For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks
There is a very tiny leak on the gas meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while they are away as no-one is opening the pantry door/other doors in the house.

When they get back, it's dark, someone opens the door an operates a light switch and boom, dead people house demolished.
Or the have a fag in their gob.

So, only the brain dead block ventilation holes appertaining to gas installations.

harry wrote:
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks
There is a very tiny leak on the gas meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while they are away as no-one is opening the pantry door/other doors in the house.

When they get back, it's dark, someone opens the door an operates a light switch and boom, dead people house demolished.
Or the have a fag in their gob.

So, only the brain dead block ventilation holes appertaining to gas installations.


Someone blew up their house near to us maybe ten years ago. Fiddling
with the meter. The noise was incredible, and we were amazed to
discover that the house was something like three miles away. It was so
loud, you'd guess it was only a few streets away.

On 10/02/2016 10:22, Dan S. MacAbre wrote:
harry wrote:
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks
There is a very tiny leak on the gas meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while
they are away as no-one is opening the pantry door/other doors in the
house.

When they get back, it's dark, someone opens the door an operates a
light switch and boom, dead people house demolished.
Or the have a fag in their gob.

So, only the brain dead block ventilation holes appertaining to gas
installations.


Someone blew up their house near to us maybe ten years ago. Fiddling
with the meter. The noise was incredible, and we were amazed to
discover that the house was something like three miles away. It was so
loud, you'd guess it was only a few streets away.

Thirty-odd years ago someone near hear had their bungalow blow up,
leaving just the bottom 12" of the walls standing - the really
unfortunate part was that they'd only bought it a couple of days earlier
and hadn't got round to insuring it.

SteveW

On Sunday, 14 February 2016 02:59:10 UTC, Steve Walker wrote:
On 10/02/2016 10:22, Dan S. MacAbre wrote:
harry wrote:
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks
There is a very tiny leak on the gas meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while
they are away as no-one is opening the pantry door/other doors in the
house.

When they get back, it's dark, someone opens the door an operates a
light switch and boom, dead people house demolished.
Or the have a fag in their gob.

So, only the brain dead block ventilation holes appertaining to gas
installations.


Someone blew up their house near to us maybe ten years ago. Fiddling
with the meter. The noise was incredible, and we were amazed to
discover that the house was something like three miles away. It was so
loud, you'd guess it was only a few streets away.

Thirty-odd years ago someone near hear had their bungalow blow up,
leaving just the bottom 12" of the walls standing - the really
unfortunate part was that they'd only bought it a couple of days earlier
and hadn't got round to insuring it.

SteveW

The reason being some part had filled up with gas due to not being ventilated. And maybe unoccupied. So no doors opened allowing a gas build up.

In article ,
Steve Walker wrote:
On 10/02/2016 10:22, Dan S. MacAbre wrote:
harry wrote:
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks
There is a very tiny leak on the gas meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while
they are away as no-one is opening the pantry door/other doors in the
house.

When they get back, it's dark, someone opens the door an operates a
light switch and boom, dead people house demolished.
Or the have a fag in their gob.

So, only the brain dead block ventilation holes appertaining to gas
installations.


Someone blew up their house near to us maybe ten years ago. Fiddling
with the meter. The noise was incredible, and we were amazed to
discover that the house was something like three miles away. It was so
loud, you'd guess it was only a few streets away.

Thirty-odd years ago someone near hear had their bungalow blow up,
leaving just the bottom 12" of the walls standing - the really
unfortunate part was that they'd only bought it a couple of days earlier
and hadn't got round to insuring it.

whereas they should have insured it from the moment they exchanged
contracts.

--
from KT24 in Surrey, England

On 14/02/2016 02:59, Steve Walker wrote:
Thirty-odd years ago someone near hear had their bungalow blow up,
leaving just the bottom 12" of the walls standing - the really
unfortunate part was that they'd only bought it a couple of days earlier
and hadn't got round to insuring it.

We've always been advised to have insurance in place before contracts
are exchanged. Under English law you still have to buy it, even if it
has burned down.

As it happens we had trouble getting insurance on this one. The previous
owners put us on to their insurance company, who said "How long has it
been thatched?". About 300 years, as it happens...

Andy

On 10/02/2016 10:13, harry wrote:
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

4. The ratio of gas to air must be in the range of ~5% to ~15%

There, fixed it for you.





--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 10/02/16 11:42, John Rumm wrote:
On 10/02/2016 10:13, harry wrote:
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

4. The ratio of gas to air must be in the range of ~5% to ~15%

There, fixed it for you.

