Foam Filled Tube Steel 1

[Gumpmaster]

I have some tube steel sections in a maritime structure that we're planning on filling with foam. The tube steel will be capped on both ends with steel plate. The foam is only to reduce the possibility of sinking the steel if the seal welds aren't perfect, and to reduce the possiblility of bursting the tubes during freezing temperatures. We've done this several times before, but the tubes were only partially filled with foam because the steel was only partially submerged.

My specific concerns are with welding the cap plates on after filling with foam. The expanding foam can produce cyanide gas when exposed to high temperatures and I don't want to hurt any welders.

Has anyone dealt with this before? How did you deal with welding? I'm thinking of having just a small injection port for injecting the section with foam and covering that with a welded plate. That should minimize the amount of welding. Are there any other ways to get around this?

Are there any other concerns when completely filling tubes with foam?

Thanks.

 

[MiketheEngineer]

Sure you can "port" the tubes but depending on size and length you might not get a good foam fill. Multiple ports could be used.

Welders can be outfitted with SCUBA like devices and work safely

 

[Gumpmaster]

Thanks. I hadn't thought of a SCUBA type setup, that would be a good precaution.

I think for the filling, they'll have to use an injection hose similar to a tremie slab to ensure good distribution of the foam.

 

[msquared48]

Why don't you hav the injection port threaded so you can screw in a pipe fitting to close it off rather than weld.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[Ron]

Agree with Mike. Have used this method for painting the inside of air manifolds. Foam injection will work the same way.

 

[Gumpmaster]

Good suggestion. Thanks for all the input.

 

[Archie264]

Couldn't you just leave it empty and seal it as described? How can the foam be lighter than air? Surely I'm missing (or misunderstanding) something.