1、Designation: D 2752 88 (Reapproved 2006)Standard Test Methods forAir Permeability of Asbestos Fibers1This standard is issued under the fixed designation D 2752; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. A 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 These test methods cover the measurement of therelative degree of openness or degree of fiberization of milledasbestos fiber by
3、 air permeability instruments.1.2 Method A is the recommended procedure and describesa determination by means of the Rapid SurfaceArea apparatus.This test method is limited to fibers with an effective surfacearea in the range from 10 to 250 dm2/g (490 to 12 000 ft2/lb).1.3 Method B is an alternative
4、 procedure and covers the useof the Dyckerhoff apparatus. This test method is limited tofibers within the range from 10 to 600 Dyckerhoff seconds.1.4 Only those asbestos specimens which are of similarspecific gravities will bear strict comparison by these airpermeability methods since differences in
5、 density result inspecimens being tested under different conditions of porosity.1.5 Samples containing excessive quantities of nonfibrousparticles or contaminants will not give reliable or meaningfulresults.1.6 The values stated in SI units are to be regarded as thestandard. The inch-pound units in
6、parentheses are provided forinformation only.1.7 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-cement products, minim
7、ize the dust that results. For informa-tion on the safe use of chrysotile asbestos, refer to “Safe Use ofChrysotile: A Manual on Preventive and Control Measures.”21.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the
8、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:3D 2590 Test Method for Sampling Chrysotile AsbestosD 3879 Test Method for Sampling Amphibole AsbestosE11 Spec
9、ification for Wire Cloth and Sieves for TestingPurposesE 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods2.2 Other Standard:4NNN-P-1475B Federal Specification for Paper, Filter, Ana-lytical3. Summary of Test Methods3.1 In both test methods the resistance to air flow of acompr
10、essed specimen of fixed weight and volume is deter-mined.3.2 Test Method A:3.2.1 The apparatus is arranged so that the total resistance toair flow remains equal to a fixed hydraulic pressure head. Totalresistance includes the resistance of the specimen and thepressure drop across a calibrated capill
11、ary tube of knownresistance. The contribution of the specimen to total resistanceis measured on a manometer calibrated in specific surface areaunits.3.2.2 Optional calibration of the manometer in equivalentDyckerhoff seconds, which are the units of Test Method B,permits comparison of results by both
12、 test methods on the samebasis.3.3 Test Method B:3.3.1 The time required to draw a given volume of airthrough the specimen under specified conditions of varyinghydraulic head is determined. This time is taken as a measureof the air permeability of the specimen.1These test methods are under the juris
13、diction of ASTM Committee C17 onFiber-Reinforced Cement Products and are the direct responsibility of Subcommit-tee C17.03 on AsbestosCement Sheet Products and Acessories.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1968. Last previous edition approved in 2002 as
14、 D 2752 88 (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 page onthe ASTM website
15、.4Available from the Superintendent of Documents, U. S. Government PrintingOffice, Washington, DC 20402.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Significance and Use4.1 The degree of fiberization or subdivision of the asbes
16、tosfiber bundles in a specimen is related to its resistance to airflow. The number and size of the pores in the specimen are afunction of the size of the fiber bundles and determine theresistance to air flow through the plug. Test specimens thathave undergone a higher degree of fiberization will yie
17、ldhigher results provided the specimens compared are of similarspecific gravities and other properties are not markedly differ-ent.4.2 These test methods are suitable for specification accep-tance, manufacturing control, development, and applied re-search.4.3 It must not be assumed that all test spe
18、cimens with equaltest results have undergone equivalent degrees of fiberization.Some types of asbestos fiberize more readily than others.Particle size distribution and harshness can also influencepermeability.5. Sampling5.1 Take a sample in accordance with the sampling proce-dure in Test Method D 25
