Yellow CSST Gas Tubing: Bonding, Repairs and Extensions

What CSST is

CSST stands for corrugated stainless steel tubing. It is a thin, ribbed stainless tube inside a yellow plastic jacket, sold in coils and run through attics, walls and crawl spaces with far fewer joints than rigid pipe. In Fullerton it often shows up where a kitchen was remodeled, a tankless water heater was added, or a gas line was extended to a new appliance.

Each manufacturer makes its own fittings and publishes its own installation instructions. Installers are expected to be trained on the specific product. That is the key difference from black iron, where any standard fitting will do.

CSST at a glance

Look: Yellow jacket, ribbed tube, brass fittings at each end
Fittings: Specific to the manufacturer; brands are generally not mixed
Bonding: Required per the maker's instructions and code
Protection: Striker plates where it passes near framing edges
Who installs: A licensed contractor trained on that product

Why bonding matters

Because the stainless wall of CSST is thin, manufacturers require the gas system to be electrically bonded to the home's grounding system. Bonding gives stray electrical energy, such as from a nearby lightning strike, a path to ground instead of arcing through the tubing. The exact method, conductor and connection point come from the maker's instructions and local code.

If you have CSST and do not know whether it was bonded, ask a licensed contractor or electrician to look. A bonding clamp is usually visible on rigid pipe near where the CSST begins, or near the meter or water heater.

Things that can go wrong with CSST

Missing or improper bonding
Fittings from a different brand mixed onto the tubing
A nail or screw driven through the tubing during later remodeling
No protection plates where it passes close to the edge of studs or joists
Jacket stripped back too far at fittings, leaving bare tubing exposed
Tubing kinked, crushed or bent tighter than the maker allows
Run outdoors or underground without the protection the maker requires

How a CSST repair or extension is usually handled

Identify the brand.The jacket is usually printed with the maker's name. That determines the fittings and instructions.
Cut out the damage.A damaged section is cut back to sound tubing, not patched.
Join with matching fittings.New tubing or a coupling from the same system is installed per the maker's steps.
Confirm bonding and protection.Bonding is checked or added, and protection plates go where the tubing passes near framing.
Pressure test.The system is tested before gas is restored, and inspected where a permit applies.

Ask before any CSST work

Are you trained on this brand of CSST?
Will you use that manufacturer's fittings?
Is my existing CSST bonded, and will you confirm it after the work?
Does this repair or extension need a permit?

Common questions

Should I replace CSST with black iron?

Not automatically. Properly installed and bonded CSST is an accepted material. Replacement makes sense where it is damaged or was installed incorrectly.

Can a handyman extend CSST?

Gas piping work should be done by a licensed contractor trained on the product. Check any license at cslb.ca.gov.

Is black CSST different?

Some products use a different jacket color and design. Ask your contractor which product you have and what its instructions require.

General information for Fullerton, not a quote or professional advice. In an emergency, call 911.