Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Related Articles


Snaking of buried large diameter HDPE fused pipe

Snaking of buried large diameter HDPE fused pipe

Snaking of buried large diameter HDPE fused pipe

For small diameter HDPE pipes, sometimes it is recommended to snake the pipe in the trench if installed in hot weather to avoid thermal expansion/contraction stresses. For large diameter hdpe pipes, is this also done and if so how do you snake a large diameter hdpe in the trench? Thanks.

RE: Snaking of buried large diameter HDPE fused pipe

Never heard of this. Where did you come up with this idea?

"Placing pipe that has been in direct sunlight in a cooler trench will result in thermal contraction of the pipe’s length. This contraction can generate force which could result in pull-out at mechanical couplings or other buried structures. Allow pipe to cool before making connections to an anchored joint, flange, or a fitting that requires protection against excessive pull-out forces. Covering the pipe with embedment will facilitate cooling."


RE: Snaking of buried large diameter HDPE fused pipe

I believe "snaking" plastic pipe has been recommended by many in the plastic pipe industries since at least as far back as the early to mid-1970's when I first saw same, and I think you will find is even also reflected in some current publications that are searchable online. While I think I have also seen varied explanations for such recommendations over the years, and/or this as a response to/cure or excuse for some past problems with welded or fused systems etc., I think all writeups or specifications I have seen basically had roots/or common thread in the very pronounced thermal expansion/contraction behavior (or very high thermal expansion coefficients) of plastic pipes as compared e.g. to common metal pipes.
Assuming there is sound technical or overriding reason for doing this e.g. with fused or welded plastic pipe systems, it sure would seem snaking the pipe wouldn't much help the hydraulics, uniform underlying soil support of piping in common trenches, future dependable locateability of the pipeline, nor necessarily the integrity of any lateral service/connections (as some folks are also now recommending bent plastic pipes should not be tapped for stress concentration/safety reasons). Also, I agree one might also wonder about the practicality of this approach in larger, stiffer pipelines in trenches, and also e.g. in HDD applications?

RE: Snaking of buried large diameter HDPE fused pipe

compacted backfill will restrain the pipe sufficiently to resist movement. However, if the pipe extends above the surface or is laying on the surface, you should expect movement due to expansion and contraction. Anchor blocks may be used to prevent pullout from fittings above ground. snaking the pipe for above ground applications with no restraint (such as commonly done in surface mining) is recommended

RE: Snaking of buried large diameter HDPE fused pipe

Ic. Thanks guys.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close