19、90 for chrysotile fibers and TestMethod D 3879 for amphibole fibers. (WarningSee 1.7.)6. Test Specimen6.1 Spread the sample on a smooth working surface inlayers to form a flat pile of uniform thickness 13 mm (0.5 in.)thick, and quarter the pile.6.2 Set aside opposite quarters and repeat 6.1 with the
20、remaining quarters.6.3 Select two 50 6 0.01-g (0.1102 6 0.00002-lb) speci-mens (Note 1) by taking pinches from each quarter of the pileuntil a quantity is obtained that will require minimum adjust-ment to the desired weight.NOTE 1The metric system of units shall be used for referee testing.6.4 When
21、pinches are taken be careful to include the totalcross section of the pile from top to bottom at the point whereit is taken, including any grit or fines which may havesegregated at the bottom.6.5 Any lumps or knots of matted fiber still remaining in thespecimen should be disentangled before cell loa
22、ding is begun.7. Calibration and Standardization7.1 Calibrating Standards5:7.1.1 The calibrating standards for both test methods consistof capillary glass tubing mounted in a holder which suitablyfills the specimen cavity in the permeability cell.7.1.2 The low standards have an equivalent surface ar
23、earange from 45 to 55 dm2/g (2200 to 2700 ft2/lb). Thiscorresponds to a Dyckerhoff time of efflux in the range from 20to 30 s. They are made from glass tubing with a bore of 0.3116 0.012 mm (0.012256 0.0005 in.) and about 13 mm (0.5 in.)long.7.1.3 The high standards have an equivalent surface areara
24、nge from 200 to 230 dm2/g (9770 to 11 200 ft2/lb). TheDyckerhoff time of efflux is fixed in the range from 350 to 450s. They are made from glass tubing with a bore of 0.178 60.013 mm (0.00706 0.0005 in.) and about 39.5 mm (1.55 in.)long.7.1.4 ADyckerhoff capillary tube holder is shown in Fig. 1.Hold
25、ers for Rapid SurfaceArea standards are of similar designbut are 38 6 0.2 mm (1.496 6 0.007 in.) in external diameter.7.1.5 For accurate results keep calibrating standards inairtight containers or in a desiccator when not in use.7.1.6 Clean capillary tubes with dry, compressed air, freefrom contamin
26、ants, at 1.4 kgf/cm2(20 psig), if permanentlymounted, or 0.35 kgf/cm2(5 psig) if temporarily mounted, priorto calibration. Allow the air to flow 1 min.7.2 Instrument Calibration for Rapid Surface Area Tester:7.2.1 Verify the apparatus as described in Section 9.7.2.2 Insert a calibrating standard mou
27、nted in its capillarytube holder into the cell using the handle shown in Fig. 2(a).Insert the end cap of the cell, and screw down the retaining ringusing the key and base provided, until there is a positiveresistance indicating that the O-ring seal is fully compressedand that metal-to-metal contact
28、has been established betweenthe cell face and the end cap.7.2.3 Proceed as directed in 10.4 and 10.5. If results differfrom the nominal value of the standard by more than 63.0 %,it may be concluded that the equipment is defective. The defectmust be rectified before proceeding.7.3 Instrument Calibrat
29、ion for the Dyckerhoff Tester:7.3.1 Fixed Electrode Apparatus:7.3.1.1 Verify the apparatus as described in Section 13.7.3.1.2 Insert a calibrating standard mounted in its capillarytube holder into the cell using the handle shown in Fig. 2(a)and clamp the cell in position on the apparatus. Omit the s
30、pacerfrom the assembly so that the plunger may seat perfectly.7.3.1.3 The liquid level in the manometer must be at theindicated etch mark on the tube before the suction head isestablished.7.3.1.4 Apply vacuum to the manometer until the lowerliquid level in the manometer is just below the tip of the
31、longestelectrode.7.3.1.5 Reset the stop clock to zero. Observe the reading onthe dial after the level of the liquid has reached the shortestelectrode, and the clock has stopped.7.3.1.6 Take two readings. If the second reading differsappreciably from the cumulative average value of the standard,refer
32、 to the instructions supplied with the standards to locateand eliminate the source of variation.7.3.1.7 Obtain readings on the calibrating standard as di-rected in 14.5 to 15.1.7.3.1.8 Each time a working standard is used, and validreadings are obtained, the average reading must be recordedand the a
33、verage of all previous readings, including the nominalvalue and the latest reading, must be computed. This all time5Calibrating standards mounted in approved capillary tube holders are obtain-able from Centre Spcialis en Technologie Minrale, CEGEP, 671 South SmithBoulevard, Thetford Mines, QC, Canad
34、a, G6G 6X9. Standards may be permanentlyor temporarily mounted; however, permanent mountings are recommended. If youare aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible t
