hyperbaric chamber

[Bob DBF]

What does he INTEND TO DO with the answer?

My guess is he's going to try to build one at home with spare parts.

There is such a thing as idle curiosity.

Now if it was me asking the question, your premonition of impending disaster might be justified, although I have walked away unscathed from all of my more interesting projects.


Bob

 

[Akimbo]

I never knew who was in charge of all of the non-land based structural stuff. When I was welding quite a bit, I got tested for any thickness plate and any thickness 6G pipe, AWS D1.1, with stick and dual shield flux core, plus both with a tig root pass.

I thought ASTM was responsible for structural welding in the US? I never worked in that arena. Structural is seperate from pressure vessels and pipelines are separate from those, by certification and often by agency in most countries.

My memory is a little fuzzy on this but I'm pretty sure that ASME isn't responsible for pipeline certification in the US. I was aboard several pipe-lay barges in the 1970 and 80s plus a few hyperbaric weld-in projects from DSVs (Diving Support Vessels) in the North Sea. Those welders were constantly being certified and recertified in different countries.

The sat-diver-welders were easily the most highly paid guys that ever went underwater to work. Taylor Diving and Salvage was one of the very early pioneers in the technology and built two large chamber complexes at their HQ with vertical wetpots primarily to certify the welders under pressure. The welds were always done dry in an open-bottom habitat clamped to the pipeline. The story I heard is they had to certify for every 100' depth range they worked in. The welding is a lot more automated now, but still highly skilled and tested. There are some animations on YouTube on hyperbaric pipeline welding.

Back to the original post -- like I wrote, this isn't a DIY kind of project.

 

[JohnnyC]

I thought ASTM was responsible for structural welding in the US? I never worked in that arena. Structural is seperate from pressure vessels and pipelines are separate from those, by certification and often by agency in most countries.

My memory is a little fuzzy on this but I'm pretty sure that ASME isn't responsible for pipeline certification in the US. I was aboard several pipe-lay barges in the 1970 and 80s plus a few hyperbaric weld-in projects from DSVs (Diving Support Vessels) in the North Sea. Those welders were constantly being certified and recertified in different countries.

Here's an interesting discussion on the cross-compatibility of certifications and who's responsible for what when it comes to structural, pipe, etc. There are definitely crossovers between ASTM, ASME, and AWS.

ASME procedures vs. AWS D1.1

 

[Akimbo]

I knew a guy that did nuclear pipe, 6G, stick with tig root. All he ever did was work in nuclear plants for probably 10 years, plus another 10 years of general fab shop welding, then went to an airline.

You can be sure that a lot of these requirements resulted from the loss of the US Submarine Thresher. The "best guess" is a hull penetration weld failed during a post overhaul deep dive test that shot a high pressure stream of salt water on a control panel. The resulting electrical shorts shut down the reactor. They probably could have powered their way to the surface since they think the leak wasn't fast enough to rapidly sink them from the water weight alone.

Most of the welds on the deep diving system I was on in the Navy had to meet the Mil-Spec nuclear codes. The smallest arc required a mountain of paperwork.

 

[Bob DBF]

True. But some questions may indicate more than curiosity. Such as a person who asks how do you learn to fly an airplane so you can take off and fly level, but has no interest in how to land it.

I can think of sinister uses for many things, but a hyperbaric chamber seems more like a discussion with Darwin than a threat to the national security.


Bob

 

[Bob DBF]

You can be sure that a lot of these requirements resulted from the loss of the US Submarine Thresher. The "best guess" is a hull penetration weld failed during a post overhaul deep dive test that shot a high pressure stream of salt water in a control panel. The resulting electrical shorts shut down the reactors. They probably could have powered their way to the surface since they think the leak wasn't fast enough to rapidly sink them from the water weight alone.

The death warrant was that steam could not be taken from the steam generators until the reactor was running, and the startup procedures were not fast. Subsafe changed some of the systems and procedures, the systems were still being upgraded when I rode the boats years later, but the procedure for a fast restart and taking steam while the reactor was being restarted solved the greatest issue and most likely would have saved that boat.


Bob
---------
former ET1(SS) RO

 

[JamesBon92007]

So, if we are going to build one, what do we have on hand to work with? An old steam boiler, perhaps?

 

[Akimbo]

So, if we are going to build one, what do we have on hand to work with? An old steam boiler, perhaps?

A never-used propane tank would probably be a better starting point for a small pirate version. Just let us know where and when you pressurize it so we can clear the blast zone.

 

[JamesBon92007]

A half a dozen hose clamps, a bicycle pump, a few rolls of air tubing, a garbage can and a designer with a dream.

I didn't realize that OP was that short

 

[Akimbo]

A never-used propane tank would probably be a better starting point for a small pirate version. Just let us know where and when you pressurize it so we can clear the blast zone.

And have the mops ready

Good point. Just in case these tongue-in-cheek comments aren't obvious enough:

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SAFETY WARNING

Using uncertified pressure vessels of any kind is incredibly dangerous, for you and anyone within the blast radius. This is true for decompression chambers, Scuba cylinders, and low pressure volume tanks in your workshop. It also exposes you and everyone that worked on it to criminal and civil liability. It is just plain stupid, don't do it!

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