Closure time of ESD valve

[Clive36]

I'm trying to generate some guidelines for closure time of emergency shutdown valves (ball and butterfly type) for an oild and gas client.

Is there any field data specifying actual closure times and giving details of the valve size, duty, process conditions etc. I have been looking intently and cannot find anything. I understand it's dependent on the application but is there any guidance out there at all?

Thanks in advance.

 

[zdas04]

You have to go to the manufacturer for that. The tables I've seen are very much dP dependent.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[bcd]

Sorry, no published guidance that I have ever seen. You can pretty much get whatever stroke times the process safety experts think they need. It all varies upon how your are operating the valve, electric, pneumatic, spring, hydraulic. We have made large butterflies that close in 0.1 seconds with hydraulic. Granted they wont do that too many times, but it has been done before.

Common rule of thumb for general stroke speeds mentioned elsewhere in this forum is 1 sec. per inch of valve size. That is a little on the slow side, but is generally good practice for normal autoamted on/off valves and minimize risk of water hammer. For pneumatically operated valves up to 24 inch, 1 to 5 seconds is the typical range.

 

[stanier]

Each system should be analysed for transient response to ESD closure. This is particularly with hydrocabon service. No valve actuation should create conditions more severe than the reason for the ESD. ie No point in an ESD to prevent a spillage causing a line break that may be even more catastrophic.

Systems I have modelled have ESD times out to 4 minutes. Others needed high pressure nitrogen actuators to close in milliseconds. You cannot have an overriding rule for such things.

Systems may require valves to have dual cloising times. The initial time may close to 20% open very quicky and the last time to full closure may time a long time. This is typical for butterfly valves where the flow is not impacted until the valve is near closed.

It is important that that the dynamic engineering is undertaken otherwise you dont know what you dont know. Guessing doesnt go down well with judges.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

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