ASTM D7314-10(2015)
(Practice)Standard Practice for Determination of the Heating Value of Gaseous Fuels using Calorimetry and On-line/At-line Sampling
Standard Practice for Determination of the Heating Value of Gaseous Fuels using Calorimetry and On-line/At-line Sampling
SIGNIFICANCE AND USE
5.1 On-line, at-line, in-line and other near-real time monitoring systems that measure fuel gas characteristics such as heating value are prevalent in various gaseous fuel industries and in industries either producing or using gaseous fuel in their industrial processes. The installation and operation of particular systems vary depending on process type, regulatory requirements, and the user’s objectives and performance requirements. This practice is intended to provide guidance for standardized start-up procedures, operating procedures, and quality assurance practices for calorimeter based on-line, at-line, in-line and other near-real time heating value monitoring systems. Users employing gas chromatographic based instrumentation for measurement of gaseous fuel heating value are referred to Practice D7164.
SCOPE
1.1 This practice is for the determination of the heating value measurement of gaseous fuels using a calorimeter. Heating value determination of sample gasses containing water vapor will require vapor phase moisture measurements of the pre-combustion sample gas as well as the non-condensed gasses exiting the calorimeter. Instruments equipped with appropriate conditioners and algorithms may provide heating value results on a net or gross and dry or wet basis.
1.2 This practice is applicable to at-line and in-line instruments that are operated from time to time on a continuous basis.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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.
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Designation: D7314 − 10 (Reapproved 2015)
Standard Practice for
Determination of the Heating Value of Gaseous Fuels using
Calorimetry and On-line/At-line Sampling
This standard is issued under the fixed designation D7314; 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.
1. Scope D4891 Test Method for Heating Value of Gases in Natural
Gas and Flare Gases Range by Stoichiometric Combus-
1.1 This practice is for the determination of the heating
tion
value measurement of gaseous fuels using a calorimeter.
D5287 Practice for Automatic Sampling of Gaseous Fuels
Heatingvaluedeterminationofsamplegassescontainingwater
D5503 Practice for Natural Gas Sample-Handling and Con-
vapor will require vapor phase moisture measurements of the
ditioning Systems for Pipeline Instrumentation
pre-combustion sample gas as well as the non-condensed
D6122 Practice for Validation of the Performance of Multi-
gasses exiting the calorimeter. Instruments equipped with
variate Online,At-Line, and Laboratory Infrared Spectro-
appropriate conditioners and algorithms may provide heating
photometer Based Analyzer Systems
value results on a net or gross and dry or wet basis.
D6299 Practice for Applying Statistical Quality Assurance
1.2 This practice is applicable to at-line and in-line instru-
and Control Charting Techniques to Evaluate Analytical
ments that are operated from time to time on a continuous
Measurement System Performance
basis.
D6621 Practice for Performance Testing of Process Analyz-
1.3 The values stated in SI units are to be regarded as ers for Aromatic Hydrocarbon Materials
standard. No other units of measurement are included in this D7164 Practice for On-line/At-line Heating Value Determi-
standard. nation of Gaseous Fuels by Gas Chromatography
1.4 This standard does not purport to address all of the 2.2 ISO Standards:
ISO 14532 Natural gas—Vocabulary
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- ISO 7504 Gas analysis—Vocabulary
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 3. Terminology
3.1 Definitions:
2. Referenced Documents
3.1.1 at-line instrument, n—See Terminology D4150, Sec-
2.1 ASTM Standards:
tion 3.
D1070 Test Methods for Relative Density of Gaseous Fuels
3.1.2 auto-verification, n—an automated means of introduc-
D1826 TestMethodforCalorific(Heating)ValueofGasesin
ing Calibration Gas Mixtures or Reference Gas Mixtures into
Natural Gas Range by Continuous Recording Calorimeter
an analyzer for the purposes of verifying the analyzer response
D3588 Practice for Calculating Heat Value, Compressibility
without making any adjustments to the calibration parameters
Factor, and Relative Density of Gaseous Fuels
of the analyzer.
D3764 Practice forValidation of the Performance of Process
Stream Analyzer Systems
3.1.3 bypass line, n—Line ultimately vented to the atmo-
D4150 Terminology Relating to Gaseous Fuels
spherethatisusedwhereitisimpracticaltoprovideasufficient
pressure differential.
