1.1 This practice covers the calculation of the International Runway Friction Index, IRFI, from measurements obtained by local friction-measurement devices on movement areas covered with ice and snow.

1.2 The IRFI is intended to provide an international unified friction index for use in harmonizing the output of devices used to measure the friction of airport movement areas during winter operations.

1.3 The IRFI reported by this practice is a harmonized value for reporting friction of movement areas.

1.4 The IRFI reported by this practice has not been extended to address the braking performance of an aircraft.

1.5 The values stated in SI units are to be regarded as the standard. The inch-pound values given in parentheses are provided for information only.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.