What is CSST?

Corrugated Stainless Steel Tubing (CSST)

Corrugated Stainless Steel Tubing (CSST) is a flexible, stainless steel pipe used to supply natural gas and propane in residential, commercial and industrial structures. Coated with a yellow, or in some cases, a black exterior plastic coating, CSST is usually routed beneath, through and alongside floor joists in your basement, inside interior wall cavities and on top of ceiling joists in attic spaces.

Benefits of CSST

CSST features many benefits over the traditional method in its durability and practicality. CSST has a proven resistance to leaks due to far fewer connections made during installation. When black iron pipe is installed, every time the pipe changes direction, a joint needs to be fitted and checked for leaks. CSST offers flexibility and is able to be snaked through walls and around obstacles with fittings placed only at the ends of the run.

Another benefit of this material is the amount of installation time it saves. By most estimates, CSST can be installed in a third of the time it takes to install black iron pipe. Even though CSST is more expensive than the traditional black iron pipe, its overall cost is less when factoring in labor and installation.

Installation & Safety

Like all gas piping systems, CSST must be properly installed. CSST must be installed by a qualified professional and in accordance with the Manufacturer's Design and Installation (D&I) Guide, which now expressly includes bonding and grounding of the system. The D&I Guide specifically calls for the system to have a minimum 6-gauge bonding wire between the CSST and the building's grounding electrode in order to reduce the chances of a natural gas leak or fire from electrical/lightning energy. Some previously installed CSST systems may not have the proper bonding for optimal safety.

If after inspecting your home or business, you find CSST, it is strongly recommended that you determine if it is properly bonded. A bonding device should be installed on your natural gas system (per CSST Direct Bonding Tech Bulletin) in order to reduce the chances of a natural gas leak or fire.

csst installed along floor joists in basement  
CSST should not be confused with natural gas appliance flexible connectors. Flexible connectors are used to attach moveable appliances to the gas piping system. CSST is typically routed beneath, through or alongside floor joists in the basement, inside interior wall cavities and on top of ceiling joists in attic spaces.
Manufacturers of black jacketed CSST products which have been tested and listed to ICC-ES LC 1024, "CSST Utilizing Arc Resistant Protective Jackets", may not require or include in their instructions for the additional direct-bonding step that is required with standard yellow CSST products. However local codes are controlling and may differ from manufacturer's requirements. Local codes are governing and must be adhered to. (back to top)