Disclaimer: I've never worked a pipeline job so don't judge me. lol

I was wondering if there is a certain amount of deflection allowed by code when lowering long sections in the trench? Or do the operators just  do the best that they can and "hope" no damage was done to the welds?
I've seen videos of lowering and it looks like alot of stress is applied to the welds. All NDE is done prior to lowering. Pressure test is all that is done after lowering, right?

Some metals are more ductile than others but all have a limit before possible damage/failure will occur. I've made spreader beams and lowered 80' sections of 18" and prefabbed expansion loops in the trench and the site QC had much concern but UT and hydro was done after lowering.

We have a potential job in a few months that the contractor wants to prefab above ground and lower as much as possible. Pipes are grouped. Hot water supply/return. Chill water supply/return. Four pipes rigged and lowered together. They have no experience with weld pipe and don't know how it will work out. Also don't know if the Corp. of Engineers will allow it.
http://www.youtube.com/watch?v=ZwzuzOGsZq0&feature=fvw
http://www.youtube.com/watch?v=gMt2h70FwoI&feature=related

I said potential job. Can't wait to get an actual job again!