CSST Gas Piping Grounding Safety Concerns Raised

Imagine a stormy night with thunder and lightning. A bolt strikes your home, and your gas piping system becomes an unintended lightning rod, potentially causing a fire or gas leak. This scenario isn't hypothetical—it's directly related to a gas piping material called Corrugated Stainless Steel Tubing (CSST).

Corrugated Stainless Steel Tubing (CSST) is a flexible piping system that has been widely used in residential and commercial buildings for natural gas delivery since the 1990s. If your home has had new gas appliances installed in recent years—such as gas stoves or furnaces—it likely uses CSST piping.

CSST pipes are typically yellow or black. It's important not to confuse CSST with the flexible connectors that attach directly to gas appliances. While appliance connectors run between the appliance and gas valve, CSST is usually installed in more concealed areas—beneath basement floor joists, inside walls, or above ceiling joists in attics.

CSST itself isn't inherently dangerous. The safety risk emerges when the system is improperly installed, particularly with inadequate grounding and bonding. During a lightning strike, electrical current may seek a path to ground through the CSST. Without proper bonding, this current can create arcing that may puncture the tubing, potentially causing gas leaks or fires.

Wisconsin has implemented specific requirements for CSST installation: all CSST systems must be properly bonded and grounded, regardless of manufacturer exemptions. First-generation CSST must be bonded to the building's electrical system using appropriately sized bonding clamps and conductors, following both the National Electrical Code (NFPA 70) and National Fuel Gas Code (NFPA 54). Installation must comply with manufacturer specifications.

• Pipe routing: CSST typically runs through concealed spaces like basements, wall cavities, and attics, unlike appliance connectors that run directly to appliances.
• Color: Most CSST is yellow or black, though color alone isn't definitive.
• Professional assessment: When in doubt, contact the company that installed your gas system for verification.

Homeowners can perform these preliminary checks:

1. Look for yellow or black corrugated tubing in basements, attics, or wall cavities.
2. Check for proper bonding—CSST should be connected to the electrical system with metal clamps and bonding conductors.
3. Inspect for corrosion, dents, or other damage.
4. Be alert for gas odors. If detected, evacuate immediately and contact your gas provider.

Even after self-inspection, professional evaluation by licensed electricians or gas technicians is strongly recommended. Professionals can:

• Verify CSST type and installation method
• Confirm proper bonding compliance with current codes
• Assess overall pipe condition
• Perform necessary repairs or replacements

Correct bonding is essential for CSST safety. It provides a controlled path for lightning or electrical fault currents to reach ground, preventing current from traveling through the gas piping where it could cause damage.

Always use licensed, experienced technicians for CSST work. Proper training ensures compliance with safety standards and correct installation practices.

While CSST offers flexibility and ease of installation, alternatives exist:

• Black iron pipe: Traditional material with excellent durability, though requiring more complex installation.
• Copper tubing: Offers good corrosion resistance but at higher cost.
• Polyethylene (PE) pipe: Flexible and corrosion-resistant but unsuitable for high-temperature applications.

Material selection should balance safety, cost, and installation requirements with professional guidance.

Gas system safety requires regular inspection and maintenance. Any concerns about CSST installation should prompt immediate professional evaluation. Proactive measures can prevent potentially dangerous situations.