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CSST into fireplaces and furnaces


msteger
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I often see CSST (Corregated Stainless Steel Tubing) into fireplaces and, more rarely, into gas furnaces. I've talked to product engineers at some of the major CSST manufacturers (Tracpipe, Diamondback, etc.) and each recommends not installing CSST into furnaces and has fireplaces. Each recommends black steel or rigid copper, for example, however using a PVC sleeve or rubber grommet will also help prevent damage to the pipe.

I have commonly found abraided CSST where it enters gas fireplaces due to the sharp metal opening of the chassis. I always call it out.

The issue is that the local code enforcement guys do NOT call this out as an issue in new construction or new gas fireplace installs.

Is it standard industry practice to call CSST out when it enters gas fireplaces, furnaces, etc.? Hopefully, someday the fuel gas and plumbing codes will catch up with this newer product.

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Originally posted by msteger

I often see CSST (Corregated Stainless Steel Tubing) into fireplaces and, more rarely, into gas furnaces. I've talked to product engineers at some of the major CSST manufacturers (Tracpipe, Diamondback, etc.) and each recommends not installing CSST into furnaces and has fireplaces.

Well, then the folks that you talked to ought to read their own installation instructions. The last ones I saw said it's just fine to run the CSST through appliance enclosures if the piping is protected.

From the Gastite manual:

Gastite® mechanical fittings are approved to be concealed and can be connected

directly to a valve controlling gas flow to a fireplace appliance. The CSST and valve

connection can be installed behind the wall, beneath the floor, hearth, or behind the

brickwork of the fireplace.

Where it is necessary to install Gastite® through sheet metal enclosures such as

gas fireplaces, and vibration from motors could cause mechanical wear, the plastic

jacket should remain intact and the tubing should be routed or supported to prevent

direct contact with the enclosure. If direct contact can not be avoided, protection

such as grommets, metal conduit or rigid pipe may be used. Materials used for

protection in fire rated constructions must be appropriate for the application. Remove

the plastic jacketing only on the portion of CSST that may be exposed to the flame

within the firebox.

Each recommends black steel or rigid copper, for example, however using a PVC sleeve or rubber grommet will also help prevent damage to the pipe.

I'd prefer to rely on the printed instructions rather than a quotation from an informal discussion with a product wonk who may or may not know what he's talking about. For instance, your statements above conflict with Gastite's instructions. Product wonks, installers and tradesmen often get it wrong. The printed instructions are really the final word.

I have commonly found abraided CSST where it enters gas fireplaces due to the sharp metal opening of the chassis. I always call it out.

Great. A quick explanation and a decent photo ought to be all you need to convince anyone that those installations are a problem and that they ought to be fixed.

The issue is that the local code enforcement guys do NOT call this out as an issue in new construction or new gas fireplace installs.

Is it standard industry practice to call CSST out when it enters gas fireplaces, furnaces, etc.?

Sady, the industry practice is to repeat whatever nonsense an inspector has in his head regardless of whether it's right or wrong or whether or not it's got any basis in reality.

If you're going to help to change that practice, it'd be a good idea to base your opinions on solid technical reference materials whenever possible. Then when you're challenged by a code official you can point to your reference and invite him to point to his reference.

Hopefully, someday the fuel gas and plumbing codes will catch up with this newer product.

On the other hand, maybe someday home inspectors will catch up with the installation instructions for a product that's been around for over a decade.

- Jim Katen, Oregon

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Jim K makes a very good point (as he usually does). Let me illustrate.

When I first saw CSST installed for distribution, I assumed some of the rules for flexible connectors would also apply to the installation. Before dictating the report, I asked for, received and read a PDF of the installation instructions from the manufacturer. I then retracted some of the on-site comments I made without too much embarrassment. My pc and laptop are both loaded with files and illustrations that I've collected in similar circumstances.

PS. It's official - All manufacturers of CSST have updated their instructions, requiring that the gas supply system be bonded directly to the grounding electrode system. It won't be in the NFGC or NEC for several years, so expect arguements from the installers.

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Originally posted by inspecthistoric

. . . PS. It's official - All manufacturers of CSST have updated their instructions, requiring that the gas supply system be bonded directly to the grounding electrode system. It won't be in the NFGC or NEC for several years, so expect arguements from the installers.

I don't understand. Gas supply piping has been required to be bonded to the GES for years. What's different?

- Jim Katen, Oregon

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Originally posted by Jim Katen

I don't understand. Gas supply piping has been required to be bonded to the GES for years. What's different?

- Jim Katen, Oregon

I should have been clearer and more specific.

The current requirement:

"Each above-ground portion of a gas piping system that is likely to become energized shall be electrically continuous and bonded to an effective ground-fault current path. Gas piping shall be considered to be bonded where it is connected to appliances that are connected to the equipment grounding conductor of the circuit supplying that appliance".

The way I understand it, the above protects against ground-faults, but does not offer complete protection against lightning strikes. The damage to CSST from lightning strikes has been because of the differences in electrical potential between parallel metallic pathways to ground, creating an arc between two imbalanced paths.

The manufacturer’s installation instructions now have specific requirements for directly bonding the CSST to the electrical system's grounding system at the service entrance.

Jim, please correct or clarify as needed.

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