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CSA ANSI LC 1-2018 (CSA 6.26-2018): Comprehensive Guide to Flexible Gas Connector Standards
Understanding the technical requirements, compliance, and implementation of the harmonized North American standard for gas appliance connectors
The CSA ANSI LC 1-2018 (CSA 6.26-2018) standard represents a harmonized North American benchmark for flexible gas connectors used in residential and commercial indoor gas appliances. Jointly developed by CSA Group and the American National Standards Institute (ANSI), this standard supersedes previous editions and establishes rigorous material, design, performance, and marking requirements for corrugated stainless steel tubing (CSST) connectors, semi-rigid connectors, and associated end fittings. Adherence to this standard is critical for manufacturers, installers, and inspectors aiming to ensure safe and reliable gas supply connections for appliances such as ranges, dryers, furnaces, and water heaters.
Scope and Application
CSA ANSI LC 1-2018 (CSA 6.26-2018) covers flexible gas connectors intended for indoor installation in systems operating on natural gas, manufactured gas, liquefied petroleum (LP) gas, or LP gas-air mixtures. The standard applies to connectors in nominal sizes up to 2 inches (50 mm) and designed for maximum working pressures of 1/2 psi (3.5 kPa) for low-pressure applications, with optional categories for higher pressures. It includes both factory-assembled connectors and field-assembled kits that meet specified leak-tightness and mechanical requirements.
The scope also addresses connector assemblies with quick-disconnect devices and/or shut-off valves, provided they are integral to the connector. Connectors for outdoor use, marine applications, or beyond building regulators are excluded and are covered by separate standards (e.g., ANSI Z21.24/CGA 6.10, ANSI Z21.75/CGA 6.27).
Tip: Always verify that the connector is certified for the specific gas type (natural gas or propane) as per the marking – connectors are often listed for one or both, and cross-application can void certification and safety.
Key Technical Requirements and Materials
The standard mandates specific materials and dimensional criteria to ensure long-term durability and leak-free performance under normal service conditions.
Materials
- Flexible Tubing: Corrugated stainless steel (typically Type 304 or 316) meeting ASTM A240 or equivalent. Minimum wall thickness is specified per nominal size to resist corrosion and mechanical damage.
- End Fittings: Brass or steel conforming to applicable ASTM standards (e.g., ASTM B16, B124). Fittings must be corrosion-resistant and compatible with mating gas piping threads (NPT or flare).
- Seals and Gaskets: Elastomeric materials (e.g., nitrile, fluorocarbon) suitable for fuel gases and temperature range –40°F to 200°F (–40°C to 93°C).
- Protective Coatings: Optional polymer jackets or wraps must pass adhesion and flame propagation tests.
Dimensional and Pressure Parameters
| Nominal Size (inch) | Maximum Length (ft) | Maximum Working Pressure (psi) | Minimum Burst Pressure (psi) |
|---|---|---|---|
| 1/4 | 6 | 1/2 | 2250 |
| 3/8 | 6 | 1/2 | 2000 |
| 1/2 | 6 | 1/2 | 1800 |
| 3/4 | 6 | 1/2 | 1500 |
| 1 | 6 | 1/2 | 1200 |
As shown in Table 1, the standard imposes a maximum length of 6 feet (1.83 m) for all sizes to minimize pressure loss and mechanical stress. Longer connectors require pressure drop verification and additional support. For higher pressure categories (up to 10 psi), reduced lengths and additional testing are mandated.
Testing, Performance, and Marking Requirements
CSA ANSI LC 1-2018 prescribes a battery of tests to validate connector integrity under extreme conditions. Key test categories include:
- Leakage Tests: Each connector must undergo gas‑pressure leak testing at 0.5 psig (3.4 kPa) with zero detectable leakage over 10 minutes. A statistical sampling plan may be used for high‑volume production.
- Hydrostatic and Burst Tests: Connectors must withstand 3× the maximum working pressure without permanent deformation, and burst pressure must exceed 4× MWP (see Table 1 minima).
- Flexure and Bending Tests: Cyclic bending at 90° radius cycles (1000 cycles) must show no leaks or cracking. This simulates installation stress and appliance movement.
- Tensile and Pull‑Out Tests: Connectors must resist pull‑out forces per the gripping mechanism without separation from end fittings.
- Stress Relaxation and Thermal Cycling: Exposure to elevated temperature (200°F for 30 days) followed by leak test ensures seal stability over lifetime.
