are met par. 8.6.7.2 applies too. All sprinklers in the hall are QR sprinklers. The sky lights are less than 914 mm deep. Each sky light is less than 4.5 m3. Every 5 or 6 sky lights make up a cluster. Spacing between the sky lights within a cluster is approx. 1 m. Each cluster is less than 28.3 m3. Spacing between clusters is more than 3.05 m. The covers are all safety glass. Your comparison of a smoke/heat vent with a plastic cover was enlightening for me. Indeed, size matters. Frans Stoop TOS architecture & fire protection Netherlands Tel. +31-24-324 0112 At 11:44 15-9-2009 -0700, you wrote: >You are mixing together your terms and it has a huge impact. You say >CEILING POCKET and reference 8.6.7 but then ask about SKY LIGHTS. > >If you really mean ceiling pockets. Considering that the omission of >sprinklers was predicated upon QR sprinklers in the lower ceiling with >a pocket activating faster than SR sprinklers in a flat ceiling and >with smoke/heat vents activated by smoke detectors will open the >pockets thus stopping ay activation of sprinklers in the lower >ceiling, I suspect the answer is self evident. One could question >whether the sprinkler in the pocket operate faster than the smoke >detector outside the pocket but I don't think that changes the answer. > >If you mean skylights: 8.5.7 allows plastic covers which are expected >to fail early in the fire which sounds a lot like a smoke/heat vent >opening early by detectors. > >The bottom line is that size matters. > >Roland > >On Sep 14, 2009, at 7:14 AM, Frans Stoop wrote: > > > Gentlemen, > > > > A client intents to build a large hall for public transportation. > > There are no cars, buses or trains in the hall itself, just plain > > walking area (interchange). > > The hall will be protected by dry pipe systems (OH1), because > > freezing can happen inside. > > Any shops and commercial booths inside, where storage might occur, > > will all be protected by a wet pipe system (OH2). > > The roof of the hall has sky lights, from which we omitted sprinklers > > in compliance with NFPA 13-2007 section 8.6.7 Ceiling Pockets. > > The covers of the sky lights are non-plastic. The shops and booths > > have no sky lights. > > > > Initially there were no heat and smoke vents required, but the > > starting-points of design have changed: > > Now the sky lights will also be used as heat and smoke vents, because > > the fire marshal requires them. > > Moreover, the heat and smoke vents will be triggered by smoke > > detectors and have to open-up before the sprinklers respond. > > > > Question: > > Can we still omit sprinklers from the sky lights? > > In section 8.6.7 there is no reference to vents. > > I know that for the performance of the sprinkler system it is better > > to delay the operation of heat and smoke vents until after the > > sprinklers have responded. > > > > Thank you in advance for sharing your insight. > > > > Frans Stoop > > TOS architecture & fire protection > > Netherlands > > Tel. +31-24-324 0112 _______________________________________________ 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)
