Well Testing/UBD ESDV closing time

[torresga]

I've been looking for a standard where it is written the criteria to choose the closing time than an ESDV (4 1"/16 - 5 1/8") should have after the shutdown is triggered. As a rule of thumb, I have always set the time in no more than 7 seconds. Even manufactures I have asked this question, cannot give an adequate answer.

I know that in the API RP 14C Recommended Practice for Analysis, Design, Installation, and Testing of Basic Surface Safety Systems for Offshore Production Platforms, it is stated that "the time it takes for any safety device (e.g. PSH, BSL, ESD station, etc.) to effect component or platform shutdown should not exceed 45 seconds", but this time seems excessive to me and most of the operating companies I have worked for.

Does anyone have a reliable source I can check?

Best regards,

torresga

 

[BigInch]

Why not base it on the fasest you can, without causing pressures higher than allowable transient pressures. That's what I've always done.

If it ain't broke, don't fix it. If it's not safe ... make it that way.

 

[torresga]

BigInch, thanks. A fast closing of the ESDV could originate a water hammer, on the other hand, the longer it is open, the bigger the problem downstream, those are the things that require balance to figure an adequate closing time, that is why I would like to estimate the time better.

 

[BigInch]

With the millions it costs for subsea safety equipment, you can't design in enough wall thickness for waterhammer, or install a surge tank to handle it? If quicktime is so important, it must be worth something. If you can't find the standard, do a cost benefit and prove it's worth the extra wall thickness to have the fastest time you can afford.

If it ain't broke, don't fix it. If it's not safe ... make it that way.