Grating is grating. It deflects and is an obstruction to the sprinkler spray pattern. Heads need to be below.
Open grid ceilings are a different animal as they typically occur moreso in light or possibly ordinary hazard occupancies. Ceilings are one thing and floor grating is another. Don't confuse the two. If you have 2007, look at 8.5.5.3.3 and A.8.5.5.3. 8.5.5.3.3* Sprinklers installed under open gratings shall be of the intermediate level/rack storage type or otherwise shielded from the discharge of overhead sprinklers. Commentary: FAQ:Where open grating is utilized, are additional sprinklers required below the open grating? Sprinklers installed under open gratings are addressed in 8.5.5.3.3. Although open grating allows heat from a fire to pass through it and reach a sprinkler, the openings are not adequate to compensate for obstructions to the sprinkler spray pattern. Thus, supplemental sprinklers under the open grating deck are necessary. Gratings or slatted decks and walkways are frequently covered with goods in storage or by a light surface dust stop. Sprinklers are required under such gratings and walkways. Sprinklers located below the open grating must be provided with a water shield or be of the intermediate level/rack storage type to prevent water from sprinklers that are operating above from wetting the thermal element and delaying sprinkler operation. Craig L. Prahl, CET Fire Protection Specialist Mechanical Department CH2MHILL Lockwood Greene 1500 International Drive PO Box 491, Spartanburg, SC 29304-0491 Direct - 864.599.4102 Fax - 864.599.8439 [email protected] http://www.ch2m.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of George Medina Jr Sent: Tuesday, April 13, 2010 7:06 PM To: [email protected] Subject: Grating What is the dimensions of grating when sprinklers are required underneath? I looked under NFPA-13 (2007 ed.) index for Grating and found no specifications. . George Medina Jr. = _______________________________________________ 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) _______________________________________________ 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)
