Air vent in lounge - can i fill it in

Mike-H · 22 Oct 2010

In my lounge there is an airvent about 6-8 inches in circumfrence. It has a plastic guard on external and internal walls. The house when built had an open fire but this is now a 3 year old gas fire.

What purpose does it serve?
Can i just fill this in?
If i fill it what is the best way?

Thanks,
Mike.

Rip44 · 22 Oct 2010

Mike-H said:
In my lounge there is an airvent about 6-8 inches in circumfrence. It has a plastic guard on external and internal walls. The house when built had an open fire but this is now a 3 year old gas fire.

What purpose does it serve?
Can i just fill this in?
If i fill it what is the best way?

Thanks,
Mike.

Hello Mike,

I've just had to fit an air vent in an extension under building regs. It used to be part of the regs that if your stove was under around 5kw you didn't need additional ventilation, however regs have changed since 1st Oct 2010 and now it's based on air permeability of the house as well as output of the stove. Not too sure about gas fires but I would have thought the vent was fitted for it. Old houses didn't tend to have vents fitted for open fires as there were enough drafts to feed the fires !

Mike-H · 22 Oct 2010

Regs, rules and legislation. Was life really so unsafe in the old days? Take you point though. Thanks.

Richard C · 22 Oct 2010

Mike-H said:
Regs, rules and legislation. Was life really so unsafe in the old days? Take you point though. Thanks.

In days of yore when houses were fitted with ill fitting windows & doors things were fine as they were more than enough draughts to allow fires & stoves a good supply of air to burn safely. Now we have efficient double glazing with no draughts at all the room can become almost hermetically sealed & that’s very dangerous. To ensure the fire flue has sufficient draught to avoid a potential life threatening build up of carbon monoxide, Building Regulations have for some time required a permanently open vent in a room fitted with a fire rated over 5Kw, even open fires. It’s there for a very good reason, for your own safety do not cover/block it up.

macfudd · 23 Oct 2010

If the rated input of the fire is below 7kw,no additional ventilation is required and the vent can be blocked up.If you can`t find the data badge where this info is,get a Gas Safe Registered engineer in,he will be able to rate the fire manually and further advise you.

foxhole · 23 Oct 2010

Mike-H said:
In my lounge there is an airvent about 6-8 inches in circumfrence. It has a plastic guard on external and internal walls. The house when built had an open fire but this is now a 3 year old gas fire.

What purpose does it serve?
Can i just fill this in?
If i fill it what is the best way?

Thanks,
Mike.

Even with no gas appliances you need good ventilation to avoid condensation and damp/mold etc.

Richard C · 23 Oct 2010

macfudd said:
If the rated input of the fire is below 7kw,no additional ventilation is required

I don’t thinks that’s correct; 5Kw was & still the limiting factor as far as I'm aware but things got a whole lot more complicated since October 1st when new B Regs were introduced;

Ventilation for stoves
The regulations covering ventilation for stoves have been updated as of 1st Oct 2010
Stoves need a supply of air for combustion, and to evacuate the flue gases otherwise they will not work. Without an air supply the stove will not light and smoke is likely to pour out into the house. The smoke will not be able to be drawn up the chimney as this requires air movement up through the chimney which is not possible if there is no source of air. If your stove smokes or does not burn very keenly, but this improves when you open a window then this is a sign that you need to install some ventilation. Read more about this on our smoking stoves page. Sometimes sufficient air can come through the building itself and no dedicated ventilation is necessary.
Stove ventilation - the regs
Ventilation rates to the stove are now based on the air permeability of the house as well as the rated output of the stove.
Stove with a draught stabiliser fitted Air permeability > 5.0m³/h.m²
300mm² for each kW up to 5kW
850mm² for each kW thereafter.