3.1.3.1 Discussion—The flowrate and pressure loss in the
This practice is under the jurisdiction of ASTM Committee D03 on Gaseous
open-ended line needs to be controlled so as to ensure that the
Fuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At-Line
sample accuracy is not affected from any cooling and conden-
Analysis of Gaseous Fuels.
sation or both (reference ISO 14532 paragraph 2.3.2.9).
CurrenteditionapprovedJune1,2015.PublishedJuly2015.Originallyapproved
in 2008. Last previous edition approved in 2010 as D7314-10. DOI: 10.1520/
D7314-10R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Available from International Organization for Standardization (ISO), 1, ch. de
Standards volume information, refer to the standard’s Document Summary page on la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http://
the ASTM website. www.iso.ch.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7314 − 10 (2015)
3.1.4 calibration gas mixture, n—a certified gas mixture 4.2 The heating value is calculated based upon the instru-
with known composition used for the calibration of a measur- ment’s response to changes in the heating value of the sample
ing instrument or for the validation of a measurement or gas gas using an algorithm.
analytical method.
4.3 Calibration (7.1), maintenance (Section 10), and perfor-
3.1.4.1 Discussion—Calibration Gas Mixtures are the ana-
mance (Section 9) protocols provide a means to validate and
logues of measurement standards in physical metrology (ref-
assess operation of the analyzer.
erence ISO 7504 paragraph 4.1)
5. Significance and Use
3.1.5 calorimeter, n—See Terminology D4150, Section 3.
5.1 On-line, at-line, in-line and other near-real time moni-
3.1.6 continuous fuel monitor, n—an instrument that
toring systems that measure fuel gas characteristics such as
samples gas directly from a source continuously and provides
heating value are prevalent in various gaseous fuel industries
an analytical result on a continuous or semi-continuous basis.
and in industries either producing or using gaseous fuel in their
3.1.7 direct sampling, adj—sampling where there is a direct
industrial processes. The installation and operation of particu-
connection between the sample source and the analytical unit,
lar systems vary depending on process type, regulatory
that is, in-line or on-line instrument.
requirements, and the user’s objectives and performance re-
3.1.8 dry gas, n—See Terminology D4150, Section 3.
quirements. This practice is intended to provide guidance for
3.1.9 fast loop/hot loop, n—Bypass loop that returns standardized start-up procedures, operating procedures, and
quality assurance practices for calorimeter based on-line,
sampled gas to the process line in a closed configuration and
used for environmental and safety considerations. at-line, in-line and other near-real time heating value monitor-
ing systems. Users employing gas chromatographic based
3.1.9.1 Discussion—The loop requires a pressure differen-
tial from the collection point to the discharge point so as to instrumentation for measurement of gaseous fuel heating value
are referred to Practice D7164.
ensure a constant and steady flowrate through the sampling
equipment located in the loop (reference ISO 14532 paragraph
6. Apparatus
2.3.2.8)
6.1 Instrument—Any instrument of standard manufacture,
3.1.10 gross heating value (also called higher heating
with hardware necessary for interfacing to a fuel gas pipeline
value), n—See Terminology D4150, Section 3.
and containing all the features necessary for the intended
3.1.11 heating value, n—the amount of energy per volume
application(s) can be used.
transferred as heat from the complete, ideal combustion of the
6.1.1 Combustion System—Operating parameters employed
gas at standard temperature.
must be capable of converting all of the volatile combustible
3.1.12 in-line instrument, n—See Terminology D4150, Sec- chemical species in the sample into carbon dioxide, water,
tion 3.
nitrogen, nitrogen dioxide, and/or sulfur dioxide, using a dry,
hydrocarbon-free oxidant which is typically air. A change of
3.1.13 net heating value (also called lower heating value),
less than or equal to 1,000 ppm/wt in the moisture content of
n—See Section 3 entitled Terminology, of D4150.
instrumentairbetweencalorimetercalibrationsisacceptableto
3.1.14 on-line instrument, n—SeeTerminologyD4150,Sec-
maintain a statistically insignificant 6 0.1% heating value
tion 3.
accuracy as denoted in Practice D4891. The less than 1,000
3.1.15 reference gas mixture, n—acertifiedgasmixturewith
ppm/wt moisture content control value is easily achieved using
known composition used as a reference standard from which
desiccant or refrigerant air dryers when the air dryers are
other compositional data are derived.
maintained according to the manufacturer’s recommendations.
