Hydro Testing 1

[Traderjo]

I am working in a new plant start up and we are using digital pressure gauges with charting capabilities for hydro testing our components. I have some experience with hydro testing with analog gauges. When testing with our digital gauges we get slight pressure variation (less than .2%) when testing and the customer witness will not pass the test. Our engineering department has not written a test procedure to let us know what is allowable. If anyone has a test procedure that references allowable pressure variation in hydro testing with digital gauges I would like to learn more about what others have done to solve this problem.

 

[weldstan]

Since analog gauges have + or - 1% accuracy, your customer's representative is out of touch with reality.

 

[bellowsmfg]

The industry standard for Hydrostatic testing is the US Department of Transportation.
Reference DOT 49 CFR 178.37 as an example. under 3AA Pressure Vessels (Hydrostatic Testing)
The gage accuracy requirement is (1%).
Where does (0.2%)become a requirement?
You can find the above reference in Google.
To prove you are within the (1%) accuracy, you could place an analog gage with 1% accuracy in
the same line as the digital gage for a side by side comparison.
I hope this helps.


Bellows Manufacturing and Research, Inc.

https://bellowsmfg.com

 

[1gibson]

Without a procedure, I'm surprised the witness even showed up for the test. Probably has nothing to do with the 0.2%.

 

[Duwe6]

Is either gauge calibrated? To a NIST-traceable standard? If not, I'd 'fail' your hydro too.