In a road near me, the put in a new yellow gas main, by running it
down the old iron gas main. It is a smaller bore of course.

I noticed they did the same across the gardens, running what is the
equivalent of 1/2" yellow plastic through 3/4 and 1" iron main pipes
to each house. One house has what looks like a 1 1/4" iron main pipe
(looks like original 60s or 70s), at the meter it has what looks like
a 1 1/4" to 1" reducer, a small short piece of 1" steel pipe, then a
1" to 3/4" reducer, with two, what looks like a 1/4" plugs in the 1"
to 3/4" fitting, with then short piece of 3/4" steel pipe and then a
brass maintap on that.

Does anyone one know what the "two" plugs are for?
How did they connect the plastic onto the house meter? Connecting
onto the 1 1/4" steel pipe under the ground?

Will a house that has a large combi using a 1" main gas pipe be OK
with a 1/2" mains plastic gas pipe? 1/2" looks way undersized to me.
If ant of these house upgrades to a larger higher water flow combi
will they be in problems?

All this plastic gas mains looks like a cheap way of upgrading the
mains for the gas company's benefit, not for the benefit of the house
who may be short changed on a gas supply.

"Bay Man" wrote in message
...
In a road near me, the put in a new yellow gas main, by running it
down the old iron gas main. It is a smaller bore of course.

I noticed they did the same across the gardens, running what is the
equivalent of 1/2" yellow plastic through 3/4 and 1" iron main pipes
to each house. One house has what looks like a 1 1/4" iron main pipe
(looks like original 60s or 70s), at the meter it has what looks like
a 1 1/4" to 1" reducer, a small short piece of 1" steel pipe, then a
1" to 3/4" reducer, with two, what looks like a 1/4" plugs in the 1"
to 3/4" fitting, with then short piece of 3/4" steel pipe and then a
brass maintap on that.

Does anyone one know what the "two" plugs are for?
How did they connect the plastic onto the house meter? Connecting
onto the 1 1/4" steel pipe under the ground?

Will a house that has a large combi using a 1" main gas pipe be OK
with a 1/2" mains plastic gas pipe? 1/2" looks way undersized to me.
If ant of these house upgrades to a larger higher water flow combi
will they be in problems?

All this plastic gas mains looks like a cheap way of upgrading the
mains for the gas company's benefit, not for the benefit of the house
who may be short changed on a gas supply.



Bear in mind that the pressure is higher than it is in your house. There is
a regulator after your meter to reduce the pressure.

On Oct 1, 9:13*am, Bay Man wrote:
In a road near me, the put in a new yellow gas main, by running it
down the old iron gas main. *It is a smaller bore of course.

I noticed they did the same across the gardens, running what is the
equivalent of 1/2" yellow plastic through 3/4 and 1" iron main pipes
to each house. One house has what looks like a 1 1/4" iron main pipe
(looks like original 60s or 70s), at the meter it has what looks like
a 1 1/4" to 1" reducer, a small short piece of 1" steel pipe, then a
1" to 3/4" reducer, with two, what looks like a 1/4" plugs in the 1"
to 3/4" fitting, *with then short piece of 3/4" steel pipe and then a
brass maintap on that.

Does anyone one know what the "two" plugs are for?
How did they connect the plastic onto the house meter? *Connecting
onto the 1 1/4" steel pipe under the ground?

Will a house that has a large combi using a 1" main gas pipe be OK
with a 1/2" mains plastic gas pipe? *1/2" looks way undersized to me.
If ant of these house upgrades to a larger higher water flow combi
will they be in problems?

All this plastic gas mains looks like a cheap way of upgrading the
mains for the gas company's benefit, not for the benefit of the house
who may be short changed on a gas supply.

I suspect that between the main and the meter, the gas is under
sufficient pressure that even with a 1/2 inch pipe, there will be
ample volume of gas available even for the hungriest of combi
boilers.

Post meter it goes down to 20mbar hence the requirement gas pipe
sizing calc within the confines of your own property. If a lack of
pressure in the gas main resulted in a pressure drop at a consumer's
appliance then the distribution company could have a ****storm on
their hands as appliances would be running under pressure and possibly
belching carbon monoxide into the air as a result.

So yeah, nothing to worry about.

Luke

On Oct 1, 9:31*am, Luke wrote:
On Oct 1, 9:13*am, Bay Man wrote:

In a road near me, the put in a new yellow gas main, by running it
down the old iron gas main. *It is a smaller bore of course.

I noticed they did the same across the gardens, running what is the
equivalent of 1/2" yellow plastic through 3/4 and 1" iron main pipes
to each house. One house has what looks like a 1 1/4" iron main pipe
(looks like original 60s or 70s), at the meter it has what looks like
a 1 1/4" to 1" reducer, a small short piece of 1" steel pipe, then a
1" to 3/4" reducer, with two, what looks like a 1/4" plugs in the 1"
to 3/4" fitting, *with then short piece of 3/4" steel pipe and then a
brass maintap on that.

