Is there a requirement in the UK for fans to stay on after light is switched off in shower room?

[t36374]

Hi everyone,

I ask the above because I have recently moved to Australia and in the current development I live in (a newly built apartment block) I've noticed that as soon as I've used the shower and leave the showerroom switching off the light behind me, the fan also goes off. This is leading to mould build up as on occasion I'll forget to leave the light on while I'm not using the shower room.

This leads me to my question.

Are there any regulations in the UK requiring the fan to stay on once the light has switched off? Or is this just good practice?

Does anyone have any idea why the Aussies don't seem to want to keep the fan on?

Cheers

Tom

 

[Adam W]

There should be a 15 minute overrun.
People don't like the fan to overrun, or even come on in the night, because of the noise. Sometimes people try to get around this by having the fan on a separate switch, but that opens it up to abuse if for example someone decides they want a quiet bath. Often people don't understand the purpose of the fan and never use it after declaring it doesn't do anything, ie cool them down in the summer.

The overrun is usually adjustable so you should be able to change it yourself fairly easily.

 

[Wilko]

Timer fans are available in Aus and I can't think of a good reason not to use them. Perhaps the building has its own inbuilt background ventilation system ? If there's one of these you could open it up a bit to increase the flow.

 

[mhar]

A lot of people think fans are to get rid of odours and don't consider moisture

 

[Ian1981]

Bathroooms/shower rooms without a window should incorporate a timed over run fan.
At least that is the case in new builds.

 

[Deleted account]

I was always under the impression that an over run was not neccissary. I've never seen it means ironed in regs or guidance notes.
I stand ready to be corrected if I'm wrong.

Personally an over run is the better option, but as for reg wise "no".


Edit- mentioned, not means ironed. Predictive text sucks.

 

[Octopus]

On new builds and extensions involving BCO's over run timers are required ................

as is now cooker hoods extracting externally ............

What a lot of people don't realise is that if there isn't enough airflow under the door, then the extractor can't do the job .................. and opening a window, in the winter will only make things worse............

 

[Ian1981]

I was always under the impression that an over run was not neccissary. I've never seen it means ironed in regs or guidance notes.
I stand ready to be corrected if I'm wrong.

Personally an over run is the better option, but as for reg wise "no".


Edit- mentioned, not means ironed. Predictive text sucks.

Part F of th building regulations gives guidance however whether it’s a regulation or not the local building inspector and builder on our new build sites require an over run fan on bathrooms and sanitation rooms containing no windows and timers in fans in utility rooms at no less than 5 inch in size.
5 inch in utility room only

 

[Deleted account]

I looked into this last year so skimmed over Part F. Couldn't find the. 15 min over run.
But countless other articles state the 15 mins.

Maybe I missed it. When I have a bit more time I will read it page to page.

 

[Octopus]

Part F of the building regulations gives guidance however whether it’s a regulation or not the local building inspector and builder on our new build sites require an over run fan on bathrooms and sanitation rooms containing no windows and timers in fans in utility rooms at no less than 5 inch in size.
5 inch in utility room only

Does it actually say that?

I thought it specified a flow rate!

EDIT: Page 19 from Part F added ..........

 

[Ian1981]

Does it actually say that?

I thought it specified a flow rate!

EDIT: Page 19 from Part F added ..........

No but it’s what our building control want

As a side note some homes near a main road require continuous running fans at low speed and a boost function.
We use icon continuous fans with boost feature.
These are all 4 inch sized so the building inspector allows in this case us to fit 4 inch in the utility.
Confused yet?

 

[Deleted account]

Confused? Of course, I've been confused since the day I took up electrics.

But I still love it.

 

[Adam W]

I looked into this last year so skimmed over Part F. Couldn't find the. 15 min over run.
But countless other articles state the 15 mins.

Maybe I missed it. When I have a bit more time I will read it page to page.

It's in the Electrician's guide to the building regs, which just happens to be the only book I have within easy reach. It may not be in BS7671.

 

[Octopus]

No but it’s what our building control want

Confused yet?

And people wonder why the tragedy of Grenfell happened?

All the paths lead back to the DCLG .................................

 

[Deleted account]

It's in the Electrician's guide to the building regs, which just happens to be the only book I have within easy reach. It may not be in BS7671.

I'll have a look later thanks

 

[Octopus]

It's in the Electrician's guide to the building regs, which just happens to be the only book I have within easy reach. It will not be in BS7671.

Edited that for you.

It won't be in BS7671 as its not a reg that applies to electrics.

A common sense approach would be for BS 7671 to refer to Part F ............ but that's too difficult for the IET et al to understand.

 

[Richard Burns]

Part F approved document table 5.2a notes states:
Controls - Intermittent extract
- May be operated manually and/or automatically by a sensor (e.g. humidity, occupancy/usage, pollutant release). Humidity controls should not be used for sanitary accommodation as odour is the main pollutant.
- In kitchens. any automatic control must provide sufficient flow during cooking with fossil fuel [e.g. gas) to avoid build-up of combustion products.
- Any automatic control should have a manual override to allow the occupant to turn the extract on.
- In a room with no openable window (i.e. an internal room) an intermittent extract fan should have a 15 minute overrun. In rooms with no natural light, the fans could be controlled by the operation of the main room light switch.


This is guidance but is generally easier to comply with than alternatives that may cause problem with building control who have no understanding.

 

[Gavin John Hyde]

Timer fans are available in Aus and I can't think of a good reason not to use them.
View attachment 41426

Only if you have the mesh screening in the extraction hole. too many dangerous creepy crawlies around them parts that might like to get into a nice moist warm bathroom!