ASTM D7309-07
(Test Method)Standard Test Method for Determining Flammability Characteristics of Plastics and Other Solid Materials Using Microscale Combustion Calorimetry
Standard Test Method for Determining Flammability Characteristics of Plastics and Other Solid Materials Using Microscale Combustion Calorimetry
SIGNIFICANCE AND USE
This laboratory test method measures thermal combustion properties of materials (1-5).3
The test uses controlled thermal decomposition of specimens and thermal oxidation of the specimen gases as they are released from the specimen to simulate the condensed and gas phase processes of flaming combustion, respectively, in a small-scale laboratory test (1-7).
The thermal combustion properties measured in the test are related to flammability characteristics of the material (4-7).
The amount of heat released in flaming combustion per unit mass of material is the fire load and the potential fire load (complete combustion) is estimated in Method A as hc.
The net calorific value of the material (see Test Method D 5865) is determined directly using Method B as hco without the need to know the atomic composition of the specimen to correct for the latent heat of evaporation of the water produced by combustion, or to perform titrations to correct for the heat of solution of acid gases. See Table X1.2 for comparison of Microscale Combustion Calorimetry (MCC) data with Test Method D 5865.
The heat release temperature Tmax of Method A approximates the surface temperature at piloted ignition in accordance with Ref. (5-7) for purposes of fire modeling (See Guide E 1591).
The heat release capacity ηc (J/g-K) is a flammability parameter measured in Method A that is unique to this test method.
SCOPE
1.1 This test method, which is similar to thermal analysis techniques, establishes a procedure for determining flammability characteristics of combustible materials such as plastics.
1.2 The test is conducted in a laboratory environment using controlled heating of milligram specimens and complete thermal oxidation of the specimen gases.
1.3 Specimens of known mass are thermally decomposed in an oxygen-free (anaerobic) or oxidizing (aerobic) environment at a constant heating rate between 0.2 and 2 K/s.
1.4 The heat released by the specimen is determined from the mass of oxygen consumed to completely oxidize (combust) the specimen gases.
1.5 The rate of heat released by combustion of the specimen gases produced during controlled thermal or thermoxidative decomposition of the specimen is computed from the rate of oxygen consumption.
1.6 The specimen temperatures over which combustion heat is released are measured.
1.7 The mass of specimen remaining after the test is measured and used to compute the residual mass fraction.
1.8 The specimen shall be a material or composite material in any form (fiber, film, powder, pellet, droplet). This test method has been developed to facilitate material development and research.
1.9 This standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products, or assemblies under actual fire conditions.
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.Note 1
There is no ISO equivalent to this test method.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D 7309 – 07
Standard Test Method for
Determining Flammability Characteristics of Plastics and
Other Solid Materials Using Microscale Combustion
Calorimetry
This standard is issued under the fixed designation D 7309; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method, which is similar to thermal analysis 2.1 ASTM Standards:
techniques, establishes a procedure for determining flamma- D 883 Terminology Relating to Plastics
bility characteristics of combustible materials such as plastics. D 5865 Test Method for Gross Calorific Value of Coal and
1.2 The test is conducted in a laboratory environment using Coke
controlled heating of milligram specimens and complete ther- E 176 Terminology of Fire Standards
mal oxidation of the specimen gases. E 1591 Guide for Obtaining Data for Deterministic Fire
1.3 Specimens of known mass are thermally decomposed in Models
an oxygen-free (anaerobic) or oxidizing (aerobic) environment
3. Terminology
at a constant heating rate between 0.2 and 2 K/s.
3.1 Definitions:
1.4 The heat released by the specimen is determined from
themassofoxygenconsumedtocompletelyoxidize(combust) 3.1.1 For definitions of terms relating to plastics, refer to
Terminology D 883.
the specimen gases.
1.5 Therateofheatreleasedbycombustionofthespecimen 3.1.2 For definitions of terms relating to fire, refer to
Terminology E 176.
gases produced during controlled thermal or thermoxidative
decomposition of the specimen is computed from the rate of 3.2 Definitions of Terms Specific to This Standard:
3.2.1 combustion residue, n—thenon-volatilechemicalspe-
oxygen consumption.
1.6 Thespecimentemperaturesoverwhichcombustionheat cies remaining after controlled thermal oxidative decomposi-
tion of a specimen.
is released are measured.
1.7 The mass of specimen remaining after the test is 3.2.2 combustion temperature, n—the specimen tempera-
measured and used to compute the residual mass fraction. tureatwhichthespecificcombustionrateisamaximumduring
controlled thermal oxidative decomposition.
1.8 The specimen shall be a material or composite material
in any form (fiber, film, powder, pellet, droplet). This test 3.2.3 controlled heating, n—a controlled temperature pro-
gramusedtoeffectthermaldecompositionoroxidativethermal
method has been developed to facilitate material development
and research. decomposition in which the temperature of the specimen is
uniform throughout and increases with time at a constant rate.
