USA: Two new FMVSS for hydrogen vehicles
The NHTSA has published a Final Rule which establishes two new Federal Motor Vehicle Safety Standards (FMVSS) specifying performance requirements for all motor vehicles that use hydrogen as a fuel source. The final rule is based on Global Technical Regulation (GTR) No. 13, Hydrogen and Fuel Cell Vehicles.
The two new FMVSS are:
- FMVSS No. 307, ”Fuel system integrity of hydrogen vehicles,” specifies requirements for the integrity of the fuel system in hydrogen vehicles during normal vehicle operations and after crashes.
- FMVSS No. 308, ”Compressed hydrogen storage system integrity,” specifies requirements for the compressed hydrogen storage system to ensure the safe storage of hydrogen onboard vehicles.
These two standards will reduce deaths and injuries from fires due to hydrogen fuel leakages and/or explosion of the hydrogen storage system.
Background:
Automakers continue to explore renewable and clean fuel sources as alternatives to gasoline and diesel. One promising option is compressed hydrogen, given its abundance in the atmosphere and its ability to serve as a motor fuel without producing tailpipe greenhouse gas emissions. However, for hydrogen to be an efficient fuel, it must be stored at high pressures, and like other motor fuels, it is highly flammable.
The National Highway Traffic Safety Administration (NHTSA) has already established regulations for the safe containment of various motor vehicle fuels, such as gasoline under FMVSS No. 301, “Fuel System Integrity,” and compressed natural gas (CNG) under FMVSS No. 304, “Compressed Natural Gas Fuel Container Integrity.” On April 17, 2024, NHTSA published a Notice of Proposed Rulemaking (NPRM) to seek public input on proposed safety standards for hydrogen fuel systems.
This final rule responds to stakeholder feedback from the NPRM and aligns hydrogen vehicle safety standards with international regulations through the Global Technical Regulation (GTR) process. As a result, two new Federal Motor Vehicle Safety Standards (FMVSS) have been introduced:
- FMVSS No. 307, “Fuel System Integrity of Hydrogen Vehicles” – This regulation ensures the integrity of hydrogen fuel systems during regular operation and following a crash. It establishes performance requirements to mitigate risks related to hydrogen leaks and discharge, including post-crash restrictions on leakage levels, gas concentration in enclosed spaces, container displacement, and fire hazards.
- FMVSS No. 308, “Compressed Hydrogen Storage System Integrity” – This standard focuses on the safety of compressed hydrogen storage systems (CHSS). It sets performance requirements to minimize the risk of leaks or bursts during use and ensures hydrogen is safely released in the event of a fire. Additionally, it specifies safety criteria for different closure mechanisms within the CHSS.
FMVSS No. 308 applies to all motor vehicles powered by compressed hydrogen gas, regardless of their gross vehicle weight rating (GVWR), except those using only cryo-compressed or solid-state hydrogen storage systems. FMVSS No. 307 also applies broadly to hydrogen-fueled vehicles, though its post-crash fuel system integrity requirements are specific to compressed hydrogen-fueled light vehicles (those with a GVWR of 4,536 kg or less).
To find out more about automotive regulations in USA, please do not hesitate to contact the Institute for Global Automotive Regulatory Research.