1、Designation: D 2985 92 (Reapproved 2006)Standard Test Method forColor of Asbestos1This standard is issued under the fixed designation D 2985; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in pa
2、rentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of color,whiteness, and yellowness of asbestos by means of a photo-electric reflectometer.1.2 The test m
3、ethod is applicable to all grades and varietiesof homogeneous milled asbestos.1.3 This test method may be applied to samples that are notdry or homogeneous, or that contain impurities or adulterants.However, in such cases, results may not be comparable withthose obtained on clean dry samples.1.4 To
4、obtain similar results from spectrophotometers, seeTest Method E 308.1.5 The values stated in SI (metric) units are to be regardedas standard. The inch-pound (customary) units are for infor-mation only.1.6 WarningBreathing of asbestos dust is hazardous.Asbestos and asbestos products present demonstr
5、ated healthrisks for users and for those with whom they come into contact.In addition to other precautions, when working with asbestos-cement products, minimize the dust that results. For informa-tion on the safe use of chrysotile asbestos, refer to “Safe Use ofChrysotile: A Manual of Preventive and
6、 Control Measures.”21.7 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 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to
7、 use.2. Referenced Documents2.1 ASTM Standards:3D 2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesD 2590 Test Method for Sampling Chrysotile AsbestosD 2946 Terminology for Asbestos and AsbestosCementProductsD 3879 Test Method for Sa
8、mpling Amphibole AsbestosE3 Guide for Preparation of Metallographic SpecimensE 259 Practice for Preparation of Pressed Powder WhiteReflectance Factor Transfer Standards for Hemisphericaland Bi-Directional GeometriesE 308 Practice for Computing the Colors of Objects byUsing the CIE System3. Terminolo
9、gy3.1 Definitions of Terms Specific to This Standard:43.1.1 black, adj, adjcolor name applied to opaque objectsthat are highly absorbing throughout the visible spectrum.3.1.2 CIE, nacronym for International Commission onIllumination, which in French is Commission Internationale delEclairage.3.1.3 CI
10、E observer, nSee observer, standard, CIE 1931and observer, supplementary, CIE 1964.3.1.4 CIE source C, nSee standard source.3.1.5 color, psychophysical, ncharacteristics of a colorstimulus (that is, light producing a sensation of color) denotedby three dimension values such as three tristimulus valu
11、es.3.1.6 daylight 0.785 rad, 0 rad (45, 0) luminous direc-tional reflectancedaylight 0.785 rad, 0 rad (45, 0) lumi-nous directional reflectance (for brevity called reflectance) isthe ratio of the luminous flux from a specimen illuminated at anangle of 0.785 rad (45) by CIE standard source C5(average
12、daylight) and viewed perpendicularly by the CIE standardobserver, to the luminous flux from the standard magnesiumoxide layer, similarly illuminated and viewed (Note 1). Thecombination of illumination at 0.785 rad (45) and viewing at0 rad (0) (perpendicularly) has been selected as being repre-sentat
13、ive of average conditions of illuminating and viewing.The property of reflectance determines which of two specimenswill appear lighter when viewed in average daylight at an angleat which the observation of highlights is avoided.NOTE 1These conditions of illumination and observation may be1This test
14、method is under the jurisdiction of ASTM Committee C17 onFiber-Reinforced Cement Products and is the direct responsibility of SubcommitteeC 17.03 on AsbestosCement Sheet Products and Accessories.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1971. Last previous edi
15、tion approved in 2002 as D 2985 92 (2002)e1.2Available from The Asbestos Institute, http:/ 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
16、 page onthe ASTM website.4Taken in part from Procedure No. B5-9 of Socete Asbestos Ltee, withpermission.5CIE standard sources and functions are defined in Test Method E 308.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.interchanged
17、 without affecting the results.3.1.7 glos, nangular selectivity of reflectance of surface-reflected light responsible for the degree to which reflectedhighlights or images of objects may be seen as superimposedon a surface.3.1.8 gloss, specular, nratio of flux reflected in a speculardirection to inc
18、ident flux for specific source and receptorapertures (usually measured relative to a standard of specifiedindex of refraction).3.1.9 gray, ncolor name applied to achromatic stimuli ofmoderate relative luminance.3.1.10 green, adjhue name applied to light of wave-lengths from 495 to 550 nm.3.1.11 hue,
