ISO 15500-15:2015

Overview

ISO 15500-15:2015 is an international standard specifying the requirements and test methods for gas-tight housing and ventilation hoses used in compressed natural gas (CNG) fuel systems of road vehicles. It applies to motor vehicles defined under ISO 3833 that utilize natural gas fuel compliant with ISO 15403-1 in mono-fuel, bi-fuel, or dual-fuel configurations. This standard ensures safety, performance, and reliability of critical CNG fuel system components designed to contain and safely vent natural gas emissions, primarily focusing on gas-tight compartments and ventilation hoses.

The standard excludes components related to liquefied natural gas (LNG) systems upstream of the vaporizer, fuel containers, stationary engines, mounting hardware, electronic fuel management systems, and refuelling receptacles.

Key Topics

• Scope and Application
  Applies exclusively to CNG fuel system components in vehicles using compressed natural gas at service pressures typically around 20 MPa (200 bar) and 15 °C. The pressures can be adjusted for different service conditions.

• Marking Requirements
  Components must be clearly marked with manufacturer identification, part/model number, temperature range, and other recommended information such as flow direction, fuel type, electrical ratings, certification symbols, and approval codes to ensure traceability and proper installation.

• Construction and Assembly
  The gas-tight housing and ventilation hoses must comply with general requirements of ISO 15500-1 & ISO 15500-2, ensuring proper assembly that does not interfere with pressure relief devices (PRDs). These parts serve to contain and vent permeation gas and minor leaks safely.

• Test Methods and Performance Criteria
  Rigorous testing is mandated to verify leakage resistance, venting ability, structural integrity, and endurance:

  • Leakage Tests: External leakage at various temperatures (-40°C to 85°C) and pressures (0.05 MPa). Ensures no unintended gas escape except through designated pathways.
  • Venting Ability and Pressure Retention: Ensures gas-tight housings and hoses vent safely without excessive pressure build-up during leaks, retaining less than 50 kPa pressure.
  • Pull-off Strength: Ventilation hoses must withstand a minimum tensile force of 100 N before detachment, ensuring secure connections under operational stresses.

• Compliance and Traceability
  Markings and testing protocols support consistent quality control and compliance with safety regulations across diverse vehicle applications.

Applications

ISO 15500-15:2015 is critical for manufacturers, suppliers, and regulators involved in the design, testing, and certification of CNG fuel system components in road vehicles, supporting:

• Passenger vehicles equipped with CNG fuel systems (mono-fuel, bi-fuel, dual-fuel)
• Commercial vehicles and buses using compressed natural gas as an alternative fuel
• Ensuring safe venting and containment of natural gas to prevent leaks and reduce fire or explosion risks
• Supporting the development of environmentally friendly and sustainable transportation by promoting natural gas as a cleaner alternative fuel
• Assisting quality assurance and product development teams in verifying component performance under operational conditions
• Facilitating compliance with international safety regulations and enhancing consumer confidence in CNG vehicle safety

Related Standards

ISO 15500-15:2015 is part of the broader ISO 15500 series focused on CNG fuel system components, which includes:

• ISO 15500-1: General requirements and definitions for CNG components
• ISO 15500-2: Performance and general test methods
• ISO 15500-3 to ISO 15500-20: Covering specific components such as valves, injectors, pressure regulators, fuel lines (rigid and flexible), filters, fittings, and additional safety devices like pressure relief valves

Other connected standards include:

• ISO 3833: Definitions and terms for road vehicle types
• ISO 15403-1: Quality designation for natural gas used as compressed fuel

Together, these standards harmonize technical requirements to ensure interoperability, safety, and performance of CNG fuel systems worldwide.

Keywords: ISO 15500-15, CNG fuel system components, compressed natural gas, gas-tight housing, ventilation hose, road vehicles, natural gas vehicle safety, CNG leakage tests, pressure retention, fuel system standards, vehicle fuel system components.