35、echnical committee,1which you may attend.D 2752 88 (2006)2average value of the working standard is referred to as thecumulative average value.7.3.1.9 If the value obtained with the calibrating standard iswithin 3 % of the cumulative average, that value is acceptedand the apparatus may be considered
36、free from defects.7.3.1.10 If the deviations exceed 3 %, examine the appara-tus for defects and rectify as described in the instructionssupplied with the standards. Then recheck the calibratingstandards.7.3.1.11 The difference between the average reading (initialor recheck) and the cumulative averag
37、e, which may be positiveor negative, must be applied as a correction to subsequentvalues obtained on unknown asbestos specimens.7.3.1.12 When the correction exceeds 6 % of the nominalvalue, the standard should be returned to the calibratinglaboratory for recalibration.7.3.2 Variable Electrode Appara
38、tus:7.3.2.1 Adjust the electrodes so that valid readings obtainedon the calibrating standard will coincide with the nominalvalue within 3 %.7.3.2.2 Measure the position of the variable electrode rela-tive to the apparatus housing whenever a new working standardis put into service, and record this ve
39、rtical distance for laterreference.FIG. 1 Capillary Tube HolderD 2752 88 (2006)37.3.2.3 When electrode adjustments exceed 2.5 mm (0.1in.), return the standard to the calibrating laboratory forrecalibration.7.3.2.4 Obtain readings on unknown asbestos specimensdirectly, without any corrections.FIG. 2
40、Miscellaneous DetailsD 2752 88 (2006)4METHOD A8. Apparatus8.1 Rapid Surface Area Tester,6including 50-g (0.1102-lb)brass sample cell, complete with perforated plate, end cap,retaining ring, and base. A schematic diagram of the apparatusis shown in Fig. 3. The following accessories which arerequired
41、are also supplied with the apparatus: filling funnel,tamping rod, and key.8.2 Source of Clean Air, at approximately 140 gf/cm2(2psig).8.3 Optional Cell Holder, shown in Fig. 4 for use with aDyckerhoff cell (Fig. 5).8.4 Standards, as described in 7.1.9. Preparation of Apparatus9.1 Check the apparatus
42、 daily before using, and make thefollowing adjustments when required (see Appendix X1 foradditional verifications, to be carried out at longer timeintervals):9.1.1 Verify the zero reading of the tester as directed in 10.4and 10.5 but with the cell empty.9.1.2 If the manometer does not read zero, che
43、ck to deter-mine if the manometer is out of plumb.9.1.3 If the water level is below zero, adjust by addingdistilled water through the hole in the reservoir cap.6Available from TAF International Ltd, PO Box 21, Ashburton Road West,Trafford Park, Manchester M17 1RQ, UK. If you are aware of alternative
44、 suppliers,please provide this information to ASTM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.ASupply of clean compressed air JTest specimenBControl valve KAir outletCWater reservoir LShut-off
45、 valveDBubbler tube MDust filter (fiber glass)ECapillary resistance NCapillary snubberFManometer leg OZero mark on manometerGManometer scale (exponential) PAir dryer or desiccator (Drierite)HPermeability cellNOTE 1Items A, L, and P are not supplied with the apparatus.FIG. 3 Schematic Diagram of Rapi
46、d Surface Area TesterFIG. 4 Dyckerhoff Cell HolderD 2752 88 (2006)59.1.4 If the level is above zero, correct it by inserting a wickthrough the hole to remove excess water. Do not tilt theapparatus.9.1.5 Ensure that the perforated disk is perfectly seated atthe bottom of the sample cell.10. Procedure
47、10.1 Place the filling funnel over the open end of the celland empty one 50-g specimen into it in stages, using thetamping rod at intervals to coax all the specimen past the neckof the funnel; avoid trapping any fiber between the rod and thefunnel. In a single motion, press the specimen into the cel
48、l untilthe transverse bar touches the upper edge of the filling funnel.10.2 Do not compress the fiber in the cell without the fillingfunnel in place.10.3 Slowly withdraw the rod, rotating it slightly to ensurethat the compressed fiber is not disturbed. Insert the end cap ofthe cell, and screw down t
49、he retaining ring using the key andbase provided, until there is a positive resistance indicating thatthe O-ring seal is fully compressed and that metal-to-metalcontact has been established between the cell face and the endcap.10.4 Connect the cell to the rubber discharge tube of thetester and turn on the air supply. Open the control valve on theapparatus until the water level in the front manometer tubebegins to fall. When air bubbles begin to issue from the escapeholes at the bottom end of the brass tube in t
