ASTM D4809-18

Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method)

SIGNIFICANCE AND USE
5.1 The heat of combustion is a measure of the energy available from a fuel. A knowledge of this value is essential when considering the thermal efficiency of equipment for producing either power or heat.  
5.2 The mass heat of combustion, that is, the heat of combustion per unit mass of fuel, is measured by this procedure. Its magnitude is particularly important to weight-limited vehicles such as airplanes, surface effect vehicles, and hydrofoils as the distance such craft can travel on a given weight of fuel is a direct function of the fuel's mass heat of combustion and its density.  
5.3 The volumetric heat of combustion, that is, the heat of combustion per unit volume of fuel, can be calculated by multiplying the mass heat of combustion by the density of the fuel (mass per unit volume). The volumetric heat of combustion, rather than the mass heat of combustion, is important to volume-limited craft such as automobiles and ships, as it is directly related to the distance traveled between refuelings.
SCOPE
1.1 This test method covers the determination of the heat of combustion of hydrocarbon fuels. It is designed specifically for use with aviation turbine fuels when the permissible difference between duplicate determinations is of the order of 0.2 %. It can be used for a wide range of volatile and nonvolatile materials where slightly greater differences in precision can be tolerated.  
1.2 In order to attain this precision, strict adherence to all details of the procedure is essential since the error contributed by each individual measurement that affects the precision shall be kept below 0.04 %, insofar as possible.  
1.3 Under normal conditions, this test method is directly applicable to such fuels as gasolines, kerosines, Nos. 1 and 2 fuel oil, Nos. 1-D and 2-D diesel fuel, and Nos. 0-GT, 1-GT, and 2-GT gas turbine fuels.  
1.4 Through the improvement of the calorimeter controls and temperature measurements, the precision is improved over that of Test Method D240.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 7, 10.6, A1.7.1, and Annex A3.  
1.7 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

• Status: Published
• Publication Date: 30-Jun-2018
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.05 - Properties of Fuels, Petroleum Coke and Carbon Material

Relations

• Replaces: ASTM D4809-13 - Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method)
• Effective Date: 01-Jul-2018
• Refers: ASTM D3701-23 - Standard Test Method for Hydrogen Content of Aviation Turbine Fuels by Low Resolution Nuclear Magnetic Resonance Spectrometry
• Effective Date: 01-Nov-2023
• Refers: ASTM D7171-20 - Standard Test Method for Hydrogen Content of Middle Distillate Petroleum Products by Low-Resolution Pulsed Nuclear Magnetic Resonance Spectroscopy
• Effective Date: 01-May-2020
• Refers: ASTM E144-14(2020) - Standard Practice for Safe Use of Oxygen Combustion Vessels
• Effective Date: 01-Feb-2020
• Refers: ASTM D5453-19a - Standard Test Method for Determination of Total Sulfur in Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel, and Engine Oil by Ultraviolet Fluorescence
• Effective Date: 01-Jul-2019
• Refers: ASTM D1266-18 - Standard Test Method for Sulfur in Petroleum Products (Lamp Method)
• Effective Date: 01-Apr-2018
• Refers: ASTM D5453-16 - Standard Test Method for Determination of Total Sulfur in Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel, and Engine Oil by Ultraviolet Fluorescence
• Effective Date: 15-Apr-2016
• Refers: ASTM D7171-05(2016) - Standard Test Method for Hydrogen Content of Middle Distillate Petroleum Products by Low-Resolution Pulsed Nuclear Magnetic Resonance Spectroscopy
• Effective Date: 01-Apr-2016
• Refers: ASTM D4294-16 - Standard Test Method for Sulfur in Petroleum and Petroleum Products by Energy Dispersive X-ray Fluorescence Spectrometry
• Effective Date: 01-Jan-2016
• Refers: ASTM E144-14e1 - Standard Practice for Safe Use of Oxygen Combustion Vessels
• Effective Date: 01-Dec-2014
• Refers: ASTM E144-14 - Standard Practice for Safe Use of Oxygen Combustion Vessels
• Effective Date: 01-Dec-2014
• Refers: ASTM D240-14 - Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter
• Effective Date: 01-Oct-2014
• Refers: ASTM E1-13 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-May-2013
• Refers: ASTM D5453-12 - Standard Test Method for Determination of Total Sulfur in Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel, and Engine Oil by Ultraviolet Fluorescence
• Effective Date: 01-Nov-2012
• Refers: ASTM D3701-01(2012) - Standard Test Method for Hydrogen Content of Aviation Turbine Fuels by Low Resolution Nuclear Magnetic Resonance Spectrometry
• Effective Date: 15-Apr-2012

Overview

ASTM D4809-18, titled Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method), is an internationally recognized ASTM standard for determining the heat of combustion of hydrocarbon fuels. This test method is particularly designed for accurate measurement in aviation turbine fuels, but is also applicable to a variety of liquid fuels including gasolines, kerosenes, fuel oils, diesel fuels, and gas turbine fuels. By using a bomb calorimeter, the standard ensures precision and repeatability essential for industrial, research, and regulatory applications.

Understanding the heat of combustion is critical because it directly indicates the energy content of a fuel. This data plays a significant role in evaluating fuel efficiency, designing power and heat generation systems, and managing fuel logistics for various transportation and energy sectors. The ASTM D4809-18 standard is widely referenced by industry, regulatory bodies, and the U.S. Department of Defense for accurate energy measurement.

Key Topics

• Precision and Methodology

  • The standard outlines detailed procedures for sample preparation, apparatus requirements, and calorimeter operation to achieve high precision, with permissible differences between duplicate determinations as low as 0.2% for aviation turbine fuels.
  • Strict adherence to the method ensures individual measurement errors remain below 0.04%, further assuring the reliability and consistency of results.

• Types of Heat of Combustion

  • Measures mass heat of combustion (MJ/kg), essential for weight-limited vehicles such as airplanes and hydrofoils.
  • Enables calculation of volumetric heat of combustion (MJ/L) by multiplying mass heat by fuel density, particularly relevant to volume-limited vehicles (e.g., automobiles, ships).

• Apparatus and Execution

  • Requires the use of a high-precision oxygen bomb calorimeter and supporting laboratory equipment, with stringent control of procedural details to minimize variables.
  • Includes test methods for calibration and correction of measurements for side reactions and apparatus-specific parameters.

• Reporting

  • Both gross and net heat of combustion values are reported to the nearest 0.002 MJ/kg.

• Units

  • All results are provided in SI units, with megajoules per kilogram (MJ/kg) as the standard reporting metric.

