1、Designation: E 2100 04Standard Practice forCalculating the International Runway Friction Index1This standard is issued under the fixed designation E 2100; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the calculation of the InternationalRunway Friction Index, IRFI, from measurements obtained bylocal friction-mea
3、surement devices2on movement areas underwinter conditions.1.2 The IRFI is the international friction index to be used forreporting the friction characteristics of airport movement areas.1.3 The IRFI reported by this practice is a harmonized valueof the pavement friction characteristics.1.4 The IRFI
4、obtained by using this practice has not beenextended to address the braking performance of an aircraft.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are provided forinformation only.1.6 This standard does not purport to address all of thesafety
5、concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E 524 Specification for Standard Sm
6、ooth Tire for PavementSkid-Resistance TestsE 867 Terminology Relating to Vehicle-Pavement SystemsE 1551 Specification for Special Purpose, Smooth-TreadTire, Operated on Fixed Braking Slip Continuous FrictionMeasuring EquipmentE 1844 Specification for a Size 1034-5 Smooth-Tread Fric-tion Test TireE 1
7、859 Test Method for Friction Coefficient Measurementsbetween Tire and Pavement Using a Variable Slip Tech-niqueE 1960 Practice for Calculating International Friction Indexof a Pavement Surface3. Terminology3.1 Definitions:3.1.1 base surface, nthe type of surface evaluated; thereare four classes (1)
8、bare pavement dry, (2) bare pavement wet,(3) bare compacted snow and (4) bare ice.3.1.2 compacted snow, na compressed solid mass ofsnow, which is sufficiently strong to prevent a normally loadedtire operating in a rolling mode from penetrating to thepavement or breaking up the surface.3.1.3 device c
9、onfiguration, na term used to designate theentire test system as used for any friction measurement; itincludes type of device (force or torque measurements), tiretype, size and inflation pressure, slip ratio, normal load andbraking system control mode.3.1.4 harmonization, nthe adjustment of the outp
10、uts ofdifferent devices used for measurement of a specific phenom-enon so that all devices report the same value.3.1.5 ice, nwater with or without contaminants frozeninto a continuous solid body with or without cracks.3.1.6 IRFI reference device, na particular friction measur-ing device selected as
11、a benchmark or reference; it is used tocalibrate any local friction device to permit master or localfriction device values to be converted to IRFI values forselected base surfaces.3.1.7 local friction device, na particular friction testingdevice used at a given location to measure the friction level
12、 ofselected base surfaces; the friction values evaluated with thisdevice may be harmonized to IRFI values.3.1.8 master friction device, na particular friction mea-suring device selected as a secondary reference that has beencalibrated with the IRFI reference device; it is used to calibrateany local
13、friction device to permit local friction device valuesto be converted to IRFI values for selected base surfaces.3.1.9 movement area, nthat part of the airport (aero-drome) used for take-off, landing and taxiing of aircraft,consisting of the maneuvering area and the apron(s).3.1.10 For additional def
14、initions, see Terminology E 867.3.2 Definitions of Terms Specific to This Standard:1This practice is under the jurisdiction of ASTM Committee E17 on Vehicle-Pavement Systems and is the direct responsibility of Subcommittee E17.22 onMeasurement on Surface Characteristics of Airport/Aerodrome Movement
15、.Current edition approved Dec. 1, 2004. Published January 2005. Originallyapproved in 2000. Last previous edition approved in 2002 as E 2100 02.2In Tribology, friction-measuring devices are referred to as Tribometers.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AST
16、M Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.1 international runway fr
17、iction index (IRFI)a unifiedindex of friction that is harmonized to the value measured bythe IRFI reference device.4. Summary of Practice4.1 This practice outlines the procedure for calculating avalue designated as the International Runway Friction Index,IRFI. This index is related to the available
18、friction level of thesurface. The IRFI for a local friction device is calculated byconverting the measured friction value by means of a pre-established empirical relationship using the linear regressionmethod.4.2 The procedure as contained in this practice is applicableto base surfaces with no more
