Fire shutdown module for ventilation and ACU

Well where are you installing the air conditioning, and what is the fire and partition strategy for the whole building ?
The answer will depend heavily on the answers - there are situations where you absolutely must stop airflow as soon as possible if there is a fire, and others where it is totally unsafe to do so. But depending where the people are, and how quickly they can get out, and if not if they have a source of breathable air is all important. Deep basement facilities are quite different to a bungalow, as are places with more plant rather than people, or places that store large quantities of potential fuel.

How the air is managed needs to be handled as part of the larger task of the building design and its fire containment and evacuation strategy. Like the deceptively simple sprinklers question a few days ago, it is not at all simple.

Mike

PS please don't trust the design of safety of life systems to AI - these are just a programs for guessing the most suitable next word, given the ones before and a lot of training material, much of which is likely to be unsuited to your situation.

you are right. Never mentioned where my ACU will be installed as that is important as well.

I am working on switchgear enclosure looks like the ones below but larger containing more modules/rooms.

so containerized plant rooms, mostly unmanned, no members of the public ? What is the procedure for any staff who may be there to follow in a fire, How is one detected ? Is there automatic extinguishing What needs to stay on in a fire, what needs to go off ?
I'm inclined to think that this is one of the cases where the stop the airflow approach is correct, but there ought to be someone designing a whole coherent strategy for fire and other fault conditions - are there batteries for example that need to be kept cool? 
Mike

If this is a place other than a dwelling, the answer is as simple as:

"What does the fire safety risk assessment require, and/or devolved Building Regulations for the particular premises."

See also BS 9999.

Tom D said:

I am working on switchgear enclosure looks like the ones below but larger containing more modules/rooms.

Also, need to consider ventilation required for gases or vapours for relevant equipment, such as batteries and some switchgear, and how they are to be considered in a fire situation, unless there is separate ventilation for these straight into 'sealed' enclosures. See BS EN IEC 62485 series for battery ventilation.

Thanks for your reply. It is very simple enclosure. As you have said most of the time unoccupied. There is an emergency walkway provided with running man em. bulkhead light above each exit door. Also fire alarm is fitted with multidetectors and manual call points but we don't do any fire extinguishing systems though. There is no battery room in there neither Atex room. We normally do shutdown for the ventilation system in the event of fire just to not bring any more fresh air but I don't think it is necessary to have similar module to shut DX ACU down in a such a small and unmanned boxes.

mapj1 said:

I'm inclined to think that this is one of the cases where the stop the airflow approach is correct,

Perhaps, but what if the container contains batteries that can emit combustible or explosive gases or vapours? Are the containers constructed to deal with this? Is separate ventilation provided for those?

Also, certain switchgear and suppression systems contain gases that might be harnful ... what about evac of persons?

Without the risk assessment, it's not really possible to speculate IMO.

Hi Graham, I agree  more info needed, and  I'm not sure of the role of the OP - there has been no mention of a design authority / system architect so perhaps there isn't one - in which case the fire plan may well not exist yet  too.  That's why I'm inclined, not suggesting and certainly not recommending...  

But there should be one of each, as part of the system design, let alone the containment design. without that it could just be very dangerous.

By way of illustration some big switchgear is intended to be fitted in a building where the roof is allowed to blow off for example, in preference to the sides being pushed outwards. Others have deliberate weak points that flap outwards in the event of an explosion within. Now it may not be that the fault levels are actually that big, but we dont really know, and the outer containment needs to reflect the needs of what it contains. 

Mike.