3.1.15.1 Discussion— Reference Gas Mixtures are the ana-
Instrumentation must satisfy or exceed analytic performance
logues of reference standards (ISO 7504 paragraph 4.1.1)
characteristics for accuracy and precision for the intended
3.1.16 wet gas, n—See Terminology D4150, Section 3. application without encountering unacceptable interference or
bias. In addition, components in contact with sample streams
3.2 Acronyms:
suchastubingandvalvingmustbeconstructedofsuitableinert
3.2.1 SOP, n—Standard Operating Procedure.
or passivated materials to ensure that the composition of the
3.2.2 QA, n—Quality Assurance.
sampled gas is not altered.
4. Summary of Practice 6.2 Sample Probes/Sample Extraction—The location and
orientation of sampling components are critical for ensuring
4.1 Arepresentative sample of the gaseous fuel is extracted
that a representative sample is analyzed. The locations and
from a process pipe, a pipeline, or other gaseous fuel stream
orientation of sampling components should be selected based
and is transferred to an analyzer sampling system. After
upon sound analytic and engineering considerations. Sampling
conditioning that maintains the sample integrity, the sample is
practices for gaseous fuels can be found in Practice D5287.
introduced into a calorimeter. Excess extracted process or
sample gas is vented to the atmosphere, a flare header, or is 6.3 Sample Inlet System—An automated gas sampling valve
returnedtotheprocessinaccordancewithapplicableeconomic is required in many applications. All sampling system compo-
and environmental requirements and regulations. Post- nents in contact with the fuel stream must be constructed of
combustion gasses from the calorimeter are typically vented to inert or passivated materials. Care should be taken to ensure
the atmosphere. that the extracted sample is maintained in a single clean
D7314 − 10 (2015)
gaseous phase. The addition of heat at the point of pressure calculational methodology employed, or both. Methods related
reduction or along the sample line to the analyzer may be to determining the relative density of gaseous fuels can be
required to ensure that the sample is maintained in the gas
found in Practice D1070. Mixtures of major components are
phase. The need for heat tracing and the extent to which it is
typically specified to achieve the desired heating value. A
required will be site specific. In general, considerations im-
minimum of major representative components is frequently
pactingheattracingdecisionsincludesamplecompositionsand
used.The number of components used is frequently minimized
the expected variations, ambient temperature fluctuations,
for economical reasons and to reduce the probability of error
operating pressures, and anticipated pressure differentials in
during the preparation of the Calibration Gas Mixture. In order
sample system components. Sample filtration should be uti-
to ensure their accuracy and stability by preventing condensa-
lized as required to remove particulate matter from the ex-
tion and degradation, Calibration Gas Mixtures must be main-
tracted sample.
tained within the temperature range specified by the manufac-
6.3.1 Combustion Air, Sample, and Carrier Gas Control—
turer. If there is any doubt concerning the validity of the
Constant flow control of combustion air, sample gas, and
Calibration Gas Mixture, a Reference Gas Mixture should be
carrier gas, if required by the measurement application, is
used to verify the validity of the Calibration Gas Mixture.
necessary for optimum and consistent analytical performance.
Control is typically achieved by use of pressure regulators and
8. Equipment Siting and Installation
fixed flow restrictors. Ambient, combustion air, sample, and
8.1 The siting and installation of an at-line or on-line
carrier gas temperature control is generally vital for ensuring
consistent operation of flow control devices. The gas flow is monitor is critical for collecting representative information on
measured and verified by appropriate means and adjusted as heating value content. Factors that should be considered in
necessary. siting an instrument include hazardous area rating, ease of
6.3.2 Detectors—Common calorimetry heating value detec- calibration, ease of access for repair or maintenance, sample
tion systems include stoichiometric combustion (Test Method
uniformity at the sampling point, appropriateness of samples
D4891), continuous recording calorimeters (Test Method
from a sampling location, ambient conditions, and of course
D1826), non-stoichiometric combustion, and residual oxygen
safety issues. A sample inlet system capable of operating
detection calorimeters. Other detectors can be used provided
continuously at or above the maximum operating sample
they have appropriate linearity, accuracy, sensitivity and mea-
temperatureisnecessary.Thelocationofthesampleinlettothe
surement range for the selected application. In selecting a
analyzer relative to the sample extraction point is critical to
detector, the user should consider the linearity and sensitivity
obtaining timely analytical results. Ideally, the analyzer is
of a particular detection system prior to installation. The user
close-coupled to the sample extraction point and there is an
should also consider potential sample compositional effects
insignificant sampling lag time. Normally, the analyzer is
that may influence the reported heating value.