19、than 25 mm of loose snow or 12mm of slush.NOTE 1Some devices may not be able to measure at these depths.4.3 The details of the IRFI reference device are given inAppendix X2.1.4.4 Amaster friction device shall be a dedicated device usedfor calibration of local devices and shall not be used in ordinar
20、yfriction measurement service except when not practical.5. Significance and Use5.1 This practice defines and prescribes how to calculateIRFI on aircraft movement areas in winter.5.2 The local device is calibrated directly or indirectly to thereference device, thereby achieving harmonization of local
21、friction devices to a common unit of measure regardless of thelocal friction device used.5.3 The IRFI can be used by airport maintenance staff tomonitor the winter frictional characteristics for surface main-tenance actions.6. Measurement Requirements6.1 The local friction device shall be harmonized
22、 by con-ducting field-testing with the IRFI reference device (seeSection 7). The field test shall collect friction data for eachsurface class for which the local device can be used. When alocal friction device has different selectable modes of operation(for example: fixed or variable slip measuremen
23、t) each mode ofoperation shall be treated separately.6.2 The local friction device shall be operated according tothe standard test method of the device and the manufacturersinstructions for the device.6.3 The minimum length of the surface segment that shallbe used for producing a friction value shal
24、l be equal to 100 m.6.4 Average surface temperature shall be measured andreported (for runways each third).6.5 The friction values shall be reported digitally (withseparate data series for each segment) in one file for therunway. The file shall have record(s) ordered by segments.6.6 The operator sha
25、ll report the surface classes of thesegments.6.7 The local friction device shall be run within the range ofspeeds for which it was harmonized.7. Harmonization7.1 The local device shall be harmonized to report an IRFIby conducting parallel friction measurements on surfaces withthe reference device or
26、 a master device on surfaces similar tothose used to calibrate the master with the reference device. Aminimum of 10 surfaces covering a range of 0.1 to 0.7 asmeasured by the master device shall be included. Harmoniza-tion constants shall be determined for the speed at which thedevice normally operat
27、es.7.2 The master device shall be harmonized by conductingparallel friction tests with the IRFI reference device. All typesof surfaces shall be included. A minimum of 35 segmentscovering a friction range of 0.1 to 0.7 as measured by the IRFIreference device shall be included. The harmonization con-s
28、tants shall be determined at speeds at which the devicenormally operates. Maintain test speeds within 63 km/h (1.6knots, 1.5 mph).7.3 The measurements with the local friction device and theIRFI reference device or a master reference device shall betaken on a segment within 2 min of each other.7.4 Li
29、near regressions shall be of the following form (seeEq 1 and Eq 2):FRref5 A 1 B 3 FRmaster(1)FRmaster5 a 1 b 3 FRlocal(2)where:FRref= the friction value reported by the referencedevice,FRlocal= the local device measured value, andA, B = harmonization constants for the master device,anda, b = harmoni
30、zation constants for the local device.The correlation coefficient of the regression and the standarderror of estimate shall be reported. Typical values for devicesthat have been harmonized are given in Appendix X1. Theseresults were for specific local devices that were harmonizedduring the Joint Win
31、ter Runway Friction Program. They arenot applicable to other local friction devices or to other testspeeds.7.5 Subsequent measurements made by the local frictiondevice can be harmonized using the regression constants of thedevice (see Eq 3):IRFI 5 A 1 B 3 a 1 B 3 bFRlocal(3)7.6 Any time the local fr
32、iction device is recalibrated, newharmonization constants shall be determined. Harmonizationof master devices and local devices shall be conducted asfrequently as the time stability of the devices mandates.8. Calculation8.1 The runway is divided into segments (see Fig. 1). Theminimum length of the s
33、egment is 100 m and the maximum isone third of the runway length. The harmonized friction valuefor an individual segment is designated, irfi (that is, by italicsand lower case). The value, IRFI, for each third of the runwayor base surface is computed as a weighted average of irfi valuesas given by E
34、q 4.IRFI 51L(li3 irfii! (4)E2100042where:L = total length of the one-third distance, m, andli= the length of segment i,m.8.2 When all segment lengths are equal, simple averagingwill give the value for IRFI.8.3 IRFI for other movement areas are computed the sameway except they are not divided into th
