Wood Blocks under Shell

[Elena_L]

I'm working on an aboveground storage tank repair/rework on an Ammonia tank. One issue that's been uncovered with the removal of the insulation is that the tank shell is supported by wood blocks. It's 111 dia tank and the wood blocks are about 5" x 7" x 6' (56 of them around the circumference). They were part of the original fabrication in 1968. They appear to be rotting at the bottom and several of them look like they need to be replaced. Due to the cold service, there is also asbestos paper under the shell where it is sitting on the wood. Has anyone else encountered this problem? I'm looking for a few things:

• How should the assessment of the wood condition be conducted?
• The drawings show that there is 1/8” thick asbestos paper underneath the shell on the wood blocks. The removal would need to be contained and an alternate material would need to be used under the shell with similar thermal properties for long term service
• Removal procedure
• Potential alternative material to replace the wood - cost is a big consideration

Any help or advice would be greatly appreciated!

 

[JStephen]

If the original wood lasted 49 years, I'd be inclined to replace with similar wood and figure that'd last the life of the tank. I don't know if they've improved wood preservatives in the meantime, and can't help on the asbestos!

 

[LittleInch]

Walk away from this.

ANYTHING to do with asbestos is a complete nightmare. If you can get away with not touching it or disturbing it in any way you might be OK, but otherwise its a health nightmare and the cost of removal is huge.

As for the wood - get a screwdriver and if you can shove it in then it's time to replace it.

a drawing or sketch of this would be good, especially the thickness of the insulation - 1/8" doesn't sound very much to me.

50 year life is pretty good - it's done its time. Time for a new one.

If you don't want wood use solid plastic / nylon and replace in short sections, but not if it disturbs asbestos anything.



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

 

[IFRs]

Jack or air-bag lift the tank, hire an asbestos removal company to get rid of all that junk. Design and install a new insulation pad, non-asbestos so you don't leave this same problem for the next person. Lower the tank back down.