Marking the impact test line
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
Prior to testing, the impact test line shall be determined for each helmet in the following manner.
(a) Position the helmet on the appropriate headform as specified by the manufacturer's helmet positioning index (HPI), with the brow parallel to the basic plane. Place a 5-kg (11-lb) preload ballast on top of the helmet to set the comfort or fit padding.
(b) Draw the impact test line on the outer surface of the helmet coinciding with the intersection of the surface of the helmet with the impact line planes defined from the reference headform as shown in:
(1) Figure 4 of this part for helmets intended only for persons 5 years of age and older.
(2) Figure 5 of this part for helmets intended for persons age 1 and older.
(c) The center of the impact sites shall be selected at any point on the helmet on or above the impact test line.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.