Does anyone one know what the "two" plugs are for?
How did they connect the plastic onto the house meter? *Connecting
onto the 1 1/4" steel pipe under the ground?

Will a house that has a large combi using a 1" main gas pipe be OK
with a 1/2" mains plastic gas pipe? *1/2" looks way undersized to me.
If ant of these house upgrades to a larger higher water flow combi
will they be in problems?

All this plastic gas mains looks like a cheap way of upgrading the
mains for the gas company's benefit, not for the benefit of the house
who may be short changed on a gas supply.

I suspect that between the main and the meter, the gas is under
sufficient pressure that even with a 1/2 inch pipe, there will be
ample volume of gas available even for the hungriest of combi
boilers.

Post meter it goes down to 20mbar hence the requirement gas pipe
sizing calc within the confines of your own property. If a lack of
pressure in the gas main resulted in a pressure drop at a consumer's
appliance then the distribution company could have a ****storm on
their hands as appliances would be running under pressure and possibly
belching carbon monoxide into the air as a result.

So yeah, nothing to worry about.

Luke

This small 1/2" plastic mains pipe looks too small to replace a 1"
steel pipe. Are you saying they raise the mains pipe gas pressure to
compensate? The meter regulator looks about 20 years old.

Around me many are going for these big combis like the Worcester Bosch
which I think is 40 kilowatts. They fill bath up a lot faster than the
older combis. The older small combis were about 24 kilowatts which is
a big difference. If most went for these bigger combis would they all
drag down the gas mains and combis not work properly?

Does anyone know what the two 1/4" plugs are for? Two next to each
other.

How did they connect the plastic onto the steel mains pipe.

On Fri, 1 Oct 2010 09:27:01 +0100, John wrote:

Bear in mind that the pressure is higher than it is in your house. There
is a regulator after your meter to reduce the pressure.

Thought the regulator was before the meter so it is measuring the
volume of gas consumed at a known pressure rather than the street
pressure that varies with local demand....

--
Cheers
Dave.

Does anyone know what the two 1/4" plugs are for? Two next to each
other.

Some of the fittings used have wire coils embedded in the plastic. To join them they apply current
through the coil to weld the joint from the inside. I suspect these plugs are the connection points.

On Oct 1, 10:16*am, Mike Harrison wrote:
Does anyone know what the two 1/4" plugs are for? Two next to each
other.

Some of the *fittings used have wire coils
embedded in the plastic. To join them they apply current
through the coil to weld the joint from the inside. I suspect
these plugs are the connection points.

I have seen them on the blue water plastic pipe. I think it is called
electro welding. They heat up the plastic fitting connecting at the
two terminals, which the fitting has copper wires running through it,
welding the fitting to the plastic pipe.

This is a steel reducer from 1" to 3/4". Can they weld the plastic
to the steel fitting?

On Oct 1, 10:16*am, Mike Harrison wrote:
Does anyone know what the two 1/4" plugs are for? Two next to each
other.

Some of the *fittings used have wire coils embedded in the plastic. To join them they apply current
through the coil to weld the joint from the inside. I suspect these plugs are the connection points.

What is the maximum volume of gas these new small plastic gas mains
can supply? Can it supply the maximum mater capacity? Do they have
to ensure the volume of gas supplied was as before?

On Oct 1, 11:15*am, Bay Man wrote:
On Oct 1, 10:16*am, Mike Harrison wrote:

Does anyone know what the two 1/4" plugs are for? Two next to each
other.

Some of the *fittings used have wire coils embedded in the plastic. To join them they apply current
through the coil to weld the joint from the inside. I suspect these plugs are the connection points.

What is the maximum volume of gas these new small plastic gas mains
can supply? *Can it supply the maximum mater capacity? *Do they have
to ensure the volume of gas supplied was as before?

It's not so much a maximum VOLUME you're interested in, but a maximum
SUPPLY RATE (i.e. m3 per hour). As to what is the maximum supply rate
for a gas main of a given size this would depend on the pressure of
the main, which nobody here will be able to tell you, as it varies
from main to main.

Regardless of the pressure of the main, the regulator in your meter
will reduce the pressure to 20mbar working pressure. Therefore,
regardless of your own consumption rate (up to a certain maximum
usually detailed on the meter) , and regardless of the mains pressure,
your meter will supply gas at the correct pressure.

Yes, if the pressure in the main were to drop significantly such that
the mains pipes were unable to sustain the required supply rate, then
you would end up with a pressure drop at the appliance end. But it is
probably a safe bet that when the replacement mains were laid,
calculations were made as to the pipe sizing bearing in mind the
prevailing pressure of the gas main. It may have involved a rise in
the mains pressure as a result of the replacement mains, as the new
plastic pipe will be able to withstand a far higher pressure than its
cast iron counterpart.

Luke

On 1 Oct, 09:13, Bay Man wrote:
In a road near me, the put in a new yellow gas main, by running it
down the old iron gas main. *It is a smaller bore of course.

