1、Designation: D1118/D1118M 95 (Reapproved 2017)Standard Test Method forMagnetic Rating of Asbestos Fiber and Asbestos Textiles1This standard is issued under the fixed designation D1118/D1118M; the number immediately following the designation indicates theyear of original adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the procedure for the determi-nation of the magnetic rating of asbestos f
3、iber and asbestostextile products. This test method is used primarily for testingasbestos insulating materials.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem sh
4、all be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 WarningBreathing of asbestos dust is hazardous.Asbestos and asbestos products present demonstrated healthrisks for users and for those with whom they come into contact.In a
5、ddition to other precautions, when working with asbestos-cement products, minimize the dust that results. For informa-tion on the safe use of chrysoltile asbestos, refer to “Safe Useof Chrysotile Asbestos: A Manual on Preventive and ControlMeasures.”21.4 This standard does not purport to address all
6、 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 use. For specific safetyhazard, see .1.5 This international standard
7、 was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Refer
8、enced Documents2.1 ASTM Standards:3D123 Terminology Relating to TextilesD2100 Specification for Asbestos Textiles Used for Electri-cal Insulating PurposesD2590 Test Method for Sampling Chrysotile AsbestosD2946 Terminology for Asbestos and AsbestosCementProductsD2947 Test Method for Screen Analysis o
9、f Asbestos FibersD3879 Test Method for Sampling Amphibole Asbestos(Withdrawn 2009)4E11 Specification for Woven Wire Test Sieve Cloth and TestSieves2.2 ASTM Adjuncts:Metallic Analyzer Drawings53. Terminology3.1 For definitions of other textile terms used in this testmethod, refer to Terminology D123.
10、 For terms relating toasbestos, refer to Terminology D2946.3.2 Definitions:3.2.1 asbestos fiber, nThe hydrous magnesium silicateserpentine mineral designated as chrysotile and having theempirical formula Mg3Si2O5(OH)4.3.2.2 atmosphere for testing textiles, nfor asbestos, airmaintained at a relative
11、humidity of 50 6 2 % at 70 6 2F 216 1C.3.2.3 magnetic rating (MR), nan empirical value reflect-ing the effect of the magnetic particles, such as magnetic ironcompounds, in asbestos material as measured by a magneticeffect analyzer. It is not a quantitative measure of the magneticparticles in the mat
12、erial. Magnetic rating is affected by the1This test method is under the jurisdiction of ASTM Committee C17 onFiber-Reinforced Cement Products and is the direct responsibility of SubcommitteeC17.03 on Asbestos - Cement Sheet Products and Accessories.Current edition approved June 1, 2017. Published Ju
13、ly 2017. Originally approvedin 1950. Last previous edition approved in 2009 as D1118/D1118M 95(2009)1.DOI: 10.1520/D1118_D1118M-95R17.2Available from The Asbestos Institute, http:/ referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. Fo
14、r Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.5Available from ASTM International Headquarters. Order Adjunct No.ADJD1118. Original adjunct produced
15、 in 1986.Copyright ASTM International, 100 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
16、 of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1quantity, concentration, particle size, shape, and orientation ofthe magnetic particles in the material.3.2.4 unit magnetic rating (1 MR), na calibrating standa
17、rdwith an MR of one is defined as containing 0.18 g of U.S.National Institute of Standards and Technology standardsample No. 29(a) or iron ore (magnetite) uniformly distributedover the space specified for a 10-g test specimen (19 mm 0.75in. diameter by 73 mm 2.875 in. long), by dispersion in amagnet
18、ically inert material. A10-g specimen has one unitmagnetic rating when it produces a magnetic effect equivalentto that of 0.18 g of standard magnetite as described above.Conversely, a 10-g specimen producing a magnetic effect suchthat the resulting induced current in the magnetic analyzergalvanomete
19、r is k times that of the 0.18 g of standard magnetiteas described above, would have a magnetic rating (MR) of k.4. Summary of Test Method4.1 The unknown electromagnetic effects of a sample ofasbestos-containing material is compared with those of areference standard in a magnetic analyzer. The induct
