LPG - Calculating minimum pipe size required to supply a gas fire
 

Hi.

I am interesting in installing an open gas fire.

I already have a half-inch gas pipe which supplies LPG to a gas heating
stove in an adjacent room. So I was thinking that a T-junction in this
pipe, enabling the addition of a second pipe through the wall to the
neighbouring room, might do the trick. The question is, how do I
calculate whether the gas flow will be sufficient to run both the
existing gas stove and the new open fire?

The specs. are;

Gas supply source - 2 tonne cylindricat gas tank
Existing supply pipe - 1/2 inch copper pipe
Existing gas stove - maximum of 4.5 kilowatts input
New open gas fire - maximum of 32 kilowatts input


The input figure (32 kilowatts) for the new open gas fire may seem
excessive, but it is correct - manufacturer's figures.

Can anyone tell me if the existing 1/2 inch supply pipe is large
enough? If so, can you advise the method of calculation so that I can
rework the figures for alternative fires or stoves?

Thanks for any advice.

LPG - Calculating minimum pipe size required to supply a gas fire
 

On 2 Feb 2006 23:19:08 -0800, "Pete"
wrote:

The input figure (32 kilowatts) for the new open gas fire may seem
excessive, but it is correct - manufacturer's figures.

Bonkers!!!

Do they quote the efficiency too...?

cheers,
Pete.

LPG - Calculating minimum pipe size required to supply a gasfire
 

The input figure (32 kilowatts) for the new open gas fire may seem
excessive, but it is correct - manufacturer's figures.

What size of gas fire is it?! Are you heating the great hall in a castle
or something?

I seem to remember that the copper development agency
(http://www.cda.org.uk/) has online tables for sizing pipes.

HTH

--
Alistair Riddell - BOFH
Microsoft - because god hates us

LPG - Calculating minimum pipe size required to supply a gas fire
 

The specs. are;

Gas supply source - 2 tonne cylindricat gas tank
Existing supply pipe - 1/2 inch copper pipe
Existing gas stove - maximum of 4.5 kilowatts input
New open gas fire - maximum of 32 kilowatts input


The input figure (32 kilowatts) for the new open gas fire may seem
excessive, but it is correct - manufacturer's figures.
I suspect they've left out the decimal point?
Maybe it should be 3.2 Kw
unless there is a very large boiler behind it :-).

Some figures from and old catalogue which may help :-
15mm pipe dia.
pipe length- 10ft 20ft 30ft 40ft
gas flow, 108 76 62 -- cu ft/hr

& for 22mm pipe 225 160 130 110 cu ft/hr

Hope this helps
Donwill

LPG - Calculating minimum pipe size required to supply a gas fire
 

Do they quote the efficiency too...?

What size of gas fire is it?! Are you heating the great hall in a castle
or something?

I suspect they've left out the decimal point?

I know, the consumption is quite astonishing isn't it? However, the
maximum heat input is definitely 32 kw; specs. can be viewed at
http://www.stovax.com/images/cms_bro...re_baskets.pdf
(the entry for a large Swan's Nest fire in the table near the bottom of
the document).

I have also spoken to Gazco's technical department, and they confirm
that the figure is correct. (Incidentally, I understand that the heat
input and output are quoted at the same figures for these fires.) The
efficiency rate is between 15% and 25%, depending on the setitng - most
of the heat disappears up the chimney, as with open wood fires. So even
the large fire version may only produce 4.8 kw of heating.

I will actually probably be looking to install the medium sized fire,
which has a (still apalling) maximum input of 21.9 kw. However, my
query mentioned the consumption figure for the large fire as installing
this size is a remote possibility.

I am looking at these fires as they match the existing wood burning
grate. A smaller fire would be lost in the seven foot wide, three foot
deep inset fireplace (it's an early 17th century farmhouse). The high
gas consumption isn't a major concern for reasons which I won't go into
here (but it's not because I'm mega-wealthy!).

Anyway, thanks for the information and the quick replies; I will look
into your suggestions this evening.

Cheers.

LPG - Calculating minimum pipe size required to supply a gas fire
 

I have also spoken to Gazco's technical department, and they confirm
that the figure is correct. (Incidentally, I understand that the heat
input and output are quoted at the same figures for these fires.) The
efficiency rate is between 15% and 25%, depending on the setitng - most
of the heat disappears up the chimney, as with open wood fires. So even
the large fire version may only produce 4.8 kw of heating.

Hmmm....

I will actually probably be looking to install the medium sized fire,
which has a (still apalling) maximum input of 21.9 kw. However, my
query mentioned the consumption figure for the large fire as installing
this size is a remote possibility.

I am looking at these fires as they match the existing wood burning
grate. A smaller fire would be lost in the seven foot wide, three foot
deep inset fireplace (it's an early 17th century farmhouse).

Why not a wood burning grate or stove for a _real_ fire? If you're in
a rural area there's always plenty of wood around...

The high
gas consumption isn't a major concern for reasons which I won't go into
here (but it's not because I'm mega-wealthy!).

Go on ;)

cheers,
Pete.