Gas Pipeline Repairs by using steel sleeves

[09091960]

When fit up is concern for type “A” steel sleeves for gas pipe line, to accommodate the pipe Seam- Weld Reinforcement one of the options to be used is listed below.

1)Removal of the seam weld ( Required Area) by grinding
2)Grinding an accommodating groove in the sleeve
3)Locating the gap between the sleeve halves over the seam
4)Filling all voids in the area where the sleeve bridges the seam weld reinforcement with epoxy or polyester filler material

These are the options given in the PCRI Pipeline repair manual. Having said that I feel that option 1 causes problems mainly due to removal of capping welding run from the weld and might causes problems on the long run. If someone had some experience of involving and having own company procedures I would like to here from you’ll regarding pros and cons of the above mentioned options

 

[stanweld]

We often made repairs with split rings by grinding the long seam of the pipe flush to permit intimate fit. This was never a problem.

The biggest problem today with flush grinding is the tendency of workers to excessively grind/gouge into the base material and weld due to inadequate training and supervsion.

 

[brimmer]

My experience with Type A sleeves is to remove the longseam weld cap (or girth weld cap) and fit the sleeve this way. Usually not an issue as the sleeve areas are not overly long/big. As mentioned by stanweld, the biggest concern is getting someone who does not know how to grind or see the importance of what they are doing. Many welders believe it or not are very poor at grinding pipe despite the fact that they do it often... We use 4.5 inch grinders rather than the 7 inch grinders as you get more control and less chance of gouging the pipe. We also pre-qualify would be grinders on our pipe before. Depending on what type of weld cap you have, we are able to get away with soft pads rather than hard discs on most of our lines, if a hard disk is required use it as a first pass to remove most of the cap and then smooth out with soft pads. Removing the cap of a weld should not cause problems as you are not removing any base metal. If your welds have other problems such as some cracking etc. I would test first, but then you probably have already completed testing in the area before you determined you needed the sleeve.
This method aside, of the others I would say epoxy filler is also a good option.

 

[09091960]

Many thanks for Stanweld and Brimmer for your useful contributions to this topic