UN R137 — 03 series of amendments

New paragraph 5.2.7. says that, in the case of a compressed hydrogen-fuelled vehicle, compliance with paragraphs 5.2.7.1. to 5.2.7.3. must be shown. Under paragraph 5.2.7.1., the hydrogen leakage rate (VH2) must not exceed an average of 118 NL per minute for Δt minutes after the crash. The rate is determined in accordance with paragraph 4. of Annex 10 for hydrogen, or paragraph 5. of Annex 10 for helium. Under paragraph 5.2.7.3., the container(s) for hydrogen storage must remain attached to the vehicle at a minimum of one attachment point.

New paragraph 5.2.7.2. sets limits for the gas concentration by volume in air in the passenger and luggage compartments. The limits are 4.0 per cent for hydrogen or 3.0 per cent for helium, at any time throughout the 60 minute post-crash measurement period. The values are determined in accordance with paragraph 6. of Annex 10. Paragraph 5.2.7.2. says that this requirement is satisfied if it is confirmed that two conditions are met. The first is that the shut-off valve of each compressed hydrogen storage system has closed within five seconds of first vehicle contact with the barrier. The second is that there is no leakage from the compressed hydrogen storage system(s).

The Annex 3 test is now considered satisfactory if all the conditions in paragraphs 5.2.1. to 5.2.7. are satisfied at the same time. Before, the list ended at paragraph 5.2.6. The former paragraph 5.2.7. is renumbered as paragraph 5.2.6.1. Paragraph 5.2.6.1. is about continuous leakage of liquid from the fuel-feed installation after the collision.

New Annex 10 gives the test conditions and procedures for the assessment of post-crash hydrogen fuel system integrity. Its purpose is the determination of compliance with the requirements of paragraph 5.2.7. It covers the preparation of the hydrogen storage system, the sensors for enclosed spaces, and post-crash leak and concentration measurements. Separate leak test measurements apply to a storage system filled with compressed hydrogen and to one filled with compressed helium. The time interval Δt starts when the vehicle comes to rest after the impact and continues for at least 60 minutes. Post-crash data from the sensors in enclosed spaces are collected at least every five seconds for a period of 60 minutes after the test.

Paragraph 2.4. now puts one "adverse effect" condition in its lead-in, instead of a "negative effect" condition in each of items (a) to (g). New item (h) is "The basic configuration and main characteristics of the compressed hydrogen storage system". New paragraphs 2.41. to 2.45. define the compressed hydrogen storage system (CHSS), the container, container attachments, the hydrogen-fuelled vehicle and the shut-off valve. Paragraph 2.5.2. now defines the "Passenger compartment for electric safety and/or hydrogen safety assessment". It also says "back door" instead of "rear gate".

Paragraph 12.1. now refers to the official date of entry into force of the 03 series of amendments and to type-approvals under that series. In paragraphs 12.2. and 12.3., the date 1 September 2023 is now 1 September 2027. Paragraph 12.4. now says that Contracting Parties applying this UN Regulation may grant type-approvals according to any preceding series of amendments. Before, it said that they must not refuse to grant type-approvals according to any preceding series, or extensions thereof. New paragraph 12.5. says that Contracting Parties applying this UN Regulation must continue to grant extensions of existing approvals to any preceding series of amendments. Paragraph 12.6. is about Contracting Parties who start to apply this Regulation after the entry into force of the most recent series of amendments.

The two Annex 2 example texts now refer to the 03 series of amendments of Regulation No. 137, instead of the 01 series. The approval mark figures in Annex 2 are also updated. Three footnotes on the Consolidated Resolution on the Construction of Vehicles now refer to document ECE/TRANS/WP.29/78/Rev.7, instead of Rev.4 or Rev.6. These footnotes now give the web address https://unece.org/transport/standards/transport/vehicle-regulations-wp29/resolutions.