ISO 12614-12:2021

Overview

ISO 12614-12:2021 is an international standard specifying the tests and requirements for rigid fuel lines made of copper and its alloys used in liquefied natural gas (LNG) fuel systems in road vehicles. It applies to fuel system components intended for motor vehicles as defined in ISO 3833, focusing on the safety, durability, and performance criteria of copper tubing used for LNG transport within these vehicles.

This standard excludes applications related to fuel containers, stationary gas engines, container mounting hardware, electronic fuel management systems, and refueling receptacles. The working pressure basis is 1.6 MPa (16 bar gauge pressure), though it allows adjustments for other pressure levels by applying a pressure ratio factor.

Key Topics

• Scope and Applicability
  Defines the scope limited to rigid LNG fuel lines in copper alloys and excludes other components like fuel containers or refueling parts.

• Material Requirements
  Copper fuel lines must be seamless tubes compliant with EN 12735-1, ensuring mechanical integrity under LNG operating conditions.

• Marking and Traceability
  Components must be clearly marked with essential information for traceability, including manufacturer details, model number, working pressure, serial number or date code. Recommended markings include flow direction, fuel type, certification symbols, and a reference to ISO 12614-12.

• Testing Procedures
  The standard prescribes critical tests to verify component reliability:

  • Hydrostatic Strength Test at 4 times the working pressure to ensure pressure resistance.
  • Leakage Test to confirm sealing integrity.
  • Bending Test simulating mechanical stresses by bending over a mandrel followed by pressurization to detect leaks or deformation.
  • Additional tests for corrosion resistance and material compatibility with brass are included via references to ISO 12614-2.

• Pressure Considerations
  All pressures in this document are gauge pressures. The standard provides a method to scale test pressures when working with systems operating at different pressures than the baseline 1.6 MPa.

Applications

ISO 12614-12:2021 provides essential guidance for manufacturers, engineers, and quality assurance professionals involved in:

• Design and Manufacture of LNG Fuel Lines
  Ensuring that copper tubing meets strict mechanical and performance standards suitable for LNG transport in road vehicles.

• Quality Control and Testing
  Implementing standardized pressure, leakage, and bending tests to validate product durability and safety before field deployment.

• Vehicle Integration
  Assisting OEMs and system integrators in selecting compliant fuel lines for LNG-powered vehicles, supporting sustainability goals via clean fuel alternatives.

• Safety and Certification
  Facilitating regulatory compliance and certification processes for LNG fuel system components to maintain high safety standards in automotive applications.

Related Standards

• ISO 12614-1: General requirements and definitions for LNG fuel system components in road vehicles.
• ISO 12614-2: Performance requirements and general test methods for LNG fuel system components.
• ISO 3833: Classification and terms for motor vehicles, providing context for applicable vehicle types.
• EN 12735-1: Requirements for seamless copper tubes used in piping systems, relevant for material compliance.

These interconnected standards together form a comprehensive framework to ensure the safety, performance, and reliability of LNG fuel systems in road transportation.

By adhering to ISO 12614-12:2021, manufacturers and stakeholders ensure that rigid copper fuel lines in LNG vehicles are constructed and tested to withstand operational pressures and mechanical stresses, promoting clean fuel usage with enhanced safety and durability in automotive fuel systems.