ASTM D3162-94(2005)
(Test Method)Standard Test Method for Carbon Monoxide in the Atmosphere (Continuous Measurement by Nondispersive Infrared Spectrometry)
Standard Test Method for Carbon Monoxide in the Atmosphere (Continuous Measurement by Nondispersive Infrared Spectrometry)
SIGNIFICANCE AND USE
Determination of carbon monoxide is essential to evaluation of many air pollution complexes. This test method derives significance from providing such determination.
Carbon monoxide is formed in the process of incomplete combustion of hydrocarbon fuels, and is a constituent of the exhaust of gasoline engines. The Environmental Protection Agency (EPA) has set primary and secondary air quality standards for CO that are designed to protect the public health and welfare (3, 4).
This test method is suitable for measurements appropriate for the purposes noted in 5.1 and 5.2.
SCOPE
1.1 This test method is applicable to the determination of the carbon monoxide (CO) concentration of the atmosphere between 0.6 mg/m 3 (0.5 ppm(v)) and 115 mg/m3 (100 ppm(v)). The measuring principle is based on the absorption of infrared radiation by CO in the 4.7 m region (1).
1.2 The test method has a limit of detection of about 0.6 mg/m3 (0.5 ppm(v)) carbon monoxide in air.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section for additional precautions.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D3162–94(Reapproved2005)
Standard Test Method for
Carbon Monoxide in the Atmosphere (Continuous
Measurement by Nondispersive Infrared Spectrometry)
This standard is issued under the fixed designation D3162; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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. Scope D3631 Test Methods for Measuring Surface Atmospheric
Pressure
1.1 This test method is applicable to the determination of
E1 Specification for ASTM Liquid-in-Glass Thermometers
the carbon monoxide (CO) concentration of the atmosphere
3 3
E180 Practice for Determining the Precision of ASTM
between 0.6 mg/m (0.5 ppm(v)) and 115 mg/m (100 ppm(v)).
Methods for Analysis and Testing of Industrial and Spe-
The measuring principle is based on the absorption of infrared
2 cialty Chemicals
radiation by CO in the 4.7 µm region (1).
1.2 The test method has a limit of detection of about 0.6
3. Terminology
mg/m (0.5 ppm(v)) carbon monoxide in air.
3.1 Definitions:
1.3 This standard does not purport to address all of the
3.1.1 For definitions of terms used in this test method, refer
safety concerns, if any, associated with its use. It is the
to Terminology D1356 and Practice D3249.
responsibility of the user of this standard to establish appro-
3.2 Definitions of Terms Specific to This Standard:
priate safety and health practices and determine the applica-
3.2.1 fall time—the time interval between initial response
bility of regulatory limitations prior to use. See Section 9 for
and 90 % of final response after a step decrease in input
additional precautions.
concentrations.
2. Referenced Documents
4. Summary of Test Method
2.1 ASTM Standards:
4.1 An atmospheric sample is introduced into a sample
D1356 Terminology Relating to Sampling and Analysis of
conditioning system and then into a nondispersive infrared
Atmospheres
spectrometer (NDIR). The spectrometer measures the absorp-
D1357 Practice for Planning the Sampling of the Ambient
tionbyCOat4.7µmusingtwoparallelinfraredbeamsthrough
Atmosphere
a sample and a reference cell and a selective detector. The
D1914 Practice for Conversion Units and Factors Relating
detectorsignalisconductedtoanamplifiercontrolsection,and
to Sampling and Analysis of Atmospheres
the analyzer output measured on a meter and recording system
D3249 Practice for General Ambient Air Analyzer Proce-
(2).
dures
4.1.1 Some instruments use gas filter correlation to compare
the IR absorption spectrum between the measured gas and
othergasespresentinthegasbeingsampled,inasinglesample
This test method is under the jurisdiction of ASTM Committee D22 on Air
cell. These instruments utilize a concentrated sample of CO as
Quality and is the direct responsibility of Subcommittee D22.03 on Ambient
Atmospheres and Source Emissions.
a filter for the IR transmitted through the sample cell to
Current edition approved Oct. 1, 2005. Published January 2006. Originally
produce a beam that cannot be further attenuated by the CO in
´1
approved in 1973. Last previous edition approved in 2000 as D3162 - 94 (2000) .
the sample, and thus produces the reference beam. The
DOI: 10.1520/D3162-94R05.
broadbandradiationthatpassesthroughthesamplecellandthe
The boldface numbers in parentheses refer to the list of references at the end of
the standard.
CO filter is filtered again by a narrow-band-pass filter that
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
allows only the CO-sensitive portion of the band to pass to the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
detector. The removal of wavelengths sensitive to other gases
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. reduces interferences.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3162–94 (2005)
4.2 The concentration of CO in the sample is determined 7.3 A typical sampling and analyzer system is described in
from a calibration curve prepared using standard calibration Fig. 1.
gases.
7.4 Thermometer—ASTM Thermometer 33C meeting the
requirements of Specification E1 will meet the requirements of
5. Significance and Use
most applications.
7.5 Barograph or Barometer, capable of measuring atmo-
5.1 Determination of carbon monoxide is essential to evalu-
spheric pressure to 60.6 kPa (5 torr). See Test Method D3631.
ation of many air pollution complexes. This test method
derives significance from providing such determination.
8. Reagents and Materials
5.2 Carbon monoxide is formed in the process of incom-
plete combustion of hydrocarbon fuels, and is a constituent of
8.1 Zero Gas—A pressurized cylinder of pure nitrogen
the exhaust of gasoline engines. The Environmental Protection
containing less than 0.1 mg/m CO (0.09 ppm(v)) and having
Agency (EPA) has set primary and secondary air quality
a regulated flow supply.
standards for CO that are designed to protect the public health
8.2 Up-Scale Span Gas—Apressurized cylinder containing
and welfare (3, 4).
a span gas mixture consisting of CO in air corresponding to
5.3 This test method is suitable for measurements appropri-
80 % of full scale. A regulated flow system must be provided.
ate for the purposes noted in 5.1 and 5.2.
