I had a major domestic crisis last week, when the bod who came to
replace my gas meter condemned my pipes as too leaky. Soon resolved by
a local fitter who replaced the sixty-odd year old iron pipes with new
copper ones.

This left me wondering how much gas had been escaping. I forget the
numbers but the manometer was dropping at about twice the allowed rate.
Has anyone got any idea how this would relate to cubic feet, roughly?
Obviously we're talking an order-of-magnitude guess here.

My gut feeling is that the loss was negligible, probably a lot less than
the gas used by a pilot light, and so I won't be noticing any reduction
in my bills.

--
Phil
Liverpool, UK

On Sun, 24 Apr 2011 23:12:09 +0100, Phil
wrote:

I had a major domestic crisis last week, when the bod who came to
replace my gas meter condemned my pipes as too leaky. Soon resolved by
a local fitter who replaced the sixty-odd year old iron pipes with new
copper ones.

This left me wondering how much gas had been escaping. I forget the
numbers but the manometer was dropping at about twice the allowed rate.
Has anyone got any idea how this would relate to cubic feet, roughly?
Obviously we're talking an order-of-magnitude guess here.

My gut feeling is that the loss was negligible, probably a lot less than
the gas used by a pilot light, and so I won't be noticing any reduction
in my bills.

This may help:

http://www.diy-forum.net/re-gas-leak-t54759.html

On Sun, 24 Apr 2011 23:12:09 +0100, Phil
wrote:

I had a major domestic crisis last week, when the bod who came to
replace my gas meter condemned my pipes as too leaky. Soon resolved by
a local fitter who replaced the sixty-odd year old iron pipes with new
copper ones.

This left me wondering how much gas had been escaping. I forget the
numbers but the manometer was dropping at about twice the allowed rate.
Has anyone got any idea how this would relate to cubic feet, roughly?
Obviously we're talking an order-of-magnitude guess here.

My gut feeling is that the loss was negligible, probably a lot less than
the gas used by a pilot light, and so I won't be noticing any reduction
in my bills.

Really I wouldn't have thought that iron pipes themselves would have
leaked - more likely it'd have been screwed joints; jointing compound
having dried out, perhaps, or faulty outlets such as gas poker bayonet
connectors.

Is there such a thing as reduction in energy bills? :-)

--
Frank Erskine

On Sun, 24 Apr 2011 23:12:09 +0100, Phil wrote:

This left me wondering how much gas had been escaping. I forget the
numbers but the manometer was dropping at about twice the allowed rate.

My gut feeling is that the loss was negligible, probably a lot less than
the gas used by a pilot light, and so I won't be noticing any reduction
in my bills.

If enough gas were escaping that it would register on your bills you and
your neighbours would likely not be around to care about it :-|


--
John Stumbles

This sig intentionally left blank

On 25/04/11 01:21, John Stumbles wrote:
If enough gas were escaping that it would register on your bills you and
your neighbours would likely not be around to care about it :-|

That's what I thought. (-:

--
Phil
Liverpool, UK

On 25/04/11 01:38, John Rumm wrote:
You can't really extrapolate a quantity of gas lost based on just a rate
of fall in pressure - without also knowing the total volume of gas
contained in the all the pipework. Needless to say - the smaller the
volume of gas contained the more pronounced the effects of any given
leak will be.

Indeed. That's why I said I was hoping someone might be able to come up
with a rough order-of-magnitude estimate.

--
Phil
Liverpool, UK

On 25/04/11 00:41, Frank Erskine wrote:

Really I wouldn't have thought that iron pipes themselves would have
leaked - more likely it'd have been screwed joints; jointing compound
having dried out, perhaps, or faulty outlets such as gas poker bayonet
connectors.

But is it worth mending loose joints on 60 year old iron pipes? Anyway,
one of the runs was under the solid kitchen floor.

--
Phil
Liverpool, UK

Phil wrote:

On 25/04/11 01:38, John Rumm wrote:
You can't really extrapolate a quantity of gas lost based on just a rate
of fall in pressure - without also knowing the total volume of gas
contained in the all the pipework. Needless to say - the smaller the
volume of gas contained the more pronounced the effects of any given
leak will be.

