CSST Flexible Gas Pipe- Is it dangerous?

| July 30, 2021

Homes with yellow CSST are at risk of perforation to the gas line caused by lightning strikes as far as a mile away. A puncture in the line can release gas into the home resulting in fire and/or explosions.


CSST is a flexible, stainless steel pipe used to supply natural gas and propane in residential, commercial, and industrial structures. CSST gas pipe has been supplied in the USA with a yellow polymer jacket since the early ’90s.  The yellow color is used to identify the pipe as a gas line.  Around 2005 the first black jacketed CSST line was introduced. The black jacket signifies a protective jacket design, which provides a level of lightning arc protection to the black CSST line.

Black jacketed CSST gas line is referred to as “arc-resistant CSST” and has met baseline lightning arcing testing tests incorporated into the CSST performance standard (ANSI LC-1)
CSST is usually routed beneath, through, and alongside basement floor joists, inside interior wall cavities, and on top of ceiling joists in attic spaces. Although national gas codes and some building codes now require new construction and remodeling projects to reduce the lightning risk associated with yellow CSST, many homes built or remodeled after 1990, but before the codes changed, are still at risk.
If you find CSST after inspecting your home, it is strongly recommended that you determine if the CSST system is properly bonded and grounded. A bonding device should be installed on your natural gas system to reduce the chances of a natural gas leak or fire. Bonding is provided primarily to prevent a possible electric shock to people who come in contact with the gas piping and other metal objects connected to the grounding system. Nearby lightning strikes can also result in an electrical surge and can potentially puncture a hole in the CSST.


The Diamond Group Home Inspections recommends a qualified electrical contractor evaluate yellow CSST gas lines for bonding and grounding. It is also recommended to have a qualified plumber evaluate all gas lines for leaks.

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