Ceiling fan

[Spoon]

Hi. A mate has just seen this on another site and has sent it to me, so I have pasted it onto here.

Got asked an interesting question by a Gas installer today.

Is there anything in the wiring or building regs that you're aware of that cause problems with installing ceiling mounted fans in rooms where there are gas fires?

Apparently the fans can cause the flue gases to spill back into the room and make a sleepy house.

Stumped me a bit, I don't recall seeing anything like this, but i haven't read every last little bit of every document ever produced.

Anyone come across this before?
​

Hes not talking about extractor fans.



http://www.bis.gov.uk/files/file11332.pdf

​

 

[Dazza1976]

Its something ive never come accross before,

but like yourself, I havent read every last little bit of every document either.

It will be interesting to hear though from someone that does know about this.

 

[Spoon]

Thanks for commenting Dazza.

 

[Marvo]

As far as I know (which isn't very far) the regs generally cover room ventilation and not air disturbance within a room. They would specify that a room with a natural draft flu should have ventilation in the form of fresh air at a certain volume per hour. The volume is often expressed as the volume of the room a certain number of times in one hour (air changes per hour or ACH). An average house with only natural ventilation might achieve 1 ACH. As a wild guess I would say you might be looking at 5 ACH as a sensible figure if there's a gas appliance in the room. The natural 'stack effect' ventilation caused by hot exhaust gasses rising up a flue might even achieve this figure without forced ventilation using a fan.

We use the ASHRAE handbook as our general guidelines.

 

[raustin]

Yeap - Part J of the Build regs covers combustion appliances and extraction rates. Had this come up as a question on my Part P.

http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADJ_2010.pdf

 

[Paul.M]

Just a question. Why would anyone have a ceiling fan and a gas fire on at the same time?

 

[telectrix]

think he's talking of circulating fans, as they draw air upwards, the concern seems to be that this could pull flue gases back into the room. interesting question.

 

[Spoon]

think he's talking of circulating fans, as they draw air upwards, the concern seems to be that this could pull flue gases back into the room. interesting question.

Got it on one telectrix. I have never heard about this and was just wondering if anyone had? What would you guys do if you was doing a PIR and was this?

 

[telectrix]

as BS7671 has nothing to do with gas fires, ignore it on a PIR. totally irrelevant .

 

[manda]

I was at a friends a few years ago when the gas guy came to do the annual inspection. She had had a ceiling fan fitted and he mentioned something to the same effect that it was not permitted to have a ceiling fan in the same room as a gas fire. He didn't go in to why exactly that was, but did waffle something about the warm air being sucked upwards towards the ceiling. The fan is still there, as is the gas fire and to be honest I've never seen the fan on at the same time as the fire and doubt it ever would be. But seems there must be some sort of reg somewhere regards this.

 

[telectrix]

thinking about it though, the fan is usually used to cool if it's too warm ( around 3 days a year in this country ) and as such, will be moving air downwards. can't see how this would draw flue gases back into the room. gas and gas fumes, we know, can be dangerous, but it's coming to the stage when we are turning into a right bunch of fairies. soon we will all be advised to stay in bed all the time for fear of swine flu, bird flu ( remember that. was going to kill millions ), SARS, ( ditto ) , CO poisoning, CO2 suffocation, radiation sickness, mad cow disease if we ate a T-Bone steak ( banned by phony blair ) , alien invasion ( that's more likely ) . global warming ( now that's a thought-- it's so warm on the planet now, we use central heating 6 months of the year just to stop freezing.

 

[IQ Electrical]

Many manufacturers have a recommended safe blade height where the fan is used in a room with a gas burning appliance.
The problem is, safe blade height is often quoted (by manufacturers and BSI) as being around 2.3 Metres, a height that is difficult to attain in modern buildings.

So the upshot seems to be that some degree of testing is recommended where the 2 appliances are in use in the same room.

Although published in 2003, this is the latest documentation that I have on the subject:

 

[manda]

I think the most dangerous worry with a lot of these fans is sitting in someone's living room, directly under one that is wobbling itself all over the shop and seemingly ready to attack and decapitate at any moment Sod the fumes!!!

 

[telectrix]

remind of the gremlins film, where he was spinning round on the fan. PMSL.

 

[RogertheBodger]

Many manufacturers have a recommended safe blade height where the fan is used in a room with a gas burning appliance.
The problem is, safe blade height is often quoted (by manufacturers and BSI) as being around 2.3 Metres, a height that is difficult to attain in modern buildings.

So the upshot seems to be that some degree of testing is recommended where the 2 appliances are in use in the same room.

Although published in 2003, this is the latest documentation that I have on the subject:

Interesting document, Seems like there is a case to answer on the potential danger of this situation, don't you just love this bit ......

Quote ......... The installation and operating instructions seemed to be quite comprehensive, and it is believed that DIY installation could be performed simply and easily. However, the
recommended safe blade height of 2.3m would be difficult to achieve in most modern
homes with a standard 8ft [2.5m] ceiling. Moreover, there is a contradiction, in that
the installation instructions warn against usage of the fan in the same room and at
the same time as a gas or fuel burning fire (unless the flue has been properly tested)
whilst the packaging and operating instructions encourage cool weather usage to
allow lower indoor heat settings.
The supplier was contacted by letter and by telephone to obtain definitive guidance
on this contradiction, but suitable technical help was not available. Instead, the rather
inappropriate advice was that “… an enclosed appliance should be alright, but if in
doubt contact an electrician”.

From what I read it appears that the onus is on the gas fitter to draw test the flues, but as you point out that was 2003, If there was a fatality from this I wonder where the finger of blame would point?