ISO 19723-1:2018/Amd 1:2021

Overview

ISO 19723-1:2018/Amd 1:2021 is an important amendment to the international standard focusing on safety requirements for liquefied natural gas (LNG) fuel systems in road vehicles. Developed by the International Organization for Standardization (ISO) under the technical committee ISO/TC 22/SC 41, this amendment enhances the safety protocols governing LNG fuel systems by updating normative references and introducing essential requirements related to electronic control units and electrical connections.

This standard serves as a critical framework for vehicle manufacturers, component suppliers, and safety regulators involved in the design, testing, and certification of LNG-powered road vehicles. By defining comprehensive safety measures, the standard aims to minimize risks associated with LNG handling, improving overall vehicle safety and reliability.

Key Topics

• Electronic Control Unit (ECU) Requirements
  The amendment defines the ECU as a device managing LNG demand and controlling critical safety functions including automatic valve shutoff during engine stalling, fuel supply pipe failure, or crashes.

  • Maximum switching-off delay of 2 seconds after engine stalling
  • Operation across temperature ranges from -40 °C/-20 °C to 105 °C/120 °C
  • Integration with ignition advance adjusters and dummy injectors for correct engine operation
  • Compliance with electromagnetic compatibility (EMC) standards, including ISO 11451 and ISO 11452 series, and ISO 7637 for electrical disturbances

• Electrical Connections and Protection Degrees
  Detailed protection level classifications for electrical connections are specified to ensure robustness against environmental and operational influences:

  • Electrical connections inside boot and passenger compartments: minimum IP 40 protection (ISO 20653)
  • All other electrical connections: minimum IP 54 protection (ISO 20653)

• Electromagnetic Compatibility (EMC) Compliance
  The amendment expands requirements to cover immunity and emission tests against electrical disturbances on the 12/24 V supply lines to maintain system integrity and consistent LNG fuel system functionality.

• Updated Normative References
  Several key ISO standards concerning electrical disturbance testing and environmental protection are referenced, enhancing the scope and precision of safety verification for LNG fuel systems.

Applications

The ISO 19723-1 amendment is essential for stakeholders involved in:

• Design and Manufacturing
  Ensuring LNG fuel systems meet rigorous electrical safety and operational reliability criteria under various environmental conditions. OEMs and component suppliers apply these safety requirements during product development.

• Vehicle Safety Certification
  Regulatory bodies and testing organizations use this standard as a basis for certifying LNG-fueled road vehicles, verifying compliance with state and international safety regulations.

• Maintenance and Repair
  Maintenance personnel benefit from clear guidelines on the protection and testing of electrical connections and control units to support safe servicing of LNG fuel systems.

• Research and Development
  Innovators working on alternative fuel technologies can apply these safety principles to enhance new LNG-related components and systems, ensuring they meet global safety standards.

Related Standards

ISO 19723-1:2018/Amd 1:2021 aligns with and references several other international standards that support comprehensive safety assurance for LNG systems and automotive electrical components:

• ISO 20653:2013 – Protection of electrical equipment against foreign objects, water, and access (IP codes)
• ISO 11451 series – Vehicle test methods for electromagnetic disturbances from radiated energy
• ISO 11452 series – Component test methods for electrical disturbances from narrowband radiated electromagnetic energy
• ISO 7637 series – Electrical disturbances from conduction and coupling, focusing on transient conduction along supply lines

These related standards provide detailed methodologies for environmental and electromagnetic testing critical to implementing the safety requirements in ISO 19723-1.

Adopting ISO 19723-1:2018/Amd 1:2021 improves the safety and resilience of LNG fuel systems in road vehicles, supporting the growing use of cleaner alternative fuels while maintaining high standards of operational safety and reliability.