+1.

In general the best* way to use gas to blow up soimeth8ing is to open a
gas valve and leave a naked flame burning.

At some point the concentration gets to critical and BOOM

*GCHQ/NSA I am not advocating this as a desirable activity. Apologies
for triggering your deep pizza inspection code.






--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

"The Natural Philosopher" wrote in message
...
4. The ratio of gas to air must be in the range of ~5% to ~15%

There, fixed it for you.

+1.

In general the best* way to use gas to blow up soimeth8ing is to open a
gas valve and leave a naked flame burning.

As used to great effect as a booby-trap in the film (originally TV
mini-series) "Bellman and True", except that in that case they used a spark,
rather than a naked flame, to ignite the gas, and a wrench operated by
opening the door to start the release of gas so that it would not explode
prematurely.

At some point the concentration gets to critical and BOOM

Conversely if you enter a house that is filled with gas, don't *just* open
the windows without also turning off any sources of ignition, otherwise the
gradually reducing gas concentration could reach critical from the opposite
direction. I had this drummed into me on a safety course - turn off the gas
and disable the ignition sources first and only then should you open the
windows. For maximum safety, do all these things and then run like bloody
hell in case it explodes as the concentration reduces to critical and you've
forgotten about an ignition source.

*GCHQ/NSA I am not advocating this as a desirable activity. Apologies for
triggering your deep pizza inspection code.

LOL

On Wednesday, February 10, 2016 at 12:01:50 PM UTC, NY wrote:
"The Natural Philosopher" wrote in message
...
4. The ratio of gas to air must be in the range of ~5% to ~15%

There, fixed it for you.

+1.

In general the best* way to use gas to blow up soimeth8ing is to open a
gas valve and leave a naked flame burning.

As used to great effect as a booby-trap in the film (originally TV
mini-series) "Bellman and True", except that in that case they used a spark,
rather than a naked flame, to ignite the gas, and a wrench operated by
opening the door to start the release of gas so that it would not explode
prematurely.

At some point the concentration gets to critical and BOOM

Conversely if you enter a house that is filled with gas, don't *just* open
the windows without also turning off any sources of ignition, otherwise the
gradually reducing gas concentration could reach critical from the opposite
direction. I had this drummed into me on a safety course - turn off the gas
and disable the ignition sources first and only then should you open the
windows. For maximum safety, do all these things and then run like bloody
hell in case it explodes as the concentration reduces to critical and you've
forgotten about an ignition source.

*GCHQ/NSA I am not advocating this as a desirable activity. Apologies for
triggering your deep pizza inspection code.

LOL

Calor gas is heavier than air so will accumulate from floor level up.( Hence the danger on boats where it will accumulate in the bilges. Proper safety measure is a spark proof extractor operated before starting engines.)

Mains gas is lighte than air so will build from the ceiling down.

Calor gas had more chance in escaping under doors etc. but mains gas will have filled the room before it gets down there.

ISTR seeing a tv programmes where they attempted to blow us a gas filled car with a spark. Very unspectacular. Same trick with the car filled with petrol fumes blew it up like a bomb

In article , fred
writes
On Wednesday, February 10, 2016 at 12:01:50 PM UTC, NY wrote:
"The Natural Philosopher" wrote in message
...
4. The ratio of gas to air must be in the range of ~5% to ~15%

There, fixed it for you.

+1.

In general the best* way to use gas to blow up soimeth8ing is to open a
gas valve and leave a naked flame burning.

As used to great effect as a booby-trap in the film (originally TV
mini-series) "Bellman and True", except that in that case they used a spark,
rather than a naked flame, to ignite the gas, and a wrench operated by
opening the door to start the release of gas so that it would not explode
prematurely.

At some point the concentration gets to critical and BOOM

Conversely if you enter a house that is filled with gas, don't *just* open
the windows without also turning off any sources of ignition, otherwise the
gradually reducing gas concentration could reach critical from the opposite
direction. I had this drummed into me on a safety course - turn off the gas
and disable the ignition sources first and only then should you open the
windows. For maximum safety, do all these things and then run like bloody
hell in case it explodes as the concentration reduces to critical and you've
forgotten about an ignition source.

*GCHQ/NSA I am not advocating this as a desirable activity. Apologies for
triggering your deep pizza inspection code.

LOL

Calor gas is heavier than air so will accumulate from floor level up.(
Hence the danger on boats where it will accumulate in the bilges.
Proper safety measure is a spark proof extractor operated before
starting engines.)

