S18.104.22.168 Buckle release. Any buckle in a child restraint system belt assembly designed to restrain a child using the system shall:
(a) When tested in accordance with S6.2.1 prior to the dynamic test of S6.1, not release when a force of less than 40 newtons (N) is applied and shall release when a force of not more than 62 N is applied;
(b) After the dynamic test of S6.1, when tested in accordance with the appropriate sections of S6.2, release when a force of not more than 71 N is applied, provided, however, that the conformance of any child restraint to this requirement is determined using the largest of the test dummies specified in S7 for use in testing that restraint when the restraint is facing forward, rearward, and/or laterally;
(c) Meet the requirements of S4.3(d)(2) of FMVSS No. 209 (§ 571.209), except that the minimum surface area for child restraint buckles designed for push button application shall be 0.6 square inch;
(d) Meet the requirements of S4.3(g) of FMVSS No. 209 (§ 571.209) when tested in accordance with S5.2(g) of FMVSS No. 209; and
(e) Not release during the testing specified in S6.1.