1、Designation: D3162 12Standard Test Method forCarbon Monoxide in the Atmosphere (ContinuousMeasurement by Nondispersive Infrared Spectrometry)1This standard is issued under the fixed designation D3162; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This te
3、st method is applicable to the determination ofthe carbon monoxide (CO) concentration of the atmospherebetween 0.6 mg/m3(0.5 ppm(v) and 115 mg/m3(100 ppm(v).The measuring principle is based on the absorption of infraredradiation by CO in the 4.7 m region (1).21.2 The test method has a limit of detec
4、tion of about 0.6mg/m3(0.5 ppm(v) carbon monoxide in air.1.3 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 determine the applica-bili
5、ty of regulatory limitations prior to use. See Section 9 foradditional precautions.2. Referenced Documents2.1 ASTM Standards:3D1356 Terminology Relating to Sampling and Analysis ofAtmospheresD1357 Practice for Planning the Sampling of the AmbientAtmosphereD1914 Practice for Conversion Units and Fact
6、ors Relatingto Sampling and Analysis of AtmospheresD3249 Practice for General Ambient Air Analyzer Proce-duresD3631 Test Methods for Measuring Surface AtmosphericPressureE1 Specification for ASTM Liquid-in-Glass ThermometersE180 Practice for Determining the Precision of ASTMMethods for Analysis and
7、Testing of Industrial and Spe-cialty Chemicals43. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, referto Terminology D1356 and Practice D3249.3.2 Definitions of Terms Specific to This Standard:3.2.1 fall timethe time interval between initial responseand 90 % of f
8、inal response after a step decrease in inputconcentrations.4. Summary of Test Method4.1 An atmospheric sample is introduced into a sampleconditioning system and then into a nondispersive infraredspectrometer (NDIR). The spectrometer measures the absorp-tion by CO at 4.7 m using two parallel infrared
9、 beams througha sample and a reference cell and a selective detector. Thedetector signal is conducted to an amplifier control section, andthe analyzer output measured on a meter and recording system(2).4.1.1 Some instruments use gas filter correlation to comparethe IR absorption spectrum between the
10、 measured gas andother gases present in the gas being sampled, in a single samplecell. These instruments utilize a concentrated sample of CO asa filter for the IR transmitted through the sample cell toproduce a beam that cannot be further attenuated by the CO inthe sample, and thus produces the refe
11、rence beam. Thebroadband radiation that passes through the sample cell and theCO filter is filtered again by a narrow-band-pass filter thatallows only the CO-sensitive portion of the band to pass to thedetector. The removal of wavelengths sensitive to other gasesreduces interferences.1This test meth
12、od is under the jurisdiction of ASTM Committee D22 on AirQuality and is the direct responsibility of Subcommittee D22.03 on AmbientAtmospheres and Source Emissions.Current edition approved April 1, 2012. Published May 2012. Originallyapproved in 1973. Last previous edition approved in 2005 as D3162
13、- 94 (2005).DOI: 10.1520/D3162-94R05.2The boldface numbers in parentheses refer to the list of references at the end ofthe standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume inform
14、ation, refer to the standards Document Summary page onthe ASTM website.4Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 The concentrati
15、on of CO in the sample is determinedfrom a calibration curve prepared using standard calibrationgases.5. Significance and Use5.1 Determination of carbon monoxide is essential to evalu-ation of many air pollution complexes. This test methodderives significance from providing such determination.5.2 Ca
16、rbon monoxide is formed in the process of incom-plete combustion of hydrocarbon fuels, and is a constituent ofthe exhaust of gasoline engines. The Environmental ProtectionAgency (EPA) has set primary and secondary air qualitystandards for CO that are designed to protect the public healthand welfare
17、(3, 4).5.3 This test method is suitable for measurements appropri-ate for the purposes noted in 5.1 and 5.2.6. Interferences6.1 Degree of interference varies among individual instru-ments. Consult manufacturers specifications for the particularanalyzer to determine whether interferences render the i
18、nstru-ment unsuitable for the proposed use.6.2 The primary interferent is water vapor. With no correc-tion, the error may be as high as 11 mg CO/m3map edit n (10ppm(v) (5).6.2.1 Water vapor interference can be minimized by usingone of the following steps:6.2.1.1 Passing the air sample through silica
