Document ID: chunk:federal_register_of_legislation:F2017L01344:body:0:p20
Version: federal_register_of_legislation:F2017L01344
Segment Type: other
Provision Reference: 
Character Range: 51047–53658

2 of Annex 4 to this Regulation)
6.6.1. The plane S1, perpendicular to the reference line and situated 65 mm below the tangent S defined in paragraph 6.5.3. above, determines a section in the head restraint bounded by the outline C.
6.6.2. The width of the head restraint to be taken into consideration in implementing the requirements of paragraph 5.11. above, is the distance "L" measured in the plane S1 between the vertical longitudinal planes P and P'.
6.6.3. The width of the head restraint shall if necessary also be determined in the plane perpendicular to the reference line 635 mm above the R point of the seat, this distance being measured along the reference line.
6.7. Determination of distance "a" of head restraint gaps, (see Annex 8 to this Regulation)
6.7.1. The distance "a" shall be determined for each gap and in relation to the front face of the head restraint, by means of a sphere having a diameter of 165 mm.
6.7.2. The sphere shall be put into contact with the gap in a point of the gap area which allows the maximum sphere intrusion, considering no load is to be applied.
6.7.3. The distance between the two points of contact of the sphere with the gap will constitute the distance "a" to be considered for the evaluation of the provisions under paragraphs 5.9. and 5.10. above.
6.8. Tests for checking energy dissipation on the seat‑back and head restraint
6.8.1. The surfaces of the rear parts of seats to be checked are those situated in the areas defined below which can be contacted by a 165 mm diameter sphere when the seat is mounted in the vehicle.
6.8.1.1. Area 1
6.8.1.1.1. In the case of separate seats without head restraints, this area shall include the rear part of the seat‑back between the longitudinal vertical planes situated at 100 mm on either side of the longitudinal median plane of the seat centre line, and above a plane perpendicular to the reference line 100 mm below the top of the seat‑back.
6.8.1.1.2. In the case of bench seats without head restraints, this area shall extend between the longitudinal vertical planes situated at 100 mm on either side of the longitudinal median plane of each designated outboard seating position defined by the manufacturer and above a plane perpendicular to the reference line 100 mm below the top of the seat‑back.
6.8.1.1.3. In the case of seats or bench seats with head restraints, this area shall extend between the longitudinal vertical planes, on either side of and 70 mm from the longitudinal median plane of the seat or of the seating position concerned and situated above the plane perpendicular to the reference