Fire Proof Requirement for Actuator

What is required depends on the zone and classification of the valve referring to the applicable code....

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Let's just say "yes".

It appears the facility has a serious process materials containment problem. Solve that problem. First.

The simplest fail-safe actuator is one that is held open by a piece of string. When the string burns through because of the fire, the spring in the actuator closes the valve.

Gas supplies to boilers are sometimes arranged in this way.

Please stipulate if the said string is conductive or non conductive for reasons of HSE auditing.

As long as the string is combustible, it would matter not a jot, audit or no audit.

Now that is an issue and the area in question is within a flammable area. If he were to employ a person, he could have him hold the actuator open and this will add to safety as the actuator holder opener (AHO) will be able to notify the site crew of any fire hazards by shouting 'Fire, fire". There by releasing the actuator, and in so doing, closing the valve.

Secondly, when the AHO has released the actuator he will run away, thereby creating a noticeable event for others to act accordingly and also run away, and all will be saved.

This is a very cost efficient system as alarms can be eliminated from the cost, reduced maintenance cost of peripheral equipment, reduced costs on builds etc and honestly, the string is susceptible to ultra violet radiation, wear and tear, bad knot tying, poor quality string and of course, mistaken identity as a small bird may believe it to be a worm or good nesting materials and it may be stolen by a person who needs a piece of string for some handy use, such as holding open another actuator.

I would recommend the AHO for this problem and avoid the string due to many variants that may affect the flow.

Besides, AHO's are fully reusable and have other handy features and may be utilised in other areas after training.

Please consider Safety First.

Do you have local codes you can refer to? That would be my first suggestion. If not, it is better to err on the safe side and fire proof away.