S1. Scope. This standard specifies side impact protection requirements for child restraint systems recommended for children in a weight range that includes weights up to 18 kilograms (40 pounds) or by children in a height range that includes heights up to 1100 millimeters (43 inches).

S2. Purpose. The purpose of this standard is to reduce the number of children killed or injured in motor vehicle side impacts. Each child restraint system subject to this standard shall also meet all applicable requirements in FMVSS No. 213 (§ 571.213).

S3. Application. This standard applies to add-on child restraint systems that are either recommended for use by children in a weight range that includes weights up to 18 kilograms (40 pounds) regardless of height, or by children in a height range that includes heights up to 1100 millimeters regardless of weight, except for car beds and harnesses.

S4. Definitions.

Add-on child restraint system means any portable child restraint system.

Belt-positioning seat means a child restraint system that positions a child on a vehicle seat to improve the fit of a vehicle Type II belt system on the child and that lacks any component, such as a belt system or a structural element, designed to restrain forward movement of the child's torso in a forward impact.

Car bed means a child restraint system designed to restrain or position a child in the supine or prone position on a continuous flat surface.

Child restraint anchorage system is defined in S3 of FMVSS No. 225 (§ 571.225).

Child restraint system is defined in S4 of FMVSS No. 213 (§ 571.213).

Contactable surface means any child restraint system surface (other than that of a belt, belt buckle, or belt adjustment hardware) that may contact any part of the head or torso of the appropriate test dummy, specified in S7, when a child restraint system is tested in accordance with S6.1.

Harness means a combination pelvic and upper torso child restraint system that consists primarily of flexible material, such as straps, webbing or similar material, and that does not include a rigid seating structure for the child.

Rear-facing child restraint system means a child restraint system that positions a child to face in the direction opposite to the normal (forward) direction of travel of the motor vehicle.

Seat orientation reference line or SORL means the horizontal line through Point Z as illustrated in Figure 1 to § 571.213a.

Tether anchorage is defined in S3 of FMVSS No. 225 (§ 571.225).

Tether strap is defined in S3 of FMVSS No. 225 (§ 571.225).

Torso means the portion of the body of a seated anthropomorphic test dummy, excluding the thighs, that lies between the top of the child restraint system seating surface and the top of the shoulders of the test dummy.

S5. Requirements. (a) Each child restraint system subject to this section shall meet the requirements in this section when, as specified, tested in accordance with S6 and this paragraph. Each child restraint system shall meet the requirements when oriented in each direction recommended by the manufacturer (i.e., forward, rearward), using any of the seat back angle adjustment positions and restraint belt routing positions designated for that direction, pursuant to S5.6 of FMVSS No. 213 (§ 571.213), and tested with the test dummy specified in S7 of this section.

(b) Each child restraint system subject to this section shall also meet all applicable requirements in FMVSS No. 213 (§ 571.213).

S5.1 Dynamic performance.

S5.1.1 Child restraint system integrity. When tested in accordance with S6.1, each child restraint system shall meet the requirements of paragraphs (a) through (c) of this section.

(a) With any padding or other flexible overlay material removed, exhibit no complete separation of any load bearing structural element and no partial separation exposing either surfaces with a radius of less than 6 millimeters or surfaces with protrusions greater than 9 millimeters above the immediate adjacent surrounding contactable surface of any structural element of the child restraint system.

(b)(1) If adjustable to different positions, remain in the same adjustment position during the testing that it was in immediately before the testing, except as otherwise specified in paragraph (b)(2).

(2)(i) Subject to paragraph (b)(2)(ii), a rear-facing child restraint system may have a means for repositioning the seating surface of the system that allows the system's occupant to move from a reclined position to an upright position and back to a reclined position during testing.

(ii) No opening that is exposed and is larger than 6 millimeters before the testing shall become smaller during the testing as a result of the movement of the seating surface relative to the child restraint system as a whole.

(c) If a front facing child restraint system, not allow the angle between the system's back support surfaces for the child and the system's seating surface to be less than 45 degrees at the completion of the test.