Applications

ASTM D4809-18 is vital across multiple industries and sectors:

• Aviation and Aerospace

  • Ensures fuels meet strict energy content specifications, which directly affect aircraft performance and range.
  • Supports optimization of both commercial and military aviation fuel supply.

• Automotive and Marine

  • Used to evaluate fuels for automobiles and ships, where volumetric energy content impacts refueling intervals and logistic planning.

• Regulatory Compliance & Quality Control

  • Compliance with national and international regulations for fuel quality, blending, and energy content validation.
  • Integral to fuel certification, blending operations, and shipment inspection.

• Industrial Research & Development

  • Supports fuel development, emissions studies, and efficiency enhancements in thermal and power generation industries.

Related Standards

ASTM D4809-18 references and is harmonized with several other relevant ASTM standards to ensure consistency and comparability across testing regimes:

• ASTM D240 - Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter
• ASTM D129 - Test Method for Sulfur in Petroleum Products
• ASTM D1018, D3701, D7171 - Methods for determining hydrogen content in fuels
• ASTM D1193 - Specification for Reagent Water
• ASTM D2622, D3120, D4294, D5453 - Sulfur measurement in petroleum and related products
• ASTM E144 - Practice for Safe Use of Oxygen Combustion Vessels
• ASTM E200 - Practice for Preparation and Standardization of Solutions

Conclusion

With its rigorous methodology and high-precision measurement capabilities, ASTM D4809-18 is the premier standard for determining the heat of combustion of liquid hydrocarbon fuels. Its widespread adoption helps guarantee fuel quality, enhance efficiency in transportation and industry, and ensure regulatory compliance. For organizations involved in fuel analysis, energy production, or regulatory oversight, conformance with ASTM D4809-18 is essential to uphold best practices and operational excellence.

