Underground Pipe Design

[lg214]

Hi!

I am working with underground piping and we are having some discussion about the requirement of installing or providing with some thrust block for the piping. As I review the ASME Code for process piping, this was not stated. What is the applicable codes for underground piping with 1.2m Dia pipe for water? Can anyone tell me about this?

brg

 

[LittleInch]

Thrust blocks are normally only required for push fit piping to make sure it doesn't come apart under end cap force. If your piping is joined together by welding or flanges, you don't normally need thrust blocks and they can cause more problems than they solve if there is any temperature difference where expansion or contraction is constrained.

What type of pipe do you have?

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Also: There's usually a good reason why everyone does it that way

 

[robyengIT]

find attached Ameron former Manual C301 chap. 9 and Appendix G with examples

 

[rconner]

fyi also

http://www.american-usa.com/system/assets/265/original/American-International-Engineering-Data.pdf

 

[BigInch]

B31.3 does not require thrust blocks. Thrust blocks are not usually needed for bonded or welded seam piping.

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[lg214]

We are using PE coated carbon steel pipe.

Thanks a lot Guys for your quick response! It helps me a lot!

 

[rconner]

Steel water pipe thrust restraint is discussed in AWWA Manual M11 (and many other references).

 

[LittleInch]

That's good, but what is your jointing technique - welding or push fit / flexible joints with little axial strength?

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[bimr]

As the others have stated, thrust blocks used to be used on on unrestrained joints. Flange joints and welded joints are restrained joints. Bell and spigot pipe joints are considered to be unrestrained joints.

Thrust blocks are no longer considered to be good piping practice. This is because thrust blocks are normally paired with undetermined soil properties and poor construction techniques. These uncertainties lead to unknown performance parameters for the piping system.