The swing joints are not installed in the plane parallel with the piping, they are already "hanging down". Provide hangers on the main before the assembly per 9.3.3.3 and let it ride. However Figure 9.3.3(a) references 4" pipe and owing to the fact that we're talking about an 8" pipe, this assembly might not be suitable.
I prefer the Metraflex because I have doubts about the ability of the multi-elbow assembly rotating properly if there would be vertical movement in the system. Longitudinal and horizontal movement would appear to present no issues but vertical, just not sure about that especially in older systems where everything has gotten a bit rusty and crusty. As stated by others, Metraflex does have an option for an intermediate hanger for large assemblies. According to text within the 2013 NFPA 13 commentary, the assembly doesn't have to be "Listed" just approved by the AHJ. (see 9.331) NFPA 13 Handbook, 9.3.3: Several listed flexible piping assemblies, such as the one shown in Exhibit 9.16, are now available that can be used as seismic separation assemblies where they provide the intended flexibility. The provision of intended flexibility means that the assemblies must be designed to allow full closure of the seismic separation, opening of the seismic separation to twice its original width, and offsets in both the vertical and horizontal planes equal to the width of the seismic separation. There is no requirement that a listed device be used for this purpose, but the piping configuration to be used as a seismic separation assembly must be approved by the authority having jurisdiction. 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$> 1041 East Butler Road Greenville, South Carolina 29606 CONTACT BY: Phone 1-864-676-5252, Email or MS TEAMS From: James Crawford <[email protected]> Sent: Wednesday, July 19, 2023 5:13 PM To: [email protected] Subject: [EXTERNAL] [Sprinklerforum] Hangers on Seismic swing joint NFPA #13 (2013) 9.3.3 Seismic Separation Assembly There has been some discussion between the designers and the field staff on whether you can put a hanger on anything other then the pipes shown as "A" & "B" on Figure A.9.3.3(a) Background 8" feed main crosses the seismic separation. Field staff say that due to the weight of the pipe and the flexible fittings, a hanger is required to stop it from swinging down. Office staff say no hanger as it would defeat the purpose of the swing joint as it would restrict movement. Comments or background either way as we can find nothing in the code for either option. Thank You James Crawford Phaser Fire Protection Ltd. Phone 604-888-0318 Cel: 604-790-0938 Email [email protected]<mailto:[email protected]> Web: www.phaserfire.ca<https://urldefense.com/v3/__http:/www.phaserfire.ca__;!!B5cixuoO7ltTeg!Cr8UrCVYZaFcwrvus53nL6wjN-HdDghH1rSpU0CtOkcXSOUVt-m7b188O3zysJo8MgR7cCoky42B-ZtQDPuu6Q4P6A$> ________________________________ 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.
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