1、Designation: D4599 03 (Reapproved 2009)1Standard Practice forMeasuring the Concentration of Toxic Gases or VaporsUsing Length-of-Stain Dosimeters1This standard is issued under the fixed designation D4599; the number immediately following the designation indicates the year oforiginal adoption or, in
2、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.1NOTEReapproved with editorial changes in October 2009.1. Scope1.1 This practice describes the d
3、etection and measurementof time weighted average (TWA) concentrations of toxic gasesor vapors using length-of-stain colorimetric dosimeter tubes. Alist of some of the gases and vapors that can be detected by thispractice is provided in Annex A1. This list is given as a guideand should be considered
4、neither absolute nor complete.1.2 Length-of-stain colorimetric dosimeters work by diffu-sional sampling. The results are immediately available byvisual observation; thus no auxiliary sampling, test nor analysisequipment are needed. The dosimeters, therefore, are ex-tremely simple to use and very cos
5、t effective.1.3 The values stated in SI units shall be regarded as thestandard.1.4 This standard does 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 dete
6、rmine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1356 Terminology Relating to Sampling and Analysis ofAtmospheres2.2 Other Document:U.S. Occupational Safety and Health StandardTitle29 1910.1000 Subpart Z33. Terminology3.1 For definitions of
7、terms used in this practice, refer toTerminology D1356.4. Summary of Practice4.1 Length-of-stain colorimetric dosimeters consist of asealed glass tube containing a detector inside the tube (1-5).4The detector is a length of granulated material impregnatedwith a reactive chemical that is sensitive to
8、 the particular gasfor which the dosimeter is designed. To use the tube, one endis opened. The gas, if present, diffuses into the tube and reactswith the chemical reagent on the carrier material, causing thelatter to change color. Each lot of dosimeters is individuallycalibrated so that by measuring
9、 the length of stain and the timeof exposure, the TWAconcentration to which the dosimeter hasbeen exposed can be determined directly and immediately.4.2 Information on the correct use of length of stain dosim-eter tubes is presented.5. Significance and Use5.1 The U.S. Occupational Safety and Health
10、Administra-tion (OSHA) in 29 CFR 1910.1000 Subpart Z designates thatcertain gases and vapors present in work place atmospheresmust be controlled so that their concentrations do not exceedspecified limits. Other countries have similar regulations.5.2 This practice will provide a means for the determi
11、nationof airborne concentrations of certain gases and vapors listed in29 CFR 1910.1000 and in other countries regulations.5.3 A partial list of chemicals for which this practice isapplicable is presented in Annex A1 with current ThresholdLimit Values (TLV) (2) and typical measurement ranges for thes
12、elected chemicals as obtained from various manufacturersspecifications.5.4 This practice may be used for either personal or areamonitoring.6. Interferences6.1 The instructions may provide correction factors to beapplied when certain interferences are present. Some commoninterfering gases or vapors f
13、or each dosimeter are listed in theinstruction sheets for the dosimeter provided by the manufac-turers1This practice is under the jurisdiction of ASTM Committee D22 on Air Qualityand is the direct responsibility of Subcommittee D22.04 on WorkplaceAir Quality.Current edition approved Oct. 1, 2009. Pu
14、blished December 2009. Originallyapproved in 1986. Last previous edition approved in 1997 as D4599 03. DOI:10.1520/D4599-03R09E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informat
15、ion, refer to the standards Document Summary page onthe ASTM website.3Code of Federal Regulations, available from U.S. Government Printing Office,Washington, DC 20402.4The boldface numbers in parentheses refer to the list of references appended tothis practice.1Copyright ASTM International, 100 Barr
16、 Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Apparatus7.1 Dosimeter Tube:7.1.1 General DescriptionA length-of-stain dosimetertube consists of a glass tube containing an inert granularmaterial impregnated with a chemical system that reacts withthe gas or vapor of int
