lockout/ tagout of pneumatic valves

[chumet1]

Dear colleagues

Plant safety regulations require the de-energizing of system when working on it including pneumatic valves. a recommendation was made to introduce lockable isolating valves in the system but the requirement has been specified to lock the actual process valve. there are hundreds of valves in the plant, replacement will be expensive so i wanted to explore modification of valves to introduce the lockout/ tagout system on current valves.
i have attached 3 pics of typical valve types in the plant. please assist with modification concepts for lockout/tagout system on the valves

 

[mk3223]

Since no block valves immediately next to these pneumatic valves for lock-out/tag-out, IMO, you may find the isolation valves by tracking further up and downstream of the process line for it.
The safety requires a physical block valve on the process line to hang the tags, but it could be located at some distance from the pneumatic valve

 

[chicopee]

Cut the air line upstream from the pneumatic valves and place manual valves with levera that can be locked up.

 

[zdas04]

Lock out manual pneumatic supply valve or remove the tubing from the valve. That will disable the actuator. You still have to address the notion of "process isolation" since control valves should never be used for isolation.

[bold]David Simpson, PE[/bold]
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist