My parents were one of the 400-odd houses which lost their gas supply near
Aylesbury when a water main burst (which quite an explosion, from witness
reports) and fractured an adjacent gas main, letting water in the gas main.
Apparently the water cause stones in the ground to be circulated by the
cascading water, abrading a hole in the gas pipe. There have been "lots of"
gas vans parked up, as they try to empty the water and restore gas supplies.

But how do they go about emptying out the water from the pipe? About 1.5
miles of pipe are affected - the houses that have lost their supply extend
about 3/4 mile either side of the burst.

On 17/10/2020 18:21, NY wrote:
My parents were one of the 400-odd houses which lost their gas supply
near Aylesbury when a water main burst (which quite an explosion, from
witness reports) and fractured an adjacent gas main, letting water in
the gas main. Apparently the water cause stones in the ground to be
circulated by the cascading water, abrading a hole in the gas pipe.
There have been "lots of" gas vans parked up, as they try to empty the
water and restore gas supplies.

But how do they go about emptying out the water from the pipe? About 1.5
miles of pipe are affected - the houses that have lost their supply
extend about 3/4 mile either side of the burst.
they never found out where the metal filings came from in the west of
Scotland....

NY wrote:
My parents were one of the 400-odd houses which lost their gas supply near
Aylesbury when a water main burst (which quite an explosion, from witness
reports) and fractured an adjacent gas main, letting water in the gas main.
Apparently the water cause stones in the ground to be circulated by the
cascading water, abrading a hole in the gas pipe. There have been "lots of"
gas vans parked up, as they try to empty the water and restore gas supplies.

But how do they go about emptying out the water from the pipe? About 1.5
miles of pipe are affected - the houses that have lost their supply extend
about 3/4 mile either side of the burst.



I dont know the answer but its a nightmare for the gas companies.

Until theyve had access to every gas meter supplied and turned of the gas
at the meter they cant restore the supply. If the meter is indoors and the
owner away, they have to dig up the pavement to disconnect the property.
Happened in our street a few years ago. Fortunately just a clumsy JCB
induced fracture, no water involved.

Tim

--
Please don't feed the trolls

On 17/10/2020 18:21, NY wrote:
My parents were one of the 400-odd houses which lost their gas supply
near Aylesbury when a water main burst (which quite an explosion, from
witness reports) and fractured an adjacent gas main, letting water in
the gas main. Apparently the water cause stones in the ground to be
circulated by the cascading water, abrading a hole in the gas pipe.
There have been "lots of" gas vans parked up, as they try to empty the
water and restore gas supplies.

But how do they go about emptying out the water from the pipe? About 1.5
miles of pipe are affected - the houses that have lost their supply
extend about 3/4 mile either side of the burst.

Gas dewatering equipment :-)

AIUI, this is an air or nitrogen powered venturi pump that sucks the
water out into a water trap.

--
Colin Bignell

"nightjar" wrote in message
...
On 17/10/2020 18:21, NY wrote:
My parents were one of the 400-odd houses which lost their gas supply
near Aylesbury when a water main burst (which quite an explosion, from
witness reports) and fractured an adjacent gas main, letting water in the
gas main. Apparently the water caused stones in the ground to be
circulated by the cascading water, abrading a hole in the gas pipe. There
have been "lots of" gas vans parked up, as they try to empty the water
and restore gas supplies.

But how do they go about emptying out the water from the pipe? About 1.5
miles of pipe are affected - the houses that have lost their supply
extend about 3/4 mile either side of the burst.

Gas dewatering equipment :-)

AIUI, this is an air or nitrogen powered venturi pump that sucks the water
out into a water trap.

So is that the real reason that all the houses' gas supplies have to be
turned off? Not just for reasons of safety but because the dewatering
equipment *requires* a sealed pipe (far end and every branch to a house) in
order for it to work? How does it cope with a gas main that may not be
completely level and so may retain water in the "troughs"?

The good news is that my parents' gas supply was restored this evening after
about 48 hours without heating or cooking - other than the electric fan
heater and cooking hob that the gas company *gave* my parents (COVID
cleaning and quarantine rules mean that it is more trouble than it is worth
to take the equipment back after the gas supply has been restored). And
their neighbours who have an electric oven rather than gas said they'd cook
a bit extra roast lamb and give it to my parents - community spirit is still
alive!

Mum and Dad got talking to the people from the gas company and found that
engineers had been brought in from all over the place as, far away as
Exeter, and there were vans as far as they eye could see parked all the way
along the layby along their road.

Are there ever cases where water gets into a gas main and the pressure of
gas forces it out of appliances - eg out of the burners of your gas hob or
boiler? ;-)

NY wrote:
"nightjar" wrote in message


AIUI, this is an air or nitrogen powered venturi pump that sucks the water
out into a water trap.

So is that the real reason that all the houses' gas supplies have to be
turned off? Not just for reasons of safety but because the dewatering
equipment *requires* a sealed pipe (far end and every branch to a house) in
order for it to work?


