1、Designation: D6494 99 (Reapproved 2010)Standard Test Method forDetermination of Asphalt Fume Particulate Matter inWorkplace Atmospheres as Benzene Soluble Fraction1This standard is issued under the fixed designation D6494; the number immediately following the designation indicates the year oforigina
2、l 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.1. Scope1.1 This test method covers the determination of asphaltfume particula
3、te matter (as benzene soluble fraction) and totalparticulate matter weight in workplace atmospheres using apolytetrafluoroethylene (PTFE) filter methodology.1.2 This procedure has been adapted from NIOSH Method5023 (withdrawn prior to 4th edition (1994) and replaced in1998 with NIOSH Method 5042) an
4、d OSHA Method 58 toreduce the level of background contamination providing betterreproducibility.1.3 This procedure is compatible with high flow rate per-sonal sampling equipment0.5 to 2.0 L/min. It can be used forpersonal or area monitoring.1.4 The sampling method develops a time-weighted average(TW
5、A) sample and can be used to determine short-termexposure limit (STEL).1.5 The applicable concentration range for the TWA sampleis from 0.2 to 2.0 mg/m3.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.7 This standard does
6、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 use. For more specificprecautionary statem
7、ents, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D1356 Terminology Relating to Sampling and Analysis ofAtmospheres2.2 Occupational Safety and Health Administration(OSHA) Methods3OSHA Method 58 Coal Tar Pitch Volatiles2.3 National Institute for Occupational Safety and Health(NIOSH) Manu
8、al of Analytical Methods4NIOSH Method 5023 Coal Tar Pitch VolatilesNIOSH Method 5042 Benzene Soluble Fraction andTotal Particulate (Asphalt Fume)3. Terminology3.1 Definitions:3.1.1 asphalt fume particulate matterparticulate mattergenerated during the processing of hot asphalt.3.1.2 For definitions o
9、f terms relating to this test method,refer to Terminology D1356.4. Summary of Test Method4.1 A known volume of sample air is passed through aPTFE filter. Asphalt fumes are removed from the air stream bydeposition on the filter.4.2 The asphalt fume is extracted with a known volume ofbenzene. The benz
10、ene extract is then evaporated to dryness ina vacuum oven. The benzene soluble fraction (BSF) is thendetermined gravimetrically.5. Significance and Use5.1 Asphalt is a material used in the construction of roadsand as a roofing material and sealant.5.2 This test method provides a means of evaluating
11、expo-sure to asphalt fume in the working environment at thepresently recommended exposure guidelines.5.2.1 The threshold limit value (TLV) for asphalt (petro-leum) fumes is 5 mg/m38-h TWA, (1998 Threshold LimitValues and Biological Exposure Indices, ACGIH5).1This test method is under the jurisdictio
12、n of ASTM Committee D22 on AirQuality and is the direct responsibility of Committee D22.04Current edition approved April 1, 2010. Published June 2010. Originallyapproved in 1999. Last previous edition approved in 2004 as D6494 - 99 (2004)e1.DOI: 10.1520/D6494-99R10.2For referenced ASTM standards, vi
13、sit 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.3Available from Occupational Safety and Health Administration (OSHA), 200Constitution Ave., NW,
14、 Washington, DC 20210, http:/www.osha.gov.4Available from National Institute for Occupational Safety and Health (NIOSH),Cincinnati, OH. http:/www.cdc.gov5Available from American Conference of Governmental Industrial Hygienists,Inc. (ACGIH), 1330 Kemper Meadow Dr., Cincinnati, OH 45240, http:/www.acg
15、ih.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3 This procedure has been adapted from NIOSH Method5023 (withdrawn prior to 4th edition (1994) and replaced in1998 with NIOSH Method 5042) and OSHA Method 58 toreduce the level
16、 of background contamination providing betterreproducibility.6. Interferences6.1 All materials (not just asphalt fume) collected that aresoluble in benzene will be included in the benzene solublefraction weight.6.2 Changes in temperature or humidity during pre- andpost-collection weighing may affect
17、 accuracy.7. Apparatus7.1 Sampling Apparatus:7.1.1 Filter Sampling CassetteA sampling cassette is atwo-piece opaque filter cassette containing a 37 mm pure PTFEfilter with 2 m pore size seated upon a 37 mm PTFE spacerring. PTFE filters should be preweighed (see 11.2.2) and thecassette labeled prior
18、to use.7.1.1.1 To accurately determine low levels of asphalt fumes,a low background PTFE filter is required. Filter blank valuesshould be checked prior to use.Aminimum of three filters fromeach lot of filters should be analyzed for benzene solublecontamination (see 11.2.3) prior to use.NOTE 1Only fi
19、lters with average background contamination below0.06 mg should be used.7.1.2 Personal Sampling Pumps, portable, battery-operated,equipped with a flow-monitoring device (rotameter, criticalorifice) or a constant-flow device and capable of drawing 2L/min of air through the 2-m PTFE filter for a perio
20、d of 8 h.7.2 Analytical Equipment:7.2.1 Balance, electronic capable of measuring 0.01 mg.7.2.2 Polonium Antistatic Strip.7.2.3 Desiccator.7.2.4 Tube Heater Block.7.2.5 Concentrator Tubes,10mL.7.2.6 Gas Sparge Manifold, for nitrogen blow down ofextracts.7.2.7 Vacuum Oven.7.2.8 Filtration Unit, contai
21、ning disposable 0.5 m PTFEfilter and syringe fitting.7.2.9 Aluminum Weighing Cups, disposable or reusableweighing cups capable of holding at least 1 mL of benzenewithout leakage.NOTE 2PTFE may be used if appropriate aluminum cups cannot beobtained.7.2.9.1 If reusable weighing cups are used, appropri
22、atecleaning procedures must be employed to ensure no crosscontamination from sample to sample.7.2.10 Pasteur Pipes, disposable, glass, or equivalent.7.2.11 Miscellaneous Borosilicate Glassware (Pipets, Sy-ringes, and so forth)All pipets and syringes shall be cali-brated Class A volumetric glassware.