I noticed they did the same across the gardens, running what is the
equivalent of 1/2" yellow plastic through 3/4 and 1" iron main pipes
to each house. One house has what looks like a 1 1/4" iron main pipe
(looks like original 60s or 70s), at the meter it has what looks like
a 1 1/4" to 1" reducer, a small short piece of 1" steel pipe, then a
1" to 3/4" reducer, with two, what looks like a 1/4" plugs in the 1"
to 3/4" fitting, *with then short piece of 3/4" steel pipe and then a
brass maintap on that.

Does anyone one know what the "two" plugs are for?
How did they connect the plastic onto the house meter? *Connecting
onto the 1 1/4" steel pipe under the ground?

Will a house that has a large combi using a 1" main gas pipe be OK
with a 1/2" mains plastic gas pipe? *1/2" looks way undersized to me.
If ant of these house upgrades to a larger higher water flow combi
will they be in problems?

All this plastic gas mains looks like a cheap way of upgrading the
mains for the gas company's benefit, not for the benefit of the house
who may be short changed on a gas supply.

Much of the old street main cast iron and steel gas pipes were laid
back in the days of town gas which had a lower supply pressure and
hence a larger pipe was required. The change to natural gas at a
higher pressure caused a lot of early failures but where the network
was good and remained so it was kept in service. Add to that the
friction pressure loss per metre in a steel pipe is greater than that
in a smooth bore plastic tube and it is entirely possible the use of a
smaller replacement pipe will deliver as much as and maybe more gas
than the old pipe did when installed.
Connection of plastic to metal pipes is a trivial exercise and can be
achieved by flanged joints for large sizes, screwed threads,
compression type sockets etc. You will not find plastic pipe used
above ground within a domestic dwelling for fire resistance reasons
although it may or may not be jointed where it emerges from the ground
via a fibreglass or other protective sleeve.
If the two plugs you mention are in a metal piece fitted between other
metal pipes they are probably for pressure drop test purposes. Did you
ask the installers?

On Oct 1, 11:51*am, Luke wrote:
On Oct 1, 11:15*am, Bay Man wrote:

On Oct 1, 10:16*am, Mike Harrison wrote:

Does anyone know what the two 1/4" plugs are for? Two next to each
other.

Some of the *fittings used have wire coils embedded in the plastic. To join them they apply current
through the coil to weld the joint from the inside. I suspect these plugs are the connection points.

What is the maximum volume of gas these new small plastic gas mains
can supply? *Can it supply the maximum meter capacity? *Do they have
to ensure the volume of gas supplied was as before?

It's not so much a maximum VOLUME you're interested in, but a maximum
SUPPLY RATE (i.e. m3 per hour). As to what is the maximum supply rate
for a gas main of a given size this would depend on the pressure of
the main, which nobody here will be able to tell you, as it varies
from main to main.

Regardless of the pressure of the main, the regulator in your meter
will reduce the pressure to 20mbar working pressure. Therefore,
regardless of your own consumption rate (up to a certain maximum
usually detailed on the meter) , and regardless of the mains pressure,
your meter will supply gas at the correct pressure.

Yes, if the pressure in the main were to drop significantly such that
the mains pipes were unable to sustain the required supply rate, then
you would end up with a pressure drop at the appliance end. *But it is
probably a safe bet that when the replacement mains were laid,
calculations were made as to the pipe sizing bearing in mind the
prevailing pressure of the gas main. It may have involved a rise in
the mains pressure as a result of the replacement mains, as the new
plastic pipe will be able to withstand a far higher pressure than its
cast iron counterpart.

Luke

Thanks Luke. I looked at the meter and its says 6 cubic metres an
hour. I assume that is the maximum "volume" of gas it can pass. From
what you say they have increased the mains gas pressure to compensate
for the small 1/2" plastic pipe from the road to the meter.

From 1" steel down to 1/2" plastic to me seems a hell of a lot of
downsizing. The gas pressure before the meter regulator must be
substantially higher to compensate. I fear that when many people go
over to these bigger combis the gas mains will not cope, whereas
before using the old steel pipe it could. The gas company could be
storing up problems for the future.

On Oct 1, 12:12*pm, cynic wrote:
On 1 Oct, 09:13, Bay Man wrote:





In a road near me, the put in a new yellow gas main, by running it
down the old iron gas main. *It is a smaller bore of course.

I noticed they did the same across the gardens, running what is the
equivalent of 1/2" yellow plastic through 3/4 and 1" iron main pipes
to each house. One house has what looks like a 1 1/4" iron main pipe
(looks like original 60s or 70s), at the meter it has what looks like
a 1 1/4" to 1" reducer, a small short piece of 1" steel pipe, then a
1" to 3/4" reducer, with two, what looks like a 1/4" plugs in the 1"
to 3/4" fitting, *with then short piece of 3/4" steel pipe and then a
brass maintap on that.

Does anyone one know what the "two" plugs are for?
How did they connect the plastic onto the house meter? *Connecting
onto the 1 1/4" steel pipe under the ground?

Will a house that has a large combi using a 1" main gas pipe be OK
with a 1/2" mains plastic gas pipe? *1/2" looks way undersized to me.
If ant of these house upgrades to a larger higher water flow combi
will they be in problems?

All this plastic gas mains looks like a cheap way of upgrading the
mains for the gas company's benefit, not for the benefit of the house
who may be short changed on a gas supply.

Much of the old street main cast iron and steel gas pipes were laid
back in the days of town gas which had a lower supply pressure and
hence a larger pipe was required. The change to natural gas at a
higher pressure caused a lot of early failures but where the network
was good and remained so it was kept in service. Add to that the
friction pressure loss per metre in a steel pipe is greater than that
in a smooth bore plastic tube and it is entirely possible the use of a
smaller replacement pipe will deliver as much as and maybe more gas
than the old pipe did when installed.
Connection of plastic to metal pipes is a trivial exercise and can be
achieved by flanged joints for large sizes, screwed threads,
compression type sockets etc. You will not find plastic pipe used
above ground within a domestic dwelling for fire resistance reasons
although it may or may not be jointed where it emerges from the ground
via a fibreglass or other protective sleeve.
If the two plugs you mention are in a metal piece fitted between other
metal pipes they are probably for pressure drop test purposes. Did you
ask the installers?

Thanks. The two plugs are about an inch apart. It was done a while
back. Why two? They are not test nipple s as on the gas meter. They
look like 1/4" threads.

Would they have connected the 1 1/4" steel pipe to the small plastic
pipe under the ground? The ground looks undisturbed. If the 1 1/4"
pipe had an elbow in it under the ground they could obviously not run
that directly into the meter cupboard.

On Oct 1, 12:14*pm, Bay Man wrote:
On Oct 1, 11:51*am, Luke wrote:





On Oct 1, 11:15*am, Bay Man wrote:

On Oct 1, 10:16*am, Mike Harrison wrote:

Does anyone know what the two 1/4" plugs are for? Two next to each
other.

Some of the *fittings used have wire coils embedded in the plastic. To join them they apply current
through the coil to weld the joint from the inside. I suspect these plugs are the connection points.

What is the maximum volume of gas these new small plastic gas mains
can supply? *Can it supply the maximum meter capacity? *Do they have
to ensure the volume of gas supplied was as before?

It's not so much a maximum VOLUME you're interested in, but a maximum
SUPPLY RATE (i.e. m3 per hour). As to what is the maximum supply rate
for a gas main of a given size this would depend on the pressure of
the main, which nobody here will be able to tell you, as it varies
from main to main.

Regardless of the pressure of the main, the regulator in your meter
will reduce the pressure to 20mbar working pressure. Therefore,
regardless of your own consumption rate (up to a certain maximum
usually detailed on the meter) , and regardless of the mains pressure,
your meter will supply gas at the correct pressure.

Yes, if the pressure in the main were to drop significantly such that
the mains pipes were unable to sustain the required supply rate, then
you would end up with a pressure drop at the appliance end. *But it is
probably a safe bet that when the replacement mains were laid,
calculations were made as to the pipe sizing bearing in mind the
prevailing pressure of the gas main. It may have involved a rise in
the mains pressure as a result of the replacement mains, as the new
plastic pipe will be able to withstand a far higher pressure than its
cast iron counterpart.

Luke

Thanks Luke. I looked at the meter and its says 6 cubic metres an
hour. I assume that is the maximum "volume" of gas it can pass. From
what you say they have increased the mains gas pressure to compensate
for the small 1/2" plastic pipe from the road to the meter.

From 1" steel down to 1/2" plastic to me seems a hell of a lot of
downsizing. The gas pressure before the meter regulator must be
substantially higher to compensate. I fear that when many people go
over to these bigger combis the gas mains will not cope, whereas
before using the old steel pipe it could. The gas company could be
storing up problems for the future.- Hide quoted text -

- Show quoted text -

Well... 6 cubic metres an hour is not a measure of volume. It is a
measure of RATE, i.e. the volume the meter can supply *over a given
time period*. To talk in terms of volume alone is not relevant,
without including a time element to the calculation. What is means if
that if you disconnected all your appliances from the meter and let
the meter **** out gas into the air, over 1 hour, 6 cubic meters would
**** out at a pressure of 20 mbar. So do you see that talking in terms
of volume alone does not relate to the capacity of the meter?

Regarding the concern over the main sizing. Almost certainly the
reason why the main was upgraded was twofold a) to replace ageing
pipes which may fail and b) to allow an increase of pressure to be
applied to the main due to increased gas consumption rate brought
about (partly) by people installing large combination boilers.

You might be able to allay your fears if you contact the distribution
company directly, but frankly, you are worrying needlessly. The dist.
co. aren't going to upgrade the main without doing a detailed
calculation of the expected demand, both present and future.

Luke

On 1 Oct,
Bay Man wrote:

This small 1/2" plastic mains pipe looks too small to replace a 1"
steel pipe. Are you saying they raise the mains pipe gas pressure to
compensate? The meter regulator looks about 20 years old.

