ISO 12614-4:2021

Overview

ISO 12614-4:2021 is an international standard published by the International Organization for Standardization (ISO) that defines the requirements and test methods for manual valves used in liquefied natural gas (LNG) fuel systems on road vehicles. This standard targets LNG fuel system components specifically designed for motor vehicles classified under ISO 3833. It ensures the safety, performance, and reliability of manual valves in automotive LNG applications by establishing consistent technical criteria for design, construction, marking, and testing.

The document excludes components such as fuel containers, stationary gas engines, container mounting hardware, electronic fuel management systems, and refuelling receptacles. It focuses exclusively on manual valves, which are critical for controlling LNG flow safely at working pressures typically around 1.6 MPa (16 bar), with provisions for higher pressure systems.

Key Topics

• Scope of Application
  Manual valves for LNG fuel systems on road vehicles as defined in ISO 3833, excluding certain other components and assemblies.

• Marking Requirements
  Essential marking information includes manufacturer details, model or part number, and working pressure or pressure-temperature range. Recommended markings consist of flow direction, fuel type, certification symbols, approval numbers, serial codes, and the ISO 12614-4 reference for traceability.

• Construction and Assembly
  Manual valves must comply with the general requirements and test methods outlined in related parts ISO 12614-1 and ISO 12614-2. The standard emphasizes robust construction to withstand high pressures and harsh operating conditions.

• Testing Protocols
  The standard mandates multiple performance and safety tests including:

  • Hydrostatic strength: Testing valves at 2.5 times the rated working pressure to validate structural integrity.
  • Leakage: Verification under various temperature and pressure conditions, simulating operational extremes.
  • Continued operation: Cycling the valve 100 times under pressure to ensure durable mechanical function without increased torque or leakage.
  • Additional tests address excess torque resistance, bending moment, corrosion resistance, vibration, and material compatibility when applicable.

• Torque Specifications
  Maximum permissible torque values are provided by valve inlet size and test temperature, ensuring manual operation remains safe and effective throughout the valve lifecycle.

Applications

ISO 12614-4:2021 manual valves are essential components in LNG-powered vehicles, including buses, trucks, and other commercial transport fitting liquefied natural gas fuel systems. These valves enable safe manual control of LNG flow for operational management and emergency situations.

Key practical benefits include:

• Ensuring fuel system safety through rigorous pressure and leakage testing.
• Providing standardized performance benchmarks supporting global vehicle manufacturing and maintenance.
• Facilitating reliable manual control of LNG flow under various environmental conditions, including cryogenic temperatures.
• Enhancing traceability and certification confidence via clear marking and documentation requirements.

Adhering to this standard enables manufacturers and service providers to deliver compliant, safe, and durable LNG fuel system components aligned with modern sustainable transportation initiatives.

Related Standards

• ISO 12614-1: General requirements and definitions for LNG fuel system components.
• ISO 12614-2: Performance criteria and general test methods for LNG fuel system components, referenced heavily in Part 4's testing procedures.
• ISO 3833: Vehicle type definitions that classify the types of motor vehicles for which LNG fuel system components like manual valves are intended.

Together, ISO 12614 series and related ISO road vehicle standards provide a comprehensive framework supporting the development, testing, and deployment of LNG fuel system technologies for improved environmental performance and safety in road transport.

For more information, visit the official ISO website at www.iso.org and search for ISO 12614-4:2021. Adhering to these international standards is key to ensuring that LNG fuel system components meet stringent safety and quality benchmarks in the rapidly evolving alternative fuel vehicle industry.