Heating Help

Gate valves for natural gas?

A contractor is installing a big pipe in the ground near me. By eyeball, it is about 12 inches in diameter, steel, with welded joints. The wall thickness seems to be almost an inch.  The part I can see is about 1/2 mile long, but I do not think it is connected at either end yet.

I was wondering what it was to be used for. About every block, there is a huge gate valve on it, coming off the side like a T. I am sure they would never use a valve like that for little gas pipes, like near my boiler. But could this be for gas? Or is it more likely a new water pipe? They are not putting in any new houses in the neighborhood, so why a new water line?

Most are not rated

Gate valves are generally taboo on gas service.

The valve has to be rated for the use in the gas line at the operating pressure.

What do they use on big gas transmission lines when they want to shut one off?

It is all in the title.

I'm not sure.

It may very well be a gate valve of sorts, but built in a much different way then a typical gate valve.

I'd be curious myself, gas utility distribution is out of my realm of expertise. Tim should be able to say for sure.

The trouble with gates is the stems have a tendency to leak. Usually on large gas lines I see plug valves, and diaphragm valves

Slowly step

away from the computer and go ask one of the workers while they're on break or leaving the jobsite.  I'm sure they'll tell you and the fresh air will do ya good.  ; )

Good idea, but ...

I have never seen any workers there. Work does seem to have taken place, a little bit at a time. Once in a while a street is blocked off and the pipe dips under the intersection. The rest of the pipe has been above ground for many months. If they expect to dig a ditch to put the pipe in, they better get to it before it freezes. It went down to 13F last night and part of this morning, but it is up to 26F now.