The original pipe was almost certainly sized for town gas distributed at low
pressure. About when north sea gas first arrived the mains pressure was
increased so that existing pipes would handle greater volume. Before then
there was always a reduction of pressure prior to Sunday lunch due to the
increased demand. The higher pressure and regulators by the meter have made
this problem nonexistent now.

--
B Thumbs
Change lycos to yahoo to reply

According to a recent National Grid visit the smallest alkathene
domestic service pipe in the UK is 15mm, a fraction over 1/2". I did
not enquire what the length restriction was on that (it might be
around 20m or 32m for that size). Most people get a 20mm pipe because
that will fit through most existing service pipes.

The street supply is something like 35 to 75mbar (min to max).

When you consider you can have a fair length of 15mm pipe inside and
have only a 1mbar pressure drop, you can see there is a large amount
of leeway between the high grid supply pressure and your meter
regulator 21mbar output.

When I asked why gas pressure seemed to drop in the 2009 winter
locally, he said that was almost always due to an undersized local
grid supply combined with local emergency maintenance. The local grid
was in fact upgraded in 2010 in the same street for just that reason
(well partly, the sub-contractor went bust as it happens so only half
got done).

On Oct 1, 12:50*pm, Luke wrote:
On Oct 1, 12:14*pm, Bay Man wrote:





On Oct 1, 11:51*am, Luke wrote:

On Oct 1, 11:15*am, Bay Man wrote:

On Oct 1, 10:16*am, Mike Harrison wrote:

Does anyone know what the two 1/4" plugs are for? Two next to each
other.

Some of the *fittings used have wire coils embedded in the plastic. To join them they apply current
through the coil to weld the joint from the inside. I suspect these plugs are the connection points.

What is the maximum volume of gas these new small plastic gas mains
can supply? *Can it supply the maximum meter capacity? *Do they have
to ensure the volume of gas supplied was as before?

It's not so much a maximum VOLUME you're interested in, but a maximum
SUPPLY RATE (i.e. m3 per hour). As to what is the maximum supply rate
for a gas main of a given size this would depend on the pressure of
the main, which nobody here will be able to tell you, as it varies
from main to main.

Regardless of the pressure of the main, the regulator in your meter
will reduce the pressure to 20mbar working pressure. Therefore,
regardless of your own consumption rate (up to a certain maximum
usually detailed on the meter) , and regardless of the mains pressure,
your meter will supply gas at the correct pressure.

Yes, if the pressure in the main were to drop significantly such that
the mains pipes were unable to sustain the required supply rate, then
you would end up with a pressure drop at the appliance end. *But it is
probably a safe bet that when the replacement mains were laid,
calculations were made as to the pipe sizing bearing in mind the
prevailing pressure of the gas main. It may have involved a rise in
the mains pressure as a result of the replacement mains, as the new
plastic pipe will be able to withstand a far higher pressure than its
cast iron counterpart.

Luke

Thanks Luke. I looked at the meter and its says 6 cubic metres an
hour. I assume that is the maximum "volume" of gas it can pass. From
what you say they have increased the mains gas pressure to compensate
for the small 1/2" plastic pipe from the road to the meter.

From 1" steel down to 1/2" plastic to me seems a hell of a lot of
downsizing. The gas pressure before the meter regulator must be
substantially higher to compensate. I fear that when many people go
over to these bigger combis the gas mains will not cope, whereas
before using the old steel pipe it could. The gas company could be
storing up problems for the future.- Hide quoted text -

- Show quoted text -

Well... 6 cubic metres an hour is not a measure of volume. It is a
measure of RATE, i.e. the volume the meter can supply *over a given
time period*. To talk in terms of volume alone is not relevant,
without including a time element to the calculation. What is means if
that if you disconnected all your appliances from the meter and let
the meter **** out gas into the air, over 1 hour, 6 cubic meters would
**** out at a pressure of 20 mbar. So do you see that talking in terms
of volume alone does not relate to the capacity of the meter?

Regarding the concern over the main sizing. Almost certainly the
reason why the main was upgraded was twofold a) to replace ageing
pipes which may fail and b) to allow an increase of pressure to be
applied to the main due to increased gas consumption rate brought
about (partly) by people installing large combination boilers.

You might be able to allay your fears if you contact the distribution
company directly, but frankly, you are worrying needlessly. The dist.
co. aren't going to upgrade the main without doing a detailed
calculation of the expected demand, both present and future.

Luke

Thanks Luke. I just did search and found this.
http://webcache.googleusercontent.co...&ct=clnk&gl=uk

Someone had problems "after" a new plastic gas main was installed. I
suppose it all depends if the gas engineers do their job properly in
sizing up the gas mains.

On Oct 1, 12:53*pm, wrote:
On 1 Oct, *
* * *Bay Man wrote:

This small 1/2" plastic mains pipe looks too small to replace a 1"
steel pipe. Are you saying they raise the mains pipe gas pressure to
compensate? *The meter regulator looks about 20 years old.