S5.1.2 Injury criteria. When tested in accordance with S6.1 and with the test dummy specified in S7, each child restraint system that, in accordance with S5.5.2 of Standard No. 213 (§ 571.213), is recommended for use by children whose mass is more than 13.6 kilograms or whose height is more than 870 mm shall—

(a) Limit the resultant acceleration at the location of the accelerometer mounted in the test dummy head as specified in Part 572 such that, for any two points in time, t1 and t2, during the event which are separated by not more than a 15 millisecond time interval and where t1 is less than t2, the maximum calculated head injury criterion (HIC) shall not exceed 570, determined using the resultant head acceleration at the center of gravity of the dummy head, ar, expressed as a multiple of g (the acceleration of gravity), calculated using the expression:

(b) The maximum chest compression (or deflection) from the output of the thoracic InfraRed Telescoping Rod for Assessment of Chest Compression (IR-TRACC) shall not exceed 23 millimeters.

S5.1.3 Occupant containment. When tested in accordance with S6.1 and the requirements specified in this section, each child restraint system recommended for use by children in a specified mass range that includes any children having a mass greater than 5 kilograms but not greater than 13.6 kilograms (30 lb), shall retain the test dummy's head such that there is no direct contact of the head to any part of the side impact seat assembly described in S6.1.1(a).

S5.1.4 Protrusion limitation. Any portion of a rigid structural component within or underlying a contactable surface shall, with any padding or other flexible overlay material removed, have a height above any immediately adjacent restraint system surface of not more than 9 millimeters and no exposed edge with a radius of less than 6 millimeters.

S5.1.5 Belt 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 the appropriate sections of S6.2, after the dynamic test of S6.1, release when a force of not more than 71 Newtons is applied.

(b) Not release during the testing specified in S6.1.

S5.1.6 Installation. Each add-on child restraint system shall be capable of meeting the requirements of this standard when installed solely by each of the means indicated in the following table:

S6. Test conditions and procedures.

S6.1 Dynamic side impact test for child restraint systems. The test conditions and test procedure for the dynamic side impact test are specified in S6.1.1 and S6.1.2, respectively.

S6.1.1 Test conditions.

(a) Test device. (1) The test device is a SISA consisting of a sliding seat, with one seating position, and a simulated door assembly as described in “NHTSA Standard Seat Assembly; FMVSS No. 213a—Side impact No. NHTSA-213a-2021” (incorporated by reference, see § 571.5). The simulated door assembly is rigidly attached to the floor of the SISA and the sliding seat is mounted on rails to allow it to move relative to the floor of the SISA in the direction perpendicular to the SORL. The SISA is mounted on a dynamic test platform so that the SORL of the seat is 10 ±1 degrees from the perpendicular direction of the test platform travel.

(2) As illustrated in the SISA drawing package, attached to the seat belt anchorage points provided on the SISA is a Type II seat belt assembly. These seat belt assemblies are certified to meet the requirements of Standard No. 209 (§ 571.209) and have webbing with a width of not more than 2 inches, and are attached to the anchorage points without the use of retractors or reels of any kind. As illustrated in the SISA drawing package, attached to the SISA is a child restraint anchorage system conforming to the specifications of Standard No. 225 (§ 571.225).

(b) Accelerate the test platform to achieve a relative velocity of 31.3 ± 0.64 km/h in the direction perpendicular to the SORL between the SISA sliding seat and the door assembly at the time they come in contact (time = T0). The front face of the armrest on the door is 38 ± 6 millimeters from the edge of the seat towards the SORL at time = T0. The test platform velocity in the direction perpendicular to the SORL during the time of interaction of the door with the child restraint system is no lower than 2.5 km/h less than its velocity at time = T0.

(c) The sliding seat acceleration perpendicular to the SORL is any pulse within the acceleration corridor shown in Figure 3 and the change in relative velocity perpendicular to the SORL between the SISA sliding seat and the door assembly is any velocity within the relative velocity corridor shown in Figure 4.

(d) Performance tests under S6.1 are conducted at any ambient temperature from 20.6 °C to 22.2 °C and at any relative humidity from 10 percent to 70 percent.

(e) The child restraint shall meet the requirements of S5 when oriented in each direction recommended by the manufacturer (i.e., forward, rearward), using any of the seat back angle adjustment positions and restraint belt routing positions designated for that direction, pursuant to S5.6 of FMVSS No. 213 (§ 571.213), and tested with the test dummy specified in S7 of this section.