1.9 This standard is used to measure and describe the
response of materials, products, or assemblies to heat and 3.2.4 controlled thermal (or thermal oxidative) decomposi-
tion, n—thermal (oxidative) decomposition under controlled
flame under controlled conditions, but does not by itself
incorporate all factors required for fire hazard or fire risk heating.
3.2.5 heat release capacity, n—the maximum specific heat
assessment of the materials, products, or assemblies under
actual fire conditions. release rate during a controlled thermal decomposition divided
by the heating rate in the test.
1.10 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.2.6 heating rate, n—the constant rate of temperature rise
of the specimen during the controlled temperature program.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 3.2.7 heat release temperature, n—the specimen tempera-
tureatwhichthespecificheatreleaserateisamaximumduring
bility of regulatory limitations prior to use.
controlled thermal decomposition.
NOTE 1—There is no ISO equivalent to this test method.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This test method is under the jurisdiction ofASTM Committee D20 on Plastics contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and is the direct responsibility of Subcommittee D20.30 on Thermal Properties. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2007. Published April 2007. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7309–07
3.2.8 maximum specific combustion rate, n—the maximum
x = time at which the oxygen analyzer signal is
value of the specific combustion rate recorded during the test.
recorded, s
3.2.9 maximum specific heat release rate, n—the maximum
Y = combustion residue, g/g
c
Y = pyrolysis residue, g/g
value of the specific heat release rate recorded during the test.
p
3.2.10 net calorific value, n—the net heat of complete
4. Summary of Test Method
combustion of the specimen measured during controlled ther-
4.1 This test method provides two procedures for determin-
mal oxidative decomposition per unit initial specimen mass.
ingflammabilitycharacteristicsofmaterialsinalaboratorytest
3.2.11 oxidative thermal decomposition, n—a process of
using controlled heating (controlled temperature program-
extensive chemical species change caused by heat and oxygen
ming)andoxygenconsumptioncalorimetry.Thistestmeasures
(thermal oxidation, oxidative pyrolysis).
flammability characteristics using a controlled temperature
3.2.12 pyrolysis residue, n—the fraction of the initial speci-
program to force the release of specimen gases, thermal
menmassremainingaftercontrolledanaerobicthermaldecom-
oxidation of the specimen gases (and optionally the specimen
position.
residue) in excess oxygen, and measurement of the oxygen
3.2.13 specific combustion rate, n—the rate at which com-
consumed to calculate the amount, rate, and temperature of
bustionheatisreleasedperunitinitialmassofspecimenduring
heat released by combustion of a solid specimen during
controlled thermal oxidative decomposition.
controlled heating.
3.2.14 specific heat of combustion of specimen gases,
4.2 Controlled Thermal Decomposition, Method A—In this
n—net calorific value of gases.
procedure the specimen is subjected to controlled heating in an
3.2.15 specific heat release rate, n—the rate at which
oxygen-free/anaerobic environment, that is, controlled thermal
combustion heat is released per unit initial mass of specimen
decomposition. The gases released by the specimen during
during controlled thermal decomposition.
controlled thermal decomposition are swept from the specimen
3.2.16 specific heat release, n—the net heat of complete
chamber by a non-oxidizing/inert purge gas (typically nitro-
combustion of the volatiles liberated during controlled thermal
gen), subsequently mixed with excess oxygen, and completely
decomposition per unit initial specimen mass.
oxidized in a high temperature combustion furnace. The
3.2.17 specimen gases, n—the volatile chemical species
volumetric flow rate and volumetric oxygen concentration of
liberated during controlled thermal (oxidative) decomposition
thegasstreamexitingthecombustionfurnacearecontinuously
of a specimen.
measured during the test to calculate the rate of heat release by
3.3 Symbols:
means of oxygen consumption. In Method A the heat of
combustion of the volatile component of the specimen (speci-
men gases) is measured but not the heat of combustion of any
b = heating rate, K/s
solid residue. Table X1.1 of Appendix X1 shows data for h ,
c
E = 13.1 kJ/g-O is the average heat released by
h , Y , and T for 14 different commercial plastics tested in
c p max
complete combustion of organic compounds per
triplicate (n = 3).