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: D4809 − 18
Standard Test Method for
Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb
Calorimeter (Precision Method)
This standard is issued under the fixed designation D4809; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method covers the determination of the heat of
combustionofhydrocarbonfuels.Itisdesignedspecificallyfor
2. Referenced Documents
use with aviation turbine fuels when the permissible difference
2.1 ASTM Standards:
between duplicate determinations is of the order of 0.2%. It
D129Test Method for Sulfur in Petroleum Products (Gen-
can be used for a wide range of volatile and nonvolatile
eral High Pressure Decomposition Device Method)
materials where slightly greater differences in precision can be
D240Test Method for Heat of Combustion of Liquid Hy-
tolerated.
drocarbon Fuels by Bomb Calorimeter
1.2 In order to attain this precision, strict adherence to all
D1018Test Method for Hydrogen In Petroleum Fractions
details of the procedure is essential since the error contributed
D1193Specification for Reagent Water
by each individual measurement that affects the precision shall
D1266TestMethodforSulfurinPetroleumProducts(Lamp
be kept below 0.04%, insofar as possible.
Method)
1.3 Under normal conditions, this test method is directly D2622Test Method for Sulfur in Petroleum Products by
applicable to such fuels as gasolines, kerosines, Nos. 1 and 2 Wavelength Dispersive X-ray Fluorescence Spectrometry
fuel oil, Nos. 1-D and 2-D diesel fuel, and Nos. 0-GT, 1-GT, D3120Test Method for Trace Quantities of Sulfur in Light
and 2-GT gas turbine fuels. Liquid Petroleum Hydrocarbons by Oxidative Microcou-
lometry
1.4 Through the improvement of the calorimeter controls
D3701Test Method for Hydrogen Content of Aviation
and temperature measurements, the precision is improved over
Turbine Fuels by Low Resolution Nuclear Magnetic
that of Test Method D240.
Resonance Spectrometry
1.5 The values stated in SI units are to be regarded as
D4294Test Method for Sulfur in Petroleum and Petroleum
standard. No other units of measurement are included in this
Products by Energy Dispersive X-ray Fluorescence Spec-
standard.
trometry
1.6 This standard does not purport to address all of the
D5453Test Method for Determination of Total Sulfur in
safety concerns, if any, associated with its use. It is the Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel
responsibility of the user of this standard to establish appro-
Engine Fuel, and Engine Oil by Ultraviolet Fluorescence
priate safety, health, and environmental practices and deter- D7171Test Method for Hydrogen Content of Middle Dis-
mine the applicability of regulatory limitations prior to use.
tillate Petroleum Products by Low-Resolution Pulsed
For specific warning statements, see Section 7, 10.6, A1.7.1, Nuclear Magnetic Resonance Spectroscopy
and Annex A3.
E1Specification for ASTM Liquid-in-Glass Thermometers
1.7 This international standard was developed in accor- E144Practice for Safe Use of Oxygen Combustion Vessels
dance with internationally recognized principles on standard-
E200Practice for Preparation, Standardization, and Storage
ization established in the Decision on Principles for the of Standard and Reagent Solutions for ChemicalAnalysis
Development of International Standards, Guides and Recom-
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
SubcommitteeD02.05onPropertiesofFuels,PetroleumCokeandCarbonMaterial. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved July 1, 2018. Published August 2018. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1988. Last previous edition approved in 2013 as D4809–13. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4809-18. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4809 − 18
3. Terminology 3.2.5 The following relationships may be used for convert-
ing to other units:
3.1 Definitions:
3 A
1 cal (International Table calorie) = 4.1868 J
3.1.1 gross heat of combustion, Qg (MJ/kg) , n—the quan-
1 Btu (British thermal unit) = 1055.06 J
tity of energy released when a unit mass of fuel is burned in
A
1 cal (I.T.)/g = 0.0041868 MJ/kg
A
oxygen in a constant volume enclosure, with the products
1 Btu/lb = 0.002326 MJ/kg
1 atm = 0.101325 MPa
being gaseous, other than water that is condensed to the liquid
state.
A
Conversion factor is exact.
3.1.1.1 Discussion—The fuel can be either liquid or solid,
and contain only the elements carbon, hydrogen, nitrogen,
4. Summary of Test Method
oxygen,andsulfur.Theproductsofcombustion,inoxygen,are
gaseous carbon dioxide, nitrogen oxides, sulfur dioxide, and
4.1 The heat of combustion is determined by burning a
liquid water. In this procedure, 25°C is the initial temperature
weighed sample in an oxygen-bomb calorimeter under con-
of the fuel and the oxygen, and the final temperature of the
trolled conditions. The temperature increase is measured by a
products of combustion.
temperature reading instrument which allows the precision of
4,5
thistestmethodtobemet.Theheatofcombustioniscalculated
3.1.2 net heat of combustion, Qn (MJ/kg) , n—thequantity
of energy released when a unit mass of fuel is burned at from temperature observations before, during, and after
constant pressure, with all the products, including water, being combustion, with proper allowance for thermochemical and
gaseous. heat-transfer corrections. Either isoperibol or adiabatic calo-
3.1.2.1 Discussion—The fuel can be either liquid or solid, rimeters may be used.
and contain only the elements carbon, hydrogen, oxygen,
nitrogen, and sulfur. The products of combustion, in oxygen,
5. Significance and Use
are carbon dioxide, nitrogen oxides, sulfur dioxide, and water,
5.1 The heat of combustion is a measure of the energy
allinthegaseousstate.Inthisprocedure,thecombustiontakes
available from a fuel. A knowledge of this value is essential
place at a constant pressure of 101.325kPa (1atm), and 25°C
when considering the thermal efficiency of equipment for
is the initial temperature of the fuel and the oxygen, and the
producing either power or heat.
final temperature of the products of combustion.
5.2 The mass heat of combustion, that is, the heat of
3.1.3 energy equivalent (effective heat capacity or water
equivalent), n—the energy equivalent of the calorimeter ex- combustion per unit mass of fuel, is measured by this proce-
dure. Its magnitude is particularly important to weight-limited
pressed as joules per degree Celsius, J/°C.
vehicles such as airplanes, surface effect vehicles, and hydro-
NOTE 1—The energy equivalent may be expressed in any energy unit
foils as the distance such craft can travel on a given weight of
and any temperature unit so long as the value is used consistently
fuel is a direct function of the fuel’s mass heat of combustion
throughout the calculations.
and its density.
3.2 Units:
3.2.1 Temperatures are measured in degrees Celsius.
5.3 The volumetric heat of combustion, that is, the heat of
3.2.2 Time is expressed in minutes and decimal fractions
combustion per unit volume of fuel, can be calculated by
thereof. It can be measured in minutes or seconds, or both.
multiplying the mass heat of combustion by the density of the
3.2.3 Masses are measured in grams. No buoyancy correc-
fuel (mass per unit volume). The volumetric heat of
tions are applied except to obtain the mass of benzoic acid.
