Forum Technical Discussions      Re: 2.5' x sch.80 Posted by: Juan Amado , E-mail: Address, on November 14, 2008 at 15:49 : In Reply to: Re: 2.5' x sch.80 posted by : tj , E-mail: Address, on November 14, 2008 at 13:54 : ----------- Start Original Message ----------- : : i am new in NDT and was given a task to shoot a 2.5" x sch.80 pipe. Can someone give me an idea on how to shoot this? Does a DWSI with the snout in contact w/ the pipe suitable or do i have to shoot it in a distance and do i have to use a number tape or just a simple A B and C? : : Thank you for your comments. : Are you looking at the pipe or a weld? If it is weld you can come in contact with the pipe for single wall viewing. You can back the source off and superimpose the walls. You can also elipse the weld with the proper source angle at a distance instead of superimposing. This is, of course, if the applicable code allows this. Number belts are useful but not required for most applications. As for letters or numbers, an agreement should be reached with your customer if not specified. ------------ End Original Message ------------ Here’s an example: for 2 ˝” sch 80 pie, with a thickness = 0.276”, and an O.D. = 2.875”, A source with a focal spot of 0.111”, using the general requirements of ASME BPV code and a bunch of other assumptions… You could go either of two ways (in general): For Double Wall Single Exposure and complying with a Geometric Unsharpness (Ug) = 0.02” a Source to Object distance of D=(0.111)(.276)/0.02=1.53” would be required. Since the O.D of the pipe is larger than this (e.g. 2.875”), you could rest the source against the pipe and would have more than enough distance for a good shot. For Double Wall Double Exposure and complying with a Geometric Unsharpness (Ug) = 0.02” a Source to Object distance of D=(0.111)(2.875)/0.02=15.95” would be required. This is so because you need to have both sides of the weld (the one closest to the film and the one farthest from the film to comply with the Ug), so the Ug calculation has to take into account the size of the whole object (pipe). Hope this works for you. Follow Ups: Post a Followup: Name: E-Mail: Subject: Comments: ----------- Start Original Message ----------- : : : i am new in NDT and was given a task to shoot a 2.5" x sch.80 pipe. Can someone give me an idea on how to shoot this? Does a DWSI with the snout in contact w/ the pipe suitable or do i have to shoot it in a distance and do i have to use a number tape or just a simple A B and C? : : : Thank you for your comments. : : Are you looking at the pipe or a weld? If it is weld you can come in contact with the pipe for single wall viewing. You can back the source off and superimpose the walls. You can also elipse the weld with the proper source angle at a distance instead of superimposing. This is, of course, if the applicable code allows this. Number belts are useful but not required for most applications. As for letters or numbers, an agreement should be reached with your customer if not specified. : : Here’s an example: for 2 ˝” sch 80 pie, with a thickness = 0.276”, and an O.D. = 2.875”, A source with a focal spot of 0.111”, using the general requirements of ASME BPV code and a bunch of other assumptions… : You could go either of two ways (in general): : For Double Wall Single Exposure and complying with a Geometric Unsharpness (Ug) = 0.02” a Source to Object distance of D=(0.111)(.276)/0.02=1.53” would be required. Since the O.D of the pipe is larger than this (e.g. 2.875”), you could rest the source against the pipe and would have more than enough distance for a good shot. : For Double Wall Double Exposure and complying with a Geometric Unsharpness (Ug) = 0.02” a Source to Object distance of D=(0.111)(2.875)/0.02=15.95” would be required. This is so because you need to have both sides of the weld (the one closest to the film and the one farthest from the film to comply with the Ug), so the Ug calculation has to take into account the size of the whole object (pipe). : Hope this works for you. ------------ 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