UN R17 — 10 series of amendments

The definition of “Head restraint” (para. 2.13.) now includes “a height equal to or greater than 700 mm at any point between two vertical longitudinal planes passing at 85 mm on either side of the torso line, in any position of backset and height adjustment, as measured in accordance with Annex 10”. Paragraph 2.13.2. now says that a detachable head restraint “which can only be detached from the seat by the use of tools and/or after partial or complete removal of the seat covering, meets the present definition”. Before, paragraph 2.12.1. said that head restraints meeting the definitions of paragraphs 2.12.2. or 2.12.3. met the “Integrated head restraint” definition if they “can only be detached from the seat or the vehicle structure by the use of tools or by partial or complete removal of the seat covering”. The “R point” (para. 2.19.) is now “a design point defined by the vehicle manufacturer for each designated seating position and established with respect to the three‑dimensional reference system as defined by Annex 3”. New definitions include “Intended for occupant use” (para. 2.6.), “Adjustable head restraint”, “Backset”, “R-point Backset”, “BioRID Reference Backset” and “Torso line”. Former paragraphs 2.6. to 2.10. are now paragraphs 2.7. to 2.11.

For front outboard designated seating positions, paragraph 5.6.2.1. requires a height of not less than 830 mm in at least one adjustment position. The height must also be not less than 720 mm in any adjustment position, and both values apply except as provided for in paragraph 5.6.2.3. Paragraph 5.6.2.3. gives an exception if “the interior surface of the vehicle roofline, including the headliner, physically prevents” a front head restraint from attaining the required height. Then the gap to the roofline, measured in accordance with Annex 10, paragraph 2.3.3.1., must not exceed 50 mm “when the head restraint is adjusted to its highest position intended for occupant use”. But the height of a front head restraint must never be less than 700 mm “when the head restraint is adjusted to its lowest position intended for occupant use”. Before, former paragraphs 5.6.2. to 5.6.5. required heights of at least 800 mm for front seats and 750 mm for other seats, with some exceptions.

The lateral width must be not less than 85 mm on either side of the torso line, measured in accordance with Annex 4 (para. 5.6.3.). Before, the head restraint had to cover not less than 85 mm to each side of the vertical median plane of the seat. If there is any gap greater than 60 mm (Annex 8), “the maximum rearward displacement of the head form shall be less than 102 mm” when tested at that gap in accordance with Annex 5 (para. 5.6.4.). For front outboard positions, paragraph 5.6.6.2. limits the backset to 45 mm, measured in accordance with Annex 11, in the height positions of paragraph 5.6.6.1. Paragraph 5.6.7. requires a front contact surface height of not less than 100 mm “except for integrated head-restraints”, measured as in Figure 10-6 of Annex 10. Before, the 100 mm minimum for the part on which the head rests applied to head restraints adjustable for height.

When the front surface is impacted in accordance with Annex 12, the headform deceleration must not exceed 785 m/s2 (80g) “continuously for more than 3 milliseconds” (para. 5.7.1.). When tested in accordance with Annex 5, the headform must not be displaced more than 102 mm “perpendicularly and rearward of the displaced extended torso reference line, "r1", during the application of a 373 Nm moment about the R-point” (para. 5.7.2.). Before, paragraph 5.12. set a maximum backward displacement of the head of less than 102 mm, measured with the static procedure of paragraph 6.4.3. In the Annex 5 strength test, the load must reach 890 N and stay there for at least 5 seconds, “unless any breakage of the seat or head restraint occurs” (para. 5.7.3.). Under paragraph 5.7.4., when tested in accordance with Annex 13, the mechanism of the adjustable head restraint “shall not fail in such a way as to allow downward movement of the head restraint by more than 25 mm”. Paragraph 5.5.2. now requires the energy absorption test in area 1 for the rear faces of head restraints, not the front and rear faces.

At the choice of manufacturer, a front outboard head restraint must meet paragraph 5.6.1.1.1., with paragraphs 5.6.6. and 5.7., or 5.6.1.1.2., with paragraph 5.9. For front centre, rear outboard and rear centre head restraints, the manufacturer chooses between a set with paragraph 5.7. and a set with paragraph 5.9. If “it is impossible to seat the test dummy at the designated seating positions specified under paragraph 5.9.”, the head restraint must conform to paragraph 5.6.1.1.1., 5.6.1.2.1., 5.6.1.3.1. or 5.6.1.4.1., as appropriate. Until further evaluation is conducted, “the use of the BioRID II UN dummy is limited to seats having a design torso angle no less than 20° and no greater than 30°” (para. 5.9.). At the manufacturer’s request, seats with a design torso angle between 15° and 20° may be tested at 20° or the closest locking position above. Table 1 of paragraph 5.9.2. gives the injury criteria, for example NIC 25 m2/s2 and upper neck FX 360N.

A driver head restraint must not have a non-use position (para. 5.8.1.). Under paragraph 5.8.2., a front outboard passenger head restraint may be adjusted to a position at which its height does not comply with paragraph 5.6.2.1. In any such position, it must meet paragraph 5.8.4.1. Under paragraph 5.8.3., all rear head restraints and any front centre head restraint “may be adjusted to a position at which its height does not comply with the requirements” of paragraphs 5.6.2.2., 5.6.2.4. or 5.6.2.6. In any such position, it must also meet one alternative requirement of paragraphs 5.8.4.1. to 5.8.4.5., at the choice of the manufacturer. One of these alternatives (para. 5.8.4.5.) is a durably affixed pictogram label that marks the presence of a non-use position.

From the official date of entry into force of the 10 series, no Contracting Party may refuse to grant or accept approvals to it. From 1 September 2022, Contracting Parties are not obliged to accept approvals to the preceding series first issued on or after 1 September 2022. Until 1 September 2026, Contracting Parties must accept approvals to the preceding series first issued before 1 September 2022. From 1 September 2026, Contracting Parties are not obliged to accept type approvals issued to the preceding series of amendments. Notwithstanding paragraph 13.13.3., Contracting Parties must continue to accept approvals to the preceding series for vehicles not affected by the 10 series changes. The first two digits of the approval number are now 10, corresponding to the 10 series of amendments (para. 4.2.).