19、 nattribute of color perception by means ofwhich objects are judged to be red, yellow, blue or intermediatebetween some adjacent pair of these. Hue is a matter of socialconsensus as opposed to an assigned frequency range.3.1.12 ideal black, nobject or material that absorbs alllight impinging on it.3
20、.1.13 illuminant, nincident luminous flux specified onlyby its spectral distribution. (The spectral composition of anilluminant may differ from the source because of spectralmodification by such means as absorption or refraction bymediae enclosing the source or by reflection from otherobjects. See d
21、efinition of source. The CIE standard illuminantsare Illuminant C and Illuminant D6500, each representingaverage daylight, and Illuminant A, 2854K).3.1.14 light, nelectromagnetic radiation in the spectralrange detectable by the normal human eye (approximately 380to 760 nm).3.1.15 light, nradiant ene
22、rgy evaluated according to theCIE photopic spectral luminous efficiency function.3.1.16 light, adjhighly reflecting, as in the term lightgreen.3.1.16.1 DiscussionFor given conditions of illuminationand surface texture, a more reflective surface is perceived aslighter in color than a less reflective
23、but otherwise identicalsurface.3.1.17 luminous, adjindicates that the radiant flux isevaluated by weighting according to the luminous efficiencyfunction of the CIE 1931 standard observer.3.1.18 luminous reflectance, nSee reflectance, luminous.3.1.19 observer, standard, CIE 1931, nhypothetical ob-ser
24、ver based on color mixture data obtained for a 2 field ofview for 17 observers, adopted by the CIE in 1931.3.1.20 observer, supplementary, CIE 1964, nhypotheticalobserver based on color mixture data obtained for a 10 field ofview for 76 observers, adopted by the CIE in 1964.3.1.21 photoelectric colo
25、r meter, ncolor-stimulus-measuring instrument using photoelectric detectors in whichsource-filter-detector response characteristics are adjusted sothat the instruments read directly the tristimulus values orrelated quantities.3.1.22 preferred white, nthe white color, usually bluish,that is judged by
26、 a given group of observers looking at a givenseries of specimens to be the whitest color attainable.3.1.23 reflectance, luminous, nratio of luminous fluxreflected by a specimen to that incident on it.3.1.24 reflection, nprocesses by which incident fluxleaves a surface or a medium from the incident
27、side.3.1.25 reflection, diffuse, nprocess by which incident fluxis distributed by reflection over a wide range of angles.3.1.26 regular, adjused to indicate flux transmitted orreflected in the image-forming state (the adjective specular isusually used to indicate regular mirror-reflected flux).3.1.2
28、7 source, nthat which furnishes light or other radia-tion; real device by which radiant flux is produced. (Seeilluminant.)3.1.28 source, CIE standard, nSee standard source.3.1.29 spectral, adjindicates either a function of wave-length as in spectral transmittance, or spectral concentration, asin spe
29、ctral flux.3.1.30 specular, adjsame as regular when applied toreflection.3.1.31 specular gloss, nSee gloss, specular.3.1.32 standard observer, nSee observer, standard.3.1.33 standard, primary, none whose calibration is de-termined by measurement according to specified parameters.3.1.34 standard, sec
30、ondary, nstandard calibrated by ref-erence to another standard such as a primary, reference,laboratory or working standard.3.1.35 standard source, nlight source whose spectralenergy distribution is known or defined. (The CIE standardsources to represent incandescent-lamp light, sunlight, anddaylight
31、, are designated A, B, and C, respectively.)3.1.36 texture, adjin evaluating the color of a surface,structural quality of a surface determined by the topography ofits constituents.3.1.37 viewing conditions, nthe conditions under which avisual observation is made, including the angular substance ofth
32、e specimen at the eye; the geometric relationship of source,specimen and eye; the photometric and spectral character of thefield of view surrounding the specimen; and the state ofadaptation of the eye.3.1.38 white, adjcolor name most usually applied toopaque, highly reflecting, highly diffusing, vis
33、ually huelessspecimens.3.1.39 whitenessthe term “whiteness” is widely used todesignate the degree to which a near-white surface approaches“perfect white,” defined as a 100 % reflectance over the wholevisible spectrum. Other terms used for this property are“lightness” or“ luminous apparent reflectanc
34、e.” The concept ofwhiteness is not only applicable to near-white surfaces but alsoto dark and colored surfaces. Whiteness may be defined as thegrading which an observer would assign to the surface,irrespective of its color or hue, when compared under daylightconditions against a scale of grays rangi
