We've just had a gas fire fitted in the living room and understand
there is a requirement for a vent. it's a victorian house which is far
from sealed and I intend to get a carbon monoxide alarm. We're most of
the way through fitting a secondary wood floor and the plan was to put
a vent into it to the underfloor cavity (we've recently made sure all
the air bricks to the cavity are clear).

So two questions:

1) Given the general draughtiness of the house do we really need the
air vent?

2) if yes, how big. The figure of 100cm3 was mentioned but our local
hardware stores don't carry stock and the minimum order requriements
mean I'd look online. However the vents i've found (on
andyplumb.co.uk) are measured, strangely, in inches. I'm presuming
that 100cm3 does not equal a vent meauring 10cmx10cm but relates to the
size of the holes.

wrote in message
ups.com...
We've just had a gas fire fitted in the living room and understand
there is a requirement for a vent. it's a victorian house which is far
from sealed and I intend to get a carbon monoxide alarm. We're most of
the way through fitting a secondary wood floor and the plan was to put
a vent into it to the underfloor cavity (we've recently made sure all
the air bricks to the cavity are clear).

So two questions:

1) Given the general draughtiness of the house do we really need the
air vent?

You need to allow for someone "draught proofing" it later.

2) if yes, how big. The figure of 100cm3 was mentioned but our local
hardware stores don't carry stock and the minimum order requriements
mean I'd look online.

Last time I checked (about 7 years) it was 16 sq in, which is about 100cm^2.

However the vents i've found (on
andyplumb.co.uk) are measured, strangely, in inches. I'm presuming
that 100cm3 does not equal a vent meauring 10cmx10cm but relates to the
size of the holes.

The area is the "free flow area" (ie area of holes) not the overall vent
dimension.

Don't muck around with this, do it right.

--
73
Brian, G8OSN
www.g8osn.org.uk

On 30 Oct 2005 03:58:39 -0800, wrote:

| We've just had a gas fire fitted in the living room and understand
| there is a requirement for a vent.

The manual for the fire should give the area required. Insist that the
fitter give you the manual.
--
Dave Fawthrop dave hyphenologist co uk
Help make Usenet a better place: English is read downwards,
please don't top post. Trim replies to quote only relevant text.
Check groups.google.com before asking an obvious question.

Brian Reay wrote:
2) if yes, how big. The figure of 100cm3 was mentioned but our local
hardware stores don't carry stock and the minimum order requriements
mean I'd look online.

Last time I checked (about 7 years) it was 16 sq in, which is about 100cm^2.

The area is the "free flow area" (ie area of holes) not the overall vent
dimension.

OK, any clues on suppliers - i've only had a quick search but it didnt
deliver me anything useful

wrote in message
ups.com...
We've just had a gas fire fitted in the living room and understand
there is a requirement for a vent. it's a victorian house which is far
from sealed and I intend to get a carbon monoxide alarm. We're most of
the way through fitting a secondary wood floor and the plan was to put
a vent into it to the underfloor cavity (we've recently made sure all
the air bricks to the cavity are clear).

So two questions:

1) Given the general draughtiness of the house do we really need the
air vent?

What is the consumption of the gas fire? Not all gas fires require vents -
only those above a certain consumption level.

2) if yes, how big. The figure of 100cm3 was mentioned but our local
hardware stores don't carry stock and the minimum order requriements
mean I'd look online. However the vents i've found (on
andyplumb.co.uk) are measured, strangely, in inches. I'm presuming
that 100cm3 does not equal a vent meauring 10cmx10cm but relates to the
size of the holes.

When I had an art-deco cast iron fireplace fitted a few years ago the inset
'decorative' gas fire required a vent and the fitter installed one by
cutting a slot into the floorboards and fitting a grille. It was terrible -
the draught coming up from the vent was like a hurricane - and freezing in
winter! In fact I would say that the amount of cold air coming into the room
from the vent was greater than the warm air coming into the room from the
fire. In the end we placed a piece of carpet over the vent and just made
sure that the lounge door was open a bit when using the fire. Never had any
problems.
We recently had a completely new contemporary fire installed (Brilliance
'slab' fire) and the fitter stated that the input was border-line for having
a vent fitted. I questioned him about the need for a vent and he pointed out
that the requirement for vents was only made in recent years and prior to
that no-one fitted them! As I was installing a laminate floor I just removed
the vent grille, placed a thin piece of aluminium sheet over the slot, and
laid the laminate flooring over it. Again the fire works fine, no evidence
of fumes coming into the room, and with the lounge door left slightly ajar,
plenty of fresh air to feed the fire.
If you are going to fit a vent into the underfloor cavity then I would think
strongly about ways of preventing draughts - on windy days it will be
horrendous!

