ISO 20766-20:2019

Overview

ISO 20766-20:2019 is an international standard specifying the requirements for filter units used in liquefied petroleum gas (LPG) fuel systems for road vehicles. This standard is part 20 of the ISO 20766 series, which focuses on components for LPG fuel systems. It applies to LPG-powered motor vehicles defined under ISO 3833, including mono-fuel, bi-fuel, or dual-fuel applications compliant with ISO 9162.

The document outlines the general design principles, marking guidelines, and testing requirements to ensure filter units meet safety, reliability, and performance standards. It specifically covers filter units functioning within a service pressure range of 110 kPa (butane rich) to 840 kPa (propane) at 20 °C.

Key Topics

• Scope and Applicability
  The standard excludes fuel containers, stationary gas engines, container mounting hardware, electronic fuel management, and refuelling receptacles. It targets devices handling specific LPG pressures and offers guidance for additional miscellaneous components under the broader ISO 20766 framework.

• Marking and Identification
  Clear and traceable markings on filter units are mandatory, including:

  • Manufacturer or agent identification (name, trademark, or symbol)
  • Model designation and part number
  • Working pressure and temperature range
  • Filter micron rating
    Recommended markings include flow direction, type of fuel, electrical ratings (if applicable), certification symbols, approval numbers, serial/date codes, and reference to this ISO standard.

• Construction Requirements
  Filter units must comply with the overall general requirements in ISO 20766-1 and performance standards in ISO 20766-2. Electrical connections should meet IP54 ingress protection as per IEC 60529.

• Testing Protocols
  The standard specifies several critical tests to verify filter unit integrity and performance:

  • Hydrostatic strength test at 2.25 times the working pressure to ensure structural robustness.
  • Low temperature test to evaluate leakage at temperatures as low as -40 °C, ensuring a maximum leak rate of 15 cm³/h under 150% working pressure after temperature conditioning.
  • High temperature test to assess leakage at elevated temperatures (65 °C to 120 °C depending on the filter), with the same leakage limits and conditioning requirements.
    Additional optional tests may include corrosion resistance, material compatibility, and thermal cycling aligned with ISO 20766-2.

Applications

ISO 20766-20:2019 is essential for manufacturers, engineers, and regulatory bodies involved in the design, production, testing, and certification of LPG fuel system components in road vehicles. Its practical applications include:

• Ensuring safety and reliability of LPG filter units by standardizing performance and durability requirements.
• Facilitating cross-border compliance and market entry by harmonizing component standards internationally.
• Supporting the development of environmentally-friendly LPG vehicle technologies by guaranteeing fuel purity and system efficiency.
• Guiding quality assurance and inspection processes for automotive suppliers and aftermarket parts manufacturers.
• Enabling customers and fleet operators to trace and verify component performance and certification status through mandated markings.

Related Standards

To fully comply with LPG fuel system requirements, ISO 20766-20:2019 should be used in conjunction with the following standards:

• ISO 20766-1: Road vehicles - Liquefied petroleum gas (LPG) fuel systems components - Part 1: General requirements and definitions
• ISO 20766-2: Road vehicles - LPG fuel systems components - Part 2: Performance and general test methods
• ISO 3833: Road vehicles - Types - Terms and definitions, to classify vehicles covered by this standard
• ISO 9162: Petroleum products - Fuels (Class F) - Liquefied petroleum gases - Specifications, aligning fuel quality standards
• IEC 60529: Degrees of protection provided by enclosures (IP Code), specifying electrical connection requirements

By adhering to ISO 20766-20:2019, stakeholders ensure that LPG filter units meet internationally recognized benchmarks for safety, durability, and performance, promoting reliable and efficient LPG fueling systems for road vehicles worldwide.