WARNING: Do not exceed the maximum length specified in the standard. Longer connectors cause excessive pressure drop and increase the risk of mechanical damage during appliance servicing. Never pull or stretch connectors to reach a connection point.
Marking and Identification
Every certified connector must be permanently marked with:
- Manufacturer’s name or trademark
- Standard designation (CSA ANSI LC 1-2018 or CSA 6.26-2018)
- Date of manufacture (month/year)
- Nominal size and maximum length
- Maximum working pressure (e.g., “1/2 PSI” or “10 PSI”)
- Gas type identification (NG, LP, or both)
- Orientation arrows (if applicable)
Compliance Success: Adhering to the marking requirements not only satisfies regulatory audits but also helps end‑users and inspectors quickly verify the connector’s suitability for the intended gas system and avoid mismatched installations.
Compliance, Certification, and Industry Implications
Manufacturers seeking to market CSA LC1 connectors must obtain certification from an accredited agency such as CSA Group, Underwriters Laboratories (UL), or Intertek (ETL). The certification process includes initial type‑testing, facility inspection, and ongoing follow‑up audits to ensure continued conformity. Importers and distributors are responsible for ensuring all connectors carry appropriate marks; inspectors routinely check for compliance during new construction and gas line upgrades.
The 2018 edition introduced several notable changes from the 2010 edition, including:
- Harmonized burst pressure requirements with ANSI Z21.24
- Updated material compatibility testing for elastomers in low‑temperature environments
- Expanded clarity on permissible end‑fitting configurations (including quick‑disconnect versions)
- Stronger guidance on installation instructions to prevent misuse in high‑stress applications
DANGER: Never reuse flexible gas connectors. They are designed for a single installation; re‑installation can cause undetectable stress fractures, leakage, and potential fire or explosion hazards. Always use a new, certified connector when connecting an appliance.
Frequently Asked Questions
Q: What is the maximum length allowed for a CSA ANSI LC 1‑2018 connector?
A: For low‑pressure connectors (½ PSI), the maximum length is 6 feet (1.83 m) for all nominal sizes. Higher pressure categories may require reduced lengths; always refer to the manufacturer’s instructions stamped on the connector sleeve or packaging.
A: For low‑pressure connectors (½ PSI), the maximum length is 6 feet (1.83 m) for all nominal sizes. Higher pressure categories may require reduced lengths; always refer to the manufacturer’s instructions stamped on the connector sleeve or packaging.
Q: Can CSA LC1 connectors be used for outdoor gas appliances?
A: No. CSA ANSI LC 1‑2018 specifically covers indoor use only. Outdoor applications require standards such as ANSI Z21.24 (outdoor connectors) or local building codes that may reference ANSI Z21.75 for flexible outdoor connectors.
A: No. CSA ANSI LC 1‑2018 specifically covers indoor use only. Outdoor applications require standards such as ANSI Z21.24 (outdoor connectors) or local building codes that may reference ANSI Z21.75 for flexible outdoor connectors.
Q: Are connectors manufactured to earlier editions (e.g., 2010) still compliant?
A: Connectors produced under previous editions and still stocked may continue to be sold until the adoption deadline set by regulatory authorities (typically 2‑3 years after publication). However, many jurisdictions require products sold after a certain date to meet the latest edition. Check local code or consult the manufacturer’s compliance statement.
A: Connectors produced under previous editions and still stocked may continue to be sold until the adoption deadline set by regulatory authorities (typically 2‑3 years after publication). However, many jurisdictions require products sold after a certain date to meet the latest edition. Check local code or consult the manufacturer’s compliance statement.
Q: How can I verify if a flexible gas connector is certified to CSA ANSI LC 1‑2018?
A: Look for a permanent marking on the connector body or a tag/label that includes the standard number (LC 1‑2018 or CSA 6.26‑2018), the certification mark (e.g., CSA, ETL, UL), and the manufacturer’s identification. You can also search the certifying agency’s online database for the listed product.
A: Look for a permanent marking on the connector body or a tag/label that includes the standard number (LC 1‑2018 or CSA 6.26‑2018), the certification mark (e.g., CSA, ETL, UL), and the manufacturer’s identification. You can also search the certifying agency’s online database for the listed product.
Article published: 2026 – Information based on CSA ANSI LC 1-2018 (CSA 6.26-2018). Always refer to the latest official standard text for complete requirements.