Shower extractor fan replacement

[peteuk]

Hi,
Sorry if this is the wrong place for this but most shower fan queries seem to be here. Also please forgive the naivety of the questions:

I have a bathroom and en-suite both without windows.
I previously installed Silavent Spotvent kits (lights above the shower) but these are not up to the job. (Ducting length from ceiling to loft wall is at least 5m from the bathroom)
I am thinking of buying 2 Silavent Vitalis 100TB's which it says will remove 44l per second.
Does anyone have experience of this fan or have a recommended alternative?
I am concerned about noise and if it would be too powerful. (My wife will NOT like a cold bathroom). But obviously I want it to do the job.
I propose to buy fans with a timer. The current fans don't have a timer. Will this mean additional wiring or will it be part of the fan installation?

By the way the fans are currently lower then the outside wall outlets so I will have to change the fan position.

Thanks,

Pete

 

[Pensdown]

The approved documents F gives minimum extract rates so you could compare them with your rates. That should give you some idea.

http://www.planningportal.gov.uk/england/professionals/en/1115314110382.html

 

[Taylortwocities]

You must have timer (15mins I believe) if the bathroom does not have an opening window.

You will need to fit an isolator switch for the fan so it can be maintained without switching off the lights - this could be in the loft if you have the in-line type
and
yes you will need to do some wiring as the timer fans need neutral, live and switched live (oh and earth)

btw this is notifiable work a la Building Regs Part P

 

[ericmark]

A timer is not required for a "Bathroom" however it is required for a loo so if you have a loo in the bathroom you need timer. 15l/s intermittent or 8l/s continuous see Part F http://www.planningportal.gov.uk/england/professionals/en/4000000000339.html this may not apply in Scotland?

 

[Taylortwocities]

Table 1.5 states that 15min timer only required if no openable window.

Look at Glossary and see the definition of bathroom. It says MAY contain sanitary accomodation. Its my understanding therefore that a bathroom without a WC still needs ventilation under the regs.

 

[ericmark]

Easy answer let PeteUK read it for himself I have given link but that is the way I read it.

Table 1.5 states that 15min timer only required if no openable window.

there are other points like manual operation also in table 1.5 and at the end of the day unless we quote whole Part F we must miss out something.
Eric

 

[peteuk]

Dear all, Thanks for the many replies:

Having read the link I believe the fans (Silavent Vitalis 100TB's) I am proposing are up to the job.
Extract rate = 44l/sec versus 15l/sec requirement and with 15 min time overrun.
I'm not an electrician (and not very practical truth as my questions reveal) so will have to ask someone to fit it - the isolator switches sound a good idea although I didn't see these mentioned.

However does anyone have experience of this fan or have a recommended alternative? I am concerned about noise and if it would be too powerful. (My wife will NOT like a cold bathroom, nor wish to hear it running for 15mins every time she uses a light). But obviously I want it to do the job.
Thanks again,

Pete

 

[Taylortwocities]

Thats the difference, building regs state the extarct rate. Wiring regs will deal with the need for an isolator..

One thing to remember - if you've got a powerful fan it still wont extract very well if the door is a snug fit. This is dealt with in the building regs document..

 

[peteuk]

Thanks for all the advice - will now get on and organise it

 

[peteuk]

Please help. I thought I had this sussed but something made me check again.
When looking for a fan supplier I found a website which supported the fan size calculation. However it then mentioned losses in the ducting.

Our rooms are:
En-suite: 2.4m x 1.27m x 2.5m = 7.62m³. The site suggests we need a fan capable of extracting 42.3l/sec = 152,000l/hr
Bathroom: 2.2 x 2.5 x 2.5 = 12.375m³. The site suggests we need a fan capable of extracting 68.8l/sec = 248,000l/hr

The fan that Silavent advised would no longer appear up to the job but the site suggests 2 that meet the spec (using the existing 100mm ducting)
But the distance from the bathroom via the fan to the wall vent is ~6m so the site then suggest that ducting losses for the more powerful fan would reduce its output to 108 m³ / hour.
I would like to stay with the exisitng 100mm ducting because I wish to keep the current ceiling outlets which includes light fittings (Spotvent 100mm)

Now my stupid question given that I have read their website's advice:
Will the fans be ok to do the job or will the ducting losses really be that high?
(The builder who installed the original Spotvent fans said those would be ok......)

If the ducting losses are really going to be so significant can anyone recomend a fan that will allow still allow us to keep a light fitting above the shower. (And hopefully not be too noisy)
[the fans I am currently considering are: Soler and Palau SL TD160T & SL TD250T]

Thanks for any advice - I don't want to buy unsuitable fans for the second time!

Pete

 

[Taylortwocities]

The cheaper makers of fans cant push much at all. Over a 6" 100mm duct you wont get much out, if anything.

.Suggest you ask Silavent tech support. Ask them what the max duct length is for the fan you want and what the ducting loss is per metre for each fan.