23、8. Reagents8.1 BenzeneHPLC grade or equivalent with evaporationresidue of 0.0005 %.NOTE 3Benzene evaporation residue should be checked by evaporat-ing 6.5 mL of benzene (see 8.1.1). Benzene with evaporation residue ofgreater than 0.03 mg for the 6.5 mL is unacceptable.8.1.1 Add the benzene to a conc
24、entrator tube, place the tubein the heater block with a gentle flow of nitrogen. Evaporatethe benzene to approximately 0.5 mL, then transfer theconcentrate with 3 small rinses of approximately 0.2, 0.2, and0.1 mL of benzene using a precleaned Pasteur pipet to apreweighed weighing boat. Let stand in
25、a laboratory fume hoodfor 1 h. Transfer the weighing boat to a vacuum oven. Allowthe sample to further evaporate in the vacuum oven at ambienttemperature and 20 to 25 mm Hg vacuum for 24 h (or at leastovernight). Slowly release vacuum. Remove weighing boatsand reweigh. The vacuum oven should be vent
26、ed into a fumehood to prevent release of benzene vapors into the work area.8.2 DichloromethaneHPLC grade.9. Safety Precautions9.1 Benzene is a known carcinogen and flammable. Dichlo-romethane is a known animal carcinogen. Dichloromethanecan cause nausea and central nervous system effects. Dermalcont
27、act can cause irritation and burns. Handling of benzene andmethylene chloride solutions should be done in an appropriatefume hood.9.2 Avoid inhalation of, or skin contact with benzene,asphalt extracts and methylene chloride. Impervious glovesshould be worn to minimize the potential for skin contact.
28、 SeeMSDS for additional hazard and handling information.10. Calibration10.1 Air Sampling PumpsAll air sampling pumps must becalibrated before use. For an accurate calibration, attach filtersto be used for collecting the samples to the pump prior to thecalibration. Calibration may be effected by draw
29、ing air througha calibrated rotameter or through a soap bubble flowmeter.Pumps should be calibrated at a flow rate of 0.5 to 2.0 L/min.10.2 BalanceCheck balance calibration and adjust permanufacturers recommendations.NOTE 4Use of a standard 100 mg weight is recommended.11. Procedure11.1 Air Sampling
30、:11.1.1 Remove end plugs from opaque sampling cassette.Place an identifying label on the cassette.11.1.2 Attach the sampling device to a sample pump thathas been calibrated at 0.5 to 2.0 L/min using rubber or plastictubing. Place the back of the sampling device closest to thepump.11.1.3 For a breath
31、ing zone sample, fasten the samplingpump to the workers clothing and attach the inlet of thesampling device as close as possible to the workers breathingzone. (WarningEnsure that the presence of the samplingequipment is not a safety hazard to the worker.)11.1.4 Turn on the pump that has previously b
32、een adjustedand calibrated in 10.1. Record the start time, end time,sampling location, sampling rate, pump number, and otherpertinent sample information.NOTE 5Typically samples are collected for8hat2L/min.D6494 99 (2010)211.1.5 Check the pump periodically to ensure that it is stillrunning and within
33、 acceptable limits.11.1.6 At the end of the sampling period, determine andrecord the flow rate, or pump register reading, if appropriate,turn the pump off, and note and record the time, temperature,and barometric pressure.NOTE 6(Minimum recommended sample volume is 15 L.)11.1.7 Disconnect the sampli
34、ng device from the samplingpump. Plug the inlet and outlet of the filter cassette usingsupplied plastic plugs.11.1.8 Blank filter cassettes should be taken into the fieldand opened along with each sample set. These field blanksshould be immediately resealed and shipped with the sampleset. No air sho
35、uld be drawn through the field blanks.11.1.9 Ship samples to the laboratory as soon as possible foranalysis.11.2 Analysis:11.2.1 Prerinse all reusable and disposable glassware withmethylene chloride before use to minimize any potentialcontamination or contribution to BSF weight.11.2.2 Total Mass Det
36、ermination:11.2.2.1 Remove the end plugs from the filter cassettes anddesiccate for 12 to 24 h.11.2.2.2 Remove the filter from the cassette with forceps(taking care not to touch the filtration area). Place the filter ona polonium antistatic strip for several seconds, then weigh onthe electronic bala