S6.1.2 Dynamic test procedure.

(a) The child restraint centerline is positioned 300 ± 2 millimeters from the SISA sliding seat edge (impact side). The child restraint system is attached in any of the following manners, at NHTSA's option.

(1) Install the child restraint system using the child restraint anchorage system in accordance with the manufacturer's instructions provided with the child restraint system pursuant to S5.6 of Standard No. 213 (§ 571.213), except as provided in this paragraph. For forward-facing restraints, attach the tether strap, if provided, to the tether anchorage on the SISA. No supplemental device is used to install the child restraint system. Tighten belt systems of the lower anchorage attachments used to attach the restraint to the SISA sliding seat to any tension of not less than 53.5 Newtons and not more than 67 Newtons. Tighten the belt of the top tether attachment used to attach the restraint to the SISA sliding seat to any tension of not less than 45 Newtons and not more than 53.5 Newtons.

(2) For forward-facing and rear-facing child restraint systems, install the child restraint system using the Type II belt system in accordance with the manufacturer's instructions provided with the child restraint system pursuant to S5.6 of Standard No. 213 (§ 571.213), except as provided in this paragraph. For forward-facing restraints, attach the top tether strap, if provided, to the top tether anchorage on the SISA. For all child restraints, no supplemental device to install the child restraint system is used. Tighten the Type II belt used to attach the restraint to the SISA sliding seat to any tension of not less than 53.5 Newtons and not more than 67 Newtons. Tighten the belt of the top tether attachment used to attach the forward-facing restraint to the SISA sliding seat to any tension of not less than 45 Newtons and not more than 53.5 Newtons. Rear-facing infant carriers with a detachable base shall only be tested using the base.

(3) For rear-facing restraints, install the child restraint system using only the lower anchorages of the child restraint anchorage system in accordance with the manufacturer's instructions provided with the child restraint system pursuant to S5.6 of Standard No. 213 (§ 571.213). No tether strap is used. No supplemental device is used to install the child restraint system. Tighten belt systems used to attach the restraint to the SISA-sliding seat to any tension of not less than 53.5 Newtons and not more than 67 Newtons. Rear-facing infant carriers with a detachable base shall only be tested using the base.

(b) Select any dummy specified in S7 for testing child restraint systems for use by children of the heights or weights for which the system is recommended in accordance with S5.5 of Standard No. 213 (§ 571.213). The dummy is assembled, clothed and prepared as specified in S8 and part 572 of this chapter, as appropriate.

(c) The dummy is placed and positioned in the child restraint system as specified in S9. Attach the child restraint belts used to restrain the child within the system, if appropriate, as specified in S9.

(d) Shoulder and pelvic belts that directly restrain the dummy are adjusted as follows: Tighten the belt system used to restrain the child within the child restraint system to any tension of not less than 9 Newtons and not more than 18 Newtons on the webbing at the top of each dummy shoulder and the pelvic region. Tighten the belt systems used to attach the restraint to the SISA sliding seat to any tension of not less than 53.5 Newtons and not more than 67 Newtons.

(e) Accelerate the test platform in accordance with S6.1.1(b).

(f) All instrumentation and data reduction is in conformance with SAE J211/1 (1995) (incorporated by reference, see § 571.5).

S6.2 Buckle release test procedure.

(a) After completion of the testing specified in S6.1 and before the buckle is unlatched, tie a self-adjusting sling to each wrist and ankle of the test dummy in the manner illustrated in Figure 4 to Standard No. 213 (§ 571.213), without disturbing the belted dummy and the child restraint system.

(b) Pull the sling that is tied to the dummy restrained in the child restraint system and apply the following force: 90 Newtons for a system tested with a 12-month-old dummy; 200 Newtons for a system tested with a 3-year-old dummy. For an add-on child restraint, the force is applied in the manner illustrated in Figure 4 to Standard No. 213 (§ 571.213) and by pulling the sling horizontally and parallel to the SORL of the SISA.

(c) While applying the force specified in S6.2(b), and using the device shown in Figure 8 of Standard No. 213 (§ 571.213) for pushbutton-release buckles, apply the release force in the manner and location specified in S6.2.1 of Standard No. 213 (§ 571.213), for that type of buckle. Measure the force required to release the buckle.

