1、Designation: D 3162 94 (Reapproved 2005)Standard Test Method forCarbon Monoxide in the Atmosphere (ContinuousMeasurement by Nondispersive Infrared Spectrometry)1This standard is issued under the fixed designation D 3162; the number immediately following the designation indicates the year oforiginal
2、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.This standard has been approved for use by agencies of the Department of Defens
3、e.1. Scope1.1 This test 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
4、 has a limit of detection 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 deter
5、mine the applica-bility of regulatory limitations prior to use. See Section 9 foradditional precautions.2. Referenced Documents2.1 ASTM Standards:3D 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 1357 Practice for Planning the Sampling of the AmbientAtmosphereD 1914 Practice for C
6、onversion Units and Factors Relatingto Sampling and Analysis of AtmospheresD 3249 Practice for General Ambient Air Analyzer Proce-duresD 3631 Test Methods for Measuring Surface AtmosphericPressureE1 Specification for ASTM Liquid-in-Glass ThermometersE 180 Practice for Determining the Precision of AS
7、TMMethods forAnalysis and Testing of Industrial and SpecialtyChemicals3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, referto Terminology D 1356 and Practice D 3249.3.2 Definitions of Terms Specific to This Standard:3.2.1 fall timethe time interval between init
8、ial responseand 90 % of final 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 us
9、ing two parallel infrared 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 absorp
10、tion spectrum between the 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, a
11、nd thus produces the reference 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 inte
12、rferences.4.2 The concentration 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 provid
13、ing such determination.5.2 Carbon monoxide is formed in the process of incom-plete combustion of hydrocarbon fuels, and is a constituent ofthe exhaust of gasoline engines. The Environmental Protection1This test method is under the jurisdiction of ASTM Committee D22 on AirQuality and is the direct re
14、sponsibility of Subcommittee D22.03 on AmbientAtmospheres and Source Emissions.Current edition approved Oct. 1, 2005. Published January 2006. Originallyapproved in 1973. Last previous edition approved in 2000 as D 3162 - 94 (2000)e1.2The boldface numbers in parentheses refer to the list of reference
15、s 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 information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 10
16、0 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Agency (EPA) has set primary and secondary air qualitystandards for CO that are designed to protect the public healthand welfare (3, 4).5.3 This test method is suitable for measurements appropri-ate for the purposes no
17、ted 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 instru-ment unsuitable for the proposed use.6.2 The primary interferent is water vapor. Wi
18、th 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 gel or similardrying agent.6.2.1.2 Maintaining constant humidity in the sample andcalibr
19、ation 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 Where sample is dried or humidified a volumecorrection may be necessary.6.2.1.6 Gas correl
20、ation 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 CO2interference at concentrations normallypresent in ambient air is minimal; that is, 1350 mg (75
21、0ppm(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) may give a response equivalent to0.6 mg CO/m3(0.5 ppm(v) (5).7. Apparatus7.1 NDIR Carbon Mo
22、noxide 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 Sample Conditioning System, consisting of pump, flowcontrol valve, pressure relief valve
23、, flowmeter, filter, andmoisture control.7.3 A typical sampling and analyzer system is described inFig. 1.7.4 ThermometerASTM Thermometer 33C meeting therequirements of Specification E1will meet the requirements ofmost applications.FIG. 1 Carbon Monoxide Monitoring System Flow ChartD 3162 94 (2005)2
24、7.5 Barograph or Barometer, capable of measuring atmo-spheric pressure to 60.6 kPa (5 torr). See Test Method D 3631.8. Reagents and Materials8.1 Zero GasA pressurized cylinder of pure nitrogencontaining less than 0.1 mg/m3CO (0.09 ppm(v) and havinga regulated flow supply.8.2 Up-Scale Span GasA press
25、urized 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 regulatedflow control are required. These should contain concentrationsof CO in air corresponding to the ins
26、trument 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 gasesshould be certified to be between 62 % of the stated value, andbe supplied in high-pressure cylinde
