1、Designation: F2508 161An American National StandardStandard Practice forValidation, Calibration, and Certification of WalkwayTribometers Using Reference Surfaces1This standard is issued under the fixed designation F2508; the number immediately following the designation indicates the year oforiginal
2、adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEEditorially corrected footnote 4 in August 2017.1. Scope1.1 This practice i
3、s intended to establish the procedures forvalidation, calibration, and certification of walkway tribom-eters.1.2 This practice provides a walkway tribometer supplierwith a procedure and suite of reference surfaces to validate hiswalkway tribometer by properly ranking and differentiating thesurfaces.
4、1.3 This practice provides the user of a walkway tribometerwith a procedure and suite of reference surfaces to testcalibration of his instrument.1.4 This practice provides a procedure through which anentity may certify a walkway tribometer model, signifying thatthe walkway tribometer model has a com
5、pleted and docu-mented validation and interlaboratory study.1.5 This practice describes the necessary materials,specifications, and the cleaning process for reference materials,as well as the requirements for the validation of a supplierswalkway tribometer and calibration of a users walkwaytribomete
6、r.1.6 This practice applies to walkway tribometers withoutreference to the nature of the scale of the readings produced bythem. The scale used in the reports of validation and calibrationmust be the same, and are to be those of the instrument ordefined for the instrument.1.7 The values stated in SI
7、units are to be regarded asstandard. The values given in parentheses are for informationonly and are not considered standard.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish app
8、ro-priate safety, health and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDe
9、velopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1349 Practice for RubberStandard Conditions for Test-ingD3244 Practice for Utilization of Test Data to Deter
10、mineConformance with SpecificationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodF1646 Terminology Relating to Walkway Safety and Foot-wear3. Terminology3.1 For terms used in this practice not identified herein, referto Terminology F1646.3.2 Definiti
11、ons:3.2.1 paired t-test, na test of statistical significance basedon the use of students t-distribution and used to compare twosample means (see Annex A2).3.2.2 supplier, nany individual, agent, company,manufacturer, or organization responsible for the walkwaytribometer prior to receipt by the user.
12、 D32443.2.3 test foot, nshoe bottom material or surrogatemounted on the walkway tribometer that comes into contactwith the surface being tested.3.2.4 walkway tribometer, nany apparatus used to mea-sure the frictional forces acting at an interface between awalkway surface and shoe material.1This prac
13、tice is under the jurisdiction of ASTM Committee F13 on Pedestrian/Walkway Safety and Footwear and is the direct responsibility of SubcommitteeF13.10 on Traction.Current edition approved July 1, 2016. Published July 2016. Originally approvedin 2011. Last previous edition approved in 2015 as F2508 15
14、. DOI: 10.1520/F2508-16E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100
15、Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Rec
16、ommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.4.1 DiscussionA judgement of the adequacy of thesefrictional forces acting on a walkway surface/shoe surfaceinterface is the basis for an assessment of slip propertiesrelative to human locomotion.3.3
17、 Definitions of Terms Specific to This Standard:3.3.1 calibration, nthe set of operations that establishes,under specified conditions, the relationship between the valuesobtained by a walkway tribometer and the correspondingsupplier reference values.3.3.2 certification test method, na specific test
18、method thatis used for all walkway tribometer operational tasks in thispractice performed as part of a certification.3.3.3 laboratory, na combination of one individual,uniquely identifiable walkway tribometer, one individual,uniquely identifiable test foot, and one operator, none of which(or whom) m
19、ay be reused for the same purpose in theinterlaboratory study being conducted.3.3.4 reference surfaces (RSs), nspecified materials, iden-tified in Section 7, that have an experimentally demonstratedslip properties for a select population of pedestrians and serveas references for walkway tribometer m
