DerbyDad03 wrote:
On Dec 3, 3:26 pm, dpb wrote:
DerbyDad03 wrote:
On Dec 3, 3:03 pm, " wrote:
On Dec 3, 2:54�pm, Edge wrote:
On Dec 3, 12:31 pm, (Chris Lewis) wrote:
According to Oren :
Recently the gas company was out to put a new meter on a new home. She
installed the meter and opened a gas line inside the garage to purge
the line. ...
For what it's worth, I was watching TOH a few weeks ago where they
tapped into the gas main to run a new line to a customer. They used
something very similiar to those needle valves you use to tap into a
water line. It was more sophisticated in that they drilled the line
first and then attached the valve, but the device they used kept the
gas line sealed at all times. I know that's not a repair, but the
point is that they kept the system both pressurized and sealed at all
times.
However, I do have a question about your repair scenario: If they
actually opened the lines and vented the gas to the open air during a
repair, wouldn't there be a "gap" in any downstream gas delivery that
would extinguish any pilot lights that were burning?
That was the new service line to the residence that was being purged,
not the main, so the answer is "no", they wouldn't have noticed.
As for the tap-in, sure they seal and are careful of sparks, too, but
the main lines are at much higher pressure/volume than a single service
line so they lose much more gas than the scenario here.
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If you were responding to my post, you may have misunderstood my
question ...
I was asking about his repair scenario, not the new service line to
the customer.
hallerb said "gas companies do it all the time, as proof whens the
last time your gas was shut off when they did repairs?"
I am assuming he means that the gas company does not shut off the gas
every time they repair a gas line. Here's my question: If they open a
line and vent it to the air during the repair, then wouldn't any
downstream customers lose pressure and therefore lose their pilot
lights? I'm not questioning the fact that they do or don't shut off
the gas, but it seems to me that to any customers downstream of the
repair, it's going to look like the gas was off if they open the
line.
Perhaps they tap around the repair before opening the line? If that's
the case, no one would lose service, but they are not really doing the
same thing as a guy installing a valve or T in a house like the OP
(and I) have seen them do.
OK, yes, I did misread your question and answered the unasked one...
If they were, indeed to completely open a line, then yes, unless there
were alternate supply there would be a loss of service downstream. IME
anything that required that level of work _would_ entail a notification
and a cessation of services. Not many residential branches have
alternate supply mains although I suppose if the work were extensive
enough they might bypass an area to not have extended outage.
In general, installed pipelines are pretty maintenance free for quite
long time periods so the consumer observation of loss of service is
quite rare. Our tap comes directly off a main (36") cross-country line
that crosses our place east of the house about a quarter mile away. To
the best of my knowledge that line hasn't had a service outage in
20-something years since they redid a section. It is flown by aerial
surveillance once/month to spot any problems. The other line just to
the west of the house that was more recently laid was worked on just
last year to lower it under the road because the county has been making
noises of re-elevating these roads sometime and if they were to do so
they just might have come close to the existing depth. It's a 42" line
and was shutdown for a period while the new section was fitted in and
welded in place. They only dug access holes to the ends on each end
about 40-ft away from the road and then a little longer trench on one
side. The then punched the new through under the road w/o trenching the
100-ft or so from one access hole to the other. The did a local
pressure test on the new section before inserting it then a pressure
test on the last connections and done. On those big lines they
don't/can't flush them anyway because of the length the amount of air in
a 100-ft section out of the 1500 miles before it gets to its ultimate
destination is inconsequential as it gets mixed up during the compressor
booster stations anyway.
For smaller side distribution lines I don't know whether they would
bother to try to purge or not or whether they just let the end users
deal with it until the air slug is gone...
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