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Allowable Negative Pressure Underground/Submarine HDPE Pipeline 5

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vs_attitude

Aerospace
Jan 25, 2021
2
AE
Hi All,

Greetings!

This is my first post in this forum.

Kindly help me with literature that would provide me more insight into the "Maximum Allowable Negative Pressure" in HDPE PE-100 Pipelines. I came across the attached document, kindly help me validate the same.

Awaiting your all positive feedback.



Rgds,
 
 https://files.engineering.com/getfile.aspx?folder=0f8705dd-a816-4116-af63-5b114f0d4828&file=Pressure-Limitations-9.pdf
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See API RP1111

Elastic collapse pressure eq 11.5b here

Need more info? Don't search for negative pressure. It is called vacuum pressure. Or just search for "pipe collapse pressure".

 
AWWA C 906 standard for PE piping has a foot note which i copied and pasted below=


The vacuum or external pressure buckling of PE pipes depend on thickness, service temperature , age of PE piping rather than tensile strength of PE.

I will suggest you to look the documents at the links;





and this snap form The Performance Pipe Field Handbook;

PE_pipe_buckling_eunica.jpg
 
I haven't checked between them, but here are two I use. One below, the other attached.

The thing with PE is that it creeps over time. So that's one reason why the table is in time as a small initial ovalisation gradually increases.

Temperature also has a LOT to do with it so if it's warmer than your standard temp of about 15C, the depth / allowable external pressure is lower.

This from a PE suppliers design handbook

image_mhq7go.png


The attached is a page from another pipe suppliers book which gives more background and that this was based on some long term data.

But in the end you probably need something from your supplier.

LI

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
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