No, its simply because without access to the house, theres no way of
being completely certain that restoring the supply isnt going to fill the
house with gas, possibly from some elderly appliance with a dodgy gas
valve.

Turning it off at the meter avoids this risk.

Arguably that risk is very small but our neighbours had their gas supply
cut off in he street (as they were away at the time) when we lost our gas
supply.

How does it cope with a gas main that may not be
completely level and so may retain water in the "troughs"?

The good news is that my parents' gas supply was restored this evening after
about 48 hours without heating or cooking - other than the electric fan
heater and cooking hob that the gas company *gave* my parents (COVID
cleaning and quarantine rules mean that it is more trouble than it is worth
to take the equipment back after the gas supply has been restored). And
their neighbours who have an electric oven rather than gas said they'd cook
a bit extra roast lamb and give it to my parents - community spirit is still
alive!

Mum and Dad got talking to the people from the gas company and found that
engineers had been brought in from all over the place as, far away as
Exeter, and there were vans as far as they eye could see parked all the way
along the layby along their road.

48 hrs was fast work for this kind of thing. They did well. Probably
helped a lot that for some reason not many folk are away on holiday at the
moment. ;-) That and a move to external meter boxes for gas.

Tim

--
Please don't feed the trolls

On 18/10/20 4:21 am, NY wrote:
My parents were one of the 400-odd houses which lost their gas supply
near Aylesbury when a water main burst (which quite an explosion, from
witness reports) and fractured an adjacent gas main, letting water in
the gas main. Apparently the water cause stones in the ground to be
circulated by the cascading water, abrading a hole in the gas pipe.
There have been "lots of" gas vans parked up, as they try to empty the
water and restore gas supplies.

But how do they go about emptying out the water from the pipe? About 1.5
miles of pipe are affected - the houses that have lost their supply
extend about 3/4 mile either side of the burst.
From the lowest point.

Depends on whether the main is totally flat or not. Often if its an old, ie
not one of the new plastic ones, then the best approach seems to be to get
as much out as possible then hope it all works. There is probably water in
the pipe of an old metal gas pipe due to them mostly being rusted up and the
clay acting as the pipe wall. The eventual result round here was about six
months down the line the whole main had to be replaced by plastic with the
associate disruption to supplies and road traffic, to several months to do
it. They attempt to fit the new pipe some way from the old one if its really
badly rusted so they can leave supplies on while most of the work is done.
Brian

--

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

Blind user, so no pictures please
Note this Signature is meaningless.!
"Tim+" wrote in message
...
NY wrote:
My parents were one of the 400-odd houses which lost their gas supply
near
Aylesbury when a water main burst (which quite an explosion, from witness
reports) and fractured an adjacent gas main, letting water in the gas
main.
Apparently the water cause stones in the ground to be circulated by the
cascading water, abrading a hole in the gas pipe. There have been "lots
of"
gas vans parked up, as they try to empty the water and restore gas
supplies.

But how do they go about emptying out the water from the pipe? About 1.5
miles of pipe are affected - the houses that have lost their supply
extend
about 3/4 mile either side of the burst.



I don't know the answer but it's a nightmare for the gas companies.

Until they've had access to every gas meter supplied and turned of the gas
at the meter they can't restore the supply. If the meter is indoors and
the
owner away, they have to dig up the pavement to disconnect the property.
Happened in our street a few years ago. Fortunately just a clumsy JCB
induced fracture, no water involved.

Tim

--
Please don't feed the trolls

On 17/10/2020 21:50, NY wrote:
"nightjar" wrote in message
...
....
Gas dewatering equipment :-)

AIUI, this is an air or nitrogen powered venturi pump that sucks the
water out into a water trap.

So is that the real reason that all the houses' gas supplies have to be
turned off? Not just for reasons of safety but because the dewatering
equipment *requires* a sealed pipe (far end and every branch to a house)
in order for it to work? How does it cope with a gas main that may not
be completely level and so may retain water in the "troughs"?..

My understanding is that the pump travels inside the pipe, picking up
water as it goes and sending it back down a hose. Hence, it does not
require a sealed pipe and is just as effective in an uneven pipe.

....
Are there ever cases where water gets into a gas main and the pressure
of gas forces it out of appliances - eg out of the burners of your gas
hob or boiler? ;-)

ISTR seeing a picture of that happening, many years ago, but I don't
recall the circumstances. It may even have been that somebody connected
the cooker to the water pipe by mistake. :-)

--
Colin Bignell

NY explained :
Are there ever cases where water gets into a gas main and the pressure of gas
forces it out of appliances - eg out of the burners of your gas hob or
boiler? ;-)

Well not a full flow, but I have heard of some water being mixed in
with gas at the burner, which can be very dangerous when the flame goes
out - especially so where the appliance has no flame failure system.

Our old living room gas fire lacks flame failure, but it was only
fitted decades ago as a back-up for those (very) rare occaisions when
our CH fails. It has only seen any use for a couple of days, since it
was installed.