The original pipe was almost certainly sized for town gas distributed at low
pressure. About when north sea gas first arrived the mains pressure was
increased so that existing pipes would handle greater volume. Before then
there was always a reduction of pressure prior to Sunday lunch due to the
increased demand. The higher pressure and regulators by the meter have made
this problem *nonexistent now.

--
* B Thumbs
* Change lycos to yahoo to reply

So these meter regulators can take in 35 to 75mbar and give out a
constant 21mbar?

On 01/10/2010 10:13, Dave Liquorice wrote:
On Fri, 1 Oct 2010 09:27:01 +0100, John wrote:

Thought the regulator was before the meter so it is measuring the
volume of gas consumed at a known pressure rather than the street
pressure that varies with local demand....

Correct, although AIUI typical street pressure is still only marginally
over atmospheric (37 mb?), so it won't make a huge difference.

--
Andy

On Oct 1, 1:21*pm, Andy Wade wrote:
On 01/10/2010 10:13, Dave Liquorice wrote:

On Fri, 1 Oct 2010 09:27:01 +0100, John wrote:

Thought the regulator was before the meter so it is measuring the
volume of gas consumed at a known pressure rather than the street
pressure that varies with local demand....

Correct, although AIUI typical street pressure is still only marginally
over atmospheric (37 mb?), so it won't make a huge difference.

--
Andy

I would assume the 37mbar is on an old large bore steel pipe gas
mains. Hopefully it would be towards 75mbar when converted to plastic
with small bore pipes..

On 1 Oct, 09:13, Bay Man wrote:
In a road near me, the put in a new yellow gas main, by running it
down the old iron gas main. *It is a smaller bore of course.

I noticed they did the same across the gardens, running what is the
equivalent of 1/2" yellow plastic through 3/4 and 1" iron main pipes
to each house. One house has what looks like a 1 1/4" iron main pipe
(looks like original 60s or 70s), at the meter it has what looks like
a 1 1/4" to 1" reducer, a small short piece of 1" steel pipe, then a
1" to 3/4" reducer, with two, what looks like a 1/4" plugs in the 1"
to 3/4" fitting, *with then short piece of 3/4" steel pipe and then a
brass maintap on that.

Does anyone one know what the "two" plugs are for?
How did they connect the plastic onto the house meter? *Connecting
onto the 1 1/4" steel pipe under the ground?

Will a house that has a large combi using a 1" main gas pipe be OK
with a 1/2" mains plastic gas pipe? *1/2" looks way undersized to me.
If ant of these house upgrades to a larger higher water flow combi
will they be in problems?

All this plastic gas mains looks like a cheap way of upgrading the
mains for the gas company's benefit, not for the benefit of the house
who may be short changed on a gas supply.

The gas grid is part of the gas storage system, the pressure in it
varies with consumption. Obviously your gas appliances and meter need
a fixed pressure to work efficiently, this is the purpose of the
pressure reducing valve before your meter.
The purpose of the plugs is to perform tests on the sytem to show
there are no leaks and that isolation valves are shutting off tight,
ie not passing gas when closed.
http://www.ukcopperboard.co.uk/liter...on-testing.pdf

On Fri, 1 Oct 2010 05:57:19 -0700 (PDT), Bay Man wrote:

Thought the regulator was before the meter so it is measuring the
volume of gas consumed at a known pressure rather than the street
pressure that varies with local demand....

Correct, although AIUI typical street pressure is still only
marginally
over atmospheric (37 mb?), so it won't make a huge difference.

I am surprised that street pressure is that low. The 35 to 75mb being
banded about is only 0.5 to 1 psi. Guess they must have higher
pressure trunk distribution to other regulators for the street
distribution.

--
Cheers
Dave.

Dave Liquorice wrote:

On Fri, 1 Oct 2010 05:57:19 -0700 (PDT), Bay Man wrote:

Thought the regulator was before the meter so it is measuring the
volume of gas consumed at a known pressure rather than the street
pressure that varies with local demand....

Correct, although AIUI typical street pressure is still only
marginally
over atmospheric (37 mb?), so it won't make a huge difference.

I am surprised that street pressure is that low. The 35 to 75mb being
banded about is only 0.5 to 1 psi. Guess they must have higher
pressure trunk distribution to other regulators for the street
distribution.


WE'RE JUST HAVING A GAS SUPPLY DONE AT WORK, MAPS ARE ALL WRONG SO sgn
CONTRACTOR PUT FORK THROUGH 32MM YELLOW PLASTIC PIPE,

We're just having a gas supply run in at work. Maps are all wrong and as a
consequence the contractor making the roadside connection put his fork
through a 32mm plastic pipe to an adjacent house, the jet sandblasted him,
he said the medium pressure pipes were 2 bar.

