CSST: Definition & Technical Guide
Call Now (855) 557-9600
CSST, or Corrugated Stainless Steel Tubing, is a flexible gas piping system made from thin-walled stainless steel formed into a corrugated profile and enclosed in a protective yellow or black jacket. CSST is used to distribute natural gas and propane within residential and commercial buildings, offering faster installation and greater routing flexibility than traditional rigid black iron pipe while meeting all national fuel gas codes.
Manifold Distribution, Lightning Bonding & Proprietary Fittings
CSST was introduced in the United States in the 1990s as an alternative to rigid steel gas piping. The corrugated design allows the tubing to bend around corners, through wall cavities, and along joists without requiring threaded fittings at every direction change. A single continuous run of CSST can replace dozens of rigid pipe sections and fittings, reducing installation time by up to 50 percent and eliminating many potential leak points at threaded joints.
The tubing connects to a gas manifold near the meter using proprietary mechanical fittings, then runs in continuous lengths to each gas appliance. Each manufacturer’s fitting system is unique and requires brand-specific tools and training for installation. The outer jacket protects the thin stainless steel wall from physical damage and UV degradation during construction.
CSST has one critical safety requirement: it must be electrically bonded to the building’s grounding electrode system. Because the thin corrugated walls are vulnerable to perforation from lightning-induced electrical surges, unbonded CSST can develop pinhole burn-throughs that cause gas leaks. Following a series of lightning-related incidents, the National Electrical Code and NFPA 54 now mandate direct bonding of CSST systems using a minimum 6 AWG copper conductor.
Yellow-Jacketed, Arc-Resistant & Manifold CSST System Types
Standard yellow-jacketed CSST is the original design, requiring both electrical bonding and physical protection where exposed. This remains the most widely installed type.
Black-jacketed (arc-resistant) CSST features a thicker stainless steel wall or additional conductive jacket layer that provides enhanced resistance to lightning-induced arcing. Products like CounterStrike and FlashShield fall in this category. Some jurisdictions accept reduced bonding requirements for arc-resistant designs.
CSST manifold systems distribute gas from a central manifold to individual appliance drops, similar to a PEX manifold for water. Each appliance gets a dedicated home run, simplifying future maintenance and isolation.
Gas Line Extensions, Bonding Retrofits & Appliance Connection Services
CSST installation and modification require a licensed plumber or gas contractor. Bonded Plumbworks’ gas line services include new CSST installations, gas line extensions for new appliances, and retrofitting bonding connections on existing CSST systems that were installed before bonding requirements were adopted.
When homeowners add gas appliances such as tankless water heaters, gas ranges, or pool heaters, Bonded Plumbworks routes new CSST runs from the manifold to the appliance location. This is significantly less disruptive than running rigid pipe, especially in finished homes where wall access is limited.
NFPA 54, ANSI LC 1/CSA 6.26 & NEC Section 250.104(B) Bonding
NFPA 54 (National Fuel Gas Code) and the International Fuel Gas Code both approve CSST for residential gas distribution. The applicable state building codes, Fuel Gas section, adopts these standards with state-specific amendments. ANSI LC 1/CSA 6.26 is the product standard for CSST. The National Electrical Code (NFPA 70) Section 250.104(B) requires bonding of CSST to the grounding electrode system. Individual CSST manufacturers hold ANSI/CSA listings that must match the installed product.
Gastite XR3, TracPipe CounterStrike & FlashShield Product Lines
Gastite manufactures one of the most widely installed CSST systems with a proprietary XR3 fitting design. TracPipe by OmegaFlex produces CounterStrike, an arc-resistant CSST with enhanced lightning protection. Ward Manufacturing offers FlashShield, another arc-resistant product line. Pro-Flex by Gastite provides a lighter-duty option for residential applications.