27、rs 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 areas unlessequipment is explosion-proof.9.2 The handling and storage of compressed gas cylinders,an
28、d the installation and use of the analyzer shall followPractice D 3249. Cylinders shall not be exposed to directsunlight.9.3 Maintain the same sample cell pressure during samplingand calibration. Use the same sample pump.10. Sampling10.1 GeneralFor planning sampling programs, refer toPractices D 135
29、7 and D 3249.10.2 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 the entry of precipitation.10.3 Since the analyzer may be temperature-sensitive, itshall be place
30、d 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 calibration procedures, refer to Annex A2.11.2 Frequency of Calibration:11.2.1 Multipoint Calibrati
31、onA 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.11.2.1.3 When the analyzer shows drift in excess of speci-fications as determined when the zero and span calibration isperformed
32、 (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 Pressure GaugeThe sample cell pres-sure gauge shall be calibrated in accordance withAnnexA2,asfollows:11.3.1 W
33、hen 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 60.014 m3/h 0.5 ft3/h.12. Procedure12.1 After proper calibration has been established, check allanalyzer sys
34、tem 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 curve in ppm(v).12.3 Perform the operational checks described in Annex A4daily, or during each sampling perio
35、d (7).13. Calculation13.1 To convert ppm(v) to mg/m3, refer to Practice D 1914.14. Precision and BiasNOTE 1The precision statements are based on an interlaboratorystudy conducted by Southwest Research Institute, Houston, Tex., in 1972on three samples of carbon monoxide in dry air. Three master cylin
36、ders 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 analyzed in triplicate andthe analyses replicated on 2 more days for a total of 810 determinations.The results
37、 from the 15 laboratories were evaluated by the proceduredescribed in Practice E 180.14.1 Precision: (6)14.1.1 Triplicate AnalysisReport the carbon monoxide(CO) content to 0.1 mg/m3. Triplicate runs (Note 2) with arange of 0.6 mg/m3are acceptable for averaging (95 %confidence level).4NOTE 2Duplicate
38、 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 determinations)obtained by the same analyst on different days has beenestimated to 0.44 mg/m3at 140 df. Two su
39、ch values should beconsidered suspect (95 % confidence level) if they differ bymore than 1.2 mg/m3(see Note 2).14.1.3 Reproducibility (Multilaboratories)The standarddeviation of the mean (each the average of triplicate determi-nations) obtained by analysts in different laboratories has beenestimated
40、 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 dependent on the bias ofthe calibrations of the gases used in pr
41、eparing the calibrationcurve.4Supporting data giving the results of the collaborative test have been filed atASTM, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA194282959, in Research Report File No. RR: D-22-1000.D 3162 94 (2005)315. Keywords15.1 ambient atmospheres; analysis; carbon mon
42、oxide; non-dispersive infrared spectroscopy; samplingANNEXES(Mandatory Information)A1. MINIMUM PERFORMANCE SPECIFICATIONS FOR NONDISPERSIVE INFRARED CARBON 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)
43、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(64 %) (maximum)A1.8 Operation Period(minimum) 3 daysA1.9 Noise Level60.5 % of full scaleA1.10 Operating Temperature Range5 to 40CA1.11 Operating
44、Temperature Fluctuation65CA1.12 Linearity2 % of full scaleFIG. 2 Calibration Set-up for Pressure GaugesD 3162 94 (2005)4A2. CALIBRATION PROCEDURESA2.1 Analyzer Multipoint CalibrationA2.1.1 Cylinder Pressure CheckCheck the cylinder pres-sure of each calibration gas. If a cylinder pressure is less tha
45、n2.1 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 stabilize (or in accordance withmanufacturers instructions).A2.1.2.2 Connect the zero gas cylinder to the analyzer.A2.1.2.3 Set pressure of sec
46、ond 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 sample 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, whic
47、hever 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 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
48、 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),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 f
49、low 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 Repeat A2.1.2.3-A2.1.2.5. Do not make any ad-justments.A2.1.2.18 Disconnect the cylinder.A2.1.2.19 Repeat A2.1.2.16-A2.1.2.18 for the 20 an