mounted at some distance away from the sample extraction
point. This increased distance will result in increased lag time
6.4 Data Acquisition—Data acquisition and storage can be
accomplished using a number of devices and media. Following between when a sample is extracted from a process and when
are some examples: an analytical result is reported. The maximum allowable lag
6.4.1 Recorder—A0 to 1 millivolt or a 4-20 milliamp range time depends on the specifics of the sampling location relative
recording potentiometer or equivalent, with a full-scale re-
totheprocessbeingsampled.Afastlooporby-passlinecanbe
sponse time of 2 s or less can be used mounted locally or
usedtominimizethelagtime.Thesamplingfrequencyrelative
remotely.
totheprocessbandwidthiscriticaltoensuringthatthereported
6.4.2 Communications Systems—Efficient communications
analytical results adequately represent the process being moni-
between the analyz
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7314 − 10 D7314 − 10 (Reapproved 2015)
Standard Practice for
Determination of the Heating Value of Gaseous Fuels using
Calorimetry and On-line/At-line Sampling
This standard is issued under the fixed designation D7314; 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.
1. Scope
1.1 This practice is for the determination of the heating value measurement of gaseous fuels using a calorimeter. Heating value
determination of sample gasses containing water vapor will require vapor phase moisture measurements of the pre-combustion
sample gas as well as the non-condensed gasses exiting the calorimeter. Instruments equipped with appropriate conditioners and
algorithms may provide heating value results on a net or gross and dry or wet basis.
1.2 This practice is applicable to at-line and in-line instruments that are operated from time to time on a continuous basis.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
D1070 Test Methods for Relative Density of Gaseous Fuels
D1826 Test Method for Calorific (Heating) Value of Gases in Natural Gas Range by Continuous Recording Calorimeter
D3588 Practice for Calculating Heat Value, Compressibility Factor, and Relative Density of Gaseous Fuels
D3764 Practice for Validation of the Performance of Process Stream Analyzer Systems
D4150 Terminology Relating to Gaseous Fuels
D4891 Test Method for Heating Value of Gases in Natural Gas and Flare Gases Range by Stoichiometric Combustion
D5287 Practice for Automatic Sampling of Gaseous Fuels
D5503 Practice for Natural Gas Sample-Handling and Conditioning Systems for Pipeline Instrumentation
D6122 Practice for Validation of the Performance of Multivariate Online, At-Line, and Laboratory Infrared Spectrophotometer
Based Analyzer Systems
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6621 Practice for Performance Testing of Process Analyzers for Aromatic Hydrocarbon Materials
D7164 Practice for On-line/At-line Heating Value Determination of Gaseous Fuels by Gas Chromatography
2.2 ISO Standards:
ISO 14532 Natural gas – Vocabularygas—Vocabulary
ISO 7504 Gas analysis – Vocabulary analysis—Vocabulary
3. Terminology
3.1 Definitions:
3.1.1 at-line instrument, n—See Terminology D4150, Section 3.
This practice is under the jurisdiction of ASTM Committee D03 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At-Line Analysis
of Gaseous Fuels.
Current edition approved Jan. 1, 2010June 1, 2015. Published February 2010July 2015. Originally approved in 2008. lastLast previous edition approved in 20082010 as
D7314D7314.-08-10. DOI: 10.1520/D7314-10.10.1520/D7314-10R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http://www.iso.ch.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7314 − 10 (2015)
3.1.2 auto-verification, n—an automated means of introducing Calibration Gas Mixtures or Reference Gas Mixtures into an
analyzer for the purposes of verifying the analyzer response without making any adjustments to the calibration parameters of the
analyzer.
3.1.3 bypass line, n—Line ultimately vented to the atmosphere that is used where it is impractical to provide a sufficient pressure
differential.
