Forum Technical Discussions      Re: Hydrotest of Sphere Posted by: Roger D , E-mail: Address, on December 09, 2008 at 02:31 : In Reply to: Hydrotest of Sphere posted by : Ashish , E-mail: Address, on November 26, 2008 at 15:39 : ----------- Start Original Message ----------- : Dear : We just need to know how much time duration required for doing hydotest of Sphere : Dia - 15.4meters : Regards : Ashish ------------ End Original Message ------------ The standard [& traditional] ASME vessel test time is 10 minutes at overload [the full test pressure with any temperature/mat'l stress corrections figured in]. This is just a 'usual & customary' time. If it's going to fail, it'll happen IMMEDIATLY. Do not allow the pressure gauge(s) to be unattended for even a minute at overload. Spheres vent well, and sunshine on a well vented vessel can cause MAJOR increases in test pressure, just due to the expansion of the water. Some company spec's call for a 1-hour hold at test pressure, but this is just added danger. Overload it, hold it at overload for a very few minutes, drop the pressure down to Design [or a little above Design] & imspect for leaks and other problems. If you're feeling suicidial, do the visual inspection at full Overload. There's a reason that ASME Sect. VIII now recommends waiting until the pressure has been decreased to do the close-up inspection. Follow Ups: Post a Followup: Name: E-Mail: Subject: Comments: ----------- Start Original Message ----------- : : Dear : : We just need to know how much time duration required for doing hydotest of Sphere : : Dia - 15.4meters : : Regards : : Ashish : The standard [& traditional] ASME vessel test time is 10 minutes at overload [the full test pressure with any temperature/mat'l stress corrections figured in]. This is just a 'usual & customary' time. If it's going to fail, it'll happen IMMEDIATLY. : Do not allow the pressure gauge(s) to be unattended for even a minute at overload. Spheres vent well, and sunshine on a well vented vessel can cause MAJOR increases in test pressure, just due to the expansion of the water. : Some company spec's call for a 1-hour hold at test pressure, but this is just added danger. Overload it, hold it at overload for a very few minutes, drop the pressure down to Design [or a little above Design] & imspect for leaks and other problems. If you're feeling suicidial, do the visual inspection at full Overload. There's a reason that ASME Sect. VIII now recommends waiting until the pressure has been decreased to do the close-up inspection. ------------ End Original Message ------------ Optional Link URL: Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP Page Title: is important! Optional Image URL: http://www....gif Attention! Please click the button only once. This may take a moment to process Forum Technical Discussions Help