1、Designation: D 1118 95 (Reapproved 2004)e2Standard Test Method forMagnetic Rating of Asbestos Fiber and Asbestos Textiles1This standard is issued under the fixed designation D 1118; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEAsbestos warning was moved from 7.1 to 1.3 in September 2004.e2NOTEAdjunct references were corrected editorially
3、 in April 2006.1. Scope1.1 This test method covers the procedure for the determi-nation of the magnetic rating of asbestos fiber and asbestostextile products. This test method is used primarily for testingasbestos insulating materials.1.2 The values stated in inch-pound units are to be regardedas th
4、e standard. The values given in parentheses are forinformation only.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 addition to other precautions, when working with asbestos
5、-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 of thesafety concerns, if any, associated with its use.
6、 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 1.3.2. Referenced Documents2.1 ASTM Standards:3D 123 Terminology Relating to TextilesD 2
7、100 Specification for Asbestos Textiles Used for Elec-trical Insulating PurposesD 2590 Test Method for Sampling Chrysotile AsbestosD 2946 Terminology for Asbestos and AsbestosCementProductsD 2947 Test Method for ScreenAnalysis ofAsbestos FibersD 3879 Test Method for Sampling Amphibole AsbestosE11 Sp
8、ecification for Wire Cloth and Sieves for TestingPurposes2.2 ASTM Adjuncts:Metallic Analyzer Drawings43. Terminology3.1 For definitions of other textile terms used in this testmethod, refer to Terminology D 123. For terms relating toasbestos, refer to Terminology D 2946.3.2 Definitions:3.2.1 asbesto
9、s 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 humidity of 50 6 2 % at 70 6 2F (216 1C).3.2.3 magnetic rating (MR), nan empirical value
10、 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 material. Magnetic rating is affected by thequantity, concentration, particle size, shape
11、, and orientation ofthe magnetic particles in the material.3.2.4 unit magnetic rating (1 MR), na calibrating standardwith 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
12、space specified for a 10-g test specimen 19 mm (0.75in.) diameter by 73 mm (2.875 in.) long, by dispersion in amagnetically 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
13、 10-g specimen producing a magnetic effect suchthat the resulting induced current in the magnetic analyzergalvanometer is k times that of the 0.18 g of standard magnetiteas described above, would have a magnetic rating (MR) of k.1This test method is under the jurisdiction of ASTM Committee C17 onFib
14、er-Reinforced Cement Products and is the direct responsibility of SubcommitteeC17.03 on AsbestosCement Sheet Products and Accessories.Current edition approved June 1, 2004. Published July 2004. Originally approvedin 1950. Discontinued 1989 and reinstated in 1995 as D 1118 95. Last previousedition ap
15、proved in 1999 as D 111895 (1999).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 page onth
16、e ASTM website.4Available from ASTM International Headquarters. Order Adjunct No.ADJD1118. Original adjunct produced in 1986.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Method4.1 The unknown electromagnetic eff
17、ects of a sample ofasbestos-containing material is compared with those of areference standard in a magnetic analyzer. The inductiveimbalance 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 th
18、e determination of magneticrating is considered satisfactory for acceptance testing ofcommercial shipments of asbestos fibers, papers, felts, yarns,rovings, textile products, rigid sheet products, and granular orpowdered products.5.2 Magnetic rating is one of the measurements used fordetermining the
19、 suitability of an asbestos material for electricalinsulation.5.3 The electrical insulating properties of asbestos materialsvary 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 magne
20、ticrating are described in Specification D 2100.6. Apparatus6.1 Magnetic AnalyzerEither the Mapes type analyzer orthe Turner each 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 coe
21、fficients of varia-tion were calculated to be:Single-operator component 4.4 % of the averageBetween-laboratory component 9.4 % of the average15.2 PrecisionFor the components of variance reported in15.1 two averages of observed values should be considered6ASTM Research Report No. D-13-1021. A copy is
22、 available on loan fromASTM International Headquarters, 100 Bar Harbor Drive, West Conshohocken, PA194282959.D 1118 95 (2004)e23significantly different at the 95 % probability level if thedifference equals or exceeds the critical differences listedbelow.Critical Differences Percent of Grand Average
23、for 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 oninfinite degrees of freedom.BTo conv
24、ert 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 wit
