Fairly certain it’s 10x the diameter required by 4.28, regardless of actual pipe/device sizes in use.
Mike Morey CFPS 3229 • NICET S.E.T. 123677 Project Manager • Fire Protection Group Shambaugh & Son, LP an EMCOR Company 7614 Opportunity Drive • Fort Wayne, IN • 46825 direct 260.487.7824 / cell 260.417.0625 / fax 260.487.7991 email [email protected] [cid:[email protected]] From: Fpdcdesign <[email protected]> Sent: Monday, October 9, 2023 9:07 AM To: Discussion list on issues relating to automatic fire sprinklers <[email protected]> Subject: [Sprinklerforum] Re: [EXTERNAL] Distance to fire pump suction Craig, the 10X does apply, but does the 10X apply to the 6” of the backflow preventer or the 4” of the suction pipe? Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT 860-535-2080 (ofc) 860-554-7054 (fax)860-608-4559 (cell)On ZjQcmQRYFpfptBannerStart This Message Is From an External Sender This message originated outside your organization. ZjQcmQRYFpfptBannerEnd Craig, the 10X does apply, but does the 10X apply to the 6” of the backflow preventer or the 4” of the suction pipe? Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT 860-535-2080<tel:860-535-2080> (ofc) 860-554-7054<tel:860-554-7054> (fax) 860-608-4559<tel:860-608-4559> (cell) On Oct 9, 2023 at 9:02 AM, <Craig Prahl<mailto:[email protected]>> wrote: 4.29.3 Devices in Suction Piping. Where located in the suction pipe of the pump, check valves and backflow prevention devices or assemblies shall be located a minimum of 10 pipe diameters from the pump suction flange. Per the wording in NFPA 20, I’d have to say yes, the 10X rule applies. It all comes back to laminar versus turbulent flow. The check valves can create turbulence. The water flow needs time to “smooth out” before hitting the pump. Craig Prahl | Jacobs | Fire Protection SME – Special Hazards | [email protected]<mailto:[email protected]> | www.jacobs.com<https://urldefense.com/v3/__http:/www.jacobs.com/__;!!KZTdOCjhgt4hgw!-_khxU8gU0_6jc895I7kRbnU8JghRDsWgqOblZ4jr7Qp2IVbR30VYw_hWvNFtphnl0uWpB9KIvbYi1pvZz4$> 1041 East Butler Road Greenville, South Carolina 29606 CONTACT BY: Phone 1-864-676-5252, Email or MS TEAMS From: Fpdcdesign <[email protected]<mailto:[email protected]>> Sent: Saturday, October 7, 2023 10:16 AM To: Discussion list on issues relating to automatic fire sprinklers <[email protected]<mailto:[email protected]>> Subject: [EXTERNAL] [Sprinklerforum] Distance to fire pump suction I have a system with a 6” backflow preventer, which reduces to 4” immediately after. There is approximately 48” of 4” pipe to the suction flange on a 4 x 3 pump. All elbows are turning correctly. Is this sufficient? Does the 10x rule apply to the size of the backflow preventer or the fitting directly attaching to the pump? Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT 860-535-2080<tel:860-535-2080> (ofc) 860-554-7054<tel:860-554-7054> (fax) 860-608-4559<tel:860-608-4559> (cell) ________________________________ NOTICE - This communication may contain confidential and privileged information that is for the sole use of the intended recipient. Any viewing, copying or distribution of, or reliance on this message by unintended recipients is strictly prohibited. If you have received this message in error, please notify us immediately by replying to the message and deleting it from your computer. _________________________________________________________ SprinklerForum mailing list: https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org<https://urldefense.com/v3/__https:/lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org__;!!FaxH778!e07b4ZXCTr3mkRQbRrZS533IOhxVbV96VNG87PnJl3X8JaPFMQ22htdpvDODER_xJbhp_UGvB5hUZLGkl1I$> To unsubscribe send an email to [email protected]<mailto:[email protected]> This message is for the named person's use only. It may contain confidential, proprietary or legally privileged information. No confidentiality or privilege is waived or lost by any mistransmission. If you receive this message in error, please immediately delete it and all copies of it from your system, destroy any hard copies of it and notify the sender. You must not, directly or indirectly, use, disclose, distribute, print, or copy any part of this message if you are not the intended recipient.
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