ISO 15500-23:2023

Overview

ISO 15500-23:2023 is an international standard specifying requirements and testing procedures for gas temperature sensors used in compressed natural gas (CNG) fuel systems on road vehicles. This standard applies to fuel system components intended for vehicles defined in ISO 3833, including mono-fuel, bi-fuel, and dual-fuel types using natural gas compliant with ISO 15403-1. The document ensures safety, reliability, and performance of gas temperature sensors in CNG systems operating at pressures typically around 20 MPa (200 bar).

This standard excludes components related to liquefied natural gas (LNG) upstream of the vaporizer, fuel containers, stationary gas engines, mounting hardware, electronic fuel management, and refuelling receptacles. ISO 15500-23 supports the development and quality assurance of CNG fuel systems by defining key design, marking, and testing criteria.

Key Topics

• Scope and Applicability
  Covers gas temperature sensors for CNG vehicles, including those running on natural gas fuels as per ISO 15403-1. Emphasis is on sensors that directly measure gas temperature within the fuel system.

• Marking Requirements
  Components must have clear markings to trace:

  • Manufacturer’s or agent’s name, trademark, or symbol
  • Model designation or part number
  • Serial number or date code
  • Direction of gas flow (if applicable)
    Additional recommended markings include working pressure and temperature ranges, fuel type, electrical ratings, certification agency symbol, and reference to this ISO standard.

• Construction and Assembly
  Gas temperature sensors must comply with general requirements and test methods defined in ISO 15500-1 and ISO 15500-2, ensuring mechanical integrity and functional accuracy.

• Testing Procedures
  A comprehensive suite of tests verifies sensor durability and safety:

  • Hydrostatic strength: Tested at 2.5 times the working pressure to ensure resistance to high pressure.
  • Continued operation: Simulates long-term pressure cycling to confirm reliability (15,000 cycles upstream, 50,000 cycles downstream of the pressure regulator).
  • Insulation resistance: Electrical testing ensures sensor insulation integrity with a minimum resistance > 240 kΩ at 1,000 V d.c.
  • Additional applicable tests include leak tightness, excess torque resistance, bending moment, corrosion, oxygen and ozone ageing, heat ageing, fluid compatibility, electrical overvoltages, vibration resistance, and material compatibility.

Applications

ISO 15500-23:2023 is essential for manufacturers, designers, and quality controllers of CNG fuel system components focusing on gas temperature sensors. Applications include:

• Automotive Industry
  Ensuring gas temperature sensors used in natural gas vehicles meet stringent performance and safety criteria. Applicable for passenger cars, commercial vehicles, and buses operating on mono- or multi-fuel configurations.

• Component Testing and Certification
  Enables testing bodies to verify compliance of new gas temperature sensors with international standards, facilitating global market access.

• Fuel System Integration
  Assists engineers integrating CNG fuel components into vehicle systems by providing reliable sensor specifications enhancing fuel system monitoring and safety.

• Aftermarket and Maintenance
  Provides guidance for replacement part manufacturers to produce certified sensors compatible with existing CNG vehicles.

Related Standards

• ISO 15500 Series
  The broader ISO 15500 family covers compressed natural gas fuel system components, including general requirements (Part 1) and performance tests (Part 2), forming the framework within which Part 23 operates.

• ISO 3833: Road Vehicles - Types - Terms and Definitions
  Defines the vehicle types applicable to this standard, ensuring appropriate component application.

• ISO 15403-1: Natural Gas for Use as Compressed Fuel
  Specifies the quality and designation of natural gas fuels compatible with the CNG systems covered by ISO 15500-23.

• ISO/TR 15403-2 (Withdrawn)
  Although withdrawn, it historically provided supplementary information regarding natural gas fuel specifications.

Keywords: ISO 15500-23, CNG fuel system, gas temperature sensor, compressed natural gas, road vehicles, fuel system components, sensor testing, gas temperature measurement, ISO standards, natural gas vehicles, sensor marking, hydrostatic strength test, insulation resistance, vehicle fuel safety, CNG sensors compliance.