8.3 Calibration Gases—Pressured cylinders with regulated
flow control are required. These should contain concentrations
6. Interferences
of CO in air corresponding to the instrument operating range.
In order to establish a calibration curve, nitrogen with CO in
6.1 Degree of interference varies among individual instru-
amounts of 10, 20, 40, and 80 % of full scale are needed.
ments. Consult manufacturer’s specifications for the particular
analyzer to determine whether interferences render the instru- 8.4 CalibrationCertificate—Thespanandcalibrationgases
shouldbecertifiedtobebetween 62 %ofthestatedvalue,and
ment unsuitable for the proposed use.
6.2 The primary interferent is water vapor. With no correc- be supplied in high-pressure cylinders with inside surfaces of a
chromium-molybdenum alloy of low iron content. Replace-
tion, the error may be as high as 11 mg CO/m map edit n (10
ppm(v)) (5). ment cylinder should be verified by procedures in Annex A3.
6.2.1 Water vapor interference can be minimized by using
one of the following steps: 9. Precautions
6.2.1.1 Passing the air sample through silica gel or similar
9.1 Operate analyzer system in nonexplosive areas unless
drying agent.
equipment is explosion-proof.
6.2.1.2 Maintaining constant humidity in the sample and
9.2 The handling and storage of compressed gas cylinders,
calibration gases by refrigeration.
and the installation and use of the analyzer shall follow
6.2.1.3 Saturating the air sample and calibration gases to
Practice D3249. Cylinders shall not be exposed to direct
maintain constant humidity.
sunlight.
6.2.1.4 Using narrow-band optical filters in combination
9.3 Maintain the same sample cell pressure during sampling
with some of the above measures.
and calibration. Use the same sample pump.
6.2.1.5 Where sample is dried or humidified a volume
correction may be necessary.
10. Sampling
6.2.1.6 Gas correlation spectrometers minimize interfer-
10.1 General—For planning sampling programs, refer to
ences and use a narrow-band-pass filter to ensure measuring
Practices D1357 and D3249.
only the CO-sensitive IR wavelengths.
10.2 When sampling the outside ambient atmosphere from
6.3 Interference may be caused by carbon dioxide (CO ).
an enclosure, a sampling line or probe shall be utilized. It shall
The effect of CO interference at concentrations normally
extend at least1m[3ft] from the enclosure, and shall be
present in ambient air is minimal; that is, 1350 mg (750
protected against the entry of precipitation.
ppm(v)) CO /m may give a response equivalent to 0.6 mg
10.3 Since the analyzer may be temperature-sensitive, it
CO/m (0.5 ppm(v)) (5).
shall be placed in an enclosure with atmosphere control so the
6.4 Hydrocarbons at concentrations normally found in the
temperature remains constant within 63°C [65°F].
ambient air do not ordinarily interfere; that is, 325 mg
10.4 Recordthetemperatureandpressureoftheatmosphere
methane/m (500 ppm(v)) may give a response equivalent to
sample.
0.6 mg CO/m (0.5 ppm(v)) (5).
11. Calibration and Standardization
7. Apparatus
11.1 For calibration procedures, refer to Annex A2.
7.1 NDIR Carbon Monoxide in Air Analyzer, complete with
11.2 Frequency of Calibration:
voltagetransformer,analyzersection,amplifier/controlsection,
11.2.1 Multipoint Calibration—A multipoint calibration is
meter, and recording system. Analyzer must meet or exceed
required when:
performance specifications described in Annex A1.
7.2 Sample Conditioning System, consisting of pump, flow 11.2.1.1 The analyzer is first purchased.
control valve, pressure relief valve, flowmeter, filter, and 11.2.1.2 The analyzer has had maintenance that could affect
moisture control. its response characteristics.
D3162–94 (2005)
FIG. 1 Carbon Monoxide Monitoring System Flow Chart
11.2.1.3 When the analyzer shows drift in excess of speci- 14. Precision and Bias
fications as determined when the zero and span calibration is
NOTE 1—The precision statements are based on an interlaboratory
performed (see 11.2.2).
study conducted by Southwest Research Institute, Houston, Tex., in 1972
11.2.2 Zero and Span Calibration—A zero and span cali-
on three samples of carbon monoxide in dry air.Three master cylinders of
bration is required before and after each sampling period, or, if gas containing nominal concentrations of 8, 30, and 53 mg/m were
prepared and subsamples in high-pressure cylinders were submitted to the
the analyzer is used continuously, daily.
collaborating laboratories. Each subsample was analyzed in triplicate and
11.3 Sample Cell Pressure Gauge—The sample cell pres-
the analyses replicated on 2 more days for a total of 810 determinations.
sure gauge shall be calibrated in accordance withAnnexA2,as
The results from the 15 laboratories were evaluated by the procedure
follows:
described in Practice E180.
11.3.1 When the analyzer is purchased.
14.1 Precision: (6)
11.3.2 At 6-month intervals.
14.1.1 Triplicate Analysis—Report the carbon monoxide
11.3.3 When the gauge shows a change larger than 6.9 kPa
(CO) content to 0.1 mg/m . Triplicate runs (Note 2) with a
[1 psi] during a sampling period in which the flow rate did not
range of 0.6 mg/m are acceptable for averaging (95 %
3 3
change more than 60.014 m /h [0.5 ft /h].
confidence level).
NOTE 2—Duplicate runs that agree within 0.5 mg/m are acceptable for
12. Procedure
averaging (95 % confid
...
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