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[SPBK]

Dear All,

 

As a project scope, we are upgrading ESD system for existing operational plant. One of the objectives is to identify ESD valves shall be provided with PST (Partial Stroke Test) facility.

 

I had checked company guidelines as listed below,

 

“As a minimum, Partial Stroke Testing (PST) shall be provided for critical valves (e.g. battery limit valves, common manifolds etc) which cannot be stroked during normal plant operation. Applicability of partial stroke testing for additional valves shall be finalized during the FEED stage and indicated on the P&ID‟s and ESD valve data sheets.”

 

“In general, following valves are not considered for partial stroke testing.

                        ♦ Bypass ESD valves installed for pressurization purposes, across main ESD valves

                        ♦ Emergency depressurization valves

                        ♦ Shutdown valves on fuel systems such as Boiler, Gas heaters etc.

                        ♦ Vent valves associated with compressors”

                         

 

If follow above guidelines, I am ending with providing PST facility for following ESD valves,

1.       ESD valves on Chemical Injection lines,

2.       ESD valves on small bore lines which are not part battery limits, (i.e sour water from SRU to solvent recover unit).

 

I require help in the form any International STD which can dictate which ESD valve shall be provided with PST facility or not.

 

We had @300 ESD valves in existing operational Plant.

[fallah]

SPBK,

 

As far as i know, all valves included in safety instrumented system (SIS) should be provided with PST facility. In many applications it's adequate having 10% movement to verify valve response without disturbing the relevant critical process line...