Why do the standards mention that the pipe length for pressure test should be no longer than 500m.

[S06]

The standards mentions that the pipes pressure tested should be no longer than 500m.
However, I have installed pvc sewer mainforce line more than 800 meter without conducting pressure test.
I just wanted to know, technical what will happen if we conduct pressure test for pipe length exceeding 500m.

 

[BridgeSmith]

Well, there's more surface area and volume for elastic expansion of the pipe, so if there's a limit for pressure and/or volume change, you could be more likely to exceed it.

 

[LittleInch]

Which "standards"??

500m seems a short arbitrary number.

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

 

[mikeofBelAir]

I witnessed a pressure test of a high pressure gas transmission line that was 2 1/2 miles long. Again, which "Standards"?

 

[S06]

LittleInch

You are right.

However, our project specification has mentioned:

e. Test sections: Limit test sections in pressure lines to not more than 500 m.

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https://res.cloudinary.com/engineering-com/image/upload/v1562647128/tips/Untitled_t3pwrr.jpg

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I thought this is specified in some standards. However after going through ASTM F 2164 and AWWA i was unable to find any upper limit for pressure test pipe length i.e. "< 500 m".

May be it is only our project specification and not standard.

Thanks for pointing out the point.

 

[GeoEnvGuy]

The only practical limits I would consider is a small leakage rate on a large diameter pipe won't show much pressure loss with longer lengths having more volume. For small diameter pipe would frictional head loss play any role in equalizing.