37、nce.NOTE 7An equilibration time of approximately 2 min should beadequate to obtain a stable weight reading for filters and the weighing cupsused in the benzene soluble procedure.11.2.2.3 Record the gross mass in milligrams to the nearesthundredth of a milligram (that is, 0.01 mg).11.2.3 Benzene Solu
38、ble Fraction Analysis:11.2.3.1 With forceps, place the filter in an appropriatelylabeled 7 mLvial with a PTFE lined cap.Add 5 mLof benzene,cap the vial, and sonicate for at least 1 h.NOTE 8Benzene must be HPLC grade with 0.0005 % residue onevaporation.11.2.3.2 Calibrate the electronic balance per ma
39、nufacturersrecommendations.11.2.3.3 Preweigh aluminum weighing cups on an elec-tronic balance or equivalent. Record the preweight.11.2.3.4 Precondition the filtration unit immediately beforeuse by filtering with nitrogen pressure ; 1 mL of benzenethrough the unit attached toa5or10mLsyringe with need
40、lefitting. The benzene wash should be blown out of the filter withnitrogen but it is not necessary to blow the filter dry. DIS-CARD THE WASH. It is not part of the sample extract.11.2.3.5 Using a clean Pasteur pipet, transfer the benzeneextract as indicated in 11.2.3.1 to a prerinsed 5 or 10 mL glas
41、ssyringe with the disposable filter attached. Use nitrogen (atpressure of approximately 48 to 69 kPa or 7 to 10 psi) to forceextract through filter into a 10 mL concentrator tube. Allglassware should be cleaned with dichloromethane prior to use.11.2.3.6 Rinse the 7 mL vial immediately after the samp
42、letransfer of the extract with two aliquots of approximately 0.5mL of benzene and filter into the 10 mL concentrator tube.11.2.3.7 Using a clean Pasteur pipe, rinse the syringe withapproximately 0.5 mL of benzene making sure to include theentire inner wall area of the syringe. Filter into the 10 mL
43、tube.NOTE 9Change the disposable filter for each new sample.11.2.3.8 Place the concentrator tube in a heater block at85C and reduce volume to approximately 0.5 mL using gentlestream of nitrogen. Exercise extreme care during this evapo-ration step to avoid blowing the sample to dryness. If thesample
44、evaporates to dryness, the sample should be voided.11.2.3.9 Transfer the extract, with three small rinses ofapproximately 0.2, 0.2, and 0.1 mL of benzene using aprecleaned Pasteur pipet from the concentrator tube to apreweighed aluminum or PTFE cup. The final 1-mL extractshould be allowed to air dry
45、 for1hinaclean fume hood beforetransferring it to a vacuum oven.11.2.3.10 Place the sample cups (in a numbered vial rack) inthe vacuum oven at ambient temperature and 20 to 25 mm Hgvacuum for 24 h (or at least overnight). Sample cups must beprotected from particulate contamination during this period
46、.NOTE 10Vacuum oven should be vented into a fume hood to preventrelease of benzene vapors into the work area.11.2.3.11 Weigh the cups using the procedure outlined in11.2.3.2 and 11.2.3.3 and record the final BSF mass.11.2.3.12 Analyze a blank filter with each sample set in thesame manner as a sample
47、 starting with 11.2.3.1 to determinethe contribution of the filter and benzene residue.12. Calculation12.1 Blank Corrected Total MassSubtract the samplefilter premass from the sample filter postmass. Also subtractany blank mass (blank filter postmass minus blank filterpremass).Total Mass 5 AsampleBs
48、ample!AblankBblank! (1)where:Asample= mass of sample filter after sample collection,mg,Bsample= initial mass of sample filter, mg,Ablank= postmass of field blank, mg, andBblank= initial mass of field blank, mg.12.2 Sample Benzene Soluble Fraction MassSubtract themass of the aluminum cup from the mas
49、s of the aluminum cupafter evaporation of the extracted sample benzene residue(11.2.3.11):BSFsample5 Csample Dsample(2)where:Csample= mass of sample cup after extract evaporation,mg, andDsample= initial mass of sample cup in mg.12.3 Blank Benzene Soluble MassSubtract the mass of thealuminum cup from the mass of the aluminum cup afterevaporation of the extracted blank benzene residue:BSFblank5 Cblank Dblank(3)where:D6494 99 (2010)3Cblank= mass of blank cup in mg after extract evapora-tion, andDblank= initial mass of blank cup, mg.12.4 Blank Co
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