I am not seeing anything in NFPA 13 that says this. Maybe just missing it, but the definition of ceiling height (2013 edition) is 3.3.3. and just mentions "to the underside of the ceiling or roof deck".
If you look at one mfrs spec sheet for k25 ESFR here is what it says. NFPA 13 Deflector-to-Ceiling Distance 6 to 18 inches (152 to 457 mm) FM 2-0 Consult FM and/or FM Guidelines for allowable deflector-to-ceiling distances as well as thermal sensing element-to-ceiling criteria. Note that FM uses the centerline of the thermal sensing element and NOT the deflector. Plus they talk about (somewhere) the width, and maybe the height of the metal deck pockets and give criteria of where to measure from - top or bottom. John Hoffman -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bob Sent: Thursday, March 13, 2014 1:40 PM To: [email protected] Subject: RE: Warehouse Ceiling Question? I think 13 addresses this with 3" and less deep the bottom is the deck, if greater than 3" than the upper part of the channel is the deck. Sorry I don't have time to look up code, but you might want to check my numbers. Thank You, Bob Knight, CET III 208-318-3057 www.Firebyknight.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of G. Tim Stone Sent: Thursday, March 13, 2014 12:32 PM To: [email protected] Subject: Warehouse Ceiling Question? What is the Ceiling in a Warehouse? Scenario: Packaged Steel Frame Building. Red iron frames spaced 30' between. 12" steel Z shaped purlins, spaced 3'-7" on center on top of the Red Iron frames. Steel Q-Deck pan (about 3.5" - 4" deep) attached to top of the Z purlins. High point of the building is 30'-0" AFF, ΒΌ : 12 roof pitch. The building insulation is on top of the Q-Deck. No vinyl insulated blanket that we usually see in warehouse construction. The occupancy is Group A Plastics, High Piled and rack storage, Storage height to 17'-0 AFF, ESFR Pendent Sprinklers, Depending on Manufacture used, deflectors can be up to 18" down below "CEILING". Is the "CEILING" at the point where the Q-Deck that rests on top of the purlin or is it the top of the pocket formed in the Q-Deck? I will rephrase, Is the "CEILING" at the top of the purlin or 3.5" - 4" higher (high point of Q-Decking)? Thank you in advance for clarification. Regards, G. Tim Stone G. Tim Stone Consulting, LLC NICET Level III Engineering Technician Fire Protection Sprinkler Design and Consulting Services 117 Old Stage Rd. - Essex Jct., VT. 05452 CELL: (802) 373-0638 TEL: (802) 434-2968 Fax: (802) 434-4343 [email protected] _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
