Utility room extractor fans

[down2earth]

Apologies if this has been discussed before, for background I am first fixing a new extension with the electrician happy to check and test when I have finished ( I have previously completed a domestic installers course), according to building regs, a utility room needs an intermittent extraction rate of 30 l/s, I am struggling to find a 100mm ceiling mounted extractor fan with this capability, however, if you look at Part F of the building regs in table 5.1a extract rates there is a note which states "total extract rates should be at least the whole dwelling ventilation rates given in table 5.1b", in our case this would be 3 bedrooms and therefore 21 l/s so which rate do I go for??
Thanks for any replies

 

[Richard Burns]

I would go for 30l/s you would generally go up to a 6" fan for this rate, but some inline fans will do this on 100mm.

 

[Toneyz]

Why does it have to be a 100mm outlet fan ? or is this is what has been fitted if so you will probably be a centrifugal fan.

 

[Octopus]

Why a ceiling fan? Icon 30 through the wall and you could add the humidstat option. You get what you pay for. Are bco involved?

 

[Toneyz]

Why a ceiling fan? Icon 30 through the wall and you could add the humidstat option. You get what you pay for. Are bco involved?

I wondered that also but came to the conclusion it was at 2nd fix stage or could not extract through a exterior wall.

 

[Octopus]

I wondered that also but came to the conclusion it was at 2nd fix stage or could not extract through a exterior wall.

We can only speculate unless the op updates us...... He's probably trying to find out what bco means.

 

[down2earth]

Thanks for the replies, BCO are involved in as much as the electrician has to satisfy them that the regs have been followed, unfortunately an external wall mounted extract is not an option due to location of new LPG boiler flue and the layout of the room. I wanted to use 100mm as I have previously installed the ducting in the roof void and it would be a nightmare to try and get it out and put in bigger ducting.
Regards down2earth

 

[Toneyz]

I would say as my previous post centrifugal fan , if you think it looks like a shoe box try looking at a recessed version.

 

[telectrix]

Thanks for the replies, BCO are involved in as much as the electrician has to satisfy them that the regs have been followed, unfortunately an external wall mounted extract is not an option due to location of new LPG boiler flue and the layout of the room. I wanted to use 100mm as I have previously installed the ducting in the roof void and it would be a nightmare to try and get it out and put in bigger ducting.
Regards down2earth

could perhaps fit a 6" fan with a ducting adaptor/reducer 6" to 4".

 

[Squid]

Inline fan in the ceiling void how long is the ducting run oh and what is 30l/s converted to m3/h if anyone is good at maths?

 

[telectrix]

it's about 400 cubic miles /fortnight.

 

[Richard Burns]

Inline fan in the ceiling void how long is the ducting run oh and what is 30l/s converted to m3/h if anyone is good at maths?

108m³/hr

 

[Squid]

108m³/hr

I will PM U for when I do the next bank job.....

 

[NDG Elecs]

108m³/hr

Is this you Richard? You are far too quick at maths for us mere mortals!!

 

[Richard Burns]

Is this you Richard? You are far too quick at maths for us mere mortals!!

I only look like that at the weekends!
30 *60*60 /1000 =30 x 3.6 = (30 x 3 = 90 + 30 x 0.6 = 18.0) =90+18 = 108

 

[telectrix]

I only look like that at the weekends!
30 *60*60 /1000 =30 x 3.6 = (30 x 3 = 90 + 30 x 0.6 = 18.0) =90+18 = 108

but did you do that in 30 seconds?

 

[Midwest]

108m³/hr

With that figure the OP could pop down to Screwfix, and pick up one of these;

Extractor Fans | Ventilation | NoLinkingToThis - http://www.NoLinkingToThis/c/heating-plumbing/extractor-fans/cat840510#category=cat840510&extractionrate=108_m__hr

 

[AJ16]

Apologies if this has been discussed before, for background I am first fixing a new extension with the electrician happy to check and test when I have finished ( I have previously completed a domestic installers course), according to building regs, a utility room needs an intermittent extraction rate of 30 l/s, I am struggling to find a 100mm ceiling mounted extractor fan with this capability, however, if you look at Part F of the building regs in table 5.1a extract rates there is a note which states "total extract rates should be at least the whole dwelling ventilation rates given in table 5.1b", in our case this would be 3 bedrooms and therefore 21 l/s so which rate do I go for??
Thanks for any replies

30l/sec is for new dwellings, for extensions a 100mm dia fan of 8L/sec 0r 15L/sec (no opening window, 15 mins overrun is the BC requirement.

 

[Octopus]

30l/sec is for new dwellings, for extensions a 100mm dia fan of 8L/sec 0r 15L/sec (no opening window, 15 mins overrun is the BC requirement.

The op is talking about a utility room. Out of interest where does the over run timer bit come into this?

 

[AJ16]

Yes I know it's about a utility room, the regs are different though for extensions and new dwellings. The overrun is for rooms that do not have an opening window, but probably just shower rooms not utility rooms, the key is to either refer to plans which have been signed off by building control, or get agreement on site from the BCI.