19、 gel or similardrying agent.6.2.1.2 Maintaining constant humidity in the sample andcalibration gases by refrigeration.6.2.1.3 Saturating the air sample and calibration gases tomaintain constant humidity.6.2.1.4 Using narrow-band optical filters in combinationwith some of the above measures.6.2.1.5 W
20、here sample is dried or humidified a volumecorrection may be necessary.6.2.1.6 Gas correlation spectrometers minimize interfer-ences and use a narrow-band-pass filter to ensure measuringonly the CO-sensitive IR wavelengths.6.3 Interference may be caused by carbon dioxide (CO2).The effect of CO2inter
21、ference at concentrations normallypresent in ambient air is minimal; that is, 1350 mg (750ppm(v) CO2/m3may give a response equivalent to 0.6 mgCO/m3(0.5 ppm(v) (5).6.4 Hydrocarbons at concentrations normally found in theambient air do not ordinarily interfere; that is, 325 mgmethane/m3(500 ppm(v) ma
22、y give a response equivalent to0.6 mg CO/m3(0.5 ppm(v) (5).7. Apparatus7.1 NDIR Carbon Monoxide in Air Analyzer, complete withvoltage transformer, analyzer section, amplifier/control section,meter, and recording system. Analyzer must meet or exceedperformance specifications described in Annex A1.7.2
23、 Sample Conditioning System, consisting of pump, flowcontrol valve, pressure relief valve, flowmeter, filter, andmoisture control.7.3 A typical sampling and analyzer system is described inFig. 1.7.4 ThermometerTemperature measuring devices such asRTDs (Resistance Temperature Devices), thermistors an
24、d or-ganic liquid-in-glass thermometers meeting the requirementsof specific applications may be used.7.5 Barograph or Barometer, capable of measuring atmo-spheric pressure to 60.6 kPa (5 torr). See Test Method D3631.8. Reagents and Materials8.1 Zero GasA pressurized cylinder of pure nitrogencontaini
25、ng less than 0.1 mg/m3CO (0.09 ppm(v) and havinga regulated flow supply.8.2 Up-Scale Span GasA pressurized cylinder containinga span gas mixture consisting of CO in air corresponding to80 % of full scale. A regulated flow system must be provided.8.3 Calibration GasesPressured cylinders with regulate
26、dflow control are required. These should contain concentrationsof CO in air corresponding to the instrument operating range.In order to establish a calibration curve, nitrogen with CO inamounts of 10, 20, 40, and 80 % of full scale are needed.8.4 Calibration Certificate The span and calibration gase
27、sshould be certified to be between 62 % of the stated value, andbe supplied in high-pressure cylinders with inside surfaces of achromium-molybdenum alloy of low iron content. Replace-ment cylinder should be verified by procedures in Annex A3.9. Precautions9.1 Operate analyzer system in nonexplosive
28、areas unlessequipment is explosion-proof.9.2 The handling and storage of compressed gas cylinders,and the installation and use of the analyzer shall followPractice D3249. Cylinders shall not be exposed to directsunlight.9.3 Maintain the same sample cell pressure during samplingand calibration. Use t
29、he same sample pump.10. Sampling10.1 GeneralFor planning sampling programs, refer toPractices D1357 and D3249.10.2 When sampling the outside ambient atmosphere froman enclosure, a sampling line or probe shall be utilized. It shallextend at least1m3ftfrom the enclosure, and shall beprotected against
30、the entry of precipitation.10.3 Since the analyzer may be temperature-sensitive, itshall be placed in an enclosure with atmosphere control so thetemperature remains constant within 63C 65F.10.4 Record the temperature and pressure of the atmospheresample.11. Calibration and Standardization11.1 For ca
31、libration procedures, refer to Annex A2.11.2 Frequency of Calibration:11.2.1 Multipoint CalibrationA multipoint calibration isrequired when:11.2.1.1 The analyzer is first purchased.11.2.1.2 The analyzer has had maintenance that could affectits response characteristics.D3162 12211.2.1.3 When the anal
32、yzer shows drift in excess of speci-fications as determined when the zero and span calibration isperformed (see 11.2.2).11.2.2 Zero and Span CalibrationA zero and span cali-bration is required before and after each sampling period, or, ifthe analyzer is used continuously, daily.11.3 Sample Cell Pres
33、sure GaugeThe sample cell pres-sure gauge shall be calibrated in accordance withAnnexA2,asfollows:11.3.1 When the analyzer is purchased.11.3.2 At 6-month intervals.11.3.3 When the gauge shows a change larger than 6.9 kPa1 psi during a sampling period in which the flow rate did notchange more than 60
34、.014 m3/h 0.5 ft3/h.12. Procedure12.1 After proper calibration has been established, check allanalyzer system operating parameters and set the sample flowrate.12.2 When the analyzer output has stabilized, take therecorder readout and determine the concentration of COdirectly from the calibration cur