combustion, rather than the mass heat of combustion, is
3.2.4 The energy unit of measurement employed in this test
important to volume-limited craft such as automobiles and
method is the joule with the heat of combustion reported in
ships, as it is directly related to the distance traveled between
megajoules per kilogram (Note 2).
refuelings.
1 MJ/kg 51000J/g (1)
NOTE 2—In SI the unit of heat of combustion has the dimension J/kg,
6. Apparatus
but for practical use a multiple is more convenient. The MJ/kg is
customarily used for the representation of heats of combustion of
6.1 Test Room, Bomb, Calorimeter, Jacket, Thermometers,
petroleum fuels.
and Accessories, as described in Annex A1.
6.2 Semimicro Analytical Balance, having a sensitivity of
Prosen, E. J., “Experimental Thermochemistry.” F. D. Rossini, editor, Inter-
0.01 mg as specified in 10.5.1.
science Publishers, 1956, pp. 129–148. Reliable values for heats of combustion of
pure compounds are given in National Bureau of Standards Circular C-461,
6.3 Heavy-Duty Analytical Balance, having a sensitivity of
“SelectedValuesofPropertiesofHydrocarbons”(U.S.GovernmentPrintingOffice,
0.05 g as specified in 10.7.2.
Washington,DC,1947)andinF.D.Rossini,etal,“SelectedValuesofPhysicaland
Thermodynamic Properties of Hydrocarbons and Related Compounds,” Carnegie
Press, Pittsburgh, PA, 1953. These compilations were prepared by F. D. Rossini, et
7. Reagents and Materials
al, as part of American Petroleum Institute Research Project 44.
Supporting data (derivation of equations) have been filed at ASTM Interna-
7.1 Purity of Reagents—Reagent grade chemicals shall be
tional Headquarters and may be obtained by requesting Research Report RR:D02-
used in all tests. Unless otherwise indicated, it is intended that
1346. Contact ASTM Customer Service at [e-mail].
all reagents shall conform to the specifications of the Commit-
Jessup, R. S., “Precise Measurement of Heat of Combustion with a Bomb
Calorimeter,” NBS Monograph 7, U.S. Government Printing Office. tee onAnalytical Reagents of theAmerican Chemical Society,
D4809 − 18
where such specifications are available. Other grades may be the bottom of the bucket and locate the thermistor with its
used, provided it is first ascertained that the reagent is of sensingelementataboutthemidpointofthethermometerbulb.
sufficiently high purity to permit its use without lessening the Mount these elements so that exactly the same length is
accuracy of the determination. immersedeachtimethecalorimeterisused.Installathermistor
in the water jacket with the element immersed to the same
7.2 Purity of Water—Unless otherwise indicated, references
depth as in the bucket. It is helpful, but not necessary to have
towatershallbeunderstoodtomeanreagentwaterconforming
liquid-in-glass calorimetric thermometers in both the bucket
to Specification D1193, Type IV or better.
andjacketforquicktemperatureobservations.Thermistorscan
7.3 Benzoic Acid —The acid must be pelleted before use.
be taped to these thermometers. If the thermistors are taped to
7.4 Firing Wire—0.127 mm (No. 36 gage) platinum wire, the thermometers, it can be done in such a manner that the
sensingelementsareatthemidpointofthethermometerbulbs.
No.34B&SgageironwireorChromelCresistancewire,cut
in 100-mm lengths. Thethermometerbulbsandtemperature-sensingelementsshall
not touch the bomb, bucket, or water jacket.
7.5 Methyl Red Indicator.
8.2 Calorimeter Jacket Controller and Auxiliary
7.6 Oxygen—Commercial oxygen produced from liquid air
Equipment—Adjustthejacketcontroller,valves,heater,andso
can be used without purification. (Warning—Oxygen vigor-
forth, as recommended by the calorimeter manufacturer.
ously accelerates combustion. See A3.1.) Oxygen prepared by
electrolysis of water cannot be used without purification as it
9. Standardization
can contain some hydrogen. Combustible impurities may be
9.1 Energy Equivalent of the Calorimeter—Benzoic acid
removed by passage over copper oxide at 500°C.
shall be used as the primary standard. (Warning—Oxygen
7.7 Pressure-Sensitive Tape—Cellophane tape 38 mm wide,
vigorously accelerates combustion. See A3.1.) Choose a
free of chlorine and sulfur.
sample mass so that the temperature rise is approximately
equivalent to an energy change of 30000J. Initially determine
7.8 Alkali, Standard Solutions.
7.8.1 Sodium Hydroxide Solution (0.0866 N)—Dissolve the energy equivalent by averaging six determinations made
using benzoic acid over a period of at least three days.
3.5g of sodium hydroxide (NaOH) in water and dilute to 1 L.
(Warning—Corrosive. Can cause severe burns or blindness. 9.1.1 A relative standard deviation (RSD) of 0.1% or less
forthesixdeterminationsmustbeachieved.Ifnot,continueto
Evolution of heat produces a violent reaction or eruption upon
too rapid mixture with water. See Annex A3.2.) Standardize rununtilsixdeterminationsestablishavaluethathasaRSDof
0.1% or better. If this degree of precision cannot be achieved,
with potassium acid phthalate and adjust to 0.0866 N as
described in Practice E200, or alternative use. review the procedure, critical measurements, mechanical op-
erations and everything that may contribute to scatter in the
7.8.2 Sodium Carbonate Solution (0.0725 N)—Dissolve
3.84gofNa CO in water and dilute to 1 L. results. After establishing an energy equivalent value, deter-
2 3
9 mine the value at frequent intervals using benzoic acid (every
7.9 2,2,4-Trimethylpentane—(isooctane), Standard.
one or two days of testing) with the average of the last six
(Warning—Extremely flammable. Harmful if inhaled. Vapors
determinations being used for the energy equivalent as long as
may cause flash fire. See Annex A3.3.)
the last six determinations have a RSD of 0.1% or less.
9.1.2 If any part of the equipment is changed or any part of
8. Preparation of Apparatus
the procedure is altered, redetermine the value. Make each
8.1 Arrangement of Apparatus—Install the thermometers as
determination in accordance with Section 10. Determine the
recommended by the manufacturer of the calorimeter. Position
correction for nitric acid (HNO ) as described in 11.3 and
the liquid-in-glass thermometer so that the bulb is halfway to
substitute in the following equation:
W 5 Q 3m1e /∆t (2)
~ !
b 1
Reagent Chemicals, American Chemical Society Specifications , American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
where:
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia W = energy equivalent of calorimeter, J/°C,
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
m = mass of benzoic acid, g,
MD.
∆t = corrected temperature rise, as calculated in accordance
Obtainable from the National Institute of Standards and Technology, Clopper
with 11.1 or 11.2, °C,
and Quince Orchard Roads, Gaithersburg, MD 20899, as Standard Sample 39i. If
e = correction for heat of formation of nitric acid, J, and
you are aware of alternative suppliers, please provide this information to ASTM 1
International Headquarters. Your comments will receive careful consideration at a Q = heatofcombustionofbenzoicacid,J/gcalculatedfrom
b
meeting of the responsible technical committee, which you may attend.
the certified value in kilojoules per gram mass given
Cellophane tape Scotch Brand No. 610, available from 3M Co., meets the
for NBS Standard39i. Multiply kilojoules per gram
specification requirements. If you are aware of alternative suppliers, please provide
