Steam Line Underground 2

[sshep]

My Friends,

We have a 400psi steam line routed across a public road with 20ft clearance. We need 45ft of clearence to pass equipment underneath for a new project. Our E&C contractor wants to reroute it underground.

I have seen alot of lines routed below roads through culverts in the plant- i.e. piping can be easily trapped out and low spots accessed, the only real problem was pumping out rainwater, which we did via air lift pump in the plant.

Under this road the line would either be buried which I have never seen and might have its own problems; or through a culvert in which case I would worry about draining rainwater and restricting public access, etc.

Any ideas or advice?

best wishes,
sshep

 

[pennpiper]

You can direct bury Steam Lines under a road. You should have a Boot at both ends of the run under the road. An internal dip pipe system can be used to force the condensate up and out (through the main line pipe wall) then to a Steam Trap.
The buried part of the line can be insulated with "Gilsulate.
(see this link -

http://www.gilsulate.com/Gilsulate_International,_Inc./Home.html)

prognosis: Lead or Lag

 

[jamesbanda]

Sheps advice is sound... you must ensure proper trapping in the line. I recall a very serious incident from steam induced water hammer from a large facility in the UK from a dead leg of condensate building up in a culvert (below the ground).. it was left unchecked for some time..

if your conserned.. i would produce a risk assessment to document your decision process and recommendations..it does'nt need to be a complex document just explain how your managing that risk..
(then if anything goes wrong you have performed due dilanage.. ) make sure the operations own that risk too..

 

[sshep]

Thanks for comments. Trapping out the ends through a dip tube (so as to avoid small underground pipe serving this purpose) is an idea which I had considered in my own head, and which I am happy to know that it is done this way.

The process design details are actually of less concern to me than the worries about thermal expansion, anchoring, insulation and protecting, effect of heat on the soil, high water table concerns, etc. At least it is comforting to know that buried steam lines are an established practice, although I still struggle to find applicable standards.

best wishes always,
sshep

 

[pennpiper]

You wrote:
I still struggle to find applicable standards.

Contact "Gilsulate"

http://www.gilsulate.com/Gilsulate_International,_..

prognosis: Lead or Lag