Re: [MW:19086] Presuure test with Hydraulic Oil.

Dear Airon,

 

Recently we have done some hydraulic pressure testing and the charts were looking normal during the holding time(No major drops). 

But during the pressurization time some times we observe some major drops.

I think those drops in our case( During pressurization) is due to in adequate venting.

 

 

Lots of other reasons also like,

where we connect the thermocouples. some times thermocouple in un shaded area and the pipe is in shaded area , vice versa also.

In both cases increase in pressure will not match with temperature.

 

Particular to the hydraulic testing, the fluid itself is having a different thermal properties compared to water.

 

So in my opinion if the test pressure is maintained during the holding time and if there is no LEAK  observed during  the test , it should be acceptable as it proves the mechanical integrity  even though there is a unusual drop.

 

Note: In our project, we accept the test even though  the test pressure is slightly less than the test pressure.

Sorry I don't have any code reference for this acceptance.

 

Regards,
Habeeb Rahman

From: Airon <isacnewt@gmail.com>
To: materials-welding@googlegroups.com
Sent: Monday, 21 October 2013 8:54 AM
Subject: [MW:19006] Presuure test with Hydraulic Oil.

Dear Folks,

Been doing pressure test  (different pressures ranging 450 - 7500 psi)  for Hydraulic piping (18-30 mm dia). 

Never had a satisfactory graph. 

Theres a sudden initial drop (mostly) or rise after pressuring. 

During holding time the rise or drop in pressure relative to the atmospheric temperature variation is too much. 

Tried the same test early morning , midnight mid noon and all different times, results are weird graphs.

Subcontractor is not giving a convincing explanation and insists its a normal thing for hydraulic pressure tests. 

Is it normal?

does anyone else have similar experiences or any presentable explanations?

Regards

Airon

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