A few years ago there was a tragic case of a gas leak on a boat in a
lock.
Mains gas is lighte than air so will build from the ceiling down.

Calor gas had more chance in escaping under doors etc. but mains gas
will have filled the room before it gets down there.

ISTR seeing a tv programmes where they attempted to blow us a gas
filled car with a spark. Very unspectacular. Same trick with the car
filled with petrol fumes blew it up like a bomb

--
bert

"The Natural Philosopher" wrote in message
...
On 10/02/16 11:42, John Rumm wrote:
On 10/02/2016 10:13, harry wrote:
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

4. The ratio of gas to air must be in the range of ~5% to ~15%

There, fixed it for you.

+1.

In general the best* way to use gas to blow up soimeth8ing is to open a
gas valve and leave a naked flame burning.

At some point the concentration gets to critical and BOOM

Didnt work when she tried to blow Adam up.

*GCHQ/NSA I am not advocating this as a desirable activity. Apologies for
triggering your deep pizza inspection code.

On Wednesday, 10 February 2016 11:42:45 UTC, John Rumm wrote:
On 10/02/2016 10:13, harry wrote:
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

4. The ratio of gas to air must be in the range of ~5% to ~15%

There, fixed it for you.





--

Not neccsarily. A burning front can run through a gas filled void/building drawing it's own combustion air in after it.

Just as the flame strikes back" in a bunsen burner if the air is progressively turned up.

On 10/02/2016 16:29, harry wrote:
On Wednesday, 10 February 2016 11:42:45 UTC, John Rumm wrote:
On 10/02/2016 10:13, harry wrote:
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated
space where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

4. The ratio of gas to air must be in the range of ~5% to ~15%

There, fixed it for you.

Not neccsarily. A burning front can run through a gas filled
void/building drawing it's own combustion air in after it.

Which is not a gas explosion...


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Wednesday, 10 February 2016 17:00:48 UTC, John Rumm wrote:
On 10/02/2016 16:29, harry wrote:
On Wednesday, 10 February 2016 11:42:45 UTC, John Rumm wrote:
On 10/02/2016 10:13, harry wrote:
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated
space where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

4. The ratio of gas to air must be in the range of ~5% to ~15%

There, fixed it for you.

Not neccsarily. A burning front can run through a gas filled
void/building drawing it's own combustion air in after it.

Which is not a gas explosion...

This is the one that knocks the building down and leaves the inhabitants (relatively) unharmed.

"harry" wrote in message
...
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks
There is a very tiny leak on the gas meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while they
are away as no-one is opening the pantry door/other doors in the house.

When they get back, it's dark, someone opens the door an operates
a light switch and boom, dead people house demolished.
Or the have a fag in their gob.

Have fun listing even a single example of that actually happening.

So, only the brain dead block ventilation holes appertaining to gas
installations.

Must be why so many are under the stairs with no ventilation holes at all.

Rod Speed wrote:
"harry" wrote in message
...
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks
There is a very tiny leak on the gas meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while
they are away as no-one is opening the pantry door/other doors in
the house.

When they get back, it's dark, someone opens the door an operates
a light switch and boom, dead people house demolished.
Or the have a fag in their gob.

Have fun listing even a single example of that actually happening.

So, only the brain dead block ventilation holes appertaining to gas
installations.

Must be why so many are under the stairs with no ventilation holes at
all.

At least 66% of gas meters are not in ventilated areas nor are they in
outside boxes.
Harry can't answer this, nor offer any explanation as to why the gas
provider allows it when swapping meters or doing other work - if it was
'against regulations' they would not be allowed by law to continue this
practice.

Likewise the millions of council owned houses where pipes run under
floorboards - they would have to have rows of vent bricks at joist level
front and back to allow ventilation across the underfloor spaces, I've never
seen one, Harry can't explain this neither

On Saturday, 13 February 2016 13:50:52 UTC, Phil L wrote:
Rod Speed wrote:
"harry" wrote in message
...
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks
There is a very tiny leak on the gas meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while
they are away as no-one is opening the pantry door/other doors in
the house.

When they get back, it's dark, someone opens the door an operates
a light switch and boom, dead people house demolished.
Or the have a fag in their gob.

Have fun listing even a single example of that actually happening.

So, only the brain dead block ventilation holes appertaining to gas
installations.

Must be why so many are under the stairs with no ventilation holes at
all.

