Support of High-Temp Piping

high-temp piping is supported via full-encirclement saddles welded completely at each end with low-hydrogen. Welds crack in the roots all the way around. This has never resulted in a leak, but has the potential to allow moisture under the saddle resulting in corrosion during down-time (piping is outdoors)and could conceivably crack into the pipe (900 psi @ 650F). Is there another way to satisfy DOT 49CFR 192 (this is natural gas) and avoid the potential for cracking? Does B31.3 govern and overrule DOT because this is piping in a plant and not actual line pipe? DOT doesn't addres situations over 450 F. Received on Wed Oct 08 14:50:00 2003