S7 Test dummies.

S7.1 Dummy selection. At NHTSA's option, any dummy specified in S7.1(a) or S7.1(b) may be selected for testing child restraint systems for use by children of the height or mass for which the system is recommended in accordance with S5.5 of Standard No. 213 (§ 571.213). A child restraint that meets the criteria in two or more of the following paragraphs may be tested with any of the test dummies specified in those paragraphs.

(a) A child restraint that is recommended by its manufacturer in accordance with S5.5 of Standard No. 213 (§ 571.213) for use either by children in a specified mass range that includes any children having a mass greater than 5 kilograms but not greater than 13.6 kilograms, or by children in a specified height range that includes any children whose height is greater than 650 millimeters but not greater than 870 millimeters, is tested with a CRABI 12-month-old test dummy conforming to 49 CFR part 572 subpart R.

(b) A child restraint that is recommended by its manufacturer in accordance with S5.5 of Standard No. 213 (§ 571.213) for use either by children in a specified mass range that includes any children having a mass greater than 13.6 kilograms but not greater than 18 kilograms, or by children in a specified height range that includes any children whose height is greater than 870 millimeters but not greater than 1100 millimeters, is tested with a 3-year-old test dummy (Q3s) conforming to 49 CFR part 572 subpart W.

S8 Dummy clothing and preparation.

S8.1 Type of clothing.

(a) 12-month-old dummy (CRABI) (49 CFR part 572, subpart R). When used in testing under this standard, the dummy specified in 49 CFR part 572, subpart R, is clothed in a cotton-polyester based tight fitting sweat shirt with long sleeves and ankle long pants whose combined weight is not more than 0.25 kilograms.

(b) 3-year-old side impact dummy (Q3s) (49 CFR part 572, subpart W). When used in testing under this standard, the dummy specified in 49 CFR part 572, subpart W, is clothed as specified in that subpart, except without shoes.

S8.2 Preparing dummies. When using the Q3s dummy, install the IR-TRACC on the test impact side according to 49 CFR part 572, subpart W. Before being used in testing under this standard, test dummies must be conditioned at any ambient temperature from 20.6° to 22.2 °C and at any relative humidity from 10 percent to 70 percent, for at least 4 hours.

S9 Positioning the dummy and attaching the belts used to restrain the child within the child restraint system and/or to attach the system to the SISA sliding seat.

S9.1 12-month-old dummy (CRABI) (49 CFR part 572, subpart R). Position the test dummy according to the instructions for child positioning that the manufacturer provided with the child restraint system under S5.6.1 or S5.6.2 of Standard No. 213 (§ 571.213), while conforming to the following:

(a) When testing rear-facing child restraint systems, place the 12-month-old dummy in the child restraint system so that the back of the dummy torso contacts the back support surface of the system. Attach all appropriate child restraint belts used to restrain the child within the child restraint system and tighten them as specified in S6.1.2 of this standard. Attach all appropriate belts used to attach the child restraint system to the SISA sliding seat and tighten them as specified in S6.1.2.

(b) When testing forward-facing child restraint systems, extend the dummy's arms vertically upwards and then rotate each arm downward toward the dummy's lower body until the arm contacts a surface of the child restraint system or the SISA. Ensure that no arm is restrained from movement in other than the downward direction, by any part of the system or the belts used to anchor the system to the SISA sliding seat.

(c) When testing forward-facing child restraint systems, extend the arms of the 12-month-old test dummy as far as possible in the upward vertical direction. Extend the legs of the test dummy as far as possible in the forward horizontal direction, with the dummy feet perpendicular to the centerline of the lower legs. Using a flat square surface with an area of 2,580 square mm, apply a force of 178 Newtons, perpendicular to the plane of the back of the standard seat assembly, first against the dummy crotch and then at the dummy thorax in the midsagittal plane of the dummy. Attach all appropriate child restraint belts used to restrain the child within the child restraint system and tighten them as specified in S6.1.2(d). Attach all appropriate belts used to attach the child restraint system (per S5.1.6) to the SISA sliding seat and tighten them as specified in S6.1.2.

