Gas stopper bags

By DanS Date 02-12-2008 21:10

How safe are gas stopper bags? My step son was welding a flange on a 14 inch gas pipeline when the gas stopper bag blew out the end of the line, striking him in the lower jaw. His welding helmet probably saved his life. He lost 7 teeth, his tongue was mascerated, his lips severly cut and he has been in intensive care for almost a week. What would make the bag blow out the end of the pipeline with such force to do all that damage?

By Kix

Date 02-12-2008 21:27

Was this a slip on flange? Had to be if his head was in the line of fire. Did the actual bag blow or did the vapors behind the bag flash? If the bag wasn't sealing then I'd say the vapors flashed behind the bag shooting the bag out like a potato out of a potato cannon. Dam that sucks man and I'm sorry to hear that about your son. Thank god he wasn't killed and I hope he has an uneventfull speedy recovery! They are suppose to sniff around the bag before any arcs and sparks fly so ask your boy if they did all the safety precautions.

By DanS Date 02-12-2008 23:36

From what I understand they had sniffed for gases and none were present. Also, the bag apparently did not deflate, therefore it almost sounds like your theory might be correct, that the vapors behind the bag blew the bag out. I believe he was welding on a slip on flange also. The back of his head was also singed somewhat which may lead more credence to the bag not sealing properly and then being blown out by the natural gas behind it. The bag must have blown out with a lot of force though.

By james1

Date 02-12-2008 23:46

Sounds like the valve or stopping fitting ahead of the bag may have leaked by packing the line causing the bag to blow out.Had thier been a couple of fittings welded and tapped out between the valve and bag 1 for a siphon, second for place to monitor for gas things may have been different.Don't know what pressure a bag will take.

Jim