5 replies to this topic

[stu]

hi all,

Recently I had come across a facility having ESDV(Emergency shutdown valve) with 2 step closure to avoid water hammer effect. Is it allowable ESDV to have 2 step closure arrangement?

regards

stu

[fallah]

 

Recently I had come across a facility having ESDV (Emergency shutdown valve) with 2 step closure to avoid water hammer effect. Is it allowable ESDV to have 2 step closure arrangement?

 

Hi,

 

In the ESDV you mentioned "Slow Continuous Closing" has been substituted by "Two Steps Closure".

 

I think the important factor is the total time of closure. If the two steps closure takes a time almost equal to that of the continuous closure (1 second per 1 inch of size, roughly), there would be no reason not to be applied in safety standpoint, but it may not be as effective as that of continuous closure to avoid subsequent water hammer.

[shvet1]

Is it allowable ESDV to have 2 step closure arrangement?

 

Yes, it is

[Hakim5]

Hi,

 

Find below the API RECOMMENDED PRACTICE 14C EIGHTH EDITION, FEBRUARY 2017. with expectation that could be helpful.

 

https://drive.google...iew?usp=sharing

[stu]

thanks all...here two step for esdv is until 70 % of closure 1 inch /sec and balance 30% to 0% closure time is more than 1inch/sec ...is it acceptable such closure action in ESDV ..please clarify

regards,

stu

[shvet1]

any closing pattern is acceptable depending on a hydraulic surge study

what does the hydraulic surge report say?