Air permeability ≤ 5.0m³/h.m²
850mm² for each kW

Stove with no draught stabiliser fitted Air permeability > 5.0m³/h.m²
550mm² for each kW above 5kW
Air permeability ≤ 5.0m³/h.m²
550mm² for each kW

I'm going to have to spend some time reading the new regs to understand exactly what it all means

WestmidsChippy · 23 Oct 2010

I thought these air vents were put in place incase of a sudden drop in air pressure :S

I guess this site is useful

macfudd · 24 Oct 2010

I don’t thinks that’s correct; 5Kw was & still the limiting factor as far as I'm aware but things got a whole lot more complicated since October 1st when new B Regs were introduced

This is a Fire we`re talking about,not a stove.
Below 7kw,adventitious air is all that is needed for a flued space heater.

Any other Registered installer want to back me up here?

I thought these air vents were put in place incase of a sudden drop in air pressure

Where do you live?On top of a mountain?

kevindgas · 24 Oct 2010

mcfudd is correct

a flued gas fire up to 7kw = no vent req
a flued gas fire over 7kw = vent 5cm square for each kw or part of over 7kw
DFE = 100cm2 irrespective of kw
ILFE = as a flued fire

but in each case where flue flow clearance is impaired and spillage occurs then a vent is required

flueless fires up to 2.7kw need 100cm2 and above 2.7 require 100cm2 + 55cm2 for each kw exceeding 2.7kw

Richard C · 24 Oct 2010

macfudd said:
This is a Fire we`re talking about, not a stove.
Below 7kw, adventitious air is all that is needed for a flued space heater.

Got to admit I’ve had no involvement with gas fires & didn’t appreciate there was any difference but, on checking, I see there is so sorry to have doubted you

. I’m not really sure I understand the logic behind it though.

Mike-H · 26 Oct 2010

Vent was in when we moved in. There was no double glazing and no central heating, plenty of drafts and it made a cold corner in the lounge.

However, we have now fitted double glazing, central heating and made some improvements so we do not notice any cold spots. The house is super warm. It was more the 'look' of the vent now, but from what i have read above i think i will leave it be. I hear asphyxiation (sp?) is over rated.

kirkgas · 29 Oct 2010

macfudd said:
If the rated input of the fire is below 7kw,no additional ventilation is required and the vent can be blocked up.If you can`t find the data badge where this info is,get a Gas Safe Registered engineer in,he will be able to rate the fire manually and further advise you.

THIS IS THE WORST ADVICE I HAVE READ ON HERE FOR YEARS
under NO circumstances can this vent be blocked UNTIL a gas engineer has confirmed it is safe to do so, what is written above is an assumption, based on adventitious ventilation entering the room, and there is no way of checking this over a computer,
PLEASE igonore macfudd's advice and talk to a properly qualified experienced gas engineer
macfudd if you are a qualified gas engineer hold your head in shame and get back to basics before you kill someone

Mickymoody · 31 Oct 2010

Mike-H said:
In my lounge there is an airvent about 6-8 inches in circumfrence. It has a plastic guard on external and internal walls. The house when built had an open fire but this is now a 3 year old gas fire.

What purpose does it serve?
Can i just fill this in?
If i fill it what is the best way?

Thanks,
Mike.

The airvent was built into the property when it was built, why take exception to it? When the gas fire was installed, the airvent was a consideration on it's install..so removing it means you like to dice with death, for no reason. Why remove a feature, that is designed into a property to protect your life? What is the reason to remove this life saving feature?

masona · 31 Oct 2010

Mike-H said:
Vent was in when we moved in. There was no double glazing and no central heating, plenty of drafts and it made a cold corner in the lounge.

However, we have now fitted double glazing, central heating and made some improvements so we do not notice any cold spots. The house is super warm. It was more the 'look' of the vent now, but from what i have read above i think i will leave it be. I hear asphyxiation (sp?) is over rated.

Might be an idea to change it to Black Hole Ventilator, I will be fitting mine shortly , http://www.stadium-ventilation.co.uk/vents/downloads/Blackhole_BM720.pdf

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Air vent in lounge - can i fill it in

Mickymoody

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