Kev

wrote in message
ups.com...
We've just had a gas fire fitted in the living room and understand
there is a requirement for a vent. it's a victorian house which is far
from sealed and I intend to get a carbon monoxide alarm. We're most of
the way through fitting a secondary wood floor and the plan was to put
a vent into it to the underfloor cavity (we've recently made sure all
the air bricks to the cavity are clear).

So two questions:

1) Given the general draughtiness of the house do we really need the
air vent?

2) if yes, how big. The figure of 100cm3 was mentioned but our local
hardware stores don't carry stock and the minimum order requriements
mean I'd look online. However the vents i've found (on
andyplumb.co.uk) are measured, strangely, in inches. I'm presuming
that 100cm3 does not equal a vent meauring 10cmx10cm but relates to the
size of the holes.


Whoever installed it should have checked and advised what ventilation was
required; if they didn't I'd be very suspicious as to their qualifications
to do such a job.

"Grouch" wrote in message
...

wrote in message
ups.com...
We've just had a gas fire fitted in the living room and understand
there is a requirement for a vent. it's a victorian house which is far
from sealed and I intend to get a carbon monoxide alarm. We're most of
the way through fitting a secondary wood floor and the plan was to put
a vent into it to the underfloor cavity (we've recently made sure all
the air bricks to the cavity are clear).

So two questions:

1) Given the general draughtiness of the house do we really need the
air vent?

2) if yes, how big. The figure of 100cm3 was mentioned but our local
hardware stores don't carry stock and the minimum order requriements
mean I'd look online. However the vents i've found (on
andyplumb.co.uk) are measured, strangely, in inches. I'm presuming
that 100cm3 does not equal a vent meauring 10cmx10cm but relates to the
size of the holes.


Whoever installed it should have checked and advised what ventilation was
required; if they didn't I'd be very suspicious as to their qualifications
to do such a job.


Further to that it should not have been installed without correct
venilation.

What fire did the guy install? not all fires need extra ventilation. Are
there any other appliances in the same room?


wrote in message
ups.com...
We've just had a gas fire fitted in the living room and understand
there is a requirement for a vent. it's a victorian house which is far
from sealed and I intend to get a carbon monoxide alarm. We're most of
the way through fitting a secondary wood floor and the plan was to put
a vent into it to the underfloor cavity (we've recently made sure all
the air bricks to the cavity are clear).

So two questions:

1) Given the general draughtiness of the house do we really need the
air vent?

2) if yes, how big. The figure of 100cm3 was mentioned but our local
hardware stores don't carry stock and the minimum order requriements
mean I'd look online. However the vents i've found (on
andyplumb.co.uk) are measured, strangely, in inches. I'm presuming
that 100cm3 does not equal a vent meauring 10cmx10cm but relates to the
size of the holes.

wrote in message
oups.com...

Brian Reay wrote:
2) if yes, how big. The figure of 100cm3 was mentioned but our local
hardware stores don't carry stock and the minimum order requriements
mean I'd look online.

Last time I checked (about 7 years) it was 16 sq in, which is about
100cm^2.

The area is the "free flow area" (ie area of holes) not the overall vent
dimension.

OK, any clues on suppliers - i've only had a quick search but it didnt
deliver me anything useful

Sorry, no. Last time I looked into this was just to check a fire already
installed was OK- not actually installing one myself.

Really, I do advise you look into this very carefully. Check what the fire
needs, then make sure that the room is so supplied.

Did the person who fitted the fire not check all this?

I noticed someone commented about draughts such vents can cause. Yes, they
can cause draughts but they also stop you being killed, so don't skimp!.
You can always position the vents so that the draught isn't drawn across the
area you sit!

--
73
Brian, G8OSN
www.g8osn.org.uk

Grouch wrote:
Whoever installed it should have checked and advised what ventilation was
required; if they didn't I'd be very suspicious as to their qualifications
to do such a job.

The fitter did check, advised us 100cm3. The floorboards that were
down at the time a) had up to 4mm gaps between them, and b) had a hole
about 10cm x 10cm where a first, aborted, attempt had been made to fit
the fire by another fitter so there was more than enough ventilation.
There was no point in him insisting on a vent being added because he
knew we were about to lay a secondary floor which would change the
situation.