AJH

In article o.uk,
"Dave Liquorice" writes:
On Fri, 1 Oct 2010 05:57:19 -0700 (PDT), Bay Man wrote:

Thought the regulator was before the meter so it is measuring the
volume of gas consumed at a known pressure rather than the street
pressure that varies with local demand....

Correct, although AIUI typical street pressure is still only
marginally
over atmospheric (37 mb?), so it won't make a huge difference.

I am surprised that street pressure is that low. The 35 to 75mb being
banded about is only 0.5 to 1 psi. Guess they must have higher
pressure trunk distribution to other regulators for the street
distribution.

Yes. Actually, the pipe capacity of the high pressure natural gas
network is a significant proportion of the country's gas storage.

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

On 1 Oct, 19:04, "Dave Liquorice"
wrote:
On Fri, 1 Oct 2010 05:57:19 -0700 (PDT), Bay Man wrote:
Thought the regulator was before the meter so it is measuring the
volume of gas consumed at a known pressure rather than the street
pressure that varies with local demand....

Correct, although AIUI typical street pressure is still only
marginally
over atmospheric (37 mb?), so it won't make a huge difference.

I am surprised that street pressure is that low. The 35 to 75mb being
banded about is only 0.5 to 1 psi. Guess they must have higher
pressure trunk distribution to other regulators for the street
distribution.

--
Cheers
Dave.

When I was working and more in touch with affairs, I understood that
once all the old pipework was replaced they were going to
substantially increase the mains gas pressure, so increasing the
storage capacity.

Interested to find a post about this as we have just had our boiler serviced and the engineer discovered low gas pressure to it. On investigation the pressure coming to the meter was too low. Had to cut off the supply and call national grid who have treated it as an emergency. Guess what, the diameter of the plastic pipes to our property installed a year or so back as part of the upgrade are too small to supply us. Half the houses in our street are as large as ours and presumably all have low pressure. Now if they discover and report this it will be treated as an emergency, but until the householder reports it, it seems national grid can ignore it. Cost cutting by national grid or their contractors, or poor project management or all three?!

On 27/01/2017 21:39, wrote:
Interested to find a post about this as we have just had our boiler serviced and the engineer discovered low gas pressure to it. On investigation the pressure coming to the meter was too low. Had to cut off the supply and call national grid who have treated it as an emergency. Guess what, the diameter of the plastic pipes to our property installed a year or so back as part of the upgrade are too small to supply us. Half the houses in our street are as large as ours and presumably all have low pressure. Now if they discover and report this it will be treated as an emergency, but until the householder reports it, it seems national grid can ignore it. Cost cutting by national grid or their contractors, or poor project management or all three?!


Surely if they replaced the main to the house the supply would have been
cut off at some time and when reinstated a qualified technician would
have safety checked each property, including a pressure test?

--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk

On 27/01/2017 21:39, wrote:
Interested to find a post about this

Rather an old thread - back in 2010, and no longer on my news server so
I can't see what it said.

as we have just had our boiler serviced and the engineer discovered
low gas pressure to it. On investigation the pressure coming to the
meter was too low. Had to cut off the supply and call national grid who
have treated it as an emergency. Guess what, the diameter of the
plastic pipes to our property installed a year or so back as part of the
upgrade are too small to supply us. Half the houses in our street are
as large as ours and presumably all have low pressure. Now if they
discover and report this it will be treated as an emergency, but until
the householder reports it, it seems national grid can ignore it. Cost
cutting by national grid or their contractors, or poor project
management or all three?!

I would be surprised if you have the type of pressure problem which you
describe. When your gas connection was updated, a plastic pipe will have
been inserted inside the original iron pipe. This obviously reduces the
diameter of pipe through which the gas flows *but* the iron pipe will
date back to the time when you had town gas - which was at a much lower
pressure than natural gas is now - so the pipe should still have
adequate capacity.

Once the gas gets to the meter, the pressure is of course reduced by the
regulator. If the pressure is low at your boiler, it's likely either
that the regulator is set wrongly or that the pipe between meter and
boiler isn't big enough. If that was installed a long time ago and if
you are now using a powerful boiler for which the pipework wasn't
designed, that could be your problem.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

In article ,
writes:
Interested to find a post about this as we have just had our boiler service=
d and the engineer discovered low gas pressure to it. On investigation the=
pressure coming to the meter was too low. Had to cut off the supply and c=
all national grid who have treated it as an emergency. Guess what, the dia=
meter of the plastic pipes to our property installed a year or so back as p=
art of the upgrade are too small to supply us. Half the houses in our stre=
et are as large as ours and presumably all have low pressure. Now if they =
discover and report this it will be treated as an emergency, but until the =
householder reports it, it seems national grid can ignore it. Cost cutting=
by national grid or their contractors, or poor project management or all t=
hree?!

So, what did they do to fix it?

They can change the pressure in the street mains, probably within some
permitted limits. I have 75mbar at the back of my mind, but can't remember
if that's the typical supply pressure or the maximum.

Pressure after the meter should be 20mbar.

