ASTM D1826-94(2017)
(Test Method)Standard Test Method for Calorific (Heating) Value of Gases in Natural Gas Range by Continuous Recording Calorimeter
Standard Test Method for Calorific (Heating) Value of Gases in Natural Gas Range by Continuous Recording Calorimeter
SIGNIFICANCE AND USE
4.1 This test method provides an accurate and reliable method to measure the total calorific value of a fuel gas, on a continuous basis, which is used for regulatory compliance, custody transfer, and process control.
SCOPE
1.1 This test method covers the determination with the continuous recording calorimeter (Note 1) of the total calorific (heating) value of fuel gas produced or sold in the natural gas range from 900 to 1200 Btu/standard ft3.
Note 1: An extensive investigation of the accuracy of the Cutler-Hammer recording gas calorimeter, when used with gases of high heating value, was made by the National Bureau of Standards in 1957 under a research project sponsored by the American Gas Association.
1.2 The subjects covered in this test method appear in the following sections:
Sections
Air-Gas Ratio Test
11
Apparatus
5
Basis of Measurement
14
Cold Balance Test
10
Compensation of Complicating Factors
13
Condition of Gas Sample
7
Definitions
2
Installation of Apparatus
6
Maintenance
Appendix X1
Operating Precautions
Appendix X2
Operation and Checking of Apparatus
9
Precision
15
Scope
1
Significance and Use
4
Standardization of Calorimeter
12
Standardization, Preliminary, of Calorimeter by Hydrogen
8
Summary of Test Method
3
1.3 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.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:D1826 −94 (Reapproved 2017)
Standard Test Method for
Calorific (Heating) Value of Gases in Natural Gas Range by
Continuous Recording Calorimeter
This standard is issued under the fixed designation D1826; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Terminology
1.1 This test method covers the determination with the 2.1 Definitions of Terms Specific to This Standard:
continuous recording calorimeter (Note 1) of the total calorific 2.1.1 The most important terms used in connection with the
(heating) value of fuel gas produced or sold in the natural gas
determination of the calorific value of gaseous fuels in record-
range from 900 to 1200 Btu/standard ft . ing calorimetry are as follows:
2.1.2 British Thermal Unit, or Btu—is the defined Interna-
NOTE 1—An extensive investigation of the accuracy of the Cutler-
tional Tables British thermal unit (symbol Btu).
Hammer recording gas calorimeter, when used with gases of high heating
value, was made by the National Bureau of Standards in 1957 under a
NOTE 2—The defining relationships are:
research project sponsored by the American Gas Association.
−1 −1
(a) 1 Btu·lb =2.326 J·g (exact)
1.2 The subjects covered in this test method appear in the (b) 1 lb=453.59237 g (exact).
By these relationships, 1 Btu = 1 055.05585262 J (exact). For most
following sections:
purposes, the value rounded to 1 Btu = 1 055.056 J is adequate.
Sections
2.1.3 combustion air—airusedforcombustion,atotalofthe
Air-Gas Ratio Test 11
Apparatus 5
portion mixed with the gas as primary air and the air supplied
Basis of Measurement 14
around the burner tube as secondary air (theoretical air plus
Cold Balance Test 10
excess air).
Compensation of Complicating Factors 13
Condition of Gas Sample 7
2.1.4 flue gases—the products, of combustion remaining in
Definitions 2
Installation of Apparatus 6 the gaseous state, together with any excess air.
Maintenance Appendix X1
2.1.5 heat-absorbing air—the heat exchange medium used
Operating Precautions Appendix X2
Operation and Checking of Apparatus 9
to absorb the heat of combustion derived from the burning of
Precision 15
gaseous fuel.
Scope 1
Significance and Use 4
2.1.6 saturated basis—the expressed total calorific value of
Standardization of Calorimeter 12
a gas when it is saturated with water vapor at standard
Standardization, Preliminary, of Calorimeter by Hydrogen 8
temperature and pressure; 1 ft of this gas is equivalent in dry
Summary of Test Method 3
gascontentto0.9826ft ofdrygasatthestandardtemperature
1.3 This standard does not purport to address all of the
of 60°F and standard pressure of 14.73 psia.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
NOTE 3—The definitions given in 2.1.6 and 2.1.10 are for total calorific
priate safety and health practices and determine the applica- (heating) values per standard cubic foot of gas. The definitions corre-
sponding to any other unit quantity of gas are obtained by substituting the
bility of regulatory limitations prior to use.
name of the desired unit in place of the term “standard cubic foot” in the
1.4 This international standard was developed in accor-
definitions. Methods of calculating calorific (heating) values per cubic
dance with internationally recognized principles on standard-
foot of gas under any desired conditions of pressure, temperature, and
ization established in the Decision on Principles for the
water vapor content are specified in Section 14.