20、iveimbalance caused by the magnetic particles in the asbestossamples is amplified and measured with the magnetic analyzer.5. Significance and Use5.1 This test method for the determination of magneticrating is considered satisfactory for acceptance testing ofcommercial shipments of asbestos fibers, p
21、apers, felts, yarns,rovings, textile products, rigid sheet products, and granular orpowdered products.5.2 Magnetic rating is one of the measurements used fordetermining the suitability of an asbestos material for electricalinsulation.5.3 The electrical insulating properties of asbestos materialsvary
22、 inversely with the magnetic rating. Therefore, a lowmagnetic iron content is required for good electrical insulating.5.4 The types of asbestos textiles classified by magneticrating are described in Specification D2100.6. Apparatus6.1 Magnetic AnalyzerEither the Mapes type analyzer orthe Turner each
23、 operatortested 2 specimens of each sample. All 26 specimens of eachmaterial came from the same lot. The components of variancefor magnetic rating results expressed as coefficients of varia-tion were calculated to be:Single-operator component 4.4 % of the averageBetween-laboratory component 9.4 % of
24、 the average15.2 PrecisionFor the components of variance reported in15.1 two averages of observed values should be consideredsignificantly different at the 95 % probability level if thedifference equals or exceeds the critical differences listedbelow.Critical Differences Percent of Grand Average for
25、 theConditions NotedABNumber of Observationsin Each AverageSingle-Operator Precision(Repeatability)Between-LaboratoryPrecision (Reproducibility)1 12.2 28.72 8.6 27.45 5.5 26.610 3.8 26.3AThe critical differences were calculated using t = 1.960 which is based on infinitedegrees of freedom.BTo convert
26、 the values as listed above to units of measure, multiply the averageof the two specific sets of data being compared by the critical differencesexpressed as a decimal fraction.NOTE 3The values of the critical differences in this table should beconsidered to be a general statement particularly with r
27、espect to between-laboratory precision. Before a meaningful statement can be made abouttwo specific laboratories, the amount of statistical bias, if any, betweenthem must be established, with each comparison being based on recentdata obtained on randomized specimens from one sample of the materialto
28、 be tested.15.3 BiasThe true value of the magnetic rating of asbestosfibers and textiles can be defined only in terms of a specific testmethod. Within this limitation, Test Method D1118 for testingmagnetic ratings has no known bias.16. Keywords16.1 asbestos; magnetic; Mapes; products; rating; test;T
29、urner ”. Fig. A2.6(b) shows the connections to be madebetween two conventional rectifiers to give the desired recti-fying unit for this apparatus. Fig.A2.6(c) is a simplified sketchof Fig. A2.6(b) corresponding to the sketch of the rectifier unitin Fig. A2.5.A2.6 Indicating InstrumentThe details of
30、the indicatinginstrument are shown in Fig. A2.7. This shall consist of aportable galvanometer G, a resistance network for adjusting theFIG. A2.2 Magnetic AnalyzerPrinciple of MethodFIG. A2.3 Magnetic AnalyzerPower Supply, Bridge, HarmonicFilter, and Range SelectorFIG. A2.4 Magnetic AnalyzerAmplifier
31、, Meter, and SwitchingFIG. A2.5 Schematic Diagram of ApparatusD1118/D1118M 95 (2017)7overall sensitivity and for changing the scale range, and acapacitor for bypassing any alternating current that may bepresent. The galvanometer shall have the following character-istics:Galvanometer resistance, ohms
32、 50Period, s 3Sensitivity, amp per 1-mm scale division 0.040Extreme critical damping resistance, ohms 700Scale length, mm 100The resistance network shall be made up of stable resistorshaving low-temperature coefficients. The values of these resis-tances are approximate as final adjustment must be ma
33、de forthe particular equipment being used. The capacitor shall be a50-V electrolytic capacitor.A2.7 Test Specimen HolderThe test specimen holder shallconsist of a wooden or plastic tube 25.4 mm in outsidediameter, with an inside diameter of 19.05 mm, and a length of111.125 mm and with two stoppers t
34、hat extend 19.05 mm intoeach end of the tube.A2.8 Calibration and Standardization:A2.8.1 With this apparatus the balance is greatly affected bythe proximity of any magnetic materials, as such materialchanges the inductance of the coils. For this reason magneticmaterials should not be used except tho
35、se that are unavoidableand whose effect can be balanced out, such as the capacitorsand the assembly bolts through the rectifier. If these parts aremagnetic, the coils shall be mounted with their axes horizontaland parallel, with the capacitors and rectifiers located midwaybetween them. There shall b
