Jerry, I've seen situation where they added thicker insulation at the ridgeline to account for a few inches of height. If it's a relatively small area that's over 30 feet, that might be a cost-effective solution.
I believe that you can use the design criteria (head pressure) for the roof height in the area of the building that you are in. You typically have to extend the higher criteria 15 feet past the point where the ceiling height changes. In your case, you could use the 35-foot criteria and extend that 15 feet past the breaking point where it drops under 30-feet. In your case, if the beam acts as a sort of draft stop, maybe you can just draw the line there rather than extending it. I'm not certain on the spacing, but I don't see why you couldn't do that. Calcs can be weird if the different criteria is part of the same system, but it might be easier if you are using a beam as the separation rather than just a point where the roof height changes. -Kyle M From: Sprinklerforum [mailto:[email protected]] On Behalf Of Mike Hairfield via Sprinklerforum Sent: Tuesday, August 20, 2019 4:52 PM To: [email protected] Cc: Mike Hairfield <[email protected]> Subject: [EXTERNAL] Re: ESFR Sprinklers Spacing and Height Criteria No and No ________________________________ From: Sprinklerforum <[email protected]<mailto:[email protected]>> on behalf of Jerry Van Kolken via Sprinklerforum <[email protected]<mailto:[email protected]>> Sent: Tuesday, August 20, 2019 7:51 PM To: [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>> Cc: [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>> Subject: ESFR Sprinklers Spacing and Height Criteria **I know this is something I would need to get a waiver on by the AHJ. 1. I have a building just over 30'-0" by 4" does anyone how critical these 4" are, if the 30'-0" criteria were used? 1. Also the building has Wide Flanges beams sectioning off the Roof. Could one use the under 30'-0" spacing criteria (12'-0") in these lower bays even if it is still the same room as the high roof? Jerry Van Kolken Millennium Fire Protection Corp. 2950 San Luis Rey Rd. Oceanside, CA 92058 (760) 722-2722 FX 722-2730
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