Part J: Air Supply Calcs...
 

I have a 6KW multi-fuel stove with ordinary multifuel liner. I am having
some work doing on the front of the house and I thought it might be
time to ensure that the stove has the correct amount of air supply
(according to the regs that is - its a draughty old cottage so
pragmatically...).

Table 2.1 in Part J says...

"Other appliance, such as a stove, cooker or
boiler, with no flue draught stabiliser."

needs

"A permanent air entry opening or openings with a total free area of at
least 550mm2 per kW of appliance rated output above 5kW."

This is 5.5cm2 in my case ... am I getting this right as it seems miniscule?

TIA,

Alex.

In message ,
AlexW wrote:

I have a 6KW multi-fuel stove with ordinary multifuel liner. I am having
some work doing on the front of the house and I thought it might be
time to ensure that the stove has the correct amount of air supply
(according to the regs that is - its a draughty old cottage so
pragmatically...).

Table 2.1 in Part J says...

"Other appliance, such as a stove, cooker or
boiler, with no flue draught stabiliser."

needs

"A permanent air entry opening or openings with a total free area of at
least 550mm2 per kW of appliance rated output above 5kW."

This is 5.5cm2 in my case ... am I getting this right as it seems miniscule?

I think you're mixing up your measurements. Remember that 1cm2 is not
10mm2 but 100mm2 (10mm by 10mm).

Never having done this calculation before, is the regulation stating
that you need 1x550mm2 or 6x550mm2? If the former then is there a
separate regulation for appliances of 5kW and under as otherwise the
regulation seems to imply no air opening is necessary for those.

HTH

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... It all comes down to treating others as you want to be treated.

Martin Angove wrote:
In message ,
AlexW wrote:


I have a 6KW multi-fuel stove with ordinary multifuel liner. I am having
some work doing on the front of the house and I thought it might be
time to ensure that the stove has the correct amount of air supply
(according to the regs that is - its a draughty old cottage so
pragmatically...).

Table 2.1 in Part J says...

"Other appliance, such as a stove, cooker or
boiler, with no flue draught stabiliser."

needs

"A permanent air entry opening or openings with a total free area of at
least 550mm2 per kW of appliance rated output above 5kW."

This is 5.5cm2 in my case ... am I getting this right as it seems miniscule?


I think you're mixing up your measurements. Remember that 1cm2 is not
10mm2 but 100mm2 (10mm by 10mm).

So 550mm2 / 100mm2(1cm2) = 5.5.

Is that not 5.5cm2? This is basic math I know, but maybe I am having a
bad day (6 month old son woke me at 4am)?


Never having done this calculation before, is the regulation stating
that you need 1x550mm2 or 6x550mm2? If the former then is there a
separate regulation for appliances of 5kW and under as otherwise the
regulation seems to imply no air opening is necessary for those.

IMO wording indicates 1x550mm2 as other parts of the table (not
applicable to my situ) state first 5kw and balance of ouput figures.

This is why I am asking the question though as a sanity check!


HTH

Hwyl!

M.


Ta,

Alex

On Tue, 14 Jun 2005 08:43:39 +0100, AlexW wrote:

I have a 6KW multi-fuel stove with ordinary multifuel liner. I am having
some work doing on the front of the house and I thought it might be
time to ensure that the stove has the correct amount of air supply
(according to the regs that is - its a draughty old cottage so
pragmatically...).

Table 2.1 in Part J says...

"Other appliance, such as a stove, cooker or
boiler, with no flue draught stabiliser."

needs

"A permanent air entry opening or openings with a total free area of at
least 550mm2 per kW of appliance rated output above 5kW."

This is 5.5cm2 in my case ... am I getting this right as it seems miniscule?

This is plausible. For a gas appliance the figure would be 4.5cm2 per kW
in excess of 7kW. This first 5 or 7 kW is known as adventitious air it
is the ventilation you'll get (somehow) even if you draught proof to very
high standard.

--
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

In message ,
Martin Angove wrote:

In message ,
AlexW wrote:

I have a 6KW multi-fuel stove with ordinary multifuel liner. I am having
some work doing on the front of the house and I thought it might be
time to ensure that the stove has the correct amount of air supply
(according to the regs that is - its a draughty old cottage so
pragmatically...).

Table 2.1 in Part J says...

"Other appliance, such as a stove, cooker or
boiler, with no flue draught stabiliser."

needs

"A permanent air entry opening or openings with a total free area of at
least 550mm2 per kW of appliance rated output above 5kW."

This is 5.5cm2 in my case ... am I getting this right as it seems miniscule?

I think you're mixing up your measurements. Remember that 1cm2 is not
10mm2 but 100mm2 (10mm by 10mm).

I think *I*'m getting mixed up! Isn't what I said just exactly what you
said?

Sounds like you could ventilate it with a not-quite-fitting door :-)

Where's me coat?

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... Even a blind pig stumbles across an acorn now and again.

Martin Angove wrote:
In message ,
Martin Angove wrote:


In message ,
AlexW wrote:


I have a 6KW multi-fuel stove with ordinary multifuel liner. I am having
some work doing on the front of the house and I thought it might be
time to ensure that the stove has the correct amount of air supply
(according to the regs that is - its a draughty old cottage so
pragmatically...).

Table 2.1 in Part J says...

"Other appliance, such as a stove, cooker or
boiler, with no flue draught stabiliser."

needs

"A permanent air entry opening or openings with a total free area of at
least 550mm2 per kW of appliance rated output above 5kW."

This is 5.5cm2 in my case ... am I getting this right as it seems miniscule?

I think you're mixing up your measurements. Remember that 1cm2 is not
10mm2 but 100mm2 (10mm by 10mm).


I think *I*'m getting mixed up! Isn't what I said just exactly what you
said?

Sounds like you could ventilate it with a not-quite-fitting door :-)

Where's me coat?

Hwyl!

M.


Yeah ... but its such a small value as to be almost unbelievable, I had
to really think about it (several times!) before I did.

Cheers,

Alex.

Ed Sirett wrote:
On Tue, 14 Jun 2005 08:43:39 +0100, AlexW wrote:


I have a 6KW multi-fuel stove with ordinary multifuel liner. I am having
some work doing on the front of the house and I thought it might be
time to ensure that the stove has the correct amount of air supply
(according to the regs that is - its a draughty old cottage so
pragmatically...).

Table 2.1 in Part J says...

"Other appliance, such as a stove, cooker or
boiler, with no flue draught stabiliser."

needs

"A permanent air entry opening or openings with a total free area of at
least 550mm2 per kW of appliance rated output above 5kW."

This is 5.5cm2 in my case ... am I getting this right as it seems miniscule?


This is plausible. For a gas appliance the figure would be 4.5cm2 per kW
in excess of 7kW. This first 5 or 7 kW is known as adventitious air it
is the ventilation you'll get (somehow) even if you draught proof to very
high standard.


Thanks Ed, I think I am happy with my interpretation of this now, as it
does indeed sound roughly in line with Gas.

I doubt I ever get to the stoves max. output of 6kw as its a secondary
source of heat and given the draughty nature of my house I think finding
the extra 5.5cm2 might not be worth it, just to tick the box!

Cheers,

Alex.