Is Your Home Safe Using Corrugated Stainless Steel Tubing?

Lightning Strike

What is 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 or crawlspace, inside interior wall cavities, and on top of ceiling joists in attic spaces.

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.

Corrugated Stainless Steel Tubing

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 sites. Flexible CSST systems have approximately 75% fewer fitting joints than rigid black iron pipe systems.

All CSST manufacturers expressly added the bonding and grounding procedure to their installation requirements in August 2006. This improved safety installation requirement reduces the likelihood of arcing damage from an electrical surge that can potentially cause a fire.

More than one billion feet of CSST gas piping has been installed in approximately eight million homes in the U.S. since 1990.

Benefits of CSST

CSST features many benefits over the traditional piping 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 and 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.

Bonding

Bonding and Grounding

If CSST is found after having your home inspected, it is strongly recommended that you determine if the CSST system is properly bonded and grounded. A bonding device and conductor should be installed on your natural gas system in order 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 when there is a failure in a branching circuit. Nearby lightning strikes can also result in an electrical surge and can potentially puncture a hole in the CSST due to arcing. 

Since 2006, manufacturer’s instructions have required direct-bonding and grounding of yellow CSST in new installations. A bonding connection installed on a gas piping system, as with any metallic system within a house, will reduce the likelihood of electrical arcing to or from other bonded metallic systems in the structure, thus reducing the likelihood of arc induced damage.

CSST Hole

Lightning

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 CSST significantly reduces the risk of damage and fire from a lightning strike.

FAQs

Corrugated Stainless Steel Tubing (CSST) is a flexible, stainless steel pipe used to supply natural gas and propane in residential, commercial and industrial structures.

CSST is often coated with a yellow, or in some cases, a black exterior plastic coating. CSST should NOT be confused with flexible gas appliance connectors — the product that joins a moveable appliance to your home or building’s gas supply line.

CSST has been supplied in the U.S. with a yellow polymer jacket since the early 1990s. The yellow color is utilized to help identify the piping as ‘gas line.’ Around 2005 the first black-jacketed CSST product was introduced. The black jacket signifies a protective jacket design, which provides a level of lightning arc protection to the CSST (tubing) underneath. Black-jacketed CSST is referred to as ‘arc-resistant CSST’ and has met a baseline lightning arcing test incorporated into the CSST product performance standard
Besides providing greater durability, CSST is flexible, allowing it to be snaked around walls and through obstacles with fittings needed only at the ends of each run. Reducing the number of fittings is beneficial as each additional joint needs to be fitted and checked for leaks. A CSST gas piping system has less joints, and therefore less potential leak paths.
CSST was first introduced in Japan in the 1980s. It was introduced in the U.S. in 1990.
CSST was first introduced in Japan in the 1980s. It was introduced in the U.S. in 1990.
In the U.S., about 300,000 new and remodeled homes per year have CSST installed; that number is about half of the number of new homes built each year that use gas for heating and cooking. As of 2012, about seven million homes in the U.S. had CSST installed. Since 1989, approximately one billion feet has been in stalled in residential, commercial, and industrial structures.
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 or connected to fixed appliances such as water heaters.
Like all approved gas piping systems, CSST is safe when properly installed. CSST must be installed by a qualified professional and in accordance with the Manufacturer’s Design and Installation (D&I) Guide, including bonding and grounding of the system.
Lightning is a highly destructive force. Even a nearby lightning strike that does not strike a structure directly can cause systems in the structure to become electrically energized. This power surge can potentially puncture a hole in CSST and cause a fire.
Lightning causes 7,216 house fires every year, according to the U.S. Fire Administration.

Bonding: Connecting metallic systems to establish electrical continuity and conductivity.
Grounding: Connecting to the ground or to a conductive body that extends to ground connection.

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 result in an electrical surge that can potentially puncture a hole in CSST and cause a fire. Proper bonding and grounding will reduce the risk of damage and fire from a lightning strike.
Bonding is considered electrical work so it is recommended that a licensed electrician is contacted to inspect or perform any electrical bonding work.
CSST should NOT be confused with flexible gas appliance connectors – the product that joins a moveable appliance to your home or building’s gas supply line. The difference is flexible connectors attach directly to the moveable appliance from the wall or floor. 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.

Leave a Reply

Your email address will not be published. Required fields are marked *

Your Comment