ID this gas pipe fitting?

[RogerT]

I have a gas line coming into my house through the basement wall. The line coming looks like it is about a 1-1/4 inch pipe. The pipe comes in, then there is a silver steel color knurled fitting, then a regular reducer fitting, then a street 90 degree L. From there, the piping goes up to the gas meter that is in the basement.

What I am trying to figure out is, what is that silver steel color knurled fitting? Whatever it is, it is threaded onto the pipe that is coming into the house and threaded into the reducer fitting.

Here are two photos:

This is in New Jersey (PSE&G is the gas company). Yes, I know I could try calling the gas company to find out, but it is next to impossible to get through to them on the phone, and I have already had them out there twice because I am trying to figure a way to relocate the meter about one foot over for remodeling. They were no help (long story), and I didn't think to ask them while they were there what the knurled fitting is. I have a hunch that the knurled steel fitting is some kind of gas company tag or marker that they put on to make sure no one has tampered with the gas line before the meter. Does anyone know if that's correct or what that fitting is?

Thanks.

[willshak]

RogerT wrote the following:

Let me be the first to make a wild ass guess. Maybe it is like a lock nut. You know, a second threaded nut to keep the other part from backing out. Because this is a potentially explosive gas line, it might be required I don't have NG at my house.

[The Daring Dufas]

It looks like an adapter bushing for electrical conduit to go up a size. Is it aluminum or plated steel? It could also be a check valve or flow restrictor if it was installed by the gas company.

TDD

[EXT]

I worked at a gas company for 40 years, and I have never seen such a fitting in use, that doesn't mean they didn't use something similar over the past

150 years, things kept changing over the years. If I was to make a wild guess, and since you seem to have a steel service line, I would venture a guess that it is part of an insulating fitting to isolate the house ground from the gas service line, so that the house ground doesn't counter the effects of anodes installed on the mains to prevent corrosion.

[dpb]

Never seen anything like it on gas before...that's a sizable entrance line for a single-family residence.

I'd vote w/ the guess of EXT re: isolation fitting concept if it was, indeed, the gas company's.

OTOH, it may just be an adapter to fit the reducing coupling the plumber had with him.

I don't think other than the former possibly it's anything special tamper-proof device or check valve or some such exotic thing.

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[RogerT]

Now that you mention it, it may be aluminum or some kind of alloy. It has maintained its silver color over the years.

[RogerT]

It's a larger entrance line because it is actually a 3-unit building with separate gas for each unit. From the point in the photo, the piping then goes to 3 separte gas meters, rather than one. I left that part out before because I didn't want to make the post too complicated. The basement is being remodeled and I want to be able to get the 3 meters moved about a foot over. Also, each meter has it's own shutoff valve, but I wanted to be able to also have a main shutoff valve installed on the main line so all of the gas for all 3 units could be shut off at once if needed during an emergency etc. That was why I had the gas company out there a couple of times, but that's a whole other story.

[dpb]

RogerT wrote: ...

OK, that explains the size...

There isn't an external shutoff??? I'd think that a Code violation of first order if not.

If there is, why do you need the gas company at all since it's all inside the building? Or, does NJ have requirement that anything on upstream side of meter _must_ be done by the utility? (Here, anything in the residence is fair game for a qualified technician).

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[RogerT]

There is an external shutoff valve, although there was even a question about that for a while. Different gas company reps who came out to the property said different things about what can and cannot be done, who can do it, whether there should be an internal main shutoff valve, etc. Originally, I was thinking of having the gas company install a new line coming in at a different location and having the meters moved to the outside of the property. That turned out to be prohibitively expensive and not recommended by the gas company reps who first came out. They did say, however, that I should have a main shutoff on the inside as a safety feature. They also said that I could have a plumber relocate the meters a little to accomodate what I want to do as long as the meters remain right by where the main line comes into the building. So, that shouldn't be an issue.

[dpb]

RogerT wrote: ...

