This SAE Recommended Practice establishes a consistently repeatable laboratory evaluation procedure and performance requirements in that evaluation for structures intended to provide operators with reasonable protection from such falling objects as trees and rocks. This recommended practice applies only to machines covered by SAE J1040c (ROPS). The evaluations are for resistance to localized penetration. The performance requirements, of a representative specimen within the manufacturer's specifications, are based on the performance of experience proven structures under the laboratory evaluation procedure. It is intended that all portions of this Recommended Practice shall be reviewed and revised as additional knowledge of FOPS Performance becomes available