Development of International Standards, Guides and Recom-
2.1.7 standard cubic foot of gas—the quantity of any gas
mendations issued by the World Trade Organization Technical
that at standard temperature and under standard pressure will
Barriers to Trade (TBT) Committee. 3
fill a space of 1 ft when in equilibrium with liquid water.
2.1.8 standard pressure—is 14.73 psia.
ThistestmethodisunderthejurisdictionofASTMCommitteeD03onGaseous
NOTE 4—This is the pressure base adopted by the American National
Fuels and is the direct responsibility of Subcommittee D03.03 on Determination of
Standards Institute in 1969 (Z132.1). According to Dalton’s law, this is
Heating Value and Relative Density of Gaseous Fuels.
equivalent to stating that the partial pressure of the gas is:
Current edition approved April 1, 2017. Published April 2017. Originally
approved in 1961. Last previous edition approved in 2010 as D1826–94(2010). 14.73−0.25636=14.47364 psia
DOI: 10.1520/D1826-94R17. where 0.25636 is the vapor pressure of water in psia at 60°F.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1826−94 (2017)
2.1.9 standard temperature—60°F, based on the interna- 5. Apparatus
tional practical temperature scale of 1968.
5.1 The recording calorimeter (Note 5) consists of two
2.1.10 total calorific value (gross heating value, higher
major units; the tank unit or calorimeter proper, Fig. 1, Fig. 2,
heating value)—of a gas is the number of British thermal units
and Fig. 3, in which the heating value of the test gas sample is
evolved by the complete combustion at constant pressure of
measured; and the recording unit which translates the heat
one standard cubic foot of gas with air, the temperature of the
measurements into an indication of calorific (heating) value
gas, air, and products of combustion being 60°F, and all the
and records it graphically on a strip chart recorder or digitally
water formed by the combustion reaction being condensed to
if the new SMART-CAL is used (Note 6).
the liquid state.
NOTE 5—The previous specified pressure base was the absolute
pressure of a column of pure mercury 30 in. in height at 32°F and under
3. Summary of Test Method
standard gravity (32.174 ft/s ). This is equivalent to 14.7346 psia.
NOTE 6—Refer to specific manufacturer’s manual for pictures of the
3.1 The heating value is determined by imparting all of the
recorder or the SMART-CAL, a digital indicating or printing device,
heat obtained from the combustion of the test gas to a stream
currently used on new or retrofitted calorimeters.
of air and measuring the rise in temperature of the air. The
6. Installation of Apparatus
streams of test gas and heat absorbing air are maintained in
fixed volumetric proportion to each other by metering devices
6.1 To secure the precise results that are possible with the
similar to the ordinary wet test meters geared together and
recording calorimeter, it is important that the instrument be
driven from a common electric motor.The meters are mounted
installed so that the surrounding conditions will not introduce
in a tank of water, the level of which is maintained and the
errors. In general, more precise results will be secured when a
temperature of which determines the temperature of the enter-
narrow range is maintained on the various conditions of the
ing gas and air.
calorimeter environment.
3.2 The flue gas resulting from combustion of the gas
6.2 Calorimeter Room—A typical installation of a single
(combustion products plus excess combustion air) is kept
recording calorimeter is shown in Fig. 4. The detailed require-
separate from the heat-absorbing air and is cooled to a few
ments for the calorimeter room are given in Table 1.
degrees above the initial temperature of gas and air. The water
NOTE 7—Adetailed discussion of these requirements is included in the
formed in the combustion is practically all condensed to the
latest edition of the manufacturer’s instruction book covering the record-
liquidstate.Consequently,thetemperatureriseproducedinthe
ing calorimeter. The information can be applied to all models of the
heat-absorbing air is directly proportional to the heating value instrument.
NOTE 8—The dimensions shown in Fig. 4 are for the latest model
of the gas. Since all the heat from the combustion of the test
calorimeter.
gas sample, including the latent heat of vaporization of the
6.3 Gas Connection—Locate the sample line that brings the
water vapor formed in the combustion, is imparted to the
heat-absorbing air, the calorimeter makes a direct determina- gas to be tested to the calorimeter tank unit so that the heating
valueisactuallyrepresentativeoftheconditionsexistinginthe
tionoftotalheatingvalue.Thetemperatureriseismeasuredby
nickel resistance thermometers and is translated into Btu per main gas line. Keep the sample line time lag as small as
possible by (1) locating the calorimeter tank unit close to the
standard cubic foot.
sample point, (2) running the sample line of small size pipe
4. Significance and Use
(Note 9), and (3) operating the sample line at low pressure.
Provideanadditionalpurgeburnerorableedtoalowpressure
4.1 This test method provides an accurate and reliable
point.
method to measure the total calorific value of a fuel gas, on a
continuous basis, which is used for regulatory compliance,
NOTE 9—Time lag may be calculated on the basis that the calorimeter
custody transfer, and process control. uses about 1.2 ft /h.