25、h respect 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 materia
26、lto be tested.15.3 BiasThe true value of the magnetic rating of asbes-tos fibers and textiles can be defined only in terms of a specifictest method. Within this limitation, Test Method D 1118 fortesting magnetic ratings has no known bias.16. Keywords16.1 asbestos; magnetic; Mapes; products; rating;
27、test;Turner ”. 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 deta
28、ils of the indicatinginstrument are shown in Fig. A2.7. This shall consist of aportable galvanometer G, a resistance network for adjusting theoverall sensitivity and for changing the scale range, and acapacitor for bypassing any alternating current that may bepresent. The galvanometer shall have the
29、 following character-istics:Galvanometer resistance, ohms 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 re
30、sis-tances are approximate as final adjustment must be made 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
31、.05 mm, and a length of111.125 mm and with two stoppers that 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 th
32、is reason magneticmaterials should not be used except those 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
33、 and rectifiers located midwaybetween them. There shall be 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 cen
34、ter of the plug should be drilled and tappedso that the machine screw can be screwed in or out of the coil.A locking nut should be used to hold this screw in place afterFIG. A2.4 Magnetic AnalyzerAmplifier, Meter, and SwitchingFIG. A2.5 Schematic Diagram of ApparatusFIG. A2.6 Schematic Diagram of Re
35、ctifiers and ConnectionsFIG. A2.7 Schematic Diagram of Indicating InstrumentD 1118 95 (2004)e27balance 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 indicat-ing instrumen
36、t must be greatly reduced. This can be done byconnecting a variable resistance of approximately 0 to 100 Vacross 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 resistanceslightly u
37、ntil 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 indicates that thescrew
38、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 coils are balan
39、cedwith 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 inAnnexA3, in the testcoil, throw the sensitivity switch to the MR1 positi
40、on, 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 sum of R1+R2 = 70
41、0 V, 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 of values used in
42、 thisapparatus.A3. CALIBRATION STANDARDS5A3.1 The test method is based historically on measure-ments determined in terms of the USA National Institute ofStandards and Technology (formerly National Bureau of Stan-dards, NBS) standard sample No. 29a of iron ore magnetite.A3.2 Any standardized iron ore
43、 magnetite calibratedagainst the original standard may be used as a primarycalibration standard.A3.3 Sets of primary calibration standards are held by thevarious manufacturers of the different types of magneticanalyzers. These are used to standardize the calibration stan-dards supplied with each ana
44、lyzer.A3.4 To safeguard the calibration standards, a set ofworking standards is also supplied with each magnetic ana-lyzer.A3.5 For those wishing to assemble their own apparatus,secondary and working standards may be prepared as describedin A3.5.1 toA3.5.10 . Since the MR values of the calibratingst
45、andards may be materially changed by tapping, dropping, orexcessive handling (due to segregation and orientation) preparestandards in duplicate. Use one set as working standards andthe other as pertinent reference standards.A3.5.1 To prepare a calibration or working standard, theapproximate quantity
46、 of approved magnetic standard materialshall be dispersed uniformly in a powdered, inert, nonmagneticmaterial occupying a volume that approximates that of a testsample, namely, a cylinder of internal diameter 19 mm by 73mm in length. An approved magnetic standard material is onethat has the full rec
47、ognition 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 %
48、 is retained on a 74 m (No. 200)sieve, when a sample of 50 g is sieved for 10 min using sievesin compliance with Specification E11by the technique de-scribed in Test Method D 2947.A3.5.3 Take a suitable clean, nonmagnetic sample containeras defined inA3.5.1 and pour into it a quantity of inert mater
49、ial,described in A3.5.2. Fill it to the defined volume and tampdown firmly, but not excessively so.A3.5.4 Weigh out, in a suitable nonmagnetic weighingscoop, a quantity of standard magnetite calculated on the basisof 0.15 g approved equivalency per unit of MR, to give therequired calibration value. Carry out the ensuing operations ona clean, smooth, white surface.A3.5.5 Return about45 of the entire contents of the samplecontainer, obtained in accordance with A3.5.3, to a 250 or 300cm3clean, borosilicate glass