3.1.3.1 Discussion—
The flowrate and pressure loss in the open-ended line needs to be controlled so as to ensure that the sample accuracy is not affected
from any cooling and condensation or both (reference ISO 14532 paragraph 2.3.2.9).
3.1.4 calibration gas mixture, n—a certified gas mixture with known composition used for the calibration of a measuring
instrument or for the validation of a measurement or gas analytical method.
3.1.4.1 Discussion—
Calibration Gas Mixtures are the analogues of measurement standards in physical metrology (reference ISO 7504 paragraph 4.1)
3.1.5 calorimeter, n—See Terminology D4150, Section 3.
3.1.6 continuous fuel monitor, n—an instrument that samples gas directly from a source continuously and provides an analytical
result on a continuous or semi-continuous basis.
3.1.7 direct sampling, adj—sampling where there is a direct connection between the sample source and the analytical unit, that
is, in-line or on-line instrument.
3.1.8 dry gas, n—See Terminology D4150, Section 3.
3.1.9 fast loop/hot loop, n—Bypass loop that returns sampled gas to the process line in a closed configuration and used for
environmental and safety considerations.
3.1.9.1 Discussion—
The loop requires a pressure differential from the collection point to the discharge point so as to ensure a constant and steady
flowrate through the sampling equipment located in the loop (reference ISO 14532 paragraph 2.3.2.8)
3.1.10 gross heating value (also called higher heating value), n—See Terminology D4150, Section 3.
3.1.11 heating value, n—the amount of energy per volume transferred as heat from the complete, ideal combustion of the gas
at standard temperature.
3.1.12 in-line instrument, n—See Terminology D4150, Section 3.
3.1.13 net heating value (also called lower heating value), n—See Section 3 entitled Terminology, of D4150.
3.1.14 on-line instrument, n—See Terminology D4150, Section 3.
3.1.15 reference gas mixture, n—a certified gas mixture with known composition used as a reference standard from which other
compositional data are derived.
3.1.15.1 Discussion—
Reference Gas Mixtures are the analogues of reference standards (ISO 7504 paragraph 4.1.1)
3.1.16 wet gas, n—See Terminology D4150, Section 3.
3.2 Acronyms:
3.2.1 SOP, n—Standard Operating Procedure.
3.2.2 QA, n—Quality Assurance.
4. Summary of Practice
4.1 A representative sample of the gaseous fuel is extracted from a process pipe, a pipeline, or other gaseous fuel stream and
is transferred to an analyzer sampling system. After conditioning that maintains the sample integrity, the sample is introduced into
a calorimeter. Excess extracted process or sample gas is vented to the atmosphere, a flare header, or is returned to the process in
accordance with applicable economic and environmental requirements and regulations. Post-combustion gasses from the
calorimeter are typically vented to the atmosphere.
D7314 − 10 (2015)
4.2 The heating value is calculated based upon the instrument’s response to changes in the heating value of the sample gas using
an algorithm.
4.3 Calibration (7.1), maintenance (Section 10), and performance (Section 9) protocols provide a means to validate and assess
operation of the analyzer.
5. Significance and Use
5.1 On-line, at-line, in-line and other near-real time monitoring systems that measure fuel gas characteristics such as heating
value are prevalent in various gaseous fuel industries and in industries either producing or using gaseous fuel in their industrial
processes. The installation and operation of particular systems vary depending on process type, regulatory requirements, and the
user’s objectives and performance requirements. This practice is intended to provide guidance for standardized start-up procedures,
operating procedures, and quality assurance practices for calorimeter based on-line, at-line, in-line and other near-real time heating
value monitoring systems. Users employing gas chromatographic based instrumentation for measurement of gaseous fuel heating
value are referred to Practice D7164.
6. Apparatus
6.1 Instrument—Any instrument of standard manufacture, with hardware necessary for interfacing to a fuel gas pipeline and
containing all the features necessary for the intended application(s) can be used.
