Hydrotesting with glycol

[roadbikeruler]

Need some advice about hydro testing in cold weather with glycol.
-Understand when pipe temp rises the pressure goes up.
-When pipe temp is dropping the pressure will drop.
-How much would you compensate for pressure drop?
-If glycol in the storage tank & the pipe temp are within 2-3 degree difference.
Should the pressure drop be minimum like a 1 to 5 pound drop. Anything over that I have been refusing lots of arguments
When I walk the line for leaks find no traces of a leak (only within the test limits)
Then it all right to sign off the hydro evening if pressure is dropping. (Told to use common sense)
I think that is wrong the PTR & specs for Company X say to Hold test for 10 minutes
Look on internet not much help.
Would you know if there is some type of chart for pressure lost at minus temperatures
Foreman’s at night shift telling me you cannot hold pressure for 10 minutes.
I think you can hold pressure…

 

[metengr]

roadbikeruler;
Is this for new construction or when repairs are performed or what? There is latitude for conducting hydrostatic or even pressure tests on existing equipment and yes, common sense is required because there can be mechanical joint leaks or equipment leaks that can result in sagging pressure over time that should be ignored. There should be a procedure to follow for hydrotesting that has been developed by the user and reviewed and approved by the in-service inspector that needs to sign off for this test.

If you have walked the line down in the past and no visual leak is observed at welded joints or in the pipe spools, a 10 minute hold may be appropriate along with some sag in pressure. I have seen hold times from 10 minutes to 30 minutes depending on how long it takes to walk the system down to check for leaks.