Hence my question:
1) in a draghty house is it still necessary (not to comply with the
regs but to be safe)
2) where can i buy a suitable vent? (and if they're measured by
external diameter rather than cubic airflow what size vent do i need?)

wrote in message
oups.com...

Grouch wrote:
Whoever installed it should have checked and advised what ventilation was
required; if they didn't I'd be very suspicious as to their
qualifications
to do such a job.

The fitter did check, advised us 100cm3. The floorboards that were
down at the time a) had up to 4mm gaps between them, and b) had a hole
about 10cm x 10cm where a first, aborted, attempt had been made to fit
the fire by another fitter so there was more than enough ventilation.
There was no point in him insisting on a vent being added because he
knew we were about to lay a secondary floor which would change the
situation.

Hence my question:
1) in a draghty house is it still necessary (not to comply with the
regs but to be safe)
2) where can i buy a suitable vent? (and if they're measured by
external diameter rather than cubic airflow what size vent do i need?)


You can buy a variety of suitable vents from your local branch of Plumb
Centre
Round, rectangular and brass finish floor ones.

On Mon, 31 Oct 2005 03:12:44 -0800, b33k34 wrote:


Grouch wrote:
Whoever installed it should have checked and advised what ventilation was
required; if they didn't I'd be very suspicious as to their qualifications
to do such a job.

The fitter did check, advised us 100cm3. The floorboards that were
down at the time a) had up to 4mm gaps between them, and b) had a hole
about 10cm x 10cm where a first, aborted, attempt had been made to fit
the fire by another fitter so there was more than enough ventilation.
There was no point in him insisting on a vent being added because he
knew we were about to lay a secondary floor which would change the
situation.

Hence my question:
1) in a draghty house is it still necessary (not to comply with the
regs but to be safe)
2) where can i buy a suitable vent? (and if they're measured by
external diameter rather than cubic airflow what size vent do i need?)

The manual will state the facts - this is the ultimate decider.
If the manual does not state the vent requirements then:

If the fire has an input gas rate of less than 7kW then no purpose
provided vent is needed PROVIDED the flue draws (which is will unless it's
blocked).

If more than 7kW then 100cm^2 will be needed.
If more than 14kW (which some display type models could be) then I would
need to look some standard docs - however that would be very big if
it's a grate burner.

Attempts to rewrite the regs based on pleading to special circumstances
are a bit like trying to argue that you can bypass some of the electric
regs "because you're only use lights".


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Ed Sirett wrote:

Attempts to rewrite the regs based on pleading to special circumstances
are a bit like trying to argue that you can bypass some of the electric
regs "because you're only use lights".

point taken - it was only in response to some comments i'd seen on
here.

So can you point me to an online supplier (with the item i need - brass
rectangular preferably) as the plumbing suppliers within walking
distance were no help.

In article .com
, writes


So can you point me to an online supplier (with the item i need - brass
rectangular preferably) as the plumbing suppliers within walking
distance were no help.

Do you need one after all?, 7kW input is an absolutely huge fire.
--
fred
Plusnet - I hope you like vanilla

On Tue, 01 Nov 2005 17:50:56 +0000, fred wrote:

In article .com
, writes


So can you point me to an online supplier (with the item i need - brass
rectangular preferably) as the plumbing suppliers within walking
distance were no help.

Do you need one after all?, 7kW input is an absolutely huge fire.

In the world of grate burners 5-14kW is the typical range from the
smallest to the largest models.

For display types 12kW is quite normal.

Inset fires and radiant outset types would typically be 4-7kW.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Ed Sirett wrote:
In the world of grate burners 5-14kW is the typical range from the
smallest to the largest models.

For display types 12kW is quite normal.


It's a Gazco Evolution VFC convector 22" which has an input of 12kw.
manual says it needs 30cm2 of ventilation -

On Wed, 02 Nov 2005 04:00:19 -0800, b33k34 wrote:


Ed Sirett wrote:
In the world of grate burners 5-14kW is the typical range from the
smallest to the largest models.

For display types 12kW is quite normal.


It's a Gazco Evolution VFC convector 22" which has an input of 12kw.
manual says it needs 30cm2 of ventilation -

That's reasonable - the required ventilation would be 22.5cm2 if it were
a 12kW boiler, but fires tend to need more ventilation to keep the
chimney well aired and dry.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html