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Topic Title: fan over run
Topic Summary: Is there a reg?
Created On: 22 December 2010 07:44 PM
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 22 December 2010 07:44 PM
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Zs

Posts: 2849
Joined: 20 July 2006

Hello,

A bathroom with no windows and a fan which is on/off with the lights. No timed over run. This is a let flat.

The council have demanded that it be changed for one with a timed over run. Getting to a permanent live in concrete ceilings is not going to be easy.

I can't find the requirement for timed over run in building regs or big red. Do you know where it is? And if you do, could you point me at it?

I'll do the work anyway but my inner geek is telling me to know more.

Thank you.

Zs
 22 December 2010 07:49 PM
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broadgage

Posts: 1279
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AFAIK the building regs require suitable ventilation in a bathroom or toilet without an opening window.
I dont think that the regs specificly state that an overrun is required, but it could be argued that a fan that stops as soon as the room is vacated is not "suitable"
 22 December 2010 07:56 PM
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spinlondon

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Not in BS7671.
 22 December 2010 07:59 PM
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ant1uk

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Lol.........I thought the timer was just an extra to get rid of extra smelly no2's
 22 December 2010 08:08 PM
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michaelbrett

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Originally posted by: Zs

Hello,



A bathroom with no windows and a fan which is on/off with the lights. No timed over run. This is a let flat.



The council have demanded that it be changed for one with a timed over run. Getting to a permanent live in concrete ceilings is not going to be easy.



I can't find the requirement for timed over run in building regs or big red. Do you know where it is? And if you do, could you point me at it?



I'll do the work anyway but my inner geek is telling me to know more.



Thank you.



Zs


Zs

If you can alter the wiring so that you have a continous live at the fan position, how about using a fan with an integral PIR? These have an over-run facility. So far as I remember, Silavent make one and so do Manrose.

This will then solve your problems with the rewiring. No wiring changes as such.

Regards

Mike
 22 December 2010 08:10 PM
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MrOther

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Zs I installed a fan in the house recently.

Snags and Solutions was pretty useful as it referenced lots of details from various sources.

As far as I can remember the main thing is a local point of isolation i.e. 3-pole isolator switch.
 22 December 2010 08:14 PM
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rikhill

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Part F of the building regs is what you are after.

References to 15 minute overrun include the crucial word 'should' and appears in the 'new dwelling' section. I'm not aware of any part of the approved doc that apply to existing buildings unless new work is being carried out.


If you lose the argument however, you may be able to overcome the concrete ceiling problem (I need 36V of SDS to even get fixings in the ones I work in locally!!) by installing a PIR or humidity fan on the existing T+E and re-wiring it to a permanent feed at the light fitting.
 22 December 2010 08:23 PM
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John Peckham

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Zs

Part F of the Building Regs.

See http://www.planningportal.gov....cuments/partf/approved

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 22 December 2010 08:57 PM
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dickllewellyn

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You could fit an extermal timer unit? They usually come fixed to a single blank plate with a variac sticking through to adjust the time. This can then be situated next to the switch, or somewhere that suits.

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Richard (Dick)

"Insert words of wisdom and/or witty pun here"
 23 December 2010 10:03 AM
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aligarjon

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i believe a fan with a humidistat is also acceptable. Just change the supply to it to mains. Gary

-------------------------
Specialised Subject. The Bleedin Obvious. John Cleese
 23 December 2010 10:53 AM
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OMS

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Originally posted by: aligarjon

i believe a fan with a humidistat is also acceptable. Just change the supply to it to mains. Gary


I guess it depends on if the bathroom also contains a WC - the dominant condition then is control of odours so a humidistat is a bit ineffective.

Part F does mention this

Regards

OMS

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 23 December 2010 11:04 AM
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perspicacious

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"so a humidistat is a bit ineffective."

It would depend on weather (sic) it is eye wateringly (sic) bad

Regards

BAD
 23 December 2010 04:28 PM
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aligarjon

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Originally posted by: OMS

Originally posted by: aligarjon



i believe a fan with a humidistat is also acceptable. Just change the supply to it to mains. Gary




I guess it depends on if the bathroom also contains a WC - the dominant condition then is control of odours so a humidistat is a bit ineffective.



Part F does mention this



Regards



OMS



Are you saying it would not comply oms ? bearing in mind a w/c with an opening window does not require an extractor, or has that changed.

Gary

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Specialised Subject. The Bleedin Obvious. John Cleese
 23 December 2010 04:43 PM
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chrishaworth

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How about this remote timer from Telco? http://www.tlc-direct.co.uk/Products/BGDT20.html

Cheers
Chris
 23 December 2010 04:49 PM
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OMS

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We are discussing enclosed spaces I believe. Try a read through Clause 4.20 of Approved Document F 2010 or Table 1.5 in AD F 2006 where bathrooms are also sanitary accomadation

Regards

OMS

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Failure is always an option
 24 December 2010 11:16 AM
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AJJewsbury

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Or an air quality switch? - e.g. http://www.justfans.co.uk/air-...ity-sensor-p-238.html
- Andy.
 24 December 2010 04:42 PM
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aligarjon

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Originally posted by: OMS

We are discussing enclosed spaces I believe. Try a read through Clause 4.20 of Approved Document F 2010 or Table 1.5 in AD F 2006 where bathrooms are also sanitary accomadation



Regards



OMS


Cheers.

100 lines for me.

I must read the OP properly.

i missed the no window bit.

Gary

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Specialised Subject. The Bleedin Obvious. John Cleese
 28 December 2010 01:04 PM
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1652

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Don't forget that a fan in a bathroom with no window requires it's own isolator. Turning off the MCB to the lighting curcuit removes light in the room.

What about fusing the fan inacordance with manufacturer's instructions.

We never have a tourch to hand do we.........
 28 December 2010 05:22 PM
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Jaymack

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Originally posted by: 1652
Don't forget that a fan in a bathroom with no window requires it's own isolator. Turning off the MCB to the lighting curcuit removes light in the room.

And for the fan in a bathroom .......... with a window?

Regards
 28 December 2010 11:28 PM
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Rulland

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Just zap em!.........

-------------------------
Those who make no mistakes do very little work!!......
IET » Wiring and the regulations » fan over run

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