Indeed. That's why I said I was hoping someone might be able to come up
with a rough order-of-magnitude estimate.

An unaccpetable leak would be something like an unlit pilot light. Maybe
20pence a day? Maybe more.

Alan.
--
To reply by e-mail, change the ' + ' to 'plus'.

On Apr 25, 12:41*am, Frank Erskine
wrote:
On Sun, 24 Apr 2011 23:12:09 +0100, Phil
wrote:

I had a major domestic crisis last week, when the bod who came to
replace my gas meter condemned my pipes as too leaky. *Soon resolved by
a local fitter who replaced the sixty-odd year old iron pipes with new
copper ones.

This left me wondering how much gas had been escaping. *I forget the
numbers but the manometer was dropping at about twice the allowed rate.
*Has anyone got any idea how this would relate to cubic feet, roughly?
*Obviously we're talking an order-of-magnitude guess here.

My gut feeling is that the loss was negligible, probably a lot less than
the gas used by a pilot light, and so I won't be noticing any reduction
in my bills.

Really I wouldn't have thought that iron pipes themselves would have
leaked - more likely it'd have been screwed joints; jointing compound
having dried out, perhaps, or faulty outlets such as gas poker bayonet
connectors.

Is there such a thing as reduction in energy bills? *:-)

--
Frank Erskine

Gas meters measure volume. I often wondered that if I could cool the
gas, I would get more of it for the same money!

On 25/04/2011 07:46, harry wrote:

Gas meters measure volume. I often wondered that if I could cool the
gas, I would get more of it for the same money!

Intriguing - that had never occurred to me before. Surely that must be
the case (albeit presumably the difference is trivial?) If you'd asked
me 30 years ago when I was a little more familiar with Boyle's law etc
al I could have workd it out...

A few years ago we had our gas meter moved indoors, from an unheated
detached garage (which certainly reached below zero during the winter) -
I wonder how much the move has cost me over the years?

David

On Mon, 25 Apr 2011 05:43:23 +0100, Phil wrote:

On 25/04/11 00:41, Frank Erskine wrote:

Really I wouldn't have thought that iron pipes themselves would have
leaked - more likely it'd have been screwed joints; jointing compound
having dried out, perhaps, or faulty outlets such as gas poker bayonet
connectors.

But is it worth mending loose joints on 60 year old iron pipes? Anyway,
one of the runs was under the solid kitchen floor.

You were lucky that the pipes were useable at all after 60 years.
Many years ago I wanted to remove a gas pipe that was sticking up out of the
floor (no gas supply anyway). It was capped with an iron coupler and a
square plug, so removing the connector and sawing off the pipe would get it
out of the way.
Stilsons on pipe, 1 turn, pipe comes out of floor about 6" down and the end
was rusted through! At that time the pipe was about 20 years old. There was
no obvious wettness so the hole was plugged.
--
Peter.
The gods will stay away
whilst religions hold sway

On Apr 25, 12:41*am, Frank Erskine
wrote:
On Sun, 24 Apr 2011 23:12:09 +0100, Phil
wrote:

I had a major domestic crisis last week, when the bod who came to
replace my gas meter condemned my pipes as too leaky. *Soon resolved by
a local fitter who replaced the sixty-odd year old iron pipes with new
copper ones.

This left me wondering how much gas had been escaping. *I forget the
numbers but the manometer was dropping at about twice the allowed rate.
*Has anyone got any idea how this would relate to cubic feet, roughly?
*Obviously we're talking an order-of-magnitude guess here.

My gut feeling is that the loss was negligible, probably a lot less than
the gas used by a pilot light, and so I won't be noticing any reduction
in my bills.

Really I wouldn't have thought that iron pipes themselves would have
leaked - more likely it'd have been screwed joints; jointing compound
having dried out, perhaps, or faulty outlets such as gas poker bayonet
connectors.

