Pipe thrust block support for grooved coupling joints 1

[Musttamoni]

Dear all, i have an inquiry about grooved coupling joints (rigid/flexible types) if it required a thrust block support at the bends and tees.. please show yours response with trusted reference.

 

[MJCronin]

Some types of underground pipe couplings require thrust blocks, other types do not.

Show us examples of the specific type you want to use ...

What does your manufacturer say about the need for thrust blocks when using his product ?

https://ebaa.com/files/pdf/connections/Connections.PD-01.pdf

MJCronin
Sr. Process Engineer

 

[Musttamoni]

My example is about several water pipe applications specially chilled water pipe suspend in high level ( under slab) with grooved coupling joint, consultant forced me to install thrust support with every 45/90 deg elbow and every tee without any studying or analysis for it which increase the installation cost and create the money site conflict spically in corridor areas that because there is no enough space to install the supports. For me I believe that thrust support insttaltion has apical conditions as per dipra an NFPA 24 (push on joint type and underground).

 

[fel3]

It all comes down to the free-body diagram(s) for your piping system. If you have a restrained joint piping system, you will have a lot of equal and opposite thrust forces cancelling out to zero, either from opposing elbows (buried or above-ground) or from elbows opposed by soil friction (buried only). In these cases, no external thrust restraint is needed. Slip joints, closed valves and control valves creating a differential pressure, connections to existing pipelines, etc. may create the need for external thrust restraints.

The best explanation for all this that I have read is "Thrust Restraint Design for Ductile Iron Pipe." The 7th edition is the most current. You can download the document in PDF format from DIPRA.org:

https://www.dipra.org/ductile-iron-pipe-resources/technical-publications.

It's the 4th document under the "Design" heading, about halfway down the webpage. BTW, the principles in this document apply to all piping systems, not just ductile iron. However, for some types of pipe (e.g. surface-laid HDPE), thermal expansion/contraction can create large additional forces to contend with.

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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

 

[Musttamoni]

Thanks fel3, i am going to download this section and check my case with it

 

[cvg]

grooved (victaulic) are generally considered restrained joints. restrained joints do not need thrust blocks) they allow some movement, but are not particularly "flexible" in my opinion. However, I would never install victaulic couplings or (grooved pipe for that matter) underground

 

[MJCronin]

It has been my experience that several clients who require underground piping systems prefer the positive gripping system (EBAA) system known as MEGALUG.

The system has been around for decades ....

You pay a bit more for the coupling but there are savings in the installation costs.

https://ebaa.com/files/pdf/brochures/Brochure.3800.pdf

MJCronin
Sr. Process Engineer