This practice defines and prescribes how to calculate IRFI on aircraft movement areas in winter.

The local device is calibrated directly or indirectly to the reference device, thereby achieving harmonization of local friction devices to a common unit of measure regardless of the local friction device used.

The IRFI can be used by airport maintenance staff to monitor the winter frictional characteristics for surface maintenance actions.

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 under winter conditions.

1.2 The IRFI is the international friction index to be used for reporting the friction characteristics of airport movement areas.

1.3 The IRFI reported by this practice is a harmonized value of the pavement friction characteristics.

1.4 The IRFI obtained by using 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 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.