20、easurements.3.3.5 validation, nthe set of operations that establishes,under specified conditions, the proper ranking and differentia-tion of reference surfaces by a walkway tribometer.4. Summary of Practice4.1 This practice establishes a procedure to: (1) validatewalkway tribometer models against a
21、human gait-based refer-ence system, (2) calibrate each individual walkway tribometersof a validated model against published suppliers referencevalues (as defined in 9.1, Eq 4), and (3) certify that thetribometer model has completed a documented validation andinterlaboratory study.4.2 This practice p
22、rovides for validation and calibration ofwalkway tribometers as a means of verifying their relationshipto reference surfaces and verifying a particular device contin-ues to produce consistent results. Certification, if conducted,formally documents the methods, data, and results of avalidation and in
23、terlaboratory study.4.3 The method of ranking walkway surface slip propertiesusing a limited population of ambulating human subjects issupported by a peer-reviewed study.34.4 Validation consists of a series of 24 tests on eachreference surface from this practice. A walkway tribometermodel is conside
24、red valid if it ranks the four reference surfacesfrom this practice in the proper order with statistically signifi-cant differentiation between results obtained for each surface.Validation is intended to be accomplished for each walkwaytribometer model when it is initially introduced and is to beacc
25、omplished by or on behalf of the supplier and madeavailable to each user.4.5 Calibration for a specific walkway tribometer requires aseries of 16 tests on each of the reference surfaces from thispractice. A specific walkway tribometer is considered withincalibration if the bias of the mean test valu
26、es for each surfacefalls within the 95 % confidence interval for the walkwaytribometer model as established by the validation tests (asdefined in 9.1, Eq 4).5. Significance and Use5.1 To be meaningful, walkway tribometer results mustcorrelate the slip characteristics of a surface or contaminant, orb
27、oth, to the actual propensity for human slips. To achieve thisgoal, walkway tribometer models must be validated against astandard with relevance to human ambulation.5.2 This practice prescribes a series of reference surfaceswith known relative slip potential ranging from very high tolow (as defined
28、by laboratory conditions only) upon whichwalkway tribometer models can be validated. The relative slippotential of each reference surface was established from humansubject walking trials.35.3 The following should be considered in applying thevalidation and calibration obtained by this practice:5.3.1
29、 The scientific study upon which the validation processis based was conducted with a select population of youngadults (mean age 26 years) who were free from gait deviationswhile walking in a straight path on a level surface with a meanwalking velocity of 2.18 m/s. This walking velocity is fasterthan
30、 the average walking velocity for the general populationwhich includes a much wider age range with greater variabil-ity; thus, the study sample population of pedestrians andconditions is not representative of the larger general populationof pedestrians.5.3.2 All subjects walked in Oxford-style shoes
31、 whose soleswere constructed of smooth styrene butadiene rubber (SBR)with 75A Shore hardness. The shoe style and sole material isnot representative of all combinations available in the market-place.5.3.3 The reference surfaces defined in this practice are notrepresentative of all walkway surfaces. T
32、he outcome of thevalidation practice reflects performance on the type of refer-ence surfaces and surface conditions defined in this practiceonly. Validation and calibration of a walkway tribometer asdefined by this practice does not imply validation and calibra-tion under all combinations of test fo
33、ot materials and walkwaysurfaces.5.3.4 The validation and calibration procedure defined bythis practice is not intended to establish a “safe threshold”value for any walkway surface.6. Apparatus6.1 The walkway tribometer shall be free of defects andoperational throughout its range. Refer to the walkw
34、ay tribom-eter instruction manual to ensure proper operation and instru-ment condition before the validation and calibration process.6.2 Test Foot Designation and Condition:3Powers, C. M., Blanchette, M. G., Brault, J. R., Flynn, J., and Siegmund, G. P.,“Validation of Walkway Tribometers: Establishi