35、ve in ppm(v).12.3 Perform the operational checks described in Annex A4daily, or during each sampling period (7).13. Calculation13.1 To convert ppm(v) to mg/m3, refer to Practice D1914.14. Precision and BiasNOTE 1The precision statements are based on an interlaboratorystudy conducted by Southwest Res
36、earch Institute, Houston, Tex., in 1972on three samples of carbon monoxide in dry air. Three master cylinders ofgas containing nominal concentrations of 8, 30, and 53 mg/m3wereprepared and subsamples in high-pressure cylinders were submitted to thecollaborating laboratories. Each subsample was analy
37、zed in triplicate andthe analyses replicated on 2 more days for a total of 810 determinations.The results from the 15 laboratories were evaluated by the proceduredescribed in Practice E180.14.1 Precision: (6)14.1.1 Triplicate AnalysisReport the carbon monoxide(CO) content to 0.1 mg/m3. Triplicate ru
38、ns (Note 2) with arange of 0.6 mg/m3are acceptable for averaging (95 %confidence level).5NOTE 2Duplicate runs that agree within 0.5 mg/m3are acceptable foraveraging (95 % confidence level).14.1.2 Repeatability (Single Analyst)The standard devia-tion of the mean (each the average of triplicate determ
39、inations)obtained by the same analyst on different days has beenestimated to 0.44 mg/m3at 140 df. Two such values should beconsidered suspect (95 % confidence level) if they differ bymore than 1.2 mg/m3(see Note 2).5Supporting data giving the results of the collaborative test have been filed atASTM,
40、 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA194282959, in Research Report File No. RR: D22-1000.FIG. 1 Carbon Monoxide Monitoring System Flow ChartD3162 12314.1.3 Reproducibility (Multilaboratories)The standarddeviation of the mean (each the average of triplicate determi-nations) obtai
41、ned by analysts in different laboratories has beenestimated to be 0.96 mg/m3at 11 df. Two such values shouldbe considered suspect (95 % confidence level) if they vary bymore than 3.0 mg/m3(see Note 2).14.2 BiasSince this infrared measurement produces rela-tive values, the bias of the method is depen
42、dent on the bias ofthe calibrations of the gases used in preparing the calibrationcurve.15. Keywords15.1 ambient atmospheres; analysis; carbon monoxide; non-dispersive infrared spectroscopy; samplingANNEXES(Mandatory Information)A1. MINIMUM PERFORMANCE SPECIFICATIONS FOR NONDISPERSIVE INFRARED CARBO
43、N MONOXIDE ANALYZERA1.1 Range(minimum)0 to 115 mg/m3(0 to 100ppm(v)A1.2 Limit of Detection0.6 mg/m3(0.5 ppm(v)A1.3 Rise Time(90 %) 5 min (maximum)A1.4 Fall Time(90 %) 5 min (maximum)A1.5 Zero Drift(61 %/day and 62 %/3 days) (maxi-mum)A1.6 Span Drift(61 %/day and 6 2%/3 days) (maxi-mum)A1.7 Precision
44、(64 %) (maximum)A1.8 Operation Period(minimum) 3 daysA1.9 Noise Level60.5 % of full scaleA1.10 Operating Temperature Range5 to 40CA1.11 Operating Temperature Fluctuation65CFIG. 2 Calibration Set-up for Pressure GaugesD3162 124A1.12 Linearity2 % of full scaleA2. CALIBRATION PROCEDURESA2.1 Analyzer Mu
45、ltipoint CalibrationA2.1.1 Cylinder Pressure CheckCheck the cylinder pres-sure of each calibration gas. If a cylinder pressure is less than2.1 MPa 300 psi, discard the cylinder.A2.1.2 Calibration Procedure:A2.1.2.1 Turn the analyzer power on, and allow it to sampleambient air for 24 to 48 h to stabi
46、lize (or in accordance withmanufacturers instructions).A2.1.2.2 Connect the zero gas cylinder to the analyzer.A2.1.2.3 Set pressure of second stage of pressure regulatorabout 34 kPa (5 psi) above desired sample cell pressure.(WarningDo not exceed pressure limit of sample cell.)A2.1.2.4 Set the sampl
47、e flow rate to the value to be usedduring sampling.A2.1.2.5 Let the zero gas flow until the recorder trace isstabilized or for 5 min, whichever is greater.A2.1.2.6 Adjust the zero control knob so the trace corre-sponds to a line representing 5 % of scale.A2.1.2.7 Repeat A2.1.2.5.A2.1.2.8 Disconnect
48、the zero gas.A2.1.2.9 Connect the span gas to the analyzer.A2.1.2.10 Repeat A2.1.2.3-A2.1.2.5.A2.1.2.11 Adjust the span control knob until the recorderreads the correct reading, calculated as follows:SCs!Cf3 100D1 5 5 Sc(A2.1)where:Cs= concentration of span gas, ppm(v),Cf= full-scale reading, ppm(v)
49、,Sc= corrected span reading,100 = factor to express concentration in percent of range,and5 = 5 % scale offset.A2.1.2.12 Let the span gas flow until the trace is stabilized,or for 5 min, whichever is greater.A2.1.2.13 Disconnect the span gas.A2.1.2.14 Repeat A2.1.2.2-A2.1.2.8. If no adjustment isrequested, proceed to A2.1.2.15. If adjustment of greater than1 ppm(v) is required, repeat A2.1.2.9-A2.1.2.13.A2.1.2.15 Lock the zero and span knob controls.A2.1.2.16 Connect the 10 % span gas cylinder to the ana-lyzer.A2.1.2.17
