UN R135 — Supplement 4 to the 01 series of amendments

Paragraph 2.3. now says that a CHSS stores “compressed hydrogen fuel” for a hydrogen-fuelled vehicle. It is composed of “a container, container attachments (if any), and all primary closure devices required to isolate the stored hydrogen”. Before, it was composed of “a pressurized container, pressure relief devices (PRDs) and shut off device”. Under paragraph 2.4., a container (for hydrogen storage) is now “the pressure-bearing component on the vehicle” that stores the primary volume of hydrogen fuel “in a single chamber or in multiple permanently interconnected chambers”. Before, it was “the component within the hydrogen storage system”. New paragraph 2.4.1. defines “Container Attachments” as “non-pressure bearing parts attached to the container that provide additional support and/or protection to the container”, which “may be only temporarily removed for maintenance and/or inspection only with the use of tools”.

Paragraph 2.10. now says that hydrogen fuel for the vehicles is specified in ISO 14687:2019 and SAE J2719_202003. Before, hydrogen fuel for passenger vehicles was specified in ISO 14687-2:2012 and SAE J2719 (Sep 2011 Revision).

Paragraph 2.14. now has only the words “Passenger compartment”, and new paragraphs 2.14.1. and 2.14.2. give two definitions. Paragraph 2.14.1. defines “Passenger compartment with regard to occupant protection” as “the space for occupant accommodation, bounded by the roof, floor, side walls, doors, outside glazing, front bulkhead and the plane of the rear compartment bulkhead or the plane of the rear-seat back support”. Before, paragraph 2.14. gave one definition of “Passenger compartment”, with these bounds. Paragraph 2.14.2. defines “Passenger compartment for hydrogen safety assessment”. This space is bounded by “the roof, floor, side walls, doors, outside glazing, front bulkhead and rear bulkhead, or back door”.

Paragraph 2.20. now says that a shut-off valve (for hydrogen-fuelled vehicles) is a valve between “the container” and the vehicle fuel system. Before, it said “the storage container”. The valve now “must default” to the “closed” position when not connected to a power source. Before, the definition said that the valve “can be automatically activated” and “defaults” to that position.

The definition of “Vehicle type” (paragraph 2.26.) now says that the design characteristics do not differ in such essential respects, “in so far as they have an adverse effect on the result of the impact test prescribed in this Regulation”. The paragraph that said “in so far as they may be considered to have a negative effect on the results of a vehicle‑to‑pole side impact test conducted in accordance with Annex 3 of this Regulation” is deleted.

In Annex 6, paragraph 2.1. now says that “Enclosed spaces” means “the special volumes within the vehicle (or the vehicle outline across openings) that are external to the hydrogen system”. The hydrogen system now lists “storage system, fuel cell system, internal combustion engine (ICE) and fuel flow management system”. The definition no longer includes “and its housings (if any) where hydrogen may accumulate (and thereby pose a hazard), such as the passenger compartment, luggage compartment and space under the hood”. Under paragraph 3.1.4., “the main stop valve and shut-off valves for hydrogen gas, located in the downstream hydrogen gas piping” are now “in the normal driving condition kept open” immediately before the impact. Before, it said “in normal driving condition”.

In Annex 6, paragraphs 4.2. and 4.3. give the formulas to calculate the initial and the final mass of hydrogen in the storage system. In the formulas for ρo' and ρf', the last term is now 1.07 instead of 0.5789. The other terms of these two formulas do not change.