mass by 1000 to obtain joules per gram (Note 4).
this information toASTM International Headquarters. Your comments will receive
careful consideration at a meeting of the responsible technical committee, which NOTE 3—2,2,4-trimethyl pentane may be used for checking the energy
you may attend.
equivalent of the system for use with volatile fuels.
Obtainable from the National Institute of Standards and Technology, Clopper
and Quince Roads, Gaithersburg, MD 20899, as Standard Sample No. 217b. If you
are aware of alternative suppliers, please provide this information to ASTM
International Headquarters. Your comments will receive careful consideration at a
meeting of the responsible technical committee, which you may attend.
D4809 − 18
NOTE 4—Multiply the heat evolved by combustion of the standard
Q = approximate heat of combustion of the sample, MJ/kg,
sample by the following factor.
and
1110 @197 P 2 3.04 1 42 m ⁄ V 2 3 (3) D = density, g/cm , of the sample.
~ ! ~~ ! !
NOTE 5—For relatively high-boiling samples, such as non-volatile (in
1 30~~M ⁄ V! 2 3! 245~t 2 25!#
otherwords,IBPabove180°C)kerosine-typejetfuels,itisnotnecessary
w
to use tape.
where:
10.5.2 Add the sample to the cup by inserting the tip of the
P = initial absolute pressure of oxygen, MPa at temperature t,
m = mass of benzoic acid, g,
needle through the tape disk at a point so that the flap of tape
M = mass of water placed in bomb before combustion, g,
w willcoverthepunctureuponremovaloftheneedle.Sealdown
V = internal volume of bomb, L, and
the flap by pressing lightly with a metal spatula. Reweigh the
t = temperature to which the combustion reaction is referred, °C
cup with the tape and sample. Take care throughout the
(final temperature of the calorimeter).
weighing and filling operation to avoid contacting the tape or
9.2 Heat of Combustion of Pressure-Sensitive Tape—
cupwithbarefingers.Placethecupinthecurvedelectrodeand
Determine the heat of combustion of the pressure-sensitive
arrange the fuse wire so that the central portion of the loop
tape in accordance with Section 10 using about 1.2 g of tape
presses down on the center of the tape disk.
and omitting the sample. Make at least three determinations
10.6 Bomb Assembly—Assemble the bomb and tighten the
and calculate the heat of combustion as follows:
cover securely. Connect the bomb to the oxygen cylinder and
Q 5 ∆t 3W 2 e /a (4)
~ !
pst 1
slowlyadmitoxygenuntilapressureof3.0MPaisattained.Do
where: not purge the bomb to remove entrapped air. Disconnect the
bomb from the oxygen cylinder and replace the valve cover.
Q = heat of combustion of the pressure-sensitive tape, J/g
pst
(Warning—Aviolent explosion may occur.) Be careful not to
∆t = corrected temperature rise, as calculated in accor-
overcharge the bomb. If by accident, the oxygen introduced
dance with 11.1 or 11.2, °C,
into the bomb does exceed 4.0 MPa, do not proceed with the
W = energy equivalent of the calorimeter, J/°C,
e = correction for the heat of formation of HNO,J,and combustion. A violent explosion, capable of rupturing the
1 3
a = mass of the pressure-sensitive tape, g.
bomb, might occur. Detach the filling connection and exhaust
the bomb in the usual manner. Discard the sample.
9.2.1 Average the determinations, and redetermine the heat
of combustion of the tape whenever a new roll is started.
NOTE 6—Pressures within the range of from 2.5MPa to 3.55MPa may
be used, provided the same pressure is used for all tests, including
10. Procedure standardization.
10.1 Turn on the apparatus. Make all electrical connections 10.7 Calorimeter Water:
and open the water lines.
10.7.1 Adjust the temperature of the calorimeter water. The
choiceofthetemperaturetowhichthewaterisadjustedbefore
10.2 Beforebeginning,besurethatthebombanditsfittings
weighing depends on a number of factors, including room
are completely dry, inside and out.
temperature, the desired initial temperature of the experiment,
10.3 Measureapieceoffiringwire100mmlongandattach
and the relative heat capacities of the calorimeter bucket,
the wire to the bomb electrodes forming a U-shaped loop.
water, and bomb. No definite rule can be given, but the
10.4 Pipet 1.0 cm of water into the bomb and cover with a
operator will learn by experience how to select the proper
watch glass.
temperature under the conditions of his particular laboratory
and apparatus. The following can be used as a guide:
10.5 Mass of Sample:
Isothermal method 3.0 °C to 3.5 °C below jacket temperature
10.5.1 Weigh the sample cup to 0.01 mg on a semimicro
Adiabatic method 1.5 °C to 1.8 °C below room temperature
analytical balance. Place a piece of pressure-sensitive type
(Note 5) across the top of the cup, trim around the edge with a 10.7.1.1 Isoperibol Method—Adjust the temperature such
razor blade, and seal tightly. Place a 3-mm by 12-mm strip of
that after assembly of the calorimeter bomb and bucket its
tapecreasedinthemiddleandsealedbyoneedgeinthecenter temperature will be a few tenths of a degree below the desired
of the tape disk to give a flap arrangement. Weigh the cup and
initial temperature.
tape.Removefromthebalancewithforceps.Fillahypodermic
10.7.1.2 Adiabatic Method—Adjust the temperature so that
syringe with the sample. The volume of sample necessary to
the initial temperature of the determination will be as close to
produce a temperature rise equivalent to approximately
somefixedvaluesaspossible.Controlthemeantemperatureof
30000J can be estimated as follows:
all determinations within more than 60.5°C and the tempera-
ture rise for all determinations within 60.3°C.
V 5 W 30.0032 / Q 3D (5)
~ ! ~ !
10.7.2 Weighthecalorimeterbucketto 60.05gonaheavy-
where:
duty analytical balance.After once establishing the dry bucket
V = volume of sample to be used, cm ,
weight, it need only be checked occasionally. Fill with the
W = energy equivalent of the calorimeter, J/°C,
desired quantity of water (2000g to 2100g) and reweigh to
0.05g(Note5).Theexactquantityofwaterisnotimportantas
longasitisenoughtocoverthebombanditsfittingsandisthe
See NBS Monograph 7,p.12. same in each determination.
D4809 − 18
NOTE7—Thechangeinthemassofthewaterinthecalorimeterbucket NOTE9—Duringtheinitialandfinalperiodsthethermometershouldbe
due to evaporation after weighings will affect the energy equivalent. The read with the highest possible care, since the overall precision of the
effectofthislossissmallandcancelsiftheprocedureofplacingthebomb determination depends directly upon these temperature measurements.
in its bucket and completing the assembly of the system is carried out in During the middle period, because of the very rapid rate of temperature
the same manner and in the same length of time in the calibration
rise, it is not possible to make readings as carefully as during the initial
experiments as in the measurement of the heat of combustion. andfinalperiods.Thisisnotimportantbecausethereadingsofthemiddle
period are used only for calculating the relatively small correction for
10.7.3 Immediately after weighing, place the bucket in
thermal leakage and heat of stirring.
position in the calorimeter jacket, carefully place the bomb in
10.9 Procedure for Adiabatic Method:
the bucket, and complete the firing circuit. Close the calorim-
eter cover and lower thermometers and thermistors. 10.9.1 Start the stirrer motor and turn on the calorimeter
controller. Use
...

