ISO 12614-5:2021

Overview

ISO 12614-5:2021 specifies tests and requirements for the tank pressure gauge used in liquefied natural gas (LNG) fuel systems for road vehicles (as defined in ISO 3833). The standard defines construction, marking, performance and durability tests to ensure safe, reliable pressure indication in LNG vehicle tanks. It applies to LNG fuel system components but is not applicable to fuel containers, stationary gas engines, container mounting hardware, electronic fuel management, or refuelling receptacles.

Key topics and requirements

• Scope and baseline working pressure: Based on a working pressure of 1,6 MPa (16 bar); other system pressures are accommodated by scaling test pressures (e.g., 2 MPa → multiply pressures by 1.25).
• Marking: Component marking must enable traceability: manufacturer/agent, model/part number, working pressure or pressure & temperature range, and serial number/date code. Recommended markings include flow direction, fuel type, electrical ratings, certification symbol and ISO 12614-5 reference.
• Construction and assembly:
  • Gauge must display at least 120% of working pressure.
  • If a gauge-type indicator, it must have a shatter-proof lens and a rear pressure relief.
  • Gauges installed inside driver/passenger compartments must be enclosed in a gas-tight housing with venting routed outside, or be self-venting within a sealed housing.
• Required tests (see ISO 12614-2 for procedures):
  • Hydrostatic strength: test at 2.5 × working pressure.
  • Leakage: tested at specified temperatures and pressure factors:
    • < −162 °C: 1.0 × WP and 0.25 × WP
    • 20 °C: 0.25 × WP and 1.5 × WP
    • 85 °C or 120 °C: 0.25 × WP
  • Continued operation: endurance cycling for 7 000 cycles (pressurize to WP, depressurize to <50% WP) followed by leakage testing.
  • Other applicable tests: excess torque resistance, bending moment, corrosion, oxygen ageing, vibration, material compatibility.

Applications and users

ISO 12614-5 is intended for:

• OEMs designing LNG fuel systems for trucks, buses and other road vehicles
• Component manufacturers producing tank pressure gauges and instrumentation
• Testing laboratories performing conformity and type approval testing
• Type approval and certification bodies assessing LNG vehicle components
• Fleet operators and safety engineers specifying compliant components for LNG vehicles

This standard helps ensure accurate pressure monitoring, safe venting, and long-term reliability of LNG tank instrumentation in vehicles.

Related standards

• ISO 12614-1 - General requirements and definitions (LNG fuel system components)
• ISO 12614-2 - Performance and general test methods
• ISO 3833 - Road vehicle types, terms and definitions

Keywords: ISO 12614-5:2021, tank pressure gauge, LNG fuel system components, LNG vehicle, pressure gauge testing, hydrostatic strength test, leakage test, working pressure.