FIG. 1 Calorimeter—Schematic Flow Diagram
D1826−94 (2017)
FIG. 2 Calorimeter—Layout Diagram
performance, it will be necessary to use distilled or demineralized water
6.4 Electrical Wiring—The four leads for the resistance
withapHof7.
thermometers between either the recorder or the Smart-Cal
NOTE 12—For actual test instructions and other information, see the
junction box and the tank unit shall be of No. 12 gage,
appropriate instruction book provided by the manufacturer.
insulated, solid copper wire without joints. Run in a separate
rigid metal conduit which is grounded and contains no other
6.6 Recorder Installation—Install the recorder so that the
leads (Note 10). Power circuit wiring should be No. 14 gage,
instrument is reasonably free from mechanical vibration. This
insulated, solid or stranded, copper wire. Provide the supply
is particularly important for those models in which a
line with a suitably fused disconnect switch. For the model
suspension-type galvanometer is used.
using an electronic recorder, it is essential that a suitable
ground connection be made at both the recorder and the tank
7. Condition of Gas Sample
unit. Details are given in the manufacturer’s instructions.
7.1 Physical Contamination—The gas sample should be
NOTE 10—Where outdoor or underground wiring must be used, special
free of dust, water, and other entrained solids. If experience
care should be exercised to protect the terminals of the cables from
indicates that the foreign materials can enter the sample line,
moisture to prevent grounds in the measuring circuit.
install a suitable sample line filter. To avoid any problems in
6.5 Initial Installation—When the calorimeter is first
the line from water accumulation, pitch the line to a low point
installed, fill the tank unit with water (Note 11) and adjust it to
and provide a drip leg.
a temperature that is 2 to 5°F below the normal room
temperature. Allow the unit to operate at least 24 h before
7.2 Chemical Contamination—The sample line should be
performing the detailed calibration tests.
practically free from hydrogen sulfide. A small, low-capacity
NOTE 11—The water may be ordinary tap water supplied by most
purifier can be constructed using iron oxide on wood shavings
municipalities.If,however,itisfoundthatexcessivequantitiesofdeposits
as the purifying material. The time lag in the purifier adds to
and sludge are formed in short duration which interfere with satisfactory
D1826−94 (2017)
FIG. 3 Calorimeter Combustion Chamber
NOTE 1—For each additional calorimeter at least 50% additional space is required; for example, for two calorimeters the room should be 12 by 18
ft inside; for three calorimeters 15 by 18 ft.
FIG. 4Calorimeter Room
D1826−94 (2017)
TABLE 1 Calorimeter Room Requirements
Detail Requirements
Space 1000 ft, min.
Ceiling height 8 ft, min.
Side wall widths 10 and 13 ft, min.
Windows One, on side normally away from sun (in northern hemisphere, the northern side).
Doors One, wth 3-ft opening, not in window wall. A door check is desirable.
Ventilation Natural ventilation using ceiling vent and a vent at floor level. Both should be located away from the tank unit.
Tank location The tank unit should be in a draft-free location with respect to heating and cooling units and natural ventilation.
Heating and cooling Controlled in the range 60 to 75°F with a variation of not more than 2.5°F from the set point.
Foundation floor The calorimeter should remain level at all times. Design for 3000-lb static and dynamic load. The tank feet should be on load
bearing parts of the floor.
Lighting No direct sunlight permitted on calorimeter tank unit.
Condition of air Essentially free from dust and absolutely free from any combustible gas for both measurement accuracy and safety. Trace
hydrocarbons can be removed from combustion air using a Hoskins furnace and a combustion air meter hood.
Vibration No vibrations or shocks shall be transmitted to the tank unit.
Water Pure pH-7 clean water shall be available for filling the tank and replenishing the reserve tank.
Power supply 115 V, 1 phase, 60 Hz, 1000 W for small motors. Lighting, heating, and cooling in addition.
1 1
Gas supply Sample pipe shall be ⁄4-in. tubing. Pressure shall be cut at the pipeline to 1 ⁄2 to 2 psig for minimum time lag. Pressure at the
calorimeter shall be 6 to 30 in. w.c.
Water supply and drain Desirable but not essential.
Radiation Tank unit shall be shielded from any hot radiation surfaces.
Safety It should be remembered that the calorimeter has open flames. Natural ventilation is sufficient in nonhazardous locations and
where only the aforementioned ⁄4-in. tubing service for natural gas at 1 psig is used. Hydrocarbon vapor detectors and purging
means should be considered for installations where location can be hazardous, where higher pressure gas is present, or where
gases heavier than air are involved. In all installations, lighting installations should be suitable for Division I, and incoming power
from underground services should have sealoffs.
the sample line time lag so that the purifier should be of small 9. Operation and Checking of Apparatus
capacity. A design that wil
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