At least 66% of gas meters are not in ventilated areas nor are they in
outside boxes.
Harry can't answer this, nor offer any explanation as to why the gas
provider allows it when swapping meters or doing other work - if it was
'against regulations' they would not be allowed by law to continue this
practice.

Likewise the millions of council owned houses where pipes run under
floorboards - they would have to have rows of vent bricks at joist level
front and back to allow ventilation across the underfloor spaces, I've never
seen one, Harry can't explain this neither

Practices, ****-fer-brains, no longer allowed.
And one of the reasons we get gas explosions.

harry wrote:
On Saturday, 13 February 2016 13:50:52 UTC, Phil L wrote:
At least 66% of gas meters are not in ventilated areas nor are they
in outside boxes.
Harry can't answer this, nor offer any explanation as to why the gas
provider allows it when swapping meters or doing other work - if it
was 'against regulations' they would not be allowed by law to
continue this practice.

Likewise the millions of council owned houses where pipes run under
floorboards - they would have to have rows of vent bricks at joist
level front and back to allow ventilation across the underfloor
spaces, I've never seen one, Harry can't explain this neither

Practices, ****-fer-brains, no longer allowed.

If they are no longer allowed, why do all councils and private landlords not
ventilate all their houses? - they have to provide smoke alarms, they have
to provide CO alarms, yet you are saying they openly flout a 'law' which
causes all these gas explosions you've dreamt up but never posted details of

And one of the reasons we get gas explosions.

No, harry, we don't.
You've read a obscure link that says gas pipes running through ducting or
voids need ventilation - none of this applies to gas meters *or* private
homes, it means gas pipes in an industrial setting.
The only meters that need their own ventilation are industrial/commercial
meters that allow a flow above 6m3 per hour, no one here has one of these in
their home as they are the size of an armchair

On Sunday, 14 February 2016 15:11:34 UTC, Phil L wrote:
harry wrote:
On Saturday, 13 February 2016 13:50:52 UTC, Phil L wrote:
At least 66% of gas meters are not in ventilated areas nor are they
in outside boxes.
Harry can't answer this, nor offer any explanation as to why the gas
provider allows it when swapping meters or doing other work - if it
was 'against regulations' they would not be allowed by law to
continue this practice.

Likewise the millions of council owned houses where pipes run under
floorboards - they would have to have rows of vent bricks at joist
level front and back to allow ventilation across the underfloor
spaces, I've never seen one, Harry can't explain this neither

Practices, ****-fer-brains, no longer allowed.

If they are no longer allowed, why do all councils and private landlords not
ventilate all their houses? - they have to provide smoke alarms, they have
to provide CO alarms, yet you are saying they openly flout a 'law' which
causes all these gas explosions you've dreamt up but never posted details of

And one of the reasons we get gas explosions.

No, harry, we don't.
You've read a obscure link that says gas pipes running through ducting or
voids need ventilation - none of this applies to gas meters *or* private
homes, it means gas pipes in an industrial setting.
The only meters that need their own ventilation are industrial/commercial
meters that allow a flow above 6m3 per hour, no one here has one of these in
their home as they are the size of an armchair

Don't talk drivel.
Go and look at any external domestic gas meter cabinet.
It has top and bottom ventilation slots on the door, whereas the identical electricity ones have none.

If you're full of ****, best to shut up.

In article ,
harry writes
For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks
There is a very tiny leak on the gas meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while
they are away as no-one is opening the pantry door/other doors in the
house.

When they get back, it's dark, someone opens the door
And smells gas so don't switch on the light.
an operates a light switch and boom, dead people house demolished.
Or the have a fag in their gob.

So, only the brain dead block ventilation holes appertaining to gas
installations.





--
bert

On 10/02/2016 10:40, Jethro_uk wrote:
On Wed, 10 Feb 2016 02:13:22 -0800, harry wrote:

For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They also need to have no sense of smell not to notice any leak.
(more common than you might think)

It's actually quite hard to get a gas leak to "explode". You need a quite
narrow ratio of gas/air. Which is one reason why a the Calor canister in
a car "bomb" they tried in Glasgow (and NYC IIRC ?) had the engineers in
the Ops department ****ing themselves with laughter when I worked there.

Obviously gas leaks aren't a great thing, and can be very dangerous. But
as a *reliable* explosive, gas (methane, propane, butane) leaves a lot to
be desired.

There was a famous one not far from me where a DIY gas CH installation
on bottled gas went up spectacularly. The blackened shell of the house
serving as a warning to others since the insurers declined to pay out.

A fracture in the high pressure (75 bar) gas grid can throw a flame 400
+metres.

