Actuated Valve Tagging - ESD, SBV, etc. 2

[302Hugo]

Can someone help point me in the right direction on whether there is a standard on the proper naming convention for actuated valves that are used for certain purposes? For instance if an actuated valve is used for an emergency situation and meet certain criteria (such as it fails last) it must be labeled as ESD, or if an actuated valve is used to isolate but only closes when given the permissive, than it doesn't have to be labelled as ESD (although it would be used in an emergency situation).

I have tried to find something like this but I am having no luck so far. I have looked through CSA Z662 and so far I cannot find anything that that states a pressure limiting/protection valve needs to be labeled a certain way. I am thinking it is basically up to the operator to determine what the valve shall be labelled, so long as the proper testing/inspection/maintenance is completed on the valve, but I wasn't sure. Note that I have yet to search though my companies specifications to try and find something internal.

 

[EmmanuelTop]

The ANSI/ISA-5.01.01 (previously ISA 5.1) standard defines instrumentation symbols and identification. There are several copies of the standard available on the internet (Google). However, as far as I know, the ISA standard does not differentiate between EIV (emergency isolation valves) and EBDV (emergency blowdown valves), because they are basically identical valves but with different functions and fail-safe characteristics.

In several projects/plants I have been involved with, slightly different terminology was followed in each case - it was probably driven either by the existing tagging specification of the operator company, or it developed as a dedicated project specification for that particular project. For SIS actuated valves used for emergency isolation, I have come across the following symbols: EIV, ESDV, XV, ZV. For SIS actuated valves used for emergency blowdown, I have seen the symbols EBV, EBDV, XV, ZV. Manually operated valves were most commonly tagged as HV.


Dejan IVANOVIC
Process Engineer, MSChE

 

[LittleInch]

You're confusing yourself. The designation of a valve does unfortunately change depening on clients and location. What you need to do is look at the function of the valve and what system it is dealing with. Lots of plants now have two separate systems - the ESD system with its own set of transmitters, valves and logic boards and the DCS or process control system.

In general the idea is the two shouldn't be mixed up. So yes, on an ESD event you can command, via the DCS, certain valves to close or open. However this is just additional back up. They are not "ESD" valves.

ESD valves should not be used for process or general isolation ppurposes, should fail in their safe position (without waiting for any external command) using some sort of local stored energy (usually a spring), generally are held in their non fail position, hence failure of the signal will "trip" them, and commonly require a local rest before they will go back to their non fail position.

All this is normally contained in the ESD and operating and control philosophy documents for the company / facility / design.

Because there are so many different situations, the codes don't specify this - as said look for an ESD philosophy and a control philosophy or something similar and this may spell out how your company does things.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[302Hugo]

Thanks fellows. I found ISA 5.1 after my OP but I didn't find it helpful as it doesn't even discuss "emergency" and only discusses safety valves in terms of a spring PSV. As both you point out it looks like there is no real standard for "emergency" valves and it all comes down to our company standard (which I don't think there is one). This is something we will have to develop to prevent future confusion on what the valves main purpose is.