35、ng from white to black.3.1.40 yellow, adjhue name applied to light wavelengthsfrom 572 to 783 nm and to visually similar stimuli.3.1.41 yellownessa yellowed or tan discolored asbestosmay have the same degree of whiteness on the gray scale as agray asbestos. It is thus necessary to measure an index o
36、fyellowness for such cases, and this may be calculated arbi-trarily from reflectance measurements using tristimulus filters.Use the following relationship for asbestos:yellowness factor 5 A 2 B!/G (1)D 2985 92 (2006)2where:A = reflectance with the amber tristimulus filter,6B = reflectance with the b
37、lue tristimulus filter, andG = reflectance with the green tristimulus filter.3.1.42 For terms relating to asbestos fibers, refer to Termi-nology D 2946.4. Summary of Test Method4.1 Specimens are pressed into a pellet and the luminousreflectance is measured by means of a simple reflectometerfitted wi
38、th an incandescent source, and a photoelectric reflec-tometer.4.2 Instructions are included for use of the suppressed zerotechnique to improve precision.4.3 The use of tristimulus color filters permitting the deter-mination of whiteness, yellowness, and CIE7color-order val-ues, is covered.5. Signifi
39、cance and Use5.1 The color of asbestos is of commercial significancewhen it is to be incorporated into products, the color of whichis affected by the color of the asbestos, and for which colorspecifications must be met.5.2 Whiteness is required of asbestos for use in white orpale-colored products.5.
40、3 Yellowness is significant in asbestos for use in pastel-colored products where discolored asbestos may prevent at-tainment of certain shades and hues detector.6. Apparatus6.1 The apparatus shall consist of a photoelectric reflecto-meter having source, filter, and receptor characteristics suchthat
41、it will measure reflectance accurately to within 1.0 % offull-scale reading. The reflectometer shall have the followingcharacteristics:6.1.1 Spectral CharacteristicsThe spectral energy distri-bution of the illuminator and the spectral sensitivity of thereceptor, in combination, shall provide the equ
42、ivalent ofillumination by CIE standard source C and observation by theCIE standard observer.6.1.2 Geometric CharacteristicsIllumination shall bewithin 0.0698 rad (4) of, and centered about, a direction of0.785 rad (45) from the perpendicular to the test surface;viewing shall be within 0.262 rad (15)
43、 of, and centered about,the perpendicular (Note 1).6.1.3 Any instrument that meets the apparatus specificationsand the precision requirements stated in Section 13 may beused. In general, commercial instruments do not conformexactly to the apparatus requirements. The suitability of agiven instrument
44、depends in large measure on its response tothe spectral selectivity range of asbestos, and on the availabil-ity of standards of similar reflectance and spectral character.Instruments that have been found satisfactory include: theHunter Multi-purpose Reflectometer; the Gardner (Hunter)Photometric Uni
45、t with 0.785 rad, 0 rad (45, 0) reflectancehead; and the General Electric Reflection Meter.6.2 Standards:6.2.1 Primary StandardThe primary standard for reflec-tance measurements is a layer of MgO freshly prepared inaccordance with Practice E 259. It is assigned a value of 100for the conditions of 0.
46、785 rad (45) illumination and perpen-dicular view (Note 1).6.2.2 Secondary StandardsPorcelain enameled metalplaques or other materials known to be reasonably permanentin reflectance, and of uniform surface, may be calibrated andused as secondary reflectance standards.NOTE 2Secondary standards of por
47、celain enamel may be obtainedfrom the National Bureau of Standards,8the Henry A. Gardner Labora-tory,9or the Photovolt Corp. Experience has shown that these secondaryreflectance standards are reasonably permanent if abrasion is avoided.Plaques stored for a year or more may develop efflorescence (blo
48、om)noticeable on black plaques, which can be removed by washing with mildsoluble soap and water.6.2.3 Standards with reflectance values as close as possibleto the values of the unknowns are recommended.6.3 Tristimulus Filters,6including amber, blue, and green,to fit the reflectometer source and dete
49、ctor.6.4 Piston and Cylinder Mold, for pressing the asbestosspecimens into pellets with a diameter of approximately 28.6mm (1.125 in.). The height of the mold cavity may beapproximately 63 mm (2.5 in.). The piston face must bepolished. Any slight texture or presence of oxidation at thepiston face may impress a texture onto the asbestos specimen(particularly to very highly fiberized grades of asbestos), andsuch texture may affect light reflectance significantly. Thepoli
