New build extractor fan

[Tyson1234]

Hello

I've recently bought a new build and was wondering if anybody knew a bit more info about the regs for extraction fans. I was sure a new build must have a timed fan in all bathrooms. However mine has a standard fan that comes on and off with the lights, I've took the fan apart to see if it was wired incorrectly but it is just a standard, none timed fan but they've ran I a 3-core cable and just put a terminal block on the wire not used. I tested the wire and it does indeed stay live when the lights are off, suggesting to me that someone has put the wrong fan up? I've asked the site foreman and he told me it's because the windows are vented so they don't need to fit timed fans anymore, however his respones seemed a bit unsure. Like I said I was next to sure a fan needs to be timed to get rid of excess steam after a shower/bath, something I feel a window vent will not do and I've never heard that mentioned before.

Cheers for any help in advance

 

[DPG]

I'd personally ask then to fit a timed fan, especially as the correct wiring is there. Seems a bit tight on a new build. And as you say, you maybe want it to overrun after the lights are turned off.

 

[MJPD29]

The difference is less than 5 quid. Even if worst comes to worst you could get one fitted yourself for relatively cheap. As for the vented window thing I don't actually know

 

[Avo Mk8]

Hello

I've recently bought a new build and was wondering if anybody knew a bit more info about the regs for extraction fans. I was sure a new build must have a timed fan in all bathrooms. However mine has a standard fan that comes on and off with the lights, I've took the fan apart to see if it was wired incorrectly but it is just a standard, none timed fan but they've ran I a 3-core cable and just put a terminal block on the wire not used. I tested the wire and it does indeed stay live when the lights are off, suggesting to me that someone has put the wrong fan up? I've asked the site foreman and he told me it's because the windows are vented so they don't need to fit timed fans anymore, however his respones seemed a bit unsure. Like I said I was next to sure a fan needs to be timed to get rid of excess steam after a shower/bath, something I feel a window vent will not do and I've never heard that mentioned before.

Cheers for any help in advance

Regarding regulations, the requirement comes from Building Regulations Approved Document F: 'Ventilation'. Bedtime reading ?

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/468871/ADF_LOCKED.pdf

My understanding is that if a bathroom/shower room has a proper openable window which can provide rapid ventilation, a run-on fan is not required. However I don't think a 'trickle vent' counts.
The regs also set minimum flows for the fan, Bathroom/shower room 15 l/sec (54 m3/hr)

Maybe try harder persuading the site foreman that the regs require a timed fan. By the way, is there a 3 pole fan switch installed outside the bathroom, which together with the permanent live would demonstrate the original plan was to include a timed fan.

 

[brianmoooore]

15 minute over run is only legally required in bath/shower rooms without an openable window.

 

[DefyG]

Taken from Part F (Ventilation) of Building Regs

 

[timhoward]

The difference is less than 5 quid. Even if worst comes to worst you could get one fitted yourself for relatively cheap.

This. I'm wondering if the wrong units were purchased, it's easily done.

 

[DPG]

This. I'm wondering if the wrong units were purchased, it's easily done.

Maybe. Although some of the house building companies do cut every cost where they can.