Can someone tell me if it is allowed to use a solenoid valve as a process shutdown valve? The line size where the SOV/PSDV will be installed is very small, i.e. DN15 tubing and injecting chemical for corrosion protection.

Thanks for your feedback.

 

Is the solenoid valve fail-safe? Is it zero leakage, i.e. "bubble tight"?

 

Technically you will achieve higher order of reliability when a solenoid valve is directly used online to replace a PSDV. Because reliability of a PSDV in totality is lower as it depends not only on the valve (ball may be preferred choice)and actuator's reliability but also on all accessories fitted into, out of which one is a solenoid valve.

Highly reliable solenoid valves are available (with IEC 61508 compliance) for fail-safe applications.

General problems with solenoid valve are,
1. Material compatibility to process is limited.
General choice on body is SS and brass only. Choice on soft parts are also limited to PTFE, Buna-N etc.
2. dP Shutt-Off is limited
3. Design pressure/temperature is also limited.
4. Instrument air failure condition, if applicable for the plant can not be directly achieved.

You may check back with reputed manufacturers for supply of 2/2 port, 3/8" SOV to meet your requirement. But as a standard engineering practice, solenoid valve do not replace PSDV.

Regards.