Repair of steel pipline inside slab 1

[MisterDonut]

Anyone out there have knowledge of how to fix a steel pipeline encased in a post-tensioned concrete slab?
The pipeline is 3” steel, welded joints, with one 90º bend. It carries hydraulic fluid at 200 psig for an elevator. The pipe is in a post-tensioned concrete slab in an outdoor parking structure. Location is subject to ambient temperatures as low as -30ºF.
The effected elevator is one of two, ech with a seperate hydraulic power unit and piping. One elevator's pipeline has a leak causing that elevator to be non-functional. Fluid can be observed oozing up from a crack in the slab. The crack may have allowed water and de-icing salt to corrode the pipe. Jack-hammering the slab to expose the leak could cause the other parallel line to start leaking, as it is likely also corroding. Having both elevators down would be a major problem.
The elevator code official will not allow a hose to be run within the pipe. Above-slab piping is possible but cost-prohibitive, as the code official requires insulating and heat-tracing the piping, along with controls changes to periodically operate the elevator to circulate fluid.
Any help is appreciated.

 

[rneill]

What about a HDPE tight liner run within the existing steel pipe (assuming it can be pulled, size and configuration issues)?

 

[MisterDonut]

My internet research has pointed me to processes called "sliplining" and "cured-in-place piping." Typical applications for these are domestic water and sewer, but some information suggests that it can be applied to pressure piping and piping with bends. Does anyone out there have direct experience or knowledge of this?

 

[dicksewerrat]

The liner to deal with the 200 psi would probbly take up about .9 inches total. It also would not go through the 90 degree bend.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[StoneCold]

What about running two temporary hoses around the problem spot. Then jackhammer out the old piping, replace with upgrated piping and coatings. Then re-attach to new piping.

Essentially doing it twice but you don't have a lot of options.

Regards
StoneCold

 

[BigInch]

with a sleeve this time.

**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch

http://virtualpipeline.spaces.live.com/

 

[BigInch]

With the prestressed slab, be careful about how much concrete you remove at any given time.

**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch

http://virtualpipeline.spaces.live.com/