Frozen gas pipes?!

[Jimmy Wilkinson Knife]

I just spotted a "What to do if your gas pipes are frozen" on my electricity/gas supply company's website (EDF).

Remind me, at what temperature does methane freeze?

[Brian Gaff]

Now how did I guess it was you before i listened to the sender. I think really unlikely the gas will freeze but the earth can and fracture gas pipes. Brian

[Nightjar]

A lot lower than the moisture in it.

[Jimmy Wilkinson Knife]

I still can't see that as something the average EDF customer would worry about.

[Jimmy Wilkinson Knife]

Should there be moisture in it?

[Ed Pawlowski]

Water can get into gas pipes and accumulate in low spots. Just as piping has a drip let at vertical elbows.

[Brian Gaff]

There is always some moisture in gas. However, not a lot. However when gas pipes of an older type run through clay, often they can rust and have holes, and moisture gets in even though the clay is so dense the supply continues. If you look at council web sites around the country especially in the SE, you will find a huge program of gas main replacement to cope with the pipe issues. This is being done around here by Southern Gas Networks and according to the blokes doing it rusty leaky pipes have been in use for years, Indeed I have no gas in my house so when it came to attempting to put their pretty yellow pipes through the old ones they found many house spurs had in fact completely rusted through. They just plugged up mine as I did not have any gas devices. However they did give me a bit of the pipe and it was wafer thin in places and mostly made of rust. The use was built in 1939, so you can see how bad older pipes might be. Brian

[GB]

How much moisture is there in the gas supply? Are we talking about hours to ice up a pipe, or months?

[Charles Law]

I had a NG regulator (before the meter) freeze and stop the flow of NG.  Fix was to slowly pour hot water over it.

[Jimmy Wilkinson Knife]

How does it let water out but not gas?

[Jimmy Wilkinson Knife]

There's certainly been a lot of gas mains replaced around here in central Scotland recently. I just assumed they were old and rusty, or getting damaged by vibrations from traffic.

[dpb]

I'm pretty sure Ed meant "leg" not "let"; it's just a collection point that keeps the condensate/entrained water have a place to go out of the main line into the appliance; not an automatic outlet.

And, yes, gas supplies are _supposed_ to be essentially dry; it's an insurance policy for the inevitable case where for some reason some moisture is introduced into the system by whatever means; could be as simple as having to opened the system somewhere else for maintenance.

Here, where many rural residences are on direct wellhead taps or a tap off of a collection line, it's a much bigger issue than "the gas company" commercial distribution most are undoubtedly thinking of, but still "stuff happens" even with them.

[Ed Pawlowski]

Correct. Instead of an elbow at 90 degree turn, they use a Tee and the bottom has a short nipple and cap. Traps anything moving in the pipe, liquid or solid.

[Nightjar]

No idea. I only know that some is expected.

[Jimmy Wilkinson Knife]

I take it someone has to milk the nipple every so often.

[Ed Pawlowski]

No, I've take them apart after years and found a little dust. Even on industrial with 4" feed.

[Jimmy Wilkinson Knife]

So it wasn't really necessary to have it there.

[dpb]

On 4/29/2018 8:36 AM, Jimmy Wilkinson Knife wrote: ...

Insurance is only necessary after the fire, too...

[Jimmy Wilkinson Knife]

Insurance is a con. Remember, insurance companies make a profit....

[Jimmy Wilkinson Knife]

But it's not likely to happen. Look at the odds. What percentage of the value of your house do you pay to the insurance company? Now on average they make a profit, so the chances of actually needing a full payout must be virtually nothing.