While I see allowable offsetting in all directions via rotation within those couplings necessary, it would appear that before some couplings will rotate, a moment arm must be created into which the strain can be transferred or it may manifest itself into a coupling in a prying fashion coaxially to Pipe A or B instead of the intended rotation about each axis A or B.
That being said, it should be noted that the couplings are all indicated to be flexible allowing for the coaxial misalignment within the listing of the coupling and of note is the dashed line on Pipe B indicating a "vertical movement" offset in the Elevation View. While perhaps not clearly defined, it appears to me that this detail is intended for vertical misalignment as well where the 'lateral movement' indicated in the lower horizontal view is also valid and would function the same regardless of initial orientation/rotation about the axes of Pipes A and B. My two cents, Ryan L. Hinson, PE*, SET** \ Burns & McDonnell Senior Fire Protection Engineer O 612-900-3755 \ M 763-688-4045 \ F 952-229-2923 [email protected] \ burnsmcd.com 8201 Norman Center Drive, Suite 500 \ Minneapolis-St. Paul, MN 55437 *Registered in: AK, LA, MD, MN, PA, TX, & UT **NICET IV - Water-Based Systems Layout -----Original Message----- From: Sprinklerforum <[email protected]> On Behalf Of Steve Leyton via Sprinklerforum Sent: Tuesday, October 19, 2021 11:46 AM To: [email protected] Cc: Steve Leyton <[email protected]> Subject: Seismic joint detail A question was raised by a project structural engineer about the NFPA 13 seismic joint detail shown in Fig. A.9.3.3(a), 2016 edition for reference. Does anyone know if this configuration has ever been tested/measured? Has it been verified as an acceptable OMNI-DIRECTIONAL solution? The engineer in question is looking at the detail and in his judgement, it's only a 2D solution. There are lateral and longitudinal movements shown, but not a vertical one. If there are installation or hanger/bracing committee people who can chime in, I'm wondering if this figure has been vetted and that's why it's still in the standard. Bottom line: Is Fig. A.9.3.3(a) equivalent to a listed seismic loop? Steve Leyton, President Protection Design and Consulting T | 619.255.8964 x 102 | https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.protectiondesign.com%2F&data=04%7C01%7Crhinson%40burnsmcd.com%7C8fe0e8835f7145371f4b08d9931fe500%7Cbfbb9a2b6d994e78b3c795005d555c8b%7C0%7C0%7C637702588200958346%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=DbzlEEtPV0OT%2B5LPlW0A5uTavKmNFWb%2BOZdjtUZAT7E%3D&reserved=0<https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.protectiondesign.com%2F&data=04%7C01%7Crhinson%40burnsmcd.com%7C8fe0e8835f7145371f4b08d9931fe500%7Cbfbb9a2b6d994e78b3c795005d555c8b%7C0%7C0%7C637702588200958346%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=DbzlEEtPV0OT%2B5LPlW0A5uTavKmNFWb%2BOZdjtUZAT7E%3D&reserved=0> 2851 Camino Del Rio South | Suite 210 | San Diego, CA 92108 Fire Protection System Design | Consulting | Planning | Training _______________________________________________ Sprinklerforum mailing list [email protected] https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.firesprinkler.org%2Flistinfo.cgi%2Fsprinklerforum-firesprinkler.org&data=04%7C01%7Crhinson%40burnsmcd.com%7C8fe0e8835f7145371f4b08d9931fe500%7Cbfbb9a2b6d994e78b3c795005d555c8b%7C0%7C0%7C637702588200963324%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=YhwXusAFof3CK6z9VugBg8I%2F90VryPRzBeeKJ3NVPIo%3D&reserved=0 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