35、ng a Reference Standard,” Journalof Forensic Sciences, Vol. 55, No. 2, March 2010, pp. 366370.F2508 16126.2.1 The supplier must provide test foot material,dimension, storage, and service life specifications. The speci-fications shall be sufficient to permit procurement of anexemplar test foot.6.2.2
36、A uniquely numbered test foot, meeting the suppliersmaterial and dimensional specifications shall be provided withthe walkway tribometer being tested.6.2.2.1 The calibration results shall apply only to the walk-way tribometer/test foot combination tested.6.2.3 Prepare the test foot as prescribed by
37、the walkwaytribometer supplier or by a fully documented procedure in-cluded in the validation or calibration report.7. Reference Surfaces (RSs)47.1 Reference Surfaces:7.1.1 RS APolished black granite whose surface beneaththe test foot is covered with a continuous film of 0.04 % byvolume solution of
38、Triton X-1005(nonionic surfactant) indistilled water (that is, 200 L of Triton X-100 per 500 mL ofdistilled water).7.1.2 RS BPorcelain whose surface beneath the test foot iscovered with a continuous film of distilled water.7.1.3 RS CVinyl composition tile whose surface beneaththe test foot is covere
39、d with a continuous film of distilled water.7.1.4 RS DCeramic whose surface beneath the test foot iscovered with a continuous film of distilled water.7.2 Each RS shall be permanently marked to designate itsreference class (that is, “A”, “B”, “C”, “D”).7.3 Reference surfaces shall be stored in a mann
40、er thatprevents deformation and contamination.7.4 Reference surfaces should not be used for validation orcalibration testing after 5 years from date of purchase.8. Procedure8.1 EnvironmentThe validation and calibration test shallbe performed at a humidity level of 50 6 5 % and atemperature range of
41、23 6 2C (73.4 6 3.6F) (derived fromPractice D1349).8.2 Reference Surface PreparationThe reference surfaceshall be free from visible dents, cracks, voids, or othersignificant blemishes.8.2.1 Cleaning:8.2.1.1 No surface treatment except as specified in thissection is permitted.8.2.1.2 Prepare a 0.05 %
42、 by volume solution of liquidsodium lauryl sulfate in distilled water (that is, 250 L ofsodium lauryl sulfate per 500 mL of distilled water).8.2.1.3 Dip a clean soft-bristled nylon brush in the cleaningsolution and gently scrub in a circular pattern the entirereference surface for a minimum of 10 s.
43、 Reapply the cleaningsolution and repeat the minimum 10-s scrubbing two times.8.2.1.4 Rinse the surface thoroughly with distilled water,ensuring that no visible suds or soap residues remain.8.2.1.5 Prepare an ethanol solution containing equal partsdenatured ethanol in distilled water.8.2.1.6 Dip a c
44、lean soft-bristled nylon brush, different fromthat used in 8.2.1.3, in the ethanol solution and gently scrub thereference surface for 10 s.8.2.1.7 Dry the reference surface with dry and oil-freecompressed air or air dry if compressed air is not available.Any visible contamination remaining after thi
45、s step willdisqualify the reference surface for use.8.2.1.8 Ensure that handling of the reference surface doesnot introduce contaminants to the surfaces, including exposingthe surfaces to contact of human skin.8.2.1.9 The cleaning procedure should be performed beforeeach testing session.8.3 Referenc
46、e Surface MountingMount the reference sur-face onto a flat and rigid substrate that prevents movement ofthe reference surface parallel to the test plane of the walkwaytribometer during testing. Select a substrate that will notdeform during wet testing.8.4 Walkway Tribometer Validation TestingUsing t
47、hewalkway tribometer being validated and the test foot preparedin 6.2.3, perform 24 tests in accordance with a uniquelyidentifiable version of the walkway tribometer suppliers op-erating instructions or any other formal procedure in the testarea of each of the four reference surfaces that have beenp
48、repared in accordance with 8.2. Of the 24 tests, perform 6 ineach of 4 orthogonal directions, that is, at 0, 90, 180, and 270relative to an arbitrarily defined direction on the referencesurface. Record the results of all tests as specified in Section10.9. Analysis of Results and Walkway TribometerVa
49、lidation9.1 For the 24 tests on each reference surface, calculate themean X!, standard deviation (SD), standard error (SE)ofthemean, and 95th percentile confidence interval (CI) for thewalkway tribometer test results for each reference surfaceusing Eq 1 through Eq 4, respectively:X51n(i51nxi! (1)where:n = number of measurements (24), andxi= test resultSD 51n 2 1(i51nxi2 xH!2(2)SE 5SD=n(3)95th percentile CI 5 X61.96 3SE! 5 X2 1.96 3SE! to X11.963SE! (4)4Available from ASTM International Headquarters. Order Adjunct No.ADJF2508CS. Origi
