Questions regarding flaw detection of branch pipes welded by drilling holes in main pipes (self-made tees)
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Is no flaw detection required when drilling a hole in the main pipe to weld a branch pipe (a self-made tee)? Why isn’t it indicated in the single-line diagram either?
This post was last edited by sjxwolf on 2011-9-8 at 12:06. Direct welding after making a hole should not require high standards regarding the medium inside the pipe; it’s usually just flushing water or tap water. If steam is involved, a boss should be used. So since direct welding after making a hole is possible, no flaw detection is necessary
It also depends on the diameter size; those larger than 2.5\" generally require it, and in some cases it depends on whether the location permits it
Inspection is required. Elbow tees are very common in the installation of process pipelines; they consist of fillet welds and can be subjected to penetrant testing (PT). If there is no reinforcement plate, PT is carried out immediately after welding; if a reinforcement plate is present, PT is performed after the branch pipe welding is completed but before the reinforcement plate is installed. Once the inspection is successful, the reinforcement plate is installed, followed by another PT test. JB4736 can be used as a reference.