Corrugated Stainless Steel Tubing (CSST) was developed in Japan in the 1980s. It was developed as a safety improvement over rigid black iron gas pipes that often failed and started fires during earthquakes. The flexible nature of the CSST system allows it to handle seismic activity without leaking gas.
In the early 1980s, the Gas Research Institute initiated research into the use of CSST systems in the U.S.; listing processes, and code approvals needed to be developed and accepted by regulatory bodies. The American National Standards Institute performance specification, AGA LC-1 1987 "Proposed Standard for Interior Fuel Gas Piping Utilizing CSST" was released in 1989.
Sales of CSST in the U.S. began in 1990 with approximately 100,000 ft. sold. Use of CSST grew in the U.S. as contractors quickly discovered it could be installed in 1/3 the time of rigid black iron pipe systems. Beyond the time saved on installations, contractors and code officials appreciated the reduction of fitting joints in a flexible gas piping system. Joints are areas for concern in gas piping systems as they represent potential leak paths. Flexible CSST systems have approximately 75% fewer fitting joints than rigid black iron pipe systems.
More than 800 million feet of CSST gas piping in approximately six million homes has been installed in the U.S. since 1990.
CSST and Lighting
Lightning is a highly destructive force. Even a nearby lightning strike that does not strike a structure directly can cause all electrically conductive systems in the structure to become energized. Nearby lightning strikes can result in a power surge that can damage certain gas tubing systems and ultimately cause a fire. Properly bonding and grounding the Corrugated Stainless Steel Tubing (CSST) significantly reduces the risk of damage and fire from a lightning strike.
Care should be taken when installing CSST to maintain as much separation as reasonably possible from other electrically conductive systems in the home. Electricians and other trained professionals should consult local building codes as to required separations for CSST from conductive systems including metallic chimney liners, metallic appliance vents, metallic ducting and piping, and electrical cables.
Areas with high lightning risk include but are not limited to: Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Louisiana, Maryland, Michigan, Mississippi, Missouri, New Mexico, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia and West Virginia.
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.