1、Designation: D6494 99 (Reapproved 2015)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using apolytetrafluoroethylene (PTFE) filter methodology.1.2 This procedure has been adapted from NIOSH Method5023 (withdrawn prior to 4th edition (1994) and replaced in1998 with NIOSH Method 5042) an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)Methods:3OSHA Method 58 Coal Tar Pitch Volatiles2.3 National Institute for Occupational Safety and Health(NIOSH) Man
8、ual of Analytical Methods:4NIOSH Method 5023 Coal Tar Pitch VolatilesNIOSH Method 5042 Benzene Soluble Fraction and TotalParticulate (Asphalt Fume)3. Terminology3.1 DefinitionsFor definitions of terms relating to this testmethod, refer to Terminology D1356.3.1.1 asphalt fume particulate matterpartic
9、ulate mattergenerated during the processing of hot asphalt.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 benzene e
10、xtract 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 expo-
11、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 jurisdiction of
12、ASTM Committee D22 on AirQuality and is the direct responsibility of Committee D22.04 on Workplace AirQuality.Current edition approved Oct. 1, 2015. Published October 2015. Originallyapproved in 1999. Last previous edition approved in 2010 as D6494 99 (2010).DOI: 10.1520/D6494-99R15.2For referenced
13、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.3Available from Occupational Safety and Health Administration (OSHA), 200Cons
14、titution Ave., NW, 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 45
15、240, http:/www.acgih.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 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 t
16、oreduce the level 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 we
17、ighing may affect 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 thecasset
18、te labeled prior 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
19、use.NOTE 1Only filters 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 f
20、ilter for a period 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, 10 mL.7.2.6 Gas Sparge Manifold, for nitrogen blow down ofextracts.7.2.7 Vacuum Oven.7.2.8 Filt
21、ration Unit, containing 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
22、 are used, appropriatecleaning 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,Syringes, and so forth)All pipets and syringes shall becalibrated Class A volume
23、tric glassware.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 be
24、nzene to a concentrator 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
25、. Let stand in 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
26、 should be vented 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 effe
27、cts. Dermalcontact 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 fo
28、r skin contact. 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 e
29、ffected by drawing 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
30、.1 Air Sampling: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
31、.3 For a breathing 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.)D6494 99 (2015)211.1.4 Turn on
32、 the pump that has previously been 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.11.1.5 Check the pump periodically to ensure that it is stillrun
33、ning and within 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 Discon
34、nect the sampling 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 sample
35、set. No air should 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
36、 Total Mass Determination: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
37、electronic balance.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
38、.3 Benzene Soluble 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
39、 balance per manufacturersrecommendations.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 toa5or10mLsy
40、ringe with needlefitting. 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
41、5 or 10 mL glasssyringe 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
42、 after the sampletransfer 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
43、into the 10 mL 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
44、. If thesample 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 all
45、owed to air dry 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 dur
46、ing this period.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 man
47、ner as a sample starting with 11.2.3.1 to determinethe contribution of the filter and benzene residue.12. Calculation12.1 Blank Corrected Total MassSubtract the sample filterpremass from the sample filter postmass. Also subtract anyblank mass (blank filter postmass minus blank filter premass).Total
48、Mass 5 Asample2 Bsample! 2 Ablank2 Bblank! (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 a
49、luminum cup from the mass of the aluminum cupafter evaporation of the extracted sample benzene residue(11.2.3.11):BSFsample5 Csample2 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:D6494 99 (2015)3BSFblank5 Cblank2 Dblank(3)where:Cblank= mass of blank cup in mg after extract evaporation,andDblank= initial mass of blank
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