I live within the danger zone for the high pressure ethylene pipeline at
1400psi (100bar). It is reckoned that any leak would roll down to the
beck and flash back after reaching the sewage pumping station. Noise
estimates for a serious breach at 30m are 140+dB

Planning permission for a fishing lake was turned down on the grounds of
the lake being too close to the pipeline!!!

--
Regards,
Martin Brown

On 2/10/2016 10:59 AM, Martin Brown wrote:
On 10/02/2016 10:40, Jethro_uk wrote:
On Wed, 10 Feb 2016 02:13:22 -0800, harry wrote:

For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They also need to have no sense of smell not to notice any leak.
(more common than you might think)

It's actually quite hard to get a gas leak to "explode". You need a quite
narrow ratio of gas/air. Which is one reason why a the Calor canister in
a car "bomb" they tried in Glasgow (and NYC IIRC ?) had the engineers in
the Ops department ****ing themselves with laughter when I worked there.

Obviously gas leaks aren't a great thing, and can be very dangerous. But
as a *reliable* explosive, gas (methane, propane, butane) leaves a lot to
be desired.

There was a famous one not far from me where a DIY gas CH installation
on bottled gas went up spectacularly. The blackened shell of the house
serving as a warning to others since the insurers declined to pay out.


Bottled gas is of course much more dangerous than natural gas,
especially if there is a cellar, because it "pools". If you have a
sudden big leak then the chill factor may add to the problem.

Similarly for boats.

Yes, try the cocoa tin with a hole trick.

I have in the past seen gas engineers looking for a leak in the street using
a naked flame and watching for its colour to change. I said, are you trying
to blow us up and the guy told me that in the open air the mixture is far
too poor to catch fire or explode.

Brian

"newshound" wrote in message
o.uk...
On 2/10/2016 10:59 AM, Martin Brown wrote:
On 10/02/2016 10:40, Jethro_uk wrote:
On Wed, 10 Feb 2016 02:13:22 -0800, harry wrote:

For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They also need to have no sense of smell not to notice any leak.
(more common than you might think)

It's actually quite hard to get a gas leak to "explode". You need a
quite
narrow ratio of gas/air. Which is one reason why a the Calor canister in
a car "bomb" they tried in Glasgow (and NYC IIRC ?) had the engineers in
the Ops department ****ing themselves with laughter when I worked there.

Obviously gas leaks aren't a great thing, and can be very dangerous. But
as a *reliable* explosive, gas (methane, propane, butane) leaves a lot
to
be desired.

There was a famous one not far from me where a DIY gas CH installation
on bottled gas went up spectacularly. The blackened shell of the house
serving as a warning to others since the insurers declined to pay out.


Bottled gas is of course much more dangerous than natural gas, especially
if there is a cellar, because it "pools". If you have a sudden big leak
then the chill factor may add to the problem.

Similarly for boats.


--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!

In article ,
Jethro_uk writes:
On Thu, 11 Feb 2016 10:30:39 +0000, Brian Gaff wrote:

Yes, try the cocoa tin with a hole trick.

I have in the past seen gas engineers looking for a leak in the street
using a naked flame and watching for its colour to change. I said, are
you trying to blow us up and the guy told me that in the open air the
mixture is far too poor to catch fire or explode.


I'm sure there was a story - years ago - where a car was stopped at
traffic lights, over a gas leak. It stalled, went to start, and the
bonnet blew off.

Fanciful, but weirder has happened.

Something similar happened near home when I was child.
Road was being resurfaced, and there was one of the large scraper
machines taking off the old road surface. On the face of it, it
seemed like it scraped through the gas pipe under the road - a
large flame was jetting through and out the top of the machine,
and all the workman had retired to a safe distance. I rather
doubt it actually reached the gas pipe, but possibly fractured
it and exposed a fissure to allow a massive gas leak.

My road was resurfaced more recently, and when it had a nice
new clean surface, the water main burst in two places, which is
apparently quite common after the large scraper machine has
gone over it. We also lost our electricity when it scraped
through a streetlamp cable which was only a few inches below
the surface.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
newshound writes
On 2/10/2016 10:59 AM, Martin Brown wrote:
On 10/02/2016 10:40, Jethro_uk wrote:
On Wed, 10 Feb 2016 02:13:22 -0800, harry wrote:

For a gas explosion to occur, there needs to be three things.

1. A leak. This can be very very small.

2. An accumulation of gas. This can occur in any non-ventilated space
where there is a leak. Over a period of weeks or months.