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

Cock up. I think the folk around here had plastic pipe shoved up the old
pipes which were rusty. I did not have mine connected as I use no gas. I've
not heard of this being a problem. Can they not simply pump it harder or
have they in fact over simplified the problem and its a pipe further down
the chain they replaced by a narrower one making it impossible to get the
pressure up when everyone wants to use gas at a higher rate, bit like a
chicane.
Brian

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

Blind user, so no pictures please!
wrote in message
...
Interested to find a post about this as we have just had our boiler serviced
and the engineer discovered low gas pressure to it. On investigation the
pressure coming to the meter was too low. Had to cut off the supply and
call national grid who have treated it as an emergency. Guess what, the
diameter of the plastic pipes to our property installed a year or so back as
part of the upgrade are too small to supply us. Half the houses in our
street are as large as ours and presumably all have low pressure. Now if
they discover and report this it will be treated as an emergency, but until
the householder reports it, it seems national grid can ignore it. Cost
cutting by national grid or their contractors, or poor project management or
all three?!

Not the latter as he said they had measured it at the meter.
More likely is what I have heard about before, that some pipework feeding
the street or area has an issue and hence cannot deliver the gas fast enough
when everyone is using it.
Brian

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

Blind user, so no pictures please!
"Roger Mills" wrote in message
...
On 27/01/2017 21:39, wrote:
Interested to find a post about this

Rather an old thread - back in 2010, and no longer on my news server so I
can't see what it said.

as we have just had our boiler serviced and the engineer discovered low
gas pressure to it. On investigation the pressure coming to the meter was
too low. Had to cut off the supply and call national grid who have
treated it as an emergency. Guess what, the diameter of the plastic pipes
to our property installed a year or so back as part of the upgrade are too
small to supply us. Half the houses in our street are as large as ours
and presumably all have low pressure. Now if they discover and report
this it will be treated as an emergency, but until the householder reports
it, it seems national grid can ignore it. Cost cutting by national grid
or their contractors, or poor project management or all three?!

I would be surprised if you have the type of pressure problem which you
describe. When your gas connection was updated, a plastic pipe will have
been inserted inside the original iron pipe. This obviously reduces the
diameter of pipe through which the gas flows *but* the iron pipe will date
back to the time when you had town gas - which was at a much lower
pressure than natural gas is now - so the pipe should still have adequate
capacity.

Once the gas gets to the meter, the pressure is of course reduced by the
regulator. If the pressure is low at your boiler, it's likely either that
the regulator is set wrongly or that the pipe between meter and boiler
isn't big enough. If that was installed a long time ago and if you are now
using a powerful boiler for which the pipework wasn't designed, that could
be your problem.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Friday, 1 October 2010 09:13:26 UTC+1, Bay Man wrote:
In a road near me, the put in a new yellow gas main, by running it
down the old iron gas main. It is a smaller bore of course.

I noticed they did the same across the gardens, running what is the
equivalent of 1/2" yellow plastic through 3/4 and 1" iron main pipes
to each house. One house has what looks like a 1 1/4" iron main pipe
(looks like original 60s or 70s), at the meter it has what looks like
a 1 1/4" to 1" reducer, a small short piece of 1" steel pipe, then a
1" to 3/4" reducer, with two, what looks like a 1/4" plugs in the 1"
to 3/4" fitting, with then short piece of 3/4" steel pipe and then a
brass maintap on that.

Does anyone one know what the "two" plugs are for?
How did they connect the plastic onto the house meter? Connecting
onto the 1 1/4" steel pipe under the ground?

Will a house that has a large combi using a 1" main gas pipe be OK
with a 1/2" mains plastic gas pipe? 1/2" looks way undersized to me.
If ant of these house upgrades to a larger higher water flow combi
will they be in problems?

All this plastic gas mains looks like a cheap way of upgrading the
mains for the gas company's benefit, not for the benefit of the house
who may be short changed on a gas supply.

The old coal gas was at very low pressure, ISTR less than 1/2psi.
The new gas mains run at various pressures.
So the new pipes can be much smaller.
Plus they are smoother inside with longer radius bends.
http://www.gasinfo.uk.com/distribution_page.htm

On 27/01/2017 22:02, alan_m wrote:
On 27/01/2017 21:39, wrote:
Interested to find a post about this as we have just had our boiler
serviced and the engineer discovered low gas pressure to it. On
investigation the pressure coming to the meter was too low. Had to
cut off the supply and call national grid who have treated it as an
emergency. Guess what, the diameter of the plastic pipes to our
property installed a year or so back as part of the upgrade are too
small to supply us. Half the houses in our street are as large as
ours and presumably all have low pressure. Now if they discover and
report this it will be treated as an emergency, but until the
householder reports it, it seems national grid can ignore it. Cost
cutting by national grid or their contractors, or poor project
management or all three?!


Surely if they replaced the main to the house the supply would have been
cut off at some time and when reinstated a qualified technician would
have safety checked each property, including a pressure test?


If the pressure test is done one house at a time, with all the other
houses capped off ....

Or during the summer when the demand for gas is low ....