35、irds.NOTE 2urThe calculated values depend on the sampling method and sample sizeof the standard test method of the device when operated according to themanufacturers instructions for the device and local airport measurementpractices. Comparisons of actual IRFI values for a runway from differentdevic
36、e types must be done with caution, especially between spot-measuring devices versus continuous-measuring device types on non-homogeneous surfaces or on surfaces with mixed surface classes.9. Report9.1 Field Friction ReportThe field report for each runwaytest shall contain data on the following items
37、:9.1.1 Airport and designation of runway or taxiway,9.1.2 Date and time of day,9.1.3 Reference to runway condition report,9.1.4 Distance from centerline tested,9.1.5 Achieved measuring speed,9.1.6 The average surface temperature for each third of therunway (optional),9.1.7 The friction value of each
38、 segment group computed asthe International Runway Friction Index, IRFI,9.1.8 The sample size of each segment group used forcomputing the International Runway Friction Index, IRFL, and9.1.9 The local friction device type and test configuration.9.2 Summary ReportTest results are entered in formsspeci
39、fied by the civil aviation authorities.APPENDIXES(Nonmandatory Information)X1. TABLE OF TYPICAL HARMONIZATION RESULTS FROM 1998-1999 JOINT WINTER RUNWAY MEASUREMENTPROGRAMX1.1 Table X1.1 illustrates typical harmonization resultswith the IRFI reference device only.FIG. 1 Illustration of a Segmented R
40、unwayTABLE X1.1 Table of Typical Harmonization Results from19981999 Joint Winter Runway Measurement ProgramHarmonizationConstantAHarmonizationConstantBCorrelationCoefficientRStandardError ofEstimate0.0565 0.4264 0.78 0.0230.0445 0.7635 0.83 0.0520.0879 0.8814 0.73 0.0450.0001 1.1109 0.82 0.0420.0907
41、 1.0231 0.92 0.0480.0226 0.7262 0.98 0.0340.0504 0.3923 0.77 0.0300.0598 0.7589 0.92 0.0340.1261 0.6727 0.67 0.044E2100043X2. DESCRIPTION OF THE IRFI REFERENCE DEVICEX2.1 GeneralX2.1.1 The IRFI reference device is a trailer (see Fig. X2.1)towed by a vehicle. It consists of a principal frame with two
42、wheels fitted on articulated arms. This frame supports anarticulated measuring frame equipped with a loaded measuringwheel and a hydraulically controlled braking system.X2.1.2 The measuring wheel can be equipped with varioustires. The standard tire is generally a smooth PIARC tire (1653 380).Aribbed
43、 tire or an aircraft tire of the same size can alsobe used. The wheel is loaded at a nominal load of 1800 N anda nominal inflation pressure of 150 KPa. The device is towedat a constant speed (0 to 130 km/h) and the measuring wheel isbraked at a slip that can be set between 0 (free rolling) and100 %
44、(locked wheel).X2.2 Braking SystemX2.2.1 The measurement wheel drives a hydraulic pumpthrough a system of pulleys and a belt. The flow of oil isreturned to the oil tank by the pump. A servo value on thedischarge side of the pump controls the oil outflow. The servovalve is controlled by a signal comi
45、ng from an electroniccontroller. The electronic controller compares signals (rota-tional speed) given by reference wheels (pulse generator) andthe measurement wheel (tachometer).X2.2.2 A computer, controlled by the operator, sets the slipratio that the controller transforms to a signal to drive the
46、servovalve that controls the outflow of the pump. In this way, theoperator can set the slip ratio for the measuring wheel at anytime.FIG. X2.1 IRFI reference device as designed, built, and operated by the French Civil Aviation Administration, S.T.B.A. Airports and AirForce Bases Engineering.E2100044
47、X2.2.3 The computer software allows a manual or auto-matic control of the braking action of the measuring wheel.X2.3 Measuring SystemX2.3.1 The combined signals given by the pulse generators,which are parts of the braking control system, are used for timeand distance related acquisition of measuring
48、 signals given bythe sensors installed on the device.X2.3.2 Vertical load on measuring wheel (FV)A loadsensor is located on the rear of the device, at the top of theshock absorber between the oil tank frame and the end of themeasuring frame. This sensor captures 70 % of the dynamicload on the wheel.
49、 This signal is used for real time calculationof friction coefficient and a global drag coefficient.X2.3.3 Friction coeffcient, MuTA torque transducer islocated between the front pulley receiving the driving belt andthe hydraulic pump. This transducer senses the braking torque,T, developed by the friction in the contact area between tire andpavement. The friction coefficient is computed in real time asMuT= (T/r)/FV.X2.3.4 Drag coeffcient, MuDTwo force transducers arelocated on each side of the bearing frame of the device. Theysense the horizontal force TDprodu
