Gas valve on flexible pipe??

[Ken]

A couple of years ago I had my furnace replaced and the installer installed the gas cutoff valve for the furnace on the flexible Gas Appliance Connector rather than on the rigid pipe feeding it. I objected and made him run additional rigid pipe up to the point at which the cutoff valve was installed because I saw it as unsafe. Yesterday I was talking to a plumber who was installing rigid pipe for a gas connection and mentioned my objection to the gas valve being installed on flexible connecting pipe. He implied that it was not illegal. The type of piping I am talking about can be seen at:

I realize there are many new choices for connecting gas that did not exist years ago, so perhaps he is referring to one of those? My question is: Is it legal (to code) to put a cutoff valve on flexible piping such as the link above shows, or must it be on rigid pipe??

[trader4]

It's an interesting question. I think the key to your question may be what's the definition of "installed on a flexible connecting pipe". Seems there are several possibilities:

A - It's installed in the middle of a flex line and the valve itself is not secured to anything other than the flex pipe.

B - It's on one end of a flex line and the other end of the valve is connected to rigid pipe.

C - It's installed in the middle of a flex line and the valve is fastened to a support

From what your furnace guy was going to do sounds like it was method A. I would not think that would be allowed, but then one would think that if this was a real HVAC company doing the install, they would be familiar with the code. If an inspection/permit was required, then you would think the installers would know what is or isn't allowed or else it's going to fail.

I would think option C would have to be allowed, because CSST is used for all kinds of gas piping now, not just for short connection to an appliance. So, if you have CSST running through a building, you're going to have to have valves in places.

Hopefully someone will know the actual code.

[Ken]

Sorry for the confusion, I guess I should have been more explicit.

Originally, the gas valve was attached to rigid pipe and a flex line (about 2 foot) was run from the gas control valve to the old furnace. This is how most gas connections are made to things like gas clothes dryers. When he took out the original furnace, he changed the position of it in a way that the existing rigid pipe was several (perhaps six) feet away from the control area of the furnace. (Where the access panels are) In order to make the connection from the existing rigid pipe to the new furnace, he removed the cut off valve from the rigid pipe, attached a flex pipe about 6-8 feet long, attached the cut off valve to the end of it, and finally ran a 2 foot flex pipe to the furnace control valve. In other words, the cut off valve was at the end of a long flex pipe and not directly attached to rigid pipe.

I hope the above clarifies the situation. Of the choices above, I would say that (A) was probably the best description. I felt uncomfortable with a flex line that long and felt it was vulnerable with no way to cut off the gas if it leaked. Perhaps I was overly cautious?

[recyclebinned]

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I don?t know the exact NPC code but that is definitely illegal.

[DD_BobK]

In other words.... he did a hack job / "scab on" because he wanted to finish in the minimum amount of time.

"He implied that it was not illegal." Of course he did... to support his poor installation job.

In dependent of whether it was legal or not, how many people would chose that installation means over piped close & valve securely anchored?

The code is the minimum acceptable standard.. the minimum is not always "best practice".

[clare]

It's legal, but certainly not "smart".

[samjohnsonus]

This is really great information

[trader4]

- Hide quoted text -

I don't think you were overly cautious. I'd say you have good sense and the installer did not. Your better description seems to indicate another problem, which is I don't believe a flexible pipe like that is permitted to pass through the cabinet opening of a furnace. The concern being that if it touches the cabinet, vibration from the furnace could cause the line to fail over time. Normally, black pipe is used to come out of the cabinet. Then you have a tee, one end going down and capped off to form a short stub that is supposed to help prevent any debris, condensate etc from getting into the furnace. The the gas valve is usually located right there by the tee, or close by, again with black pipe.

Was there a permit? Inspection required? You sure would think that someone doing pro furnace installs would know what it takes to pass inspection. It ain't that hard. I put my own furnace in and it passed first time. I used all rigid black pipe, but the flex stuff is permitted too, at least in most areas.

[micky]

Isn't the weakness of flex pipe that it leaks after enough flexing?

What good is it to put the valve on the end of a leaking pipe?

It should be on the end of a pipe that doesn't leak.

[trader4]

While I agree it should go before the flex pipe when connecting an appliance, there is still some purpose to the valve in any case. It's primary use is to shut off the gas while connecting or disconnecting the appliance.

[clare]

And pipe that can leak should not be allowed.