UN R92 — 03 series of amendments

The NORESS and its components must be designed and constructed considering tamper proofing measures, and any tampering event must cause irrecoverable damage to the assembly. Software of the NORESS, if any, must also be designed and programmed considering tamper proofing measures. At the request of the type-approval authority or its technical service, the manufacturer must describe the tamper proofing measures applied and demonstrate their practical effectiveness. Compliance with the anti-tampering provisions is required in any case, whatever the vehicle's year of production or the noise regulation of its type approval. Annex 5 gives a “Recommendation to comply with the anti-tampering provisions”, and its general principles apply to designs and constructions that it does not list. Before, the NORESS or its components had to be “constructed in a way that does not permit removal of baffles, exit-cones and other parts whose primary function is as part of the silencing/expansion chambers”.

New Annex 5 “Anti-tampering provisions” helps to interpret the definitions and gives guidance and good practices for existing NORESS designs, constructions and manufacturing methods. Annex 5 says that “Manufacturers shall either comply with this Annex or alternative solutions may be agreed with the Type Approval Authority or its designated Technical Service, provided that they reach the same objective”. Annex 5 is based on construction methods that are commonly used to date (2024) and does not claim to be complete. Under the Annex 5 general principles, manufacturers must apply tamper proofing measures to avoid impairment of NORESS integrity, and unlawful modifications must be easily detectable. End-consumers must not be able to modify the NORESS performance into a state that does not conform to the type approval without extensive effort. For hardware, permanent evidence of tampering is easily visible damage to parts of the silencer system that cannot be erased with general tools.

For components whose main function is to contribute to sound attenuation, welding is considered a primary tamper proofing construction method for metals and alloys. Possible tamper-proofing attachment methods are welding or permanent gluing of a sufficient perimeter to avoid removals, and sufficient and expedient stainless-steel rivets. Threaded fixing, aluminium rivets, circlips and conventional fasteners are in any case deemed insufficient. Possible attachment points are the exhaust casing, the exhaust pipe in the exhaust silencing system and, under two conditions, the exit cone. Under the two conditions of paragraph 3.3.1., cosmetic end caps may be attached with conventional fasteners. Possible tamper proofing methods for software are a sealed control box that shows signs of opening when software is changed, and protected update interfaces.

New paragraphs 2.8. to 2.11. define “Exit-cone”, “Exhaust casing”, “Baffle” and “Fastener”. The definition of “Exit-cone” refers to new Figure 1, “Exhaust silencer”. Under paragraph 2.12., “Tamper proofing” means the activity to hinder and deter unlawful modifications, and to ease the detection of unlawful modifications. A “Tampering event” is any action which puts the exhaust silencing system into a state which is not any more compliant with the approved type. “Irrecoverable damage (related to tamper proofing exhaust silencing systems)” means damage that constitutes permanent evidence of a tampering event.

From the entry into force of the 03 series, no Contracting Party applying this Regulation may refuse to grant or accept type approvals to it. From 24 months after the 03 series enters into force, Contracting Parties need not accept approvals to the preceding series first issued after that time. Until 36 months after the 03 series enters into force, Contracting Parties must accept approvals to the preceding series first issued before the 24-month point. From 36 months after the 03 series enters into force, Contracting Parties are not obliged to accept approvals to the preceding series, “unless the equipment or part is intended as a replacement for fitting on vehicles in use and that it would not be technically feasible for the equipment or part in question to satisfy the new requirements”. Before, from 12 and 24 months after entry into force, approvals and extensions, respectively, could be granted only to types that met the 02 series. Before, approvals to the preceding series stayed valid, and Contracting Parties had to continue to accept them.

Paragraph 5.2. now says that the first two digits of the approval number are at present 03, for the 03 series, instead of 01. In Annex 2, the example approval mark now shows approval No. 032439 instead of 022439. The first two digits of this approval number, 03, indicate an approval to UN Regulation No. 92 as amended by the 03 series of amendments. Before, the explanation also said that the approval number 00 indicates an approval to UN Regulation No. 92 in its original form. Annex 2 now refers to “paragraph 5.4. of this Regulation” instead of “paragraph 5.4. of this UN Regulation”.

Paragraph 4.1.(a) now reads “of the NORESS or its components” instead of “of the NORESS of its components”. In paragraph 4.6., “The approval mark” moves from paragraph 4.7. to item (d), and items (a) to (c) end with commas. Paragraphs 5.6. and 6.1.(b) have wording corrections: “need not to be repeated” becomes “does not need to be repeated”, and “corrosion phenomena” becomes “corrosion”. In paragraph 6.2., “shall not exceed the values” becomes “shall not exceed either of the values”, and “and the stationary test” becomes “and during the stationary test”. In paragraph 6.3.4.3., the ASEP tests “shall be done” instead of “has to be done” and “have to be done”, and paragraph 6.3.4.9.1. becomes one sentence. In Annex 1, items 16.1., 16.2. and 16.4. now give “dB(A)” instead of “db(A)”, and item 16.3. on the partial power factor gives “--”.