Yeah, the 12" armover limit goes away when using flexible sprinkler connections. It's in the code:
NFPA 13, 2022 Edition: 17.4.3.4.4.4 "Unless flexible hose fittings... are used..." Actually, now that I read that, it just says that you aren't required to use hangers that restrain the pipe from upward movement but doesn't explicitly state the 12" limit goes away. But I understand that is the intent. >From a practical standpoint, the directive is achieved by the flex >connection's bracket. Maybe an opportunity to clean up the language a bit in the next cycle. -Kyle M From: Matt Grise <[email protected]> Sent: Friday, May 12, 2023 6:19 AM To: Discussion list on issues relating to automatic fire sprinklers <[email protected]> Subject: [EXTERNAL] [Sprinklerforum] Re: Flex Drops in excess of 100psi It was my understanding that the arm over requirements were to mitigate the increased jet effect of the sprinkler at high pressure. I would imagine that the bracket for the flex drop would control that issue. As long as they are rated for the pressure you want. Matt From: [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>> Sent: Thursday, May 11, 2023 11:41 AM To: [email protected]<mailto:[email protected]> Subject: [Sprinklerforum] Flex Drops in excess of 100psi Having an internal discussion, and the thought came up.., Are there any discussions or considerations on the reduced arm over length when pressure is above 100psi? In other words, since the common flex fittings are rated to 175psi in a bracket, attached to a ceiling assembly, can we go to 36" for 1" with more than 100psi at the sprinkler? I know as written you cannot. But was wondering if this had been brought up. R/ Matt
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