Sounds like you're good to go, then, since the gas can be isolated for working. One hopes the valve isn't so old that it (a) is still operable and (b) seals. :)

I'd agree that there ought to be a main shutoff too as well as the individual ones but if they're all within reaching distance of each other there's really no distinct advantage other than redundancy has some benefit and convenience of isolating the meters for maintenance/repair w/o outside access.

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[The Daring Dufas]

If you can scratch a grove in it with a screwdriver, it's aluminum. Come to think of it, I've installed bushings on gas lines going into gas valves. It could simply be a bushing that a gas fitter had on the truck.

TDD

[dpb]

The Daring Dufas wrote: ...

That's certainly my candidate for most likely...

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[RogerT]

Here's a new twist. It just dawned on me that I could check another property that I own and see what the gas line looks like coming in. It turns out that it also has the same type of silver fitting. Here are photos of that one:

On this one, the silver metal part and the fitting look like they are all one piece. I tried scratching it with a metal screw and the screw does mark it.

[The Daring Dufas]

It's starting to look like a check valve.

TDD

[Ala]

That's exactly what my mother said

[The Daring Dufas]

Roger, I just had a thought, I've never seen those type fittings on any of Alabama Gas systems so I have a hunch the fittings could be a thermal shutoff valve that would snap shut in case of fire. Perhaps you could ask one of the fire marshals or a city inspector if that's the case. I believe the engineering department of your city or county would be glad to tell you what it's for.

TDD

[dpb]

RogerT wrote: ...

That looks like it could be the dielectric fitting as somebody else mentioned earlier -- the whole thing instead of having just used the one end as a bushing as appears to have been done in the other case.

What's the dark section the el is screwed into on this one?

I suppose it is still possible it could be a TCV (thermal check valve) but the only ones of that size I'm familiar with look similar to this one from Dresser...

Couldn't find the requirements from PSE&G on their website other than did find a reqm't for inline check valves on jeweler's NG/oxy- torches and the like, but they are a much smaller device, of course.

Don't guess there are any manufacturer marks, of course???

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[RogerT]

That could be correct. I'll have to wait to find out (see below), unless someone else here knows what it is.

The dark section didn't show up well on the photos, but it appeared to me to be threads that are eithe part of the fitting or are a threaded nipple that goes between the fitting and the L.

There are no manufacturer marks anywhere.

I went to another property I have today and it has the same type of fitting. Here are two photos from that property:

The gas company is now going to come back out to the original property (the

3-unit) next week and switch the 3 existing meters over to meters that can be read remotely (they call them ERT meters, or something like that). When they show up, I'm going to ask them what the fitting is and what it is for. I'll post what they tell me back here when I find out.

[dpb]

RogerT wrote: ...

...

No better guess than before--that clearly is a nipple out the back end on this one. I'm having trouble envisioning it being a check valve but won't say it's impossible...

Sounds like a plan. Was going to say you'll find out what it is when the plumber moves them but same goes for this route, too.

Will be interested to hear what the mystery part is finally determined to be. I'll be particularly interested in whether that first one is complete or the actual working piece is gone in lieu of the reducing coupling...

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[RogerT]

Here's the follow-up answer:

I recently wrote,

"The gas company is now going to come back out to the original property (the

3-unit) next week and switch the 3 existing meters over to meters that can be read remotely (they call them ERT meters, or something like that). When they show up, I'm going to ask them what the fitting is and what it is for. I'll post what they tell me back here when I find out."

They came out today and I asked them what the fitting is. They said it is called a "posilock" fitting. It is used because the old steel gas lines that came into buildings are no longer used for gas supply. Instead, the steel pipe is now used as a conduit. Inside the steel conduit is a plastic gas supply line that comes in from the street. The posilock fitting connects the plastic gas supply line to the gas line that is inside the building that goes to the meter.

I did a bunch of Google searches on posilock etc. and I still couldn't find too much additional information, but here's what I did find:

"posilock transition fitting"

Inner-Tite (manufacturer?)

"The posilock seals together the larger plastic pipe from the street to a smaller metal pipe in the basement of a home or business."