3. A source of ignition. Electric spark is ideal.

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They also need to have no sense of smell not to notice any leak.
(more common than you might think)

It's actually quite hard to get a gas leak to "explode". You need a quite
narrow ratio of gas/air. Which is one reason why a the Calor canister in
a car "bomb" they tried in Glasgow (and NYC IIRC ?) had the engineers in
the Ops department ****ing themselves with laughter when I worked there.

Obviously gas leaks aren't a great thing, and can be very dangerous. But
as a *reliable* explosive, gas (methane, propane, butane) leaves a lot to
be desired.

There was a famous one not far from me where a DIY gas CH installation
on bottled gas went up spectacularly. The blackened shell of the house
serving as a warning to others since the insurers declined to pay out.


Bottled gas is of course much more dangerous than natural gas,
especially if there is a cellar, because it "pools". If you have a
sudden big leak then the chill factor may add to the problem.

Similarly for boats.

Propane is heavier than air and can roll along invisibly for many
metres. That's why caravans and motorhomes have ventilation holes at the
lowest points and why if it is necessary to empty a cylinder it should
be done in short burst in an open field on a windy day.
--
bert

On 10/02/2016 16:31, Jethro_uk wrote:
On Wed, 10 Feb 2016 10:59:27 +0000, Martin Brown wrote:

On 10/02/2016 10:40, Jethro_uk wrote:
[quoted text muted]

They also need to have no sense of smell not to notice any leak.
(more common than you might think)

We had deodorised gas at Calor - not sure why.

An Engineering company that I worked at had 15 tons of liquified natural
gas, with a "boiling" unit and an odouriser (the gas supply to the site
was too small for testing large gas engine or turbine driven units).
They once had half the local housing estate evacuated when a major gas
leak was suspected, but it turned out to be just the concentrated
chemicals for the odour leaking!

SteveW

On Wed, 10 Feb 2016 11:05:43 +0000, Jonno wrote:

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks There is a very tiny leak on the gas
meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while
they are away as no-one is opening the pantry door/other doors in the
house.

When they get back, it's dark, someone opens the door an operates a
light switch and boom, dead people house demolished.

So this airbrick in the pantry is the ONLY ventilation in the whole
house? Hermetically sealed apart from that?

On 10/02/2016 11:15, Adrian wrote:
On Wed, 10 Feb 2016 11:05:43 +0000, Jonno wrote:

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks There is a very tiny leak on the gas
meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while
they are away as no-one is opening the pantry door/other doors in the
house.

When they get back, it's dark, someone opens the door an operates a
light switch and boom, dead people house demolished.

So this airbrick in the pantry is the ONLY ventilation in the whole
house? Hermetically sealed apart from that?

Have you not seen harry's house?


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Wed, 10 Feb 2016 11:45:48 +0000, John Rumm wrote:

So this airbrick in the pantry is the ONLY ventilation in the whole
house? Hermetically sealed apart from that?

Have you not seen harry's house?

We know there's some way of a lot of hot air getting out of it...

"Adrian" wrote in message
...
On Wed, 10 Feb 2016 11:45:48 +0000, John Rumm wrote:

So this airbrick in the pantry is the ONLY ventilation in the whole
house? Hermetically sealed apart from that?

Have you not seen harry's house?

We know there's some way of a lot of hot air getting out of it...

Trouble is that while usenet works fine for hot air, it doesnt for gas with
harry.

En el artículo , John
Rumm escribió:

Have you not seen harry's house?

He

http://i2.wp.com/viz.co.uk/wp-conten...1/Screen-Shot-
2014-11-04-at-12.47.39.png

or http://tinyurl.com/z2lfjll

--
(\_/)
(='.'=) Bunny says: Windows 10? Nein danke!
(")_(")

On Wednesday, 10 February 2016 11:15:47 UTC, Adrian wrote:
On Wed, 10 Feb 2016 11:05:43 +0000, Jonno wrote:

Typical scenario.
Someone blocks up the pantry ventilation where there is a gas meter.

They go on holiday for a few weeks There is a very tiny leak on the gas
meter.
Normally this would be dissipated by the pantry ventilation.
But there is no ventilation and the whole house fills with gas while
they are away as no-one is opening the pantry door/other doors in the
house.

When they get back, it's dark, someone opens the door an operates a
light switch and boom, dead people house demolished.

So this airbrick in the pantry is the ONLY ventilation in the whole
house? Hermetically sealed apart from that?

Possibly well sealed enough to cause a problem.