Logic? NFPA 13? Considering the exception to section 11.2.3.1.8 (3) only encompass 5 of the 14 situations described in 8.14.1.2, my guess would be that the 3000 sqft requirement would apply.
At 10:09 PM 5/7/2009, you wrote: >No takers for my original questions. So let me try again. > >16" deep TJI's (composite wood construction). Sprinklers can be upto 6" >below the bottom of the TJI's and comply with NFPA for obstructed >construction. Same scenario, but with drywall or insulation at the bottom of >the TJI's forming an unsprinklered combustible space. Does it trigger the >3000 sq.ft. design? If it does, I fail to see the logic. > >Tony > >-----Original Message----- >From: [email protected] >[mailto:[email protected]] On Behalf Of A.P.Silva >Sent: May 5, 2009 2:41 PM >To: [email protected] >Subject: Combustible crawlspace > > >A crawlspace comprising of a wood deck, 16" deep TJI's and open space below >the TJI's. Between the TJI's there is batt insulation, kept in place with >wire mesh attached to the bottom flanges of the TJI's. The insulation is >only couple of inches (approx) thick and doesn't fill the entire TJI space. >The crawlspace is 1 foot deep at the perimeter and 4 feet at the centre of >the building. The depth is from bottom of the TJI's to the ground. The >crawlspace is being sprinklered. > >Questions: > >(1) Are the pockets formed by the TJI's and insulation have to be >sprinklered? If there was no insulation, the sprinklers could be below the >bottom of the TJI's due to obstructed construction. The pockets are less >than 160 cuft in volume, but there is no non-combustible or limited >combustible ceiling at the bottom. Just non-combustible insulation and wire >mesh. My opinion is the insulation can be ignored. The sprinklers will be at >the permitted distance below the deck, so the pockets don't have to be >sprinklered and the 3000 sq.ft. design is not required. Anyone disagree? > >(2) The height below the bottom of the TJI's vary from 1 foot to 4 feet. Are >combustible concealed space sprinklers required? (using NFPA 13, 2007) I >don't think it will be a good design to have them only at the perimeter and >standard heads at the centre. Section 8.15.1.7 states that the listed >sprinklers are "permitted" to be used to protect composite wood joist >construction less than 36" "between the top of the bottom joists and bottom >of the upper jpists". (In other words the depth of the TJI's. Could this be >a mistake, as the TYCO cut sheets show this distance from the bottom of the >TJI's to the ceiling). In anycase, it appears that the listed heads don't >have to be used for composite wood joist construction, due to the use of the >word "permitted". Anyone agree/disagree? > >Sub-questions: > >(3) If the construction was combustible wood truss or joists, the listed >sprinklers may have to be used, depending on the height of the space. What >happens when the height varies such as in my case? > >(4) NFPA imposes the requirement of cc sprinklers depending on the depth of >the space. However, Tyco imposes other restrictions, such as maximum 54" >from deck to deck for solid wood joist consruction. What happens if Tyco >requirements are not met, and the listed heads are required by NFPA? > >Tony > >_______________________________________________ >Sprinklerforum mailing list >http://lists.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 >http://lists.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, Connecticut www.fpdc.com 860.535.2080 _______________________________________________ Sprinklerforum mailing list http://lists.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)