6.1.1 Combustion System—Operating parameters employed must be capable of converting all of the volatile combustible
chemical species in the sample into carbon dioxide, water, nitrogen, nitrogen dioxide, and/or sulfur dioxide, using a dry,
hydrocarbon-free oxidant which is typically air. A change of less than or equal to 1,000 ppm/wt in the moisture content of
instrument air between calorimeter calibrations is acceptable to maintain a statistically insignificant 6 0.1% heating value accuracy
as denoted in Practice D4891. The less than 1,000 ppm/wt moisture content control value is easily achieved using desiccant or
refrigerant air dryers when the air dryers are maintained according to the manufacturer’s recommendations. Instrumentation must
satisfy or exceed analytic performance characteristics for accuracy and precision for the intended application without encountering
unacceptable interference or bias. In addition, components in contact with sample streams such as tubing and valving must be
constructed of suitable inert or passivated materials to ensure that the composition of the sampled gas is not altered.
6.2 Sample Probes/Sample Extraction—The location and orientation of sampling components are critical for ensuring that a
representative sample is analyzed. The locations and orientation of sampling components should be selected based upon sound
analytic and engineering considerations. Sampling practices for gaseous fuels can be found in Practice D5287.
6.3 Sample Inlet System—An automated gas sampling valve is required in many applications. All sampling system components
in contact with the fuel stream must be constructed of inert or passivated materials. Care should be taken to ensure that the
extracted sample is maintained in a single clean gaseous phase. The addition of heat at the point of pressure reduction or along
the sample line to the analyzer may be required to ensure that the sample is maintained in the gas phase. The need for heat tracing
and the extent to which it is required will be site specific. In general, considerations impacting heat tracing decisions include
sample compositions and the expected variations, ambient temperature fluctuations, operating pressures, and anticipated pressure
differentials in sample system components. Sample filtration should be utilized as required to remove particulate matter from the
extracted sample.
6.3.1 Combustion Air, Sample, and Carrier Gas Control—Constant flow control of combustion air, sample gas, and carrier gas,
if required by the measurement application, is necessary for optimum and consistent analytical performance. Control is typically
achieved by use of pressure regulators and fixed flow restrictors. Ambient, combustion air, sample, and carrier gas temperature
control is generally vital for ensuring consistent operation of flow control devices. The gas flow is measured and verified by
appropriate means and adjusted as necessary.
6.3.2 Detectors—Common calorimetry heating value detection systems include stoichiometric combustion (Test Method
D4891), continuous recording calorimeters (Test Method D1826), non-stoichiometric combustion, and residual oxygen detection
calorimeters. Other detectors can be used provided they have appropriate linearity, accuracy, sensitivity and measurement range
for the selected application. In selecting a detector, the user should consider the linearity and sensitivity of a particular detection
system prior to installation. The user should also consider potential sample compositional effects that may influence the reported
heating value.
6.4 Data Acquisition—Data acquisition and storage can be accomplished using a number of devices and media. Following are
some examples:
6.4.1 Recorder—A 0 to 1 millivolt or a 4-20 milliamp range recording potentiometer or equivalent, with a full-scale response
time of 2 s or less can be used mounted locally or remotely.
6.4.2 Communications Systems—Efficient communications between the analyzer and the host depend on resolving any and all
interface issues. Signals to and from the host are typically isolated from each other in an appropriate manner.
D7314 − 10 (2015)
7. Reagents and Materials
7.1 Warning—Compressed gas standards should only be handled in well ventilated locations away from sparks and flames.
Improper handling of compressed gas cylinders containing calibration standards or air can result in explosion. Compressed air
supports combustion.
7.1.1 Standards—Components in the Calibration Gas Mixture should be representative of the monitored gas. The heating value
is either determined instrumentally or is calculated using a certified gas composition of the standard. Practice D3588 or other
methods as required for regulatory purposes can be used to calculate the heating value of a gas mixture. Other heating value
calculational algorithms can be used so long as all interested parties are advised of and are in agreement with the calculational
methodology employed, or both. Methods related to determining the relative density of gaseous fuels can be found in Practice
D1070. Mixtures of major components are typically specified to achieve the desired heating value. A minimum of major
representative components is frequently used. The number of components used is frequently minimized for economical reasons
and to reduce the probability of error during the preparation of the Calibration Gas Mixture. In order to ensure their accuracy and
stability by preventing condensation and degradation, Calibration Gas Mixtures must be maintained within the temperature range
specified by the manufacturer. If there is any doubt concerning the validity of the Calibration Gas Mixture, a Reference Gas
Mixture should be used to verify the validity of the Calibration Gas M
...
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