Gas Shut Off

[Gasmeter]

I've been asked if it is advisable to link the automatic gas shut off in a roof top boiler room to the fire alarm system in such a way that if there is a gas leak the fire alarm will sound. Of course, the gas shut off activates when the fire alarm activates but I've never heard of doing it the other way round.  The safety measures mean the risk of an uncontrolled leak is very remote, I doubt if it would be a useful arrangement. All opinions gratefully received.

[kurnal]

Fire alarms should only be used to give warning of fire. To use them for other purposes - gas leaks or bomb scares can put people at risk because they may require a different response. The fire alarm system could even cause an explosion of gas if conditions were right!

I recollect there was a  terrorist incident at an army barracks where the terrorists phoned in a call to say there was a bomb in the building and actually placed the bomb at the fire assembly point where it detonated killing many servicemen.

[Wiz]

My opinion is that it depends on how reliable the gas detection system is in respect of 'unwanted alarms' and what type of building it was in.
If it was very reliable, then shutting off the gas and also giving a warning of a gas leak via the fire alarm system wouldn't be a bad thing in some circumstances i.e. a HMO. But I would never argue against Professor Kurnal's advice - it is only my initial thought.

[kurnal]

If the fire alarm sounds call the fire brigade? Or Transco? Or both? Spend time shutting off the gas as a matter of course delaying your evacuation from what may be a fire?

Would be useful for a gas leak detector to shut off the gas. At the gasmeter?

Wiz him speak with forked tongue. Him dare find me wanting on technical forum. Him heap right too.

[Gasmeter]

Hello Chaps, thanks for your replies; the gas leak detection shuts off the supply in the boiler room and at the main intake to the site. I tend to agree with Kurnal that the fire alarm should only give warning of fire, so I'm going to advise that if they want a gas leak warning throughout the building a distinct separate alarm should be installed.

[Wiz]

If the fire alarm sounds call the fire brigade? Or Transco? Or both? Spend time shutting off the gas as a matter of course delaying your evacuation from what may be a fire?

Would be useful for a gas leak detector to shut off the gas. At the gasmeter?

Wiz him speak with forked tongue. Him dare find me wanting on technical forum. Him heap right too.

After my success over Kurnal in the Technical Forum, I momentarily overestimated my abilities and thought I could catch him out again. Obviously I failed miserably so I will now retreat into my room and consider a new plan of action.

[wee brian]

If the shut off valve operates then the problem has gone away so there's no need to evacuate.

[Wiz]

If the shut off valve operates then the problem has gone away so there's no need to evacuate.

Unless the leak is before the shut-off valve!

[Ken Taylor]

I'm not keen on the idea but, in as much as fire alarm sounders are sometimes used to provide (by a different sound) lesson change notification in schools, someone might want to argue that a different and recognisable sound could be provided to warn of something like a major uncontrolled gas leak in very specific circumstances.

[Thebeardedyorkshireman]

Electrical equipment used to warn persons of a hazardous situation should by design not conribute towards making the situation worse. Thus in the event of a major gas leak the warning sounders should be incapable of igniting the gas in the atmosphere EG flameproof or IS.
 The energy levels into the environment from the fire detection system are significantly increased in an evacuation mode and consideration should be given to powering down the system.
This is the trap everybody falls into when trying to link other warnings into a standard fire alarm. Tee shirt anybody?
Dave