Welded Cryogenic Pipe Supports

[RVAmeche]

Most cryogenic supports I've come across have been the off the shelf insulated clamshell type shoes and protective sleeves for clevises and clamps and that sort of thing. I've also seen welded trunnion type anchors with an isolation block between the support baseplate and concrete/steel.

Does anyone know of a cryogenic support guide that shows details for welded pipe supports? My structural guys are the temperatures are just too low and we can't do a welded support which doesn't feel right. Pipe service is CO2, material is 304 SS, and operating/design temps are -40F/-325F.

Thanks

 

[1503-44]

Maybe they're worried about the welds becoming axial restraint anchors, in which case they are probably right to worry about it. There will be immense stresses created wherever you anchor a line without sufficient flexibility. If you do the pipe stress run and show them that the line is flexible and force's involved are small, they will say OK.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

I'm confused. What do you mean by "welded pipe supports"?

Can you post a sketch or drawing of what you mean?

I've seen trunnion supports and then enclosed in insulation with wood being a surprising material often used in LNG service for things like this.

You can't have a direct connection to the outside because it will become a big heat conduit.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[EngrPaper]

Physically, you can make a shoe or other standard support out of stainless steel and the support itself will be fine. As mentioned above, the problem with doing that is you are creating a fin through your insulation and you are going to get a big ole ball of ice on it. That ice can effectively turn the support into an anchor and damage the piping system (or connecting equipment) as a result.

Stay with a pre-insulated clamp on support that is load rated (Piping Tech has good ones, as I am sure others do too), stress the line to ensure you are within the load ratings, and enjoy the thermal efficiencies of not breaking your insulation.

 

[GBTorpenhow]

A break in the insulation also offers a spot where moisture can infiltrate. Try to avoid it if at all possible.

Rilco Manufacturing has a couple good if not exactly cheap options for pre-insulated supports using aerogel insulation. Within their stated lateral loading limits, the lateral guide versions don't require anything welded to the pipe but their 'anchor' version that includes a line stop function has a lug that needs to be welded to the pipe. It is retained internally to the shoe assembly and doesn't protrude through the insulation.

https://www.rilco.com/products/cryo_anchor_support