(d) After the steps specified in paragraph (c), rotate each dummy limb downwards in the plane parallel to the dummy's midsagittal plane until the limb contacts a surface of the child restraint system or the standard seat assembly. Position the limbs, if necessary, so that limb placement does not inhibit torso or head movement in tests conducted under S6.

S9.2 3-year-old side impact dummy (Q3s) (49 CFR part 572, subpart W) in forward-facing child restraints. Position the test dummy according to the instructions for child positioning that the restraint manufacturer provided with the child restraint system in accordance with S5.6.1 or S5.6.2 of Standard No. 213 (§ 571.213), while conforming to the following:

(a) Holding the test dummy torso upright until it contacts the child restraint system's design seating surface, place the test dummy in the seated position within the child restraint system with the midsagittal plane of the test dummy head coincident with the center of the child restraint system.

(b) Extend the arms of the test dummy as far as possible in the upward vertical direction. Extend the legs of the dummy as far as possible in the forward horizontal direction, with the dummy feet perpendicular to the center line of the lower legs.

(c) For a child restraint system with a fixed or movable surface, position each movable surface in accordance with the instructions that the manufacturer provided under S5.6.1 or S5.6.2 of Standard No. 213 (§ 571.213). For forward-facing restraints, attach all appropriate child restraint belts used to restrain the child within the child restraint system and tighten them as specified in S6.1.2(d). Attach all appropriate belts or lower anchorage attachments used to attach the child restraint system to the SISA or to restrain the child and tighten them as specified in S6.1.2. For belt-positioning seats, attach all appropriate vehicle belts used to restrain the child within the child restraint system and tighten them as specified in S6.1.2(d).

(d) After the steps specified in paragraph (c) of this section, rotate each of the dummy's legs downwards in the plane parallel to the dummy's midsagittal plane until the limb contacts a surface of the child restraint or the SISA. Rotate each of the dummy's arms downwards in the plane parallel to the dummy's midsagittal plane until the arm is engaged on the detent that positions the arm at a 25-degree angle with respect to the thorax. For child restraint systems with a fixed or movable surface that does not allow the dummy's arm to be positioned at a 25-degree angle, rotate each dummy arm downwards in the plane parallel to the dummy's midsagittal plane until the arm contacts a surface of the child restraint system or the standard seat assembly.

S9.3 3-year-old side impact dummy (Q3s) (49 CFR part 572, subpart W) in rear-facing child restraints. Position the test dummy according to the instructions for child positioning that the restraint manufacturer provided with the child restraint system in accordance with S5.6.1 or S5.6.2 of Standard No. 213 (§ 571.213), while conforming to the following:

(a) Extend the arms of the test dummy as far as possible in the upward vertical direction. Extend the legs of the dummy as far as possible in the forward horizontal direction, with the dummy feet perpendicular to the center line of the lower legs.

(b) Place the Q3s dummy in the child restraint system so that the back of the dummy torso contacts the back support surface of the system. Place the test dummy in the child restraint system with the midsagittal plane of the test dummy head coincident with the center of the child restraint system. Rotate each of the dummy's legs downwards in the plane parallel to the dummy's midsagittal plane until the leg or feet of the dummy contacts the seat back of the SISA or a surface of the child restraint system.

(c) For a child restraint system with a fixed or movable surface, position each movable surface in accordance with the instructions that the manufacturer provided under S5.6.1 or S5.6.2 of Standard No. 213 (§ 571.213). Attach all appropriate child restraint belts used to restrain a child within the child restraint system and tighten them as specified in S6.1.2(d). Attach all appropriate belts or lower anchorage attachments used to attach the child restraint system to the SISA and tighten them as specified in S6.1.2.

(d) After the steps specified in paragraph (c) of this section, rotate each dummy arm downwards in the plane parallel to the dummy's midsagittal plane until the limb is positioned at a 25-degree angle with respect to the thorax. For child restraint systems with a fixed or movable surface that does not allow the dummy's arm to be positioned at a 25-degree angle, rotate each dummy arm downwards in the plane parallel to the dummy's midsagittal plane until the arm contacts a surface of the child restraint system or the standard seat assembly.

[87 FR 39310, June 30, 2022, as amended at 89 FR 81846, Oct. 9, 2024]