Air Con in the workplace

[bobbyross]

Hi Guys,

Need a bit of advice regards air con units in the workplace, as they are a source of oxygen and can fuel a fire, what is the law on how they should shutdown if a fire does occur? Is it mandatory that they close down automatically when a fire occurs i.e. sensors fitted or connected into fire detection system?
Are they allowed to be operated manually only?

Thanks for any replies

Bobby

[kurnal]

I guess it depends whether they are local units covering a single room in which case manual control would be fine, but if the units serve a number of rooms then in the event of a fire  the air conditioning will circulate smoke and oxygen around the building and in such a case the system should automatically shut down on operation of the fire alarm.

I guess that a possible reason to interface units serving a single room to an alarm would be if the room was used for  assembly purposes and the airflow could direct smoke towards the exits.

[Ken Taylor]

Bobby is asking about the law on this one. Other than being a sensible control measure when determined by risk assessment, is there something more specific around to which reference could be made?

[Chris Houston]

Bobby,

Are you aware that "split" units don't introduce new air, but just chill the existing air, therefore not introducing any fresh air or oxygen?

With regards to full system, they tend to be shut down upon activation of the fire alarm system, but there is not specific piece of legislation that requestes this, as in the UK we have a risked based approach to fire safety.

[wee brian]

BS 5588 Part 9 - give best practice advice - Auto shut down is only necessary wehre air is recirculated from different parts of the building.

Common practice is to shut everything down.

[Ashley Wood]

As Chris says, it is best to assess the system and the effects it would have if you did or did not shut it down. In a typical large IT site, shutting down the a/c will enable the temperature within the cooled room to reach 'melt down' very quickly due to the heat load being produced by hundreds of units. So the solution you may say is shut down the units as well? The problem then is one of power supply as tripping the mains will introduce UPS or generator power, it could also cost the client a huge sum of money. One client I recently did work for said that they would loose in the region of £90 million per day if the system was shut down!