Is there such a thing as reduction in energy bills? *:-)

--
Frank Erskine

I once had a customer with iron/steel pipes under the floor. At annual
service time over the years the soundness test showed a slow but
progressive move from entirely sound to eventually outside permitted
drop thus un-acceptable. On detailed investigation I found a section
under the kitchen floor which had been covered with builders sweepings
(shavings, dust, bits of brick) possibly since the house was built.
The covered section of pipe had corroded slowly and after cutting it
out and replacing it I could see the steel had become thinner and
thinner until it was like tissue with pitting. The rest of the pipe
was still perfectly sound. after some 40 years.

On 25/04/11 13:02, John Rumm wrote:

Well I spose one could make a guesstimate...

Say the system has a total equivalent volume of 30m of 15mm pipe, that
would equate to length x area or 30 x (3.14 x (0.0075)^2) = 0.005 m^3

So lets say it starts your two minute test period at an absolute
pressure of 1020 mbar, and drops twice the allowed[1] 4 mbar in the
time, giving a final pressure of 1012.

We will assume the temperature remains constant, and so can assume
Boyle's Law applies and that P1V1 = P2V2, giving 1020 x 0.005 = 1012 x
V2, or V2 = 1020 x 0.005 / 1012 = 0.00504, or an escape of P2 - P1 =
0.00004 m^3 of gas in 2 mins, or 0.0012 m^3 / hour.

That's about 10.5m^3 per year, or 370 cu ft. About what a 35kW boiler
could get through in 11 hours or so.

So all in all less than a fivers worth of gas per year - quite possibly
less than a quid.

[1] Allowed with appliances connected, without there is no allowed drop.



Many thanks for that. My school physics was just too long ago. So - as
expected - no cash bonus!

Thanks to everyone else for their contributions as well.

--
Phil
Liverpool, UK

In message
,
harry writes
On Apr 25, 12:41*am, Frank Erskine
wrote:
On Sun, 24 Apr 2011 23:12:09 +0100, Phil
wrote:

I had a major domestic crisis last week, when the bod who came to
replace my gas meter condemned my pipes as too leaky. *Soon resolved by
a local fitter who replaced the sixty-odd year old iron pipes with new
copper ones.

This left me wondering how much gas had been escaping. *I forget the
numbers but the manometer was dropping at about twice the allowed rate.
*Has anyone got any idea how this would relate to cubic feet, roughly?
*Obviously we're talking an order-of-magnitude guess here.

My gut feeling is that the loss was negligible, probably a lot less than
the gas used by a pilot light, and so I won't be noticing any reduction
in my bills.

Really I wouldn't have thought that iron pipes themselves would have
leaked - more likely it'd have been screwed joints; jointing compound
having dried out, perhaps, or faulty outlets such as gas poker bayonet
connectors.

Is there such a thing as reduction in energy bills? *:-)

--
Frank Erskine

Gas meters measure volume. I often wondered that if I could cool the
gas, I would get more of it for the same money!
Yes, as with Autogas (liquefied propane)
--
hugh
"Believe nothing. No matter where you read it, Or who said it, Even if
I have said it, Unless it agrees with your own reason And your own
common sense." Buddha

On 25/04/2011 13:32, John Rumm wrote:
On 25/04/2011 10:21, Lobster wrote:
On 25/04/2011 07:46, harry wrote:

Gas meters measure volume. I often wondered that if I could cool the
gas, I would get more of it for the same money!

Intriguing - that had never occurred to me before. Surely that must be
the case (albeit presumably the difference is trivial?) If you'd asked
me 30 years ago when I was a little more familiar with Boyle's law etc
al I could have workd it out...

I think they include temperature compensation because the difference is
not actually that trivial. (a 10 degree upward shift would add about 5%
to your bill at a guess)

That's interesting as there's got to be at least a 20 degree difference
between the temperature of an uninsulated garage and a centrally heated
house for much of the winter (when most gas is being used)? But if they
apply temperature correction, wouldn't they need to do that on a
per-user basis, depending on whether the meter is inside or out? And
whether any outbuilding is completely uninsulated or not? Or do they
just assume the gas is flowing through the meter fast enough, and the
meter is close enough to the exterior, for the gas to still be at
ambient (external) temperature?

