BURIED FLANGES STANDAR 1

[anyan1]

Morning

Somebody know if exist a standard that prohibit to install buried flanges.

Thanks in advance.

 

[Thomasjl]

anyan1,

An underground flange connection has some disadvantages. The ones I can think off at this moment:
1. When leakage occur nobody notices
2. It acts as an anchor. Long straight underground lines (even for warm or hot service) don't move. Underground lines, for warm or hot service, near an underground bend or elbow (R=< 30 m) do move over the last approx 20-30m (depending on the type of soil) before the bend. A flange connection in this 20-30m will act as an anchor. I don't have to explain what happens with this connection when it is not strong enough.

Can't think of anymore disadvamtages, there might be more)(The figures are out the top of my head and approx)

 

[dcasto]

Not a published one that I know of, but there are not many companies that would allow it. The corrsion problems are major. Trying to get everything coated correctly and inspected, a real challange.

 

[Fizzhead]

Anyan1

Thomasjl is right, principal reasons are anchorage and leakage monitoring. Dcasto makes a very important point that corrosion protection is difficult at best.

I do not know of a published piping standard that specifically prohibits this practice, but I can tell you that in my work with buried fuel lines we quickly learn not to even mention this as it unanimously receives a quick and very negative response from Owners and engineers.

I think the reasons are clear enough, but then again, I don't know exactly what your application is. If the fluid is water, then environmental monitoring concerns may not be valid. But, the anchorage and corrosion concerns are certainly still valid and I would expect that they still make this an unacceptable solution.