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: D4809 − 13 D4809 − 18
Standard Test Method for
Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb
Calorimeter (Precision Method)
This standard is issued under the fixed designation D4809; 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 U.S. Department of Defense.
1. Scope*
1.1 This test method covers the determination of the heat of combustion of hydrocarbon fuels. It is designed specifically for use
with aviation turbine fuels when the permissible difference between duplicate determinations is of the order of 0.2 %. It can be
used for a wide range of volatile and nonvolatile materials where slightly greater differences in precision can be tolerated.
1.2 In order to attain this precision, strict adherence to all details of the procedure is essential since the error contributed by each
individual measurement that affects the precision shall be kept below 0.04 %, insofar as possible.
1.3 Under normal conditions, thethis test method is directly applicable to such fuels as gasolines, kerosines, Nos. 1 and 2 fuel
oil, Nos. 1-D and 2-D diesel fuel, and Nos. 0-GT, 1-GT, and 2-GT gas turbine fuels.
1.4 Through the improvement of the calorimeter controls and temperature measurements, the precision is improved over that
of Test Method D240.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. For specific warning statements, see Section 7, 10.6, A1.7.1, and Annex A3.
1.7 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.
2. Referenced Documents
2.1 ASTM Standards:
D129 Test Method for Sulfur in Petroleum Products (General High Pressure Decomposition Device Method)
D240 Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter
D1018 Test Method for Hydrogen In Petroleum Fractions
D1193 Specification for Reagent Water
D1266 Test Method for Sulfur in Petroleum Products (Lamp Method)
D2622 Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry
D3120 Test Method for Trace Quantities of Sulfur in Light Liquid Petroleum Hydrocarbons by Oxidative Microcoulometry
D3701 Test Method for Hydrogen Content of Aviation Turbine Fuels by Low Resolution Nuclear Magnetic Resonance
Spectrometry
D4294 Test Method for Sulfur in Petroleum and Petroleum Products by Energy Dispersive X-ray Fluorescence Spectrometry
D5453 Test Method for Determination of Total Sulfur in Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel,
and Engine Oil by Ultraviolet Fluorescence
D7171 Test Method for Hydrogen Content of Middle Distillate Petroleum Products by Low-Resolution Pulsed Nuclear Magnetic
Resonance Spectroscopy
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.
Current edition approved May 1, 2013July 1, 2018. Published May 2013August 2018. Originally approved in 1988. Last previous edition approved in 20092013 as
ε1
D4809 – 09aD4809 – 13. . DOI: 10.1520/D4809-13.10.1520/D4809-18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4809 − 18
E1 Specification for ASTM Liquid-in-Glass Thermometers
E144 Practice for Safe Use of Oxygen Combustion Vessels
E200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis
D4809 − 18
3. Terminology
3.1 Definitions:
3.1.1 gross heat of combustion—expressed as megajoules per kilogram. The gross heat of combustion at constant volume of a
liquid or solid fuel containing only the elements carbon, hydrogen, oxygen, nitrogen, and sulfur is the quantity of heat liberated
when a unit mass of the fuel is burned in oxygen in an enclosure of constant volume, the products of combustion being gaseous
carbon dioxide, nitrogen, sulfur dioxide, and liquid water, with the initial temperature of the fuel and the oxygen and the final
temperature of the products at 25°C. Gross heat of combustion (see Note 1) is represented by the symbol Q .
g
NOTE 1—Users of this test method desiring to calculate Δ H° for a pure compound should note that corrections must be applied to the value of Q
g
for buoyancy of air, heat capacities of reaction components, reduction to a constant-pressure process, and deviations of the reaction from the
thermodynamic standard state. In any comparison of measurements on pure compounds with those cited in these compilations , the user of this test
method should realize that impurities of various kinds, including water and foreign hydrocarbons may cause significant effects on the values obtained
for particular samples of material.
3.1.1 netgross heat of combustion—combustion, Qg (MJ/kg) , n—expressed as megajoules per kilogram. The net heat of
combustion at constant pressure of a liquid or a solid fuel containing only the elements carbon, hydrogen, oxygen, nitrogen, and
sulfur is the quantity of heat liberatedthe quantity of energy released when a unit mass of the fuel is burned in oxygen at a constant
pressure of 0.101 MPa, the products of combustion being carbon dioxide, nitrogen, sulfur dioxide, and water, all in the gaseous
state, with the initial temperature of the fuel and the oxygen and the final temperature of the products of combustion at 25°C. The
,
net heat of combustionin a constant volume enclosure, with the products being gaseous, other than water that is represented by
the symbol condensed Q and is related to the gross heat of combustion by the following equation: to the liquid state.
n
Q net, 25°C 5 Q gross, 25°C 2 0.2122 3H (1)
~ ! ~ !
n g
where:
Q (net, 25°C) = net heat of combustion at constant pressure, MJ/kg,
n
Q (gross, 25°C) = gross heat of combustion at constant volume, MJ/kg, and
g
H = mass % of hydrogen in the sample.
3.1.1.1 Discussion—
The fuel can be either liquid or solid, and contain only the elements carbon, hydrogen, nitrogen, oxygen, and sulfur. The products
of combustion, in oxygen, are gaseous carbon dioxide, nitrogen oxides, sulfur dioxide, and liquid water. In this procedure, 25 °C
is the initial temperature of the fuel and the oxygen, and the final temperature of the products of combustion.
4,5
3.1.2 net heat of combustion, Qn (MJ/kg) , n—the quantity of energy released when a unit mass of fuel is burned at constant
pressure, with all the products, including water, being gaseous.
3.1.2.1 Discussion—
The fuel can be either liquid or solid, and contain only the elements carbon, hydrogen, oxygen, nitrogen, and sulfur. The products
of combustion, in oxygen, are carbon dioxide, nitrogen oxides, sulfur dioxide, and water, all in the gaseous state. In this procedure,
the combustion takes place at a constant pressure of 101.325 kPa (1 atm), and 25 °C is the initial temperature of the fuel and the
oxygen, and the final temperature of the products of combustion.
3.1.3 energy equivalent (effective heat capacity or water equivalent)equivalent), —n—the energy equivalent of the calorimeter
expressed as joules per degree Celsius, J/°C.
NOTE 1—The energy equivalent may be expressed in any energy unit and any temperature unit so long as the value is used consistently throughout
the calculations.
3.2 Units:
3.2.1 Temperatures are measured in degrees Celsius.
3.2.2 Time is expressed in minutes and decimal fractions thereof. It can be measured in minutes or seconds, or both.
3.2.3 Masses are measured in grams. No buoyancy corrections are applied except to obtain the mass of benzoic acid.
Prosen, E. J., “Experimental Thermochemistry.” F. D. Rossini, editor, Interscience Publishers, 1956, pp. 129–148. Reliable values for heats of combustion of pure
compounds are given in National Bureau of Standards Circular C-461, “Selected Values of Properties of Hydrocarbons” (U.S. Government Printing Office, Washington, DC,
1947) and in F. D. Rossini, et al, “Selected Values of Physical and Thermodynamic Properties of Hydrocarbons and Related Compounds,” Carnegie Press, Pittsburgh, PA,
