I was working on a boiler at the old paper mill in Tacoma and saw a weld fail under pressure

We were doing a hydrostatic test on a newly installed section of steam drum. The pressure was only at 80% of the test spec, around 450 psi, when a longitudinal seam weld on a 12-inch pipe just gave way. Water shot out like a cannon and took out a section of insulation on the adjacent line. The foreman yelled 'kill the pump' and we shut it down fast. It turned out the weld procedure sheet was for the wrong grade of steel. Has anyone else had a close call because of paperwork mix-ups on site?

4 comments

4 Comments

lindag332mo agoMost Upvoted

You said the valve was stamped for 150 but the tag said 250... that's a huge difference. How does nobody see the actual number on the metal? That's not fine print, that's the whole point of the stamp.

the_alice1mo ago

Hate to jump in but @evanc59 has a point about visuals catching stuff, but honestly have you ever tried reading a stamp on a valve that's been in service for years? That thing's gonna be covered in grease, paint, and scratches half the time. Squinting at tiny stamped numbers while it's bolted up in a dark corner isn't as easy as everyone makes it sound. Plus if the tag says 250 on it, your brain just defaults to that number and moves on to the next thing on the list. It's lazy but it's also how people work when they're doing the same check for the hundredth time that week.

piper7792mo ago

Yeah the whole "visual check before test" thing evanc59 mentioned sounds good on paper. I saw something like that go wrong with a pressure relief valve tag once. The paperwork said it was set for 250 psi but the actual valve was stamped for 150. Nobody caught it because they just matched the tag numbers, didn't read the fine print on the valve body. It blew early during a heat-up and steamed up the whole bay. Makes you wonder how many other tags are floating around with the wrong info.

evanc592mo ago

I mean, paperwork mix-ups are scary but that's why you're supposed to do a visual and material check before the test, right? Maybe it's just me but that seems like a step they missed.