(Oh actually I was spouting rubbish in my previous post as I was
forgetting the gas meter was moved to an outside cupboard on the side of
the house; it's just the lecky one which is inside. But still
interested in principle!)

David

In message
,
harry writes



Gas meters measure volume. I often wondered that if I could cool the
gas, I would get more of it for the same money!

Same with filling station pumps, and deliveries of central hearing oil.

I expect that petrol/diesel, being stored underground, remains at a
reasonably constant temperature, summer and winter, and never has time
to warm up or cool down while it is being delivered to your vehicle fuel
tank.

However, CH oil, coming out of a tanker driving all day around the
countryside, could vary a lot in temperature by the time it is delivered
to you. Presumably, in the depth of winter, and the oil will be
contracted when you get it, you get more calories for your money. On the
other hand, in the depth of winter, CH oil prices are often higher than
in the summer. I suppose it's a swings-and-roundabout situation.
--
Ian

PeterC wrote:
Stilsons on pipe, 1 turn, pipe comes out of floor about 6" down and the end
was rusted through! At that time the pipe was about 20 years old. There was
no obvious wettness so the hole was plugged.

http://pics.mdfs.net/2011/03/110301.htm

JGH

On Tue, 26 Apr 2011 00:42:17 -0700 (PDT), jgharston wrote:

PeterC wrote:
Stilsons on pipe, 1 turn, pipe comes out of floor about 6" down and the end
was rusted through! At that time the pipe was about 20 years old. There was
no obvious wettness so the hole was plugged.

http://pics.mdfs.net/2011/03/110301.htm

JGH

That's not a leak, it's an unfinished T-junction!
--
Peter.
The gods will stay away
whilst religions hold sway

On Mon, 25 Apr 2011 17:42:52 +0100, Ian Jackson wrote:

However, CH oil, coming out of a tanker driving all day around the
countryside, could vary a lot in temperature by the time it is delivered
to you. Presumably, in the depth of winter, and the oil will be
contracted when you get it, you get more calories for your money. On the
other hand, in the depth of winter, CH oil prices are often higher than
in the summer. I suppose it's a swings-and-roundabout situation.

That's sort of been on my mind for a while but I don't think the
chnage is particulary significant. Our tank sits in full sun during
the day so gets "quite warm" I take weekly level readings to get a
rough prediction as to when we will need some more. I can't say I've
noticed that the level goes up or falls less slowly than expected in
long hot periods of weather.

With curisoity peaqued wanders off to google. Kerosene has an
coeffcient of expansion of 0.00099/k. So for 2000l and say 40 K temp
range that is 2000 * 0.00099 * 40 = 79.2l at 60p/l = £47.52 hum...

But I very much doubt that the delivery temperature of our oil varies
by 40K. It might from the coldest part of winter to the hottest
summer vary 20K but that's still 40l in a 2000l delivery. I shall
have to ask them if their meter is oil temperature compenstated.

--
Cheers
Dave.

Very little monetary cost because of the smell - even a small sized
leak has a "disproportionate" smell to it which even if above head
height will be noticeable in the general area enough times in a year
to get noticed.

Iron pipes can really catch you out re corrosion. Lead and block tin
can be perfectly serviceable if they have copper/brass fittings at
each end, but are subject to crystalline fracture particularly if
festooned on cramps spaced too far apart or corrosion related failure
surprisingly if run by black mortar (sulphuric acid) by leaking gutter
(over years). That last one caught a long gone relative in 1984 when a
slight smell on removing blown plaster browning became a full blast.
Gas pressure is relatively low, so you have have a "net curtain" which
can become a full bore leak. Likewise lead & iron in floors can rot
just below the surface under stairs. This caught out ICL in ?scotland?
where seemingly ok pipework was net-curtains and small leaks became
sudden full bore leaks.

Best pipework is 1 piece copper plastic coated where necessary or
tracpipe, although tracpipe can introduce more joints and is more
costly. Soldering skill is highly variable these days with flux left
in place and solder trails like ancient candles. Compression joints
are permitted with gas (Tracpipe) but absolutely must be accessible -
the interpretation of which is usually lax on the day, tight on any
subsequent inspection :-)