1953. These compilations were prepared by F. D. Rossini, et al, as part of American Petroleum Institute Research Project 44.
Supporting data (derivation of equations) have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1346. Contact
ASTM Customer Service at [e-mail].
Jessup, R. S., “Precise Measurement of Heat of Combustion with a Bomb Calorimeter,” NBS Monograph 7, U.S. Government Printing Office.
D4809 − 18
3.2.4 The energy unit of measurement employed in this test method is the joule with the heat of combustion reported in
megajoules per kilogram (Note 32).
1 MJ/kg 5 1000 J/g (1)
NOTE 2—In SI the unit of heat of combustion has the dimension J/kg, but for practical use a multiple is more convenient. The MJ/kg is customarily
used for the representation of heats of combustion of petroleum fuels.
3.2.5 The following relationships may be used for converting to other units:
A
1 cal (International Table calorie) = 4.1868 J
1 Btu (British thermal unit) = 1055.06 J
A
1 cal (I.T.)/g = 0.0041868 MJ/kg
A
1 Btu/lb = 0.002326 MJ/kg
1 atm = 0.101325 MPa
A
Conversion factor is exact.
4. Summary of Test Method
4.1 The heat of combustion is determined by burning a weighed sample in an oxygen-bomb calorimeter under controlled
conditions. The temperature increase is measured by a temperature reading instrument which allows the precision of thethis test
method to be met. The heat of combustion is calculated from temperature observations before, during, and after combustion, with
proper allowance for thermochemical and heat-transfer corrections. Either isoperibol or adiabatic calorimeters may be used.
5. Significance and Use
5.1 The heat of combustion is a measure of the energy available from a fuel. A knowledge of this value is essential when
considering the thermal efficiency of equipment for producing either power or heat.
5.2 The mass heat of combustion, that is, the heat of combustion per unit mass of fuel, is measured by this procedure. Its
magnitude is particularly important to weight-limited vehicles such as airplanes, surface effect vehicles, and hydrofoils as the
distance such craft can travel on a given weight of fuel is a direct function of the fuel’s mass heat of combustion and its density.
5.3 The volumetric heat of combustion, that is, the heat of combustion per unit volume of fuel, can be calculated by multiplying
the mass heat of combustion by the density of the fuel (mass per unit volume). The volumetric heat of combustion, rather than the
mass heat of combustion, is important to volume-limited craft such as automobiles and ships, as it is directly related to the distance
traveled between refuelings.
6. Apparatus
6.1 Test Room, Bomb, Calorimeter, Jacket, Thermometers, and Accessories, as described in Annex A1.
6.2 Semimicro Analytical Balance, having a sensitivity of 0.01 mg as specified in 10.5.1.
6.3 Heavy-Duty Analytical Balance, having a sensitivity of 0.05 g as specified in 10.7.2.
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
7.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to
Specification D1193, Type IV or better.
7.3 Benzoic Acid —The acid must be pelleted before use.
7.4 Firing Wire—0.127 mm (No. 36 gage) platinum wire, No. 34 B & S gage iron wire or Chromel C resistance wire, cut in
100-mm lengths.
7.5 Methyl Red Indicator.
7.6 Oxygen—Commercial oxygen produced from liquid air can be used without purificationpurification. (Warning—Oxygen
vigorously accelerates combustion. (SeeSee A3.1.)).) Oxygen prepared by electrolysis of water cannot be used without purification
as it can contain some hydrogen. Combustible impurities may be removed by passage over copper oxide at 500°C.500 °C.
Reagent Chemicals, American Chemical Society Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
Obtainable from the National Institute of Standards and Technology, Clopper and Quince Orchard Roads, Gaithersburg, MD 20899.20899, as Standard Sample 39i. If
you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting
of the responsible technical committee, which you may attend.
D4809 − 18
7.7 Pressure-Sensitive Tape—Cellophane tape 38 mm wide, free of chlorine and sulfur.
7.8 Alkali, Standard Solutions . Solutions.
7.8.1 Sodium Hydroxide Solution (0.0866 (0.0866 N)—Dissolve 3.5 g 3.5 g of sodium hydroxide (NaOH) in water and dilute
to 1 L. (Warning—Corrosive. Can cause severe burns or blindness. Evolution of heat produces a violent reaction or eruption upon
too rapid mixture with water (seewater. See Annex A3.2.)).) Standardize with potassium acid phthalate and adjust to 0.0866 N as
described in Practice E200, or alternative use.
7.8.2 Sodium Carbonate Solution (0.0725 (0.0725 N)—Dissolve 3.84 g of Na CO in water and dilute to 1 L.
2 3
7.9 2,2,4-Trimethylpentane—(isooctane), StandardStandard. (Warning—Extremely flammable. Harmful if inhaled. Vapors
may cause flash fire. (SeeSee Annex A3.3.)).)
8. Preparation of Apparatus
8.1 Arrangement of Apparatus—Install the thermometers as recommended by the manufacturer of the calorimeter. Position the
liquid-in-glass thermometer so that the bulb is halfway to the bottom of the bucket and locate the thermistor with its sensing
element at about the midpoint of the thermometer bulb. Mount these elements so that exactly the same length is immersed each
time the calorimeter is used. Install a thermistor in the water jacket with the element immersed to the same depth as in the bucket.
It is helpful, but not necessary to have liquid-in-glass calorimetric thermometers in both the bucket and jacket for quick temperature
observations. Thermistors can be taped to these thermometers. If the thermistors are taped to the thermometers, it can be done in
such a manner that the sensing elements are at the midpoint of the thermometer bulbs. The thermometer bulbs and
temperature-sensing elements shall not touch the bomb, bucket, or water jacket.
8.2 Calorimeter Jacket Controller and Auxiliary Equipment—Adjust the jacket controller, valves, heater, etc., and so forth, as
recommended by the calorimeter manufacturer.
9. Standardization
9.1 Energy Equivalent of the Calorimeter—Benzoic acid shall be used as the primary standardstandard. (Warning—Oxygen
vigorously accelerates combustion. See A3.1).) Choose a sample mass so that the temperature rise is approximately equivalent
to an energy change of 30 000 J. 30 000 J. Initially determine the energy equivalent by averaging six determinations made using
benzoic acid over a period of at least 3three days.
9.1.1 A relative standard deviation (RSD) of 0.1 % or less for the six determinations must be achieved. If not, continue to run
until six determinations establish a value that has a RSD of 0.1 % or better. If this degree of precision cannot be achieved, review
the procedure, critical measurements, mechanical operations and everything that may contribute to scatter in the results. After
establishing an energy equivalent value, determine the value at frequent intervals using benzoic acid (every 1one or 2two days of
testing) with the average of the last six determinations being used for the energy equivalent as long as the last six determinations
have a RSD of 0.1 % or less.
9.1.2 If any part of the equipment is changed or any part of the procedure is altered, redetermine the value. Make each
determination in accordance with Section 10. Determine the correction for nitric acid (HNO ) as described in 11.3 and substitute
in the following equation:
W 5 Q 3m1e /Δt (2)
~ b 1!
where:
W = energy equivalent of calorimeter, J/°C,
m = mass of benzoic acid, g,
