Interpretation ID: 7854-2
1311 N. 35th St.
Seattle, WA 98103
Dear Mr. McAusland:
This responds to your letter asking whether your design of an infant seat would comply with S5.2.4 of Federal Motor Vehicle Safety Standard No. 213, Child Restraint Systems. You state that your infant seat would have a frame made from 1/4 inch thick polyethylene sheet, and that all the edges of the frame are rounded to a radius of 1/8 inch. As discussed below, the design would not comply if the edges of the seat frame are contactable by the infant dummy's head or torso during the standard's dynamic test.
Some background information on Federal motor vehicle safety laws and regulations may be helpful. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., Safety Act) authorizes this agency to issue safety standards applicable to new motor vehicles and items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead, the Safety Act establishes a "self- certification" process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. The following represents our opinion based on the facts set forth in your letter.
Standard No. 213 specifies requirements for child restraint systems used in motor vehicles and aircraft, to reduce the number of children killed or injured in motor vehicle crashes and in aircraft. S5.2.4, "Protrusion limitation," of Standard No. 213 states:
Any portion of a rigid structural component within or underlying a contactable surface, or any portion of a child restraint system surface that is subject to the requirements of S5.2.3 [the head impact protection requirements for infant seats], shall, with any padding or other flexible overlay material removed, have a height above any immediately adjacent restraint system surface of not more than 3/8 inch and no exposed edge with a radius of less than 1/4 inch. (Emphasis added.)
The term "contactable surface" is defined in S4 of the standard as "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."
Under S5.2.4, any edges of a rigid structural component within or underlying a surface that can be contacted by the head or torso of the appropriate test dummy during Standard No. 213's dynamic test must have a radius of at least 1/4 inch. Since the frame edges of your infant seat have a radius of only 1/8 inch, the seat would not comply with S5.2.4 if the surfaces overlying those edges can be contacted by the infant dummy during the dynamic test.
You ask whether, since side loading is not specified in Standard No. 213, can you conclude that there is no way that the child's head or torso could contact the sides of the frame, i.e., that the surfaces overlying those edges cannot be contacted by the infant dummy during the dynamic test. We assume that you believe the infant's head and torso are unlikely to contact the frame's edges in the 213 dynamic test since, due to the forward motion of the test, the dummy's components are likely to move forward and rearward, rather than laterally.
I note that, for purposes of compliance testing, NHTSA would determine whether the surfaces are contactable surfaces for the purposes of S5.2.4 by observing a dynamic test, conducted according to the procedures in Standard No. 213. With respect to the issue of what information or analysis would be sufficient, for purposes of certification, for you to conclude that the surfaces overlying those edges cannot be contacted by the infant dummy during the dynamic test, manufacturers must have some basis for their certification that a product complies with all applicable safety standards. However, this does not necessarily mean that a manufacturer must conduct the specific tests set forth in an applicable standard. Certifications may be based on, among other things, engineering analyses, actual testing, and computer simulations.
You should be aware, however, that the direction of dummy movement during the Standard No. 213 dynamic test depends on many variables other than the direction of the test, such as the performance of the restraint's belt system. For example, in the event a child seat's upper torso restraint slipped off the dummy's shoulder in the dynamic test, the dummy could move laterally and strike the sides of the restraint system. You should consider all of the variables that could affect the dummy's performance when determining whether frame contact can occur.
I also note that manufacturers of motor vehicles and motor vehicle equipment are subject to the defect provisions of the National Traffic and Motor Vehicle Safety Act. Infant restraints are involved in real-world crashes other than the frontal impacts simulated in Standard No. 213. If data indicated that a child seat exposed occupants to an unreasonable risk of injury, such as sharp edges resulting in injuries in a side crash, the agency might conduct a defect investigation which could lead to a safety recall.
Enclosed is an information sheet which provides additional information for new manufacturers of motor vehicles and motor vehicle equipment. If you have further questions, please call Ms. Deirdre Fujita of my staff at (202) 366- 2992.
Sincerely,
Paul Jackson Rice Chief Counsel
Enclosure
ref:213 d:12/16/92