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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Fire Safety => Topic started by: GB on February 23, 2006, 12:56:29 PM

Title: Smoke Extract Fans
Post by: GB on February 23, 2006, 12:56:29 PM

I have a domestic environment where I am looking to remove smoke via extract fans - hopefully not the same size as used on the Queen Mary and don't cost the same to install!!!!

Can anyone help??

Title: Smoke Extract Fans
Post by: wee brian on February 23, 2006, 03:29:32 PM

Smoke control is rarely a viable option in domestic size areas. You tend to need bigger fans than you would in a larger building.

Why do you want one?

Title: Smoke Extract Fans
Post by: GB on February 23, 2006, 04:14:26 PM

I have completed a CFD model of a domestic premise that the architect wants to deviate from the standards. Untenable conditions exist in the property due to reduced visibility due to smoke in a fire simulation. I have modelled natural ventilation where ossible but the time taken to clear the premise is unacceptable.

Title: Smoke Extract Fans
Post by: kurnal on February 23, 2006, 07:08:59 PM

Have you considered residential sprinklers- active fire protection. proven track record, and general acceptance by the authorities in terms of trade offs ( usually better described as trade ups!)

Title: Smoke Extract Fans
Post by: Paul on February 23, 2006, 08:36:46 PM

GB,

Not a cheap option, although I guess if you need to employ CFD methods you already know this.  I did something along the same lines using a Plenum chamber.

Not sure if it would be possible for you if the premise has already been errected, although I think it is somethng that is worth considering as the size of extracts required may be greatly reduced, along with the fact that the smoke is taken directly out of the compartment and for a period relies upon the natural bouyancy of the hot smoke.

Worth considering.  If you want to discuss or want more detail, drop me a line via my email.

TA

Paul

Title: Smoke Extract Fans
Post by: GB on February 24, 2006, 09:57:56 AM

Thanks guys.

K. I have looked at domestic sprinklers but my problem that using the required safe egress time and occupancy charateristics, I have untenable conditions due to reduced visibilty. Altough travel distance around 9m a small ignition soucre aorund 10kw is fine, but a larger ignition source of 100kw gives me a problem. Bcontrol won't accept the sprinklers alone. This is the reason for the extraction.

PS. I will drop you an e-mail and chat further - thanks.

Title: Smoke Extract Fans
Post by: wee brian on February 24, 2006, 12:05:31 PM

Trust me on this - mechanical extraction will be unviable. You need a decent reservoir and domestic rooms are just too small.

Title: Smoke Extract Fans
Post by: Firewolf on February 24, 2006, 12:17:23 PM

Yeah have to agree with Wee Brian on this. Smoke Extraction in this scenario would be impractical and more than likely astronomically expensive.

If you are going to go to all that trouble you may wish to consider other trade offs, dependant on what kind of occupancy you are expecting within the building of course...can you offer any further info on that?