Δt = corrected temperature rise, as calculated in accordance with 11.1 or 11.2, °C,
e = correction for heat of formation of nitric acid, J, and
Q = heat of combustion of benzoic acid, J/g calculated from the certified value in kilojoules per gram mass given for NBS
b
Standard 39i. Multiply kilojoules per gram mass by 1000 to obtain joules per gram (Note 5).
Q = heat of combustion of benzoic acid, J/g calculated from the certified value in kilojoules per gram mass given for NBS
b
Standard 39i. Multiply kilojoules per gram mass by 1000 to obtain joules per gram (Note 4).
NOTE 3—2,2,4-trimethyl pentane may be used for checking the energy equivalent of the system for use with volatile fuels.
Cellophane tape Scotch Brand No. 610, available from 3M Co., meets the specification requirements. If you are aware of alternative suppliers, please provide this
information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may
attend.
Obtainable from the National Institute of Standards and Technology, Clopper and Quince Roads, Gaithersburg, MD 20899, as Standard Sample No. 217b. If you are aware
of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible
technical committee, which you may attend.
D4809 − 18
NOTE 4—Multiply the heat evolved by combustion of the standard sample by the following factor.
1110 @197 ~P 2 3.04! 1 42 ~~m/V! 2 3! (3)
1 30 M /V 2 3 2 45 t 2 25 #
~~ ! ! ~ !
w
1110 197 P 2 3.04 1 42 m ⁄ V 2 3 (3)
@ ~ ! ~~ ! !
1 30~~M ⁄ V! 2 3!2 45~t 2 25!#
w
where:
P = initial absolute pressure of oxygen, MPa at temperature t,
m = mass of benzoic acid, g,
M = mass of water placed in bomb before combustion, g,
w
V = internal volume of bomb, L, and
t = temperature to which the combustion reaction is referred,° C (final temperature of the calorimeter).
t = temperature to which the combustion reaction is referred, °C (final temperature of the calorimeter).
9.2 Heat of Combustion of Pressure-Sensitive Tape—Determine the heat of combustion of the pressure-sensitive tape in
accordance with Section 10 using about 1.2 g of tape and omitting the sample. Make at least three determinations and calculate
the heat of combustion as follows:
Q 5 Δt 3W 2 e /a (4)
~ !
pst 1
where:
Q = heat of combustion of the pressure-sensitive tape, J/g
pst
Δt = corrected temperature rise, as calculated in accordance with 11.1 or 11.2, °C,
W = energy equivalent of the calorimeter, J/°C,
e = correction for the heat of formation of HNO , J, and
1 3
a = mass of the pressure-sensitive tape, g.
9.2.1 Average the determinations, and redetermine the heat of combustion of the tape whenever a new roll is started.
10. Procedure
10.1 Turn on the apparatus. Make all electrical connections and open the water lines.
10.2 Before beginning, be sure that the bomb and its fittings are completely dry, inside and out.
10.3 Measure a piece of firing wire 100 mm long and attach the wire to the bomb electrodes forming a U-shaped loop.
10.4 Pipet 1.0 cm of water into the bomb and cover with a watch glass.
10.5 Mass of Sample:
10.5.1 Weigh the sample cup to 0.01 mg on a semimicro analytical balance. Place a piece of pressure-sensitive type (Note 65)
across the top of the cup, trim around the edge with a razor blade, and seal tightly. Place a 33-mm by 12-mm strip of tape creased
in the middle and sealed by one edge in the center of the tape disk to give a flap arrangement. Weigh the cup and tape. Remove
from the balance with forceps. Fill a hypodermic syringe with the sample. The volume of sample necessary to produce a
temperature rise equivalent to approximately 30 000 J 30 000 J can be estimated as follows:
V 5 W 30.0032 / Q 3D (5)
~ ! ~ !
where:
V = volume of sample to be used, cm ,
W = energy equivalent of the calorimeter, J/°C,
Q = approximate heat of combustion of the sample, MJ/kg, and
D = density, g/cm , of the sample.
NOTE 5—For relatively high-boiling samples, such as non-volatile (i.e. (in other words, IBP above 180°C)180 °C) kerosine-type jet fuels, it is not
necessary to use tape.
10.5.2 Add the sample to the cup by inserting the tip of the needle through the tape disk at a point so that the flap of tape will
cover the puncture upon removal of the needle. Seal down the flap by pressing lightly with a metal spatula. Reweigh the cup with
the tape and sample. Take care throughout the weighing and filling operation to avoid contacting the tape or cup with bare fingers.
Place the cup in the curved electrode and arrange the fuse wire so that the central portion of the loop presses down on the center
of the tape disk.
10.6 Bomb Assembly—Assemble the bomb and tighten the cover securely. Connect the bomb to the oxygen cylinder and slowly
admit oxygen until a pressure of 3.0 MPa is attained. Do not purge the bomb to remove entrapped air. Disconnect the bomb from
See NBS Monograph 7, p. 12.
D4809 − 18
the oxygen cylinder and replace the valve cover. (Warning—A violent explosion may occur.) Be careful not to overcharge the
bomb. If by accident, the oxygen introduced into the bomb does exceed 4.0 MPa, do not proceed with the combustion. A violent
explosion, capable of rupturing the bomb, might occur. Detach the filling connection and exhaust the bomb in the usual manner.
Discard the sample.
NOTE 6—Pressures within the range of from 2.52.5 MPa to 3.55 MPa 3.55 MPa may be used, provided the same pressure is used for all tests, including
standardization.
10.7 Calorimeter Water:
10.7.1 Adjust the temperature of the calorimeter water. The choice of the temperature to which the water is adjusted before
weighing depends on a number of factors, including room temperature, the desired initial temperature of the experiment, and the
relative heat capacities of the calorimeter bucket, water, and bomb. No definite rule can be given, but the operator will learn by
experience how to select the proper temperature under the conditions of his particular laboratory and apparatus. The following can
be used as a guide:
Isothermal method 3.0 to 3.5°C below jacket temperature
Adiabatic method 1.5 to 1.8°C below room temperature
Isothermal method 3.0 °C to 3.5 °C below jacket temperature
Adiabatic method 1.5 °C to 1.8 °C below room temperature
10.7.1.1 Isoperibol Method—Adjust the temperature such that after assembly of the calorimeter bomb and bucket its
temperature will be a few tenths of a degree below the desired initial temperature.
10.7.1.2 Adiabatic Method—Adjust the temperature so that the initial temperature of the determination will be as close to some
fixed values as possible. Control the mean temperature of all determinations within more than 60.5°C60.5 °C and the temperature
rise for all determinations within 60.3°C.60.3 °C.
10.7.2 Weigh the calorimeter bucket to 60.05 g 60.05 g on a heavy-duty analytical balance. After once establishing the dry
bucket weight, it need only be checked occasionally. Fill with the desired quantity of water (2000(2000 g to 2100 g) 2100 g) and
reweigh to 0.05 g 0.05 g (Note 65). The exact quantity of water is not important as long as it is enough to cover the bomb and
its fittings and is the same in each determination.
NOTE 7—The change in the mass of the water in the calorimeter bucket due to evaporation after weighings will affect the energy equivalent. The effect
of this loss is small and cancels if the procedure of placing the bomb in its bucket and completing the assembly of the system is carried out in the same
manner and in the same length of time in the calibration experiments as in the measurement of the heat of combustion.
10.7.3 Immediately after weighing, place the bucket in position in the calorimeter jacket, carefully place the bomb i
...