Installing PVC Vertically

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jmfellow23

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We are currently working on a project for an Elevated Storage Tank. The engineer has specified to run PVC Schedule 80 conduit vertically, to the top of the tank on the interior wall for lighting and monitoring the tank level. It is 200 feet to the top of the tank and it is specified that we secure our runs at 8 foot intervals on flat metal brackets stood off 3 inches from the tank wall. The conduit will only be in contact with the supports every 8 feet. Does the code allow for this? Does any one have any suggestions for this?
 
You didn't mention what size conduit but Table 352.30 Support of Rigid Polyvinyl Chloride Conduit
(PVC) will tell you the maximum spacing permitted for the supports.

Welcome to the Forum. :)
 
What kind of temp extremes will it be subject to? With the kind of vertical rise you are talking about here it may be difficult to account for thermal expansion and contraction and keep the pipe from sliding down on every expansion fitting that may be needed.

Seems like metal raceway would be a better alternative here.
 
I would go with what the engineer dictates on his drawings. Just make sure you have a set of stamped, sealed and signed drawings so when the PVC expands, warps and splits apart you're not on the hook for the failure. Then they'll pay you to re-install the wiring in metal conduit. IMHO, even if you use expansion fittings the PVC will expand and contract and possibly warp. You probably won't be able to use PVC straps either. I would use metal cowboys for support myself.
 
jmfellow23 said:
The engineer has specified to run PVC Schedule 80 conduit vertically, to the top of the tank on the interior wall for lighting and monitoring the tank level.
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Does this mean that the pipe will be in contact with the contents of the storage tank? Is it liquid or solid?
 
goldstar said:
I would go with what the engineer dictates on his drawings. Just make sure you have a set of stamped, sealed and signed drawings so when the PVC expands, warps and splits apart you're not on the hook for the failure. Then they'll pay you to re-install the wiring in metal conduit. IMHO, even if you use expansion fittings the PVC will expand and contract and possibly warp. You probably won't be able to use PVC straps either. I would use metal cowboys for support myself.
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Could be an issue for getting past inspection regardless of what the engineer dictates.
 
Coppersmith said:
Does this mean that the pipe will be in contact with the contents of the storage tank? Is it liquid or solid?
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I guess I presumed it was like some municipal water towers that have an enclosed support with standpipe, ladder, or even a lift of some sort and other items in that support enclosure, but at same time I guess a valid question.
 
goldstar said:
I would go with what the engineer dictates on his drawings. Just make sure you have a set of stamped, sealed and signed drawings so when the PVC expands, warps and splits apart you're not on the hook for the failure. Then they'll pay you to re-install the wiring in metal conduit. IMHO, even if you use expansion fittings the PVC will expand and contract and possibly warp. You probably won't be able to use PVC straps either. I would use metal cowboys for support myself.
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There is also a chance the owner will hire someone else to fix it, and they will be "in" and you will be "out".
 
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