17、erest. As a result of this reaction, theimpregnated chemical changes color. The granular material isheld in place within the glass tube by porous plugs of a suitableinert material. To protect the contents during storage, the endsof the glass tube are flame sealed. The calibration scale isprinted on
18、the tube to make it easy to read the length of stainof reacted chemical.7.1.2 Stability on StorageStability on storage may varydepending on manufacturer and type of dosimeter, but mostdosimeter tubes can be stored for at least 24 months with nodeleterious effects.7.2 Tube HoldersDuring use, the dosi
19、meter tube is held ina lightweight, plastic holder. The tube holder protects thedosimeter during use and also helps to minimize effects of aircurrents on performance. The holder has a clip that allows it tobe fastened to a collar or pocket during personal sampling or tosome appropriate object during
20、 area sampling.8. Reagents8.1 The reagents used to impregnate the granular material inthe dosimeters are specific for each tube, and, to detect aspecific gas or vapor, may vary from manufacturer to manu-facturer. The instruction sheets supplied by the manufacturersusually give the principal chemical
21、 reaction(s) that occur(s) inthe tube.9. Diffusional Sampling Theory9.1 Ficks First Law of Diffusion states that the mass (m) ofmaterial that diffuses is directly proportional to the diffusioncoefficient (D) of the material, the diffusional cross sectionalarea (A), the concentration gradient (Dc) an
22、d the time (t), andinversely proportional to the length of the diffusion path (l).These parameters are linked by Ficks First Law of Diffusionas follows:dmdt5DADcl(1)The molecules of the contaminant reach the granular reagentlayer. At this point the chemical conversion to a coloredreaction product ta
23、kes place. The increase in length of the colorzone dl is proportional to the converted mass of contaminantdm (Eq 1).dl 5dmkA(2)where:k = absorption capacity of a layer element, ng/cm3, andA = cross-sectional area of the reagent layer, cm2(assumedconstant).This process, called chemisorption, has the
24、following effectson the remaining measuring process:9.1.1 Since the gas molecules to be measured are boundchemically, they are practically no longer present in theatmosphere directly above the granular carrier material. Thus,additional sample molecules are able to flow into the detectortube accordin
25、g to Ficks First Law of Diffusion, since theconcentration gradient Dc is maintained.9.1.2 The effect of the color zone formed in the process isthat the subsequent contaminant molecules must cover a longerdiffusion path, l, until they reach the unused reagent layer. Thismeans that the diffusion path,
26、 l, as defined in the diffusion law,is not constant, but becomes greater with progressive exposure.The transport rate dm/dt of the sample molecules decreases inthe process. The slowdown in mass transport has a direct effecton the shape of the calibration curves of the indicating tubes.The mathematic
27、al correlation can be traced to Formulas 1 and2. Eliminating the contaminant mass, dm, from Eq 1 and 2 andintegrating yields:cTWA1t*0tDcdt5Sk2DtD3 l2(3)where cTWAis the time-weighted average of the time-dependent concentration, Dc. Calibration curves described bythis equation are not linear, but hav
28、e the shape of a parabolawhen cTWAis plotted versus l. Accounting for an air gapbetween tube entrance and sorbent, and also transverse analyteflow (if present), modifies Eq 3 through an additive constantand also a term proportional to the stain length, l (5).9.1.3 The correlation of Eq 3 is confirme
29、d by actualcalibration curves of diffusion tubes. The influence of theproduct resulting from the concentration c and the measuringduration t on the detector tube indication l is shown in Fig. 1.A linear correlation is obtained between the square of thedetector tube indication and the product resulti
30、ng from theconcentration and increasing time as shown by Fig. 2.9.2 Measurement RangeThe measurement range of thevarious length-of-stain dosimeters is shown in Annex A1.9.3 Air VelocityThe sampling rate of the dosimeter tubesis very slow (of the order of 0.1 cm3/min); thus the “starving”effect in st
