Road vehicles - Liquefied natural gas (LNG) fuel systems - Part 1: Safety requirements
1Key Takeaways
This document specifies the minimum safety requirements applicable to liquefied natural gas (LNG) on-board fuel system intended for use on the types of motor vehicles defined in ISO 3833. This document is applicable to vehicles (mono-fuel, bi-fuel or dual-fuel applications) using liquefied natural gas in accordance wit…
2Expert Interpretation
A comprehensive interpretation of ISO 19723-1:2018, the safety technical requirements for liquefied natural gas (LNG) onboard fuel systems, covering key aspects such as system design, component specifications, and leakage control. This guide serves as a professional safety standard implementation guide for M/N vehicles.
Analysis of the core requirements of the standard
The ISO 19723-1:2018 standard proposes three core safety dimensions for LNG fuel systems:
| Safety dimensions | Technical requirements | Test indicators |
|---|---|---|
| System design | Compliance with ISO 12614 component specifications | Pressure resistance of 1.5 times the working pressure |
| Leakage control | Dual pressure relief valve configuration | Leakage rate ≤0.25 Ncm³/min |
| Installation protection | 20g shock acceleration tolerance | Vibration test ≥ 1 million times |
Key Component Technical Specifications
1. LNG Storage Tank
Must comply with ISO 12991. Installation requirements:
- M1/N1 vehicles must withstand 20g longitudinal acceleration
- Maintain a clearance of ≥ 100mm from the exhaust system
- On-site welding on the tank is prohibited
2. Pressure Relief System
Typical Configuration Example: The primary relief valve must be connected to a vertical exhaust pipe, and the secondary relief valve must be independently discharged. The exhaust pipe's inner diameter must not be smaller than the valve outlet diameter and must meet a bursting requirement of 1.5 times the working pressure.
Technological Evolution and Implementation Recommendations
Background of Standard Development
With the increasing application of -162℃ low-temperature LNG in commercial vehicles, the traditional CNG standard (ISO 15501) can no longer cover the special safety risks brought about by low-temperature characteristics.
Key points of implementation
- The filling port must comply with the 3.1MPa connection standard of ISO 12617
- The protection level of electronic components must reach IP54 (IEC 60529)
- Category M vehicles must be equipped with a natural gas detector
Relationship with other standards
| Related standards | Scope of application | Differences |
|---|---|---|
| ISO 15501 | CNG system | Does not cover cryogenic components |
| ISO 12614 | LNG components | Referenced specifications of this standard |