Emergency Valve Selection

[scdaiwei]

am wanting to select a emergency shutoff valve in accident operation.
But I have no idea of the emergency valve. Could you tell me the ways to select the emergency valves and how to choose the type of emergency valve?
I normally see the emergency valve is ball valve. Why?
Thank you in advance.

 

[pennpiper]

Are you a Piper?
If not go talk to a Piper.
If you are a piper then go to "Google" and "ESDV" for some general information.

Then select a valve that meets the criteria for the applicable Line Class.
Then talk to a valve vendor.

 

[ash9144]

You need to talk to operations people and understand what emergency scenario you are trying to minimize. The emergency shut down scenarios should be evaluated for what action the valve should take.

Often emergency valves are ball valves because they are fast acting, high torque, least likely to stick or scale up, and have better shutoff (closer to 100%) than other valves.

 

[dcasto]

Ball valves are 90 degree turn to close. Gate valves can take more than 15 360 Degree turns to close. The time to close becomes a factor for safety valves.

Orbit valves are used too. They are like ball valve but in a manual operation they take 10 or more 360 degree turns to close, however, they can be automated to close very quickly.

I usually do not get concerned about time to close on emergency valves. The amount of flow over a several minute time span to close as compared to hundreds of thounsands of hydrocarbons already in the area where the emergency is not significant.

 

[JimCasey]

Sometimes ESVs are needed to isolate control rooms or other ventilation systems. In such a case it is common to use a butterfly valve tweaked to close very rapidly.

It IS impressive to see a 36" butterfly snap shut in 0.2 seconds. Also a good idea to call the local seismographic office ahead of time. ..it makes an impressive "clang", in addition to all the noise from the air flowing from the actuator.

 

[scdaiwei]

Thank you.
I have some idea of emergency valve.