Buried SS Piping for High Pressure Water
Buried SS Piping for High Pressure Water
(OP)
I was just reading with interest a post in this forum concerning corrsion of buried stainless piping for hydrogen.
I have an application where I need to convey water from a pressure washer (at 1500 psi) for about 300 feet underground (approx. 5 feet deep), between the pressure washer pump and the point of use. Pressure in the line will fluctuate to the extent that the pump cycles on and off. All power lines in the vicinity are above ground.
The line will run under a concrete slab for about 100 feet, making access after construction very difficult. I had considered placing the SS piping in a casing underneath the slab, but have since decided that's probably overkill for this application.
I had assumed I would specify 316 ss for the carrier pipe. I chose ss because I couldn't find anything that would handle the pressure, if there are other options, please advise.
Any recommendations for reference reading or suggestions of how this construction should be specified? What other questions would I need to answer in developing an acceptable solution?
I have an application where I need to convey water from a pressure washer (at 1500 psi) for about 300 feet underground (approx. 5 feet deep), between the pressure washer pump and the point of use. Pressure in the line will fluctuate to the extent that the pump cycles on and off. All power lines in the vicinity are above ground.
The line will run under a concrete slab for about 100 feet, making access after construction very difficult. I had considered placing the SS piping in a casing underneath the slab, but have since decided that's probably overkill for this application.
I had assumed I would specify 316 ss for the carrier pipe. I chose ss because I couldn't find anything that would handle the pressure, if there are other options, please advise.
Any recommendations for reference reading or suggestions of how this construction should be specified? What other questions would I need to answer in developing an acceptable solution?





RE: Buried SS Piping for High Pressure Water
RE: Buried SS Piping for High Pressure Water
Based on your original post, I would specify construction of this high pressure water line to ASME B31.1. This is a recognized Piping Code that provides rules for design, fabrication (welding) and inspection.
I disagree. If you are going to run this line under concrete and in soil, you need to be sure that exterior corrosion is not a factor due to the cost of trenching to make repairs. I would use a casing to encapsulate the stainless steel water line.
RE: Buried SS Piping for High Pressure Water
NFPA 24 might also provide some useful background considerations.
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Buried SS Piping for High Pressure Water
In your case a plastic pipe of suitable strength for the ground loads would be fine for the outer pipe. People make plastic 'spiders' that are used to keep the inner pipe centered and not laying against the outer one.
Make sure that there is enough slope that any moisture that collects in the containment pipe will run to one end where you have a way to pump it out.
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Plymouth Tube
RE: Buried SS Piping for High Pressure Water
I'm familiar with the spiders and casing, but only for straight runs in a bore and jack scenario. I'm wondering how to address the bends, which are required to make this pipe run. My first thought is that I could turn the stainless carrier pipe in a manhole, but thought there might be something a little easier or cheaper? Although a manhole would facilitate regular inspection of the piping. Anyone have any other thoughts? This is really outside my area of regular practice. Thanks for the info.
RE: Buried SS Piping for High Pressure Water
RE: Buried SS Piping for High Pressure Water
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Buried SS Piping for High Pressure Water
My next question (which I think may be a silly question, but I'm going to ask it anyway), does the bured piping need blocking and restraints for water hammer scenarios? I'm guessing no, since the joints will be welded.
Last question, who should I call for assistance with this type of design? A mechanical engineer? This piping is a very small piece of a larger civil project, but the high pressure piping is not something I'm familiar with. Although I'm getting there.
RE: Buried SS Piping for High Pressure Water
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Buried SS Piping for High Pressure Water
Since the last question above was left unanswered, my recommendation is yes, hire the services of a piping engineer or firm that performs this type of engineering practice. Even small aspects of a project can result in overall failure of a project.
RE: Buried SS Piping for High Pressure Water
RE: Buried SS Piping for High Pressure Water