1、Designation: D 6494 99 (Reapproved 2004)e1Standard Test Method forDetermination of Asphalt Fume Particulate Matter inWorkplace Atmospheres as Benzene Soluble Fraction1This standard is issued under the fixed designation D 6494; the number immediately following the designation indicates the year ofori
2、ginal adoption or, in the case of revision, the 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.e1NOTEEditorial changes were made throughout in April 2004.1. Scope1.1 Th
3、is test method covers the determination of asphaltfume particulate 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using apolytetrafluoroethylene (PTFE) filter methodology.1.2 This procedure has been adapted from NIOSH Method5023 (withdrawn prior to 4
4、th edition (1994) and replaced in1998 with NIOSH Method 5042) and 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 monito
5、ring.1.4 The sampling method develops a time-weighted average(TWA) 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 This standard does not purport to address all of thesafety concerns, if any, as
6、sociated 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 statements, see Section 9.2. Referenced Documents2.1 ASTM Standard
7、s:2D 1356 Terminology Relating to Sampling and Analysis ofAtmospheres2.2 Occupational Safety and Health Administration(OSHA) Methods3OSHA 58 Coal Tar Pitch Volatiles2.3 National Institute for Occupational Safety and Health(NIOSH) Manual of Analytical Methods4NIOSH 5023 Coal Tar Pitch VolatilesNIOSH
8、5042 Benzene Soluble Fraction and Total Par-ticulate (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 of terms relating to this test method,refer to Terminology D 1356.4. Summary of
9、 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 extract is then evaporated to dryness ina vacuum oven. The benzene solubl
10、e 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-sure to asphalt fume in the working environment at thepresently recommen
11、ded 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).5.3 This procedure has been adapted from NIOSH Method5023 (withdrawn prior to 4th edition (1994) and replaced in1998 wi
12、th NIOSH Method 5042) and OSHA Method 58 toreduce the level of background contamination providing betterreproducibility.1This test method is under the jurisdiction of ASTM Committee D22 onSampling and Analysis of Atmospheres and is the direct responsibility of CommitteeD22.04 on Workplace Atmosphere
13、s.Current edition approved April 1, 2004. Published June 2004. Originallyapproved in 1999. Last previous edition approved in 1999 as D 6494 - 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
14、volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Occupational Safety and Health Administration, Salt LakeTechnical Ctr., 1781 S. 300 W., Salt Lake City, UT 84115.4Available from National Institute for Occupational Safety and Health (NIOSH),Cincinnat
15、i, OH.5Available from The American Conference of Governmental Industrial Hygien-ists, Inc. (ACGIH), 1330 Kemper Meadow Dr., Suite 600, Cincinnati, OH 45240.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Interferences6.1 All mater
16、ials (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 accuracy.7. Apparatus7.1 Sampling Apparatus:7.1.1 Filter Sampling CassetteA sampling cass
17、ette 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 to use.7.1.1.1 To accurately determine low levels of asphalt fumes,a low background PTFE f
18、ilter is required. Filter blank valuesshould be checked prior to use. A minimum of three filters fromeach lot of filters should be analyzed for benzene solublecontamination (see 11.2.3) prior to use.NOTE 1Only filters with average background contamination below0.06 mg should be used.7.1.2 Personal S
19、ampling 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 period of 8 h.7.2 Analytical Equipment:7.2.1 Balance, electronic capable of measuring 0.01 mg
20、.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, containing disposable 0.5 m PTFEfilter and syringe fitting.7.2.9 Aluminum Weighing Cups, dispo
21、sable 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, appropriatecleaning procedures must be employed to ensure no crosscontamination from sample to s
22、ample.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.8. Reagents8.1 BenzeneHPLC grade or equivalent with evaporationresidue of 0.0005 %.NOTE
23、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 concentrator tube, place the tubein the heater block with a gentle flow of nitrogen. Evapora
24、tethe 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 a laboratory fume hoodfor 1 h. Transfer the weighing boat to a vacuum oven. Allowthe sam
25、ple 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 vented into a fumehood to prevent release of benzene vapors into the work area.8.2 Dichlorom
26、ethaneHPLC 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. Dermalcontact can cause irritation and burns. Handling of benzene andmethylene chloride solutions
27、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. SeeMSDS for additional hazard and handling information.10. Calibration10.1 Air Sampling
28、 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 drawing air througha calibrated rotameter or through a soap bubble flowmeter.Pumps should be
29、 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:11.1.1 Remove end plugs from opaque sampling cassette.Place an identifying label on the
30、 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 breathing zone sample, fasten the samplingpump to the workers clothing and attach the inlet of
31、 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 been adjustedand calibrated in 10.1. Record the start time, end time,sampling location, s
32、ampling 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 stillrunning and within acceptable limits.11.1.6 At the end of the sampling period, determine andrecord the flow rate, or pump
33、register reading, if appropriate,D 6494 99 (2004)e12turn 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 sampling device from the samplingpump. Plug the inlet and outlet of the filter cassette usi
34、ngsupplied 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 should be drawn through the field blanks.11.1.9 Ship samples to the laboratory as soon a
35、s 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 Determination:11.2.2.1 Remove the end plugs from the filter cassettes anddesiccate for 1
36、2 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 balance.NOTE 7An equilibration time of approximately 2 min should beadequate to obtain a
37、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 Soluble Fraction Analysis:11.2.3.1 With forceps, place the filter in an appropriatelylabe
38、led 7 mL vial with a PTFE lined cap. Add 5 mL of 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 manufacturersrecommendations.11.2.3.3 Preweigh aluminum weighing cups on an elec-tro
39、nic 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 needlefitting. The benzene wash should be blown out of the filter withnitrogen but it
40、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 glasssyringe with the disposable filter attached. Use nitrogen (atpressure of approxim
41、ately 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 sampletransfer of the extract with two aliquots of approximately 0.5mL of benzene and
42、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 tube.NOTE 9Change the disposable filter for each new sample.11.2.3.8 Place the con
43、centrator 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 evaporates to dryness, the sample should be voided.11.2.3.9 Transfer the extract,
44、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 for1hinaclean fume hood beforetransferring it to a vacuum oven.11.2.3.10 Place th
45、e 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.NOTE 10Vacuum oven should be vented into a fume hood to preventrelease of benzene
46、 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 starting with 11.2.3.1 to determinethe contribution of the filter and benzene res
47、idue.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 AsampleBsample!AblankBblank! (1)where:Asample= mass of sample filter after sample collectio
48、n,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 mass of the aluminum cupafter evaporation of the extracted sample benzene residue(11.
49、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:Cblank= mass of blank cup in mg after extract evapora-tion, andDblank= initial mass of blank cup, mg.12.4 Blank Corrected Benzene Soluble Fraction MassSubtract the blank mass (12.2) from the sample mass (12.1).D 6494