36、e at least 8 cm between the side ofthe coils and the capacitors. A simple balancing arrangementconsists of a nonmetallic plug, capable of fitting tightly into theend of one of the coils, with a magnetic machine screw throughits center. The center of the plug should be drilled and tappedso that the m
37、achine screw can be screwed in or out of the coil.A locking nut should be used to hold this screw in place afterbalance has been obtained. The length and size of this screwcan be determined when the procedure described in A2.8.2 isperformed.A2.8.2 For the initial balance, the sensitivity of the indi
38、cat-ing instrument must be greatly reduced. This can be done byconnecting a variable resistance of approximately 0 to 100 across the instrument connections to the capacitors. Set theresistor at 0, shorting out the instrument, energize the circuitwith a 115-V, 60-Hz supply, and then increase the resi
39、stanceslightly until a few millimeters deflection is obtained on thegalvanometer. It will then be found that bringing a magneticscrew near the end of one of the coils will cause thegalvanometer deflection to decrease to zero and then reverse asthe screw is pushed further into the coil. This indicate
40、s that thescrew is bringing the coils into balance and then unbalancingthem in the opposite direction. Then fit the plug into the desiredcoil and lock the screw in the position for zero balance.Increase the shunt across the instrument and adjust the balanc-ing screw to maintain the balance until the
41、 coils are balancedwith the resistance at its highest value. Remove the resistanceand readjust the balance. The instrument resistances may nowbe adjusted to give the desired scale sensitivities. Place anMR1 calibrating standard, as described in AnnexA3, in the testcoil, throw the sensitivity switch
42、to the MR1 position, and varyR4 to give 100-mm deflection. If desired, a smaller variableresistance can be placed in series with R4 to give fineadjustment of the sensitivity. Throw the sensitivity switch tothe MR6 position and place an MR6 calibrating standard in thetest coil. Adjust R1 keeping the
43、sum of R1+R2 = 700 , untila 60-mm deflection is obtained on the galvanometer. Ifcalibrating standards of other MR values are available, otherpoints on the scale can be checked and a correction curveobtained, although the deflections are nearly directly propor-tional to the MR values over the range o
44、f values used in thisapparatus.FIG. A2.6 Schematic Diagram of Rectifiers and ConnectionsFIG. A2.7 Schematic Diagram of Indicating InstrumentD1118/D1118M 95 (2017)8A3. CALIBRATION STANDARDS6A3.1 The test method is based historically on measurementsdetermined in terms of the USANational Institute of S
45、tandardsand Technology (formerly National Bureau of Standards, NBS)standard sample No. 29a of iron ore magnetite.A3.2 Any standardized iron ore magnetite calibrated againstthe original standard may be used as a primary calibrationstandard.A3.3 Sets of primary calibration standards are held by thevar
46、ious manufacturers of the different types of magneticanalyzers. These are used to standardize the calibration stan-dards supplied with each analyzer.A3.4 To safeguard the calibration standards, a set of work-ing standards is also supplied with each magnetic analyzer.A3.5 For those wishing to assembl
47、e their own apparatus,secondary and working standards may be prepared as describedin A3.5.1 toA3.5.10 . Since the MR values of the calibratingstandards may be materially changed by tapping, dropping, orexcessive handling (due to segregation and orientation) preparestandards in duplicate. Use one set
48、 as working standards andthe other as pertinent reference standards.A3.5.1 To prepare a calibration or working standard, theapproximate quantity of approved magnetic standard materialshall be dispersed uniformly in a powdered, inert, nonmagneticmaterial occupying a volume that approximates that of a
49、 testsample, namely, a cylinder of internal diameter 19 mm by 73mm in length. An approved magnetic standard material is onethat has the full recognition of the ASTM Committee C-17.A3.5.2 A powdered aluminum oxide or zinc oxide ofanalytical grade, containing not more than 0.01 % iron oxides,is deemed to be a suitable inert material. It shall have a particlesize distribution such that 100 % passes through a 150 m (No.100) sieve and 30 to 40 % is retained on a 74 m (No. 200)sieve, when a sample of 50 g is si
