Piping testing pressures

[mowlin]

I know this may be a generic and easy question but w.r.t. testing pressures for piping either as per B 31.3 or 31.8, what is the hydro test pressre? is it 1.5 x class of the line e.g 600# line would be tested at 900 psig? or is it 1.5 x the maximum rated pressure of the materials for a certain temperature.

 

[Cockroach]

CSA Z245.15 in Canada, API 6D in the USA: both specify 1.5 X MOP which is "maximum operating pressure".

In your case, ANSI Class 600 which is 1460 psi will have to be pressure tested to 1.5(1460 psi) = 2190 psi. I like to hold the test medium, typically a glycol mixed water solution to supress rusting, for 15 minutes and chart it with compensation for temperature variation within a confined volume.

Some of my clients ask for third party witness, look for a loss of no more than a single line cross over on the chart, i.e. about fifty pounds WITHOUT external fluid leak. Then you can blame it on the test stand and still remain within the spirit of the code.

External leaks are automatic failures.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[XL83NL]

Isnt the hydro test pressure 1.5 * design pressure * ratio of the component pressure rating at the test temperature to the component pressure rating at the component design temperature for components with established ratings(, but shall not exceed 6.5)?

Of course you have to keep in mind specific components rating (e.g. flanges), and not exceed them by a certain factor (1.5 * component rating at test pressure).

Refer to B31.3 para 345.4, it's all in there.