Joe, The AHJ's interpretation sounds incorrect. What is supposed to take place is as follows: 23.4.4.2.5 Where the total design discharge from these operating sprinklers is less than the minimum required discharge determined by multiplying the required design density times the required minimum design area, an additional flow shall be added at the point of connection of the branch line to the cross main furthest from the source to increase the overall demand, not including hose stream allowance, to the minimum required discharge.
In other words, we are now required to add additional flow to calculations when we are in a situation like yours. The minimum required flow for a 1500 sf design area for OH1 is 210 gpm, and the minimum required flow For 1950 sf is 292.5 gpm. If your areas are not flowing these minimus you will need to add the additional flow as stated above. It's a pain in the neck but other than one more step in the calc that's it. Thank you, Bob Knight, CET III Fire by Knight, LLC 208-318-3057 -----Original Message----- From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On Behalf Of Joe Burtell via Sprinklerforum Sent: Thursday, February 11, 2021 11:47 AM To: sprinklerforum@lists.firesprinkler.org Cc: Joe Burtell Subject: Multiple System Calculation I have a situation where an engineer is telling me I have to calculate a wet and dry system together because neither space meets the 1500 s.f minimum. I have a penthouse mechanical room OH 1 (WET) of 1014 s.f. and an adjacent room OH1 (DRY) of 469 s.f. I have calculated each room separate of each other. There is a full-height wall with a door that separates the rooms. The wall and door are not fire rated, so the large room method is out. This does not make any sense to me. Any sections that would require this to be done. He is saying 11.1.2 of NFPA 13 2016 requires it. I argue exception #2 says it does not apply. Best regards, *Joe Burtell, SET, CFPS* [image: Burtell Fire_Small] Phone | Fax | Mobile| Text *406-204-4653 <++1-406-204-4653>* 116 N. 11th Street | Billings, MT 59101 Email: j...@burtellfire.com Web Site: http://www.burtellfire.com *“**The bitterness of poor quality remains long after the sweetness of low price is forgotten.**”* *NOTICE:* The information contained in this e-mail transmission is intended only for use of the individual or entity named above. This e-mail transmission, and any documents, files, previous e-mail transmissions or other information attached to it, may contain confidential information that is legally privileged. If you are not the intended recipient of this e-mail transmission, or the employee or agent responsible for delivering it to the intended recipient, you are hereby notified that any disclosure, dissemination, distribution, copying or other use of this transmission or any of the information contained in or attached to this e-mail is strictly prohibited. If you have received this e-mail transmission in error, please immediately notify us by return e-mail transmission and destroy the original e-mail transmission as well as its attachments without reading or saving it in any manner. Thank you. _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
