Why do gas pipelines run straight for a few hundred metres/yards then do a bit of a U-bend, straight run for a bit, then another U-bend etc. Why the bend? No valves or anything where the bend is.

794 views

Why do gas pipelines run straight for a few hundred metres/yards then do a bit of a U-bend, straight run for a bit, then another U-bend etc. Why the bend? No valves or anything where the bend is.

In: 7658

11 Answers

Anonymous 0 Comments

Journeyman pipefitter here and as the top comment states, it’s a thermal expansion loop. I’d like to add a story to the thread. I sometimes work in a refinery and one year they replaced a 24″ steam line that was about 400′ long complete with expansion loops and gate valves with other pipes leading off of it to deliver steam to different units.

After completion a new operator decided that rather than let the steam into it slowly to allow the piping system to warm up over time, he simply opened the valve rather quickly. The screaming and cracking of the steel was something I’ll never forget. It sounded like a train was derailing. The pipes were bouncing and ripping off they’re supports (some were welded) It caused one of the expansion loops to basically explode.

Needless to say the whole system needed replacing because the pipe had multiple fractures and cracks. Some of the welds blew apart. It’s something I never hope to hear again but we got more work out of it tho.

You are viewing 1 out of 11 answers, click here to view all answers.