Round here they dig a series of holes and expose the old metal
gas pipe, then break into it and drag the new yellow 'plastic'
stuff through the old pipe. Then they have to dig a hole outside
every property and connect to the new pipe.

Not sure how the affected properties manage for the few days that
it takes. Maybe they only do it in mid summer ?.


Andrew

On 18/10/2020 09:02, Brian Gaff (Sofa) wrote:
Depends on whether the main is totally flat or not. Often if its an old, ie
not one of the new plastic ones, then the best approach seems to be to get
as much out as possible then hope it all works. There is probably water in
the pipe of an old metal gas pipe due to them mostly being rusted up and the
clay acting as the pipe wall. The eventual result round here was about six
months down the line the whole main had to be replaced by plastic with the
associate disruption to supplies and road traffic, to several months to do
it. They attempt to fit the new pipe some way from the old one if its really
badly rusted so they can leave supplies on while most of the work is done.
Brian

On 17/10/2020 19:43, nightjar wrote:
On 17/10/2020 18:21, NY wrote:
My parents were one of the 400-odd houses which lost their gas supply
near Aylesbury when a water main burst (which quite an explosion, from
witness reports) and fractured an adjacent gas main, letting water in
the gas main. Apparently the water cause stones in the ground to be
circulated by the cascading water, abrading a hole in the gas pipe.
There have been "lots of" gas vans parked up, as they try to empty the
water and restore gas supplies.

But how do they go about emptying out the water from the pipe? About
1.5 miles of pipe are affected - the houses that have lost their
supply extend about 3/4 mile either side of the burst.

Gas dewatering equipment :-)

AIUI, this is an air or nitrogen powered venturi pump that sucks the
water out into a water trap.


When this happned in West Sussex in 1986, people closest to the
point where an impact mole plough went through a high pressure gas main
after penetrating an adjacent water main, had water squirting out of
their gas appliances !

On Saturday, 17 October 2020 at 18:40:31 UTC+1, Tim+ wrote:
NY wrote:
My parents were one of the 400-odd houses which lost their gas supply near
Aylesbury when a water main burst (which quite an explosion, from witness
reports) and fractured an adjacent gas main, letting water in the gas main.
Apparently the water cause stones in the ground to be circulated by the
cascading water, abrading a hole in the gas pipe. There have been "lots of"
gas vans parked up, as they try to empty the water and restore gas supplies.

But how do they go about emptying out the water from the pipe? About 1.5
miles of pipe are affected - the houses that have lost their supply extend
about 3/4 mile either side of the burst.


I dont know the answer but its a nightmare for the gas companies.

Until theyve had access to every gas meter supplied and turned of the gas
at the meter they cant restore the supply. If the meter is indoors and the
owner away, they have to dig up the pavement to disconnect the property.
Happened in our street a few years ago. Fortunately just a clumsy JCB
induced fracture, no water involved.

Tim

--
Please don't feed the trolls

Depending on how the gas supply pipe enters your property they can cut off the supply without access to the inside. Our supply emerges out of the ground for about 1 meter high it has a tee- section on top with the right angle branch disappearing through the wall to the internal gas cock and meter. The other branch simply has a stopper with a square protrusion fitted.

When we had the internal gas cock replaced because the old one was awkwardly jammed against the wall, the gas engineer simply took off the stopper outside and pushed a rather delicate looking bung device into the pipe and did not even put the stopper back whilst he worked on the internal gas cock. Job done bung device out stopper back on and if I recall correctly no PTFE tape either.

Richard

On Sunday, 18 October 2020 10:18:29 UTC+1, wrote:
NY explained :
Are there ever cases where water gets into a gas main and the pressure of gas
forces it out of appliances - eg out of the burners of your gas hob or
boiler? ;-)

Well not a full flow, but I have heard of some water being mixed in
with gas at the burner, which can be very dangerous when the flame goes
out - especially so where the appliance has no flame failure system.

Our old living room gas fire lacks flame failure, but it was only
fitted decades ago as a back-up for those (very) rare occaisions when
our CH fails. It has only seen any use for a couple of days, since it
was installed.

When I was at school it was not unusual for the gas and water taps
to get connected together in one of the chemistry labs.
The short term effect was that all the bunsen burners went out. Later,
the rusted gas pipe under the central "island" bench fractured and
the gas ignited in the void under the bench. The bench relocated
itself by around a metre after having become airborne.

John

Harry Bloomfield, Esq. Wrote in message:
NY explained :
Are there ever cases where water gets into a gas main and the pressure of gas
forces it out of appliances - eg out of the burners of your gas hob or
boiler? ;-)

Well not a full flow, but I have heard of some water being mixed in
with gas at the burner, which can be very dangerous when the flame goes
out - especially so where the appliance has no flame failure system.

Our old living room gas fire lacks flame failure, but it was only
fitted decades ago as a back-up for those (very) rare occaisions when
our CH fails. It has only seen any use for a couple of days, since it
was installed.


time that got serviced & condemned then.
--
Jimk


----Android NewsGroup Reader----
http://usenet.sinaapp.com/