31、atic air is not significant for these devices, so that airvelocity is not critical. However, a stream of high velocity airshould not be permitted to flow directly into the open end of thetube (parallel to the axis of the tube). The tube holder providesadditional protection from turbulence within the
32、 dosimeter.10. Sampling with Length-Of-Stain Dosimeter Tubes10.1 GeneralSince these dosimeters work by diffusion,the procedure for using them is very simple. All that isnecessary is to open one end of the dosimeter properly, placethe opened tube into its holder, and fasten the holder to anobject at
33、a point where the sampling is to be done. Follow theinstruction sheet of the manufacturer for the proper use of eachdosimeter tube. The sampling starting time and ending timemust be recorded so that the sampling time is known. This isneeded to estimate the average concentration (TWA) over thesamplin
34、g time.10.2 Determining the Concentration from the DosimeterTubeThe dosimeter tubes are calibrated in units of concen-tration 3 time, typically ppm(v) 3 hours. The average gasconcentration can be determined by the following formula:average concentration ppmv!# (4)5dosimeter tube reading ppmv! hoursa
35、ctual sampling time hoursD4599 03 (2009)1211. Accuracy of Dosimeter Tubes (4-5)11.1 The accuracy of dosimeter tubes is generally within625 %; however, some tube types may vary from this, andspecific tube accuracy may vary from lot to lot and manufac-turer to manufacturer. Therefore, if users want to
36、 know theaccuracy of a certain tube, they should check with themanufacturer for an accuracy statement or run their own teststo determine accuracy under their particular conditions of use.12. Keywords12.1 air monitoring; colorimetric dosimeter tubes; diffu-sional sampling; dosimeter tubes; sampling a
37、nd analysis; toxicgases and vapors; workplace atmospheresFIG. 1 Dosimeter Calibration Curve Relating Length of Color Zone to Concentration 3 TimeFIG. 2 Dosimeter Calibration Curve Relating Square of Color Zone Length to Concentration 3 TimeD4599 03 (2009)13ANNEX(Mandatory Information)A1. SOME GASES
38、AND VAPORS THAT CAN BE MEASURED BY LENGTH-OF-STAIN DOSIMETER TUBESREFERENCES(1) Pannwitz, Karl-Heinz, “Direct-Reading Diffusion Tubes,” DrgerReview, Vol 53, 1984, pp. 1014.(2) American Conference of Governmental Industrial Hygienists, Thresh-old Limit Values for Chemical Substances and Physical Agen
39、ts andBiological Exposure Indices, 2009 (updated annually), Cincinnati, OH.(3) Palmes, E. D., and Lindenboom, R. H., “Ohms Law, Ficks Law andDiffusion Samplers for Gases,” Analytical Chemistry, Vol 51, 1974,pp. 24002401.(4) Roberson, R. W., Matsunobu, K., Hoshino, F., and Komatsu, T.,“Per-formance T
40、esting of Sensidyne/Gastec Dosimeter Tubes for CO, H2S,SO2and HCN,” presented at the American Industrial Hygiene Con-ference (1985).(5) Bartley, D. L., “Diffusive Samplers Using Longitudinal SorbentStrips,” American Industrial Hygiene Assoc. Journal, Vol 47, No. 8,1986, pp. 571577.ASTM International
41、 takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their ow
42、n responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be ad
43、dressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, a
44、t the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585
45、 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE A1.1 Threshold Limit Values (2)NOTE 1The measurement ranges given in the table a
46、re not for a singletube. They are the lowest and highest concentrations (over 8 h exposure)listed in the various manufacturers brochures.SubstanceTLVRTWA ValuesAMeasurement Range(ppm(v)ppm(v) mg/m3Acetic acid 10 25 0.6325Acetone 500 1187 6.3187.5Ammonia 25 17 2.5187.5Butadiene 2 4.4 1.337.5Carbon di
47、oxide 5000 9000 62.537 500Carbon monoxide 25 29 1.3125Chlorine 0.5 1.5 0.36.3Ethanol 1000 1881 1253125Ethyl acetate 400 1440 62.51250Formaldehyde C0.3BC0.37B0.132.5Hydrogen chloride C5BC7.5B1.325Hydrogen cyanide C4.7BC551.325Hydrogen peroxide 1 1.4 0.635Hydrogen sulfide 10 14 1.337.5Methyl ethyl ket
48、one 200 590 2.575Nitrogen dioxide 3 5.6 0.125Olefin . . 12.5250Perchloroethylene 25 170 3.1187.5Sulfur dioxide 2 5.2 0.618.8Toluene 50 188 12.5250Trichloroethylene 50 269 3.1125Water vapor . . 0.6312.5 mg/lAValues for ppm(v) and mg/m3are Time-Weighted Average (TWA).BC = Ceiling limit.D4599 03 (2009)14