unit mass of oxygen consumed
4.3 Controlled Thermal Oxidative Decomposition,
F = volumetric flow rate of the combustion stream at
Method B—In this procedure the specimen is subjected to
ambient temperature and pressure measured at
controlled heating in an oxidizing/aerobic environment, that is,
the terminal flow meter, cm /s
controlled thermal oxidative decomposition. The specimen
h = specific heat release of sample, J/g
c
o
gases evolved during the controlled heating program are swept
h = net calorific value of sample, J/g
c
from the specimen chamber by the oxidizing purge gas (for
h = specific heat of combustion of specimen gases,
c,gas
example, dry air) and mixed with additional oxygen, if
J/g
necessary, prior to entering a high temperature combustion
h = heat release capacity, J/g-K
c
furnace where the gases are completely oxidized. The volu-
m = initial specimen mass, g
o
m = residual specimen mass after oxidative pyrolysis,
metric flow rate and volumetric oxygen concentration of the
c
g gas stream exiting the combustion furnace are continuously
m = residual specimen mass after the anaerobic py-
measured during the test to calculate the specific combustion
p
rolysis, g
rate by means of oxygen consumption. In Method B the net
D[O ] = the change in the concentration (volume fraction)
2 calorific value of the specimen gases and solid residue are
of O in the gas stream due to combustion
measured during the test.
3 3
measured at the oxygen sensor at time t,cm /cm
Q(t) = specific heat release rate at time t, W/g 5. Significance and Use
Q = maximum specific heat release rate, W/g
max
5.1 This laboratory test method measures thermal combus-
o
Q = maximum specific combustion rate, W/g
max
tion properties of materials (1-5).
r = density of oxygen at ambient conditions, g/cm
5.2 Thetestusescontrolledthermaldecompositionofspeci-
t = time synchronized to temperature, x - t,s
mens and thermal oxidation of the specimen gases as they are
T = heat release temperature, K
max
o
T = combustion temperature, K
max
t = transit time of the gas stream between the speci-
The boldface numbers in parentheses refer to a list of references at the end of
men location and the oxygen analyzer, s
this standard.
D7309–07
NOTE 2—In typical materials tests a material is exposed to a particular
released from the specimen to simulate the condensed and gas
set of test conditions and the material’s response to those particular test
phase processes of flaming combustion, respectively, in a
conditions is measured and reported as the test result. In these tests
small-scale laboratory test (1-7).
changing the test conditions has an effect on the result of the test. In this
5.3 The thermal combustion properties measured in the test
test, the heat release capacity (h ) is independent of the test parameters as
c
are related to flammability characteristics of the material (4-7).
it is a material property and not a response of a material to a particular set
5.4 The amount of heat released in flaming combustion per
of conditions. Thus, changing the test condition (within certain con-
unit mass of material is the fire load and the potential fire load
straints) will have no effect on the test result. As such, the apparatus
required to perform this test shall operate to provide test parameters that
(complete combustion) is estimated in Method A as h .
c
remain within certain constraints for each section of the device, for
5.5 The net calorific value of the material (see Test Method
o
example, specimen chamber, mixing section, combustor. The diameter,
D 5865) is determined directly using Method B as h without
c
length and shape of each section will have no effect on the test result
the need to know the atomic composition of the specimen to
provided the section meets the performance given in Annex A1.
correct for the latent heat of evaporation of the water produced
7.3 Figure 1 illustrates the basic components of an appara-
by combustion, or to perform titrations to correct for the heat
tus,(1,5,8-11),satisfactoryforthistestmethodwhichinclude:
of solution of acid gases. See Table X1.2 for comparison of
Microscale Combustion Calorimetry (MCC) data with Test
7.4 A specimen chamber (sample chamber) that is capable
Method D 5865.
of holding and heating a small (milligram sized) specimen in a
5.6 The heat release temperature T of MethodAapproxi-
continuous flow of purge gas.
max
mates the surface temperature at piloted ignition in accordance
7.5 Temperature controller, capable of executing a tempera-
with Ref. (5-7) for purposes of fire modeling (See Guide
ture program that changes the specimen chamber temperature
E 1591).
between ambient and 1123 K at a rate that is constant to within
5.7 The heat release capacity h (J/g-K) is a flammability
c
5 % of the nominal value in the range 0.05-5 K/s.
parameter measured in Method A that is unique to this test
7.6 A means of purging the specimen chamber environment
method.
withaconstantflowofinert(forexample,nitrogen)orreactive
(nitrogen/oxygenmixture)gasatarateof50-100cm /minwith
6. Limitations
an accuracy of 61%.
6.1 The heat release capacity (h ) is independent of the
c
7.7 A temperature sensor, to provide an indication of the
form, mass, and heating rate of the specimen as long as the
specimen temperature to 60.5 K.
specimen temperature is uniform at all times during the test
7.8 A mixing chamber, where the specimen and purge gases
(1-5).
are mixed with sufficient oxygen to effect complete oxidation
6.2 Test results obtained from small (milligram) samples by
of the specimen gases in the combustion chamber.
this method do not include physical behavior such as melting,
dripping, swelling, shrinking, delamination, and char/barrier
7.9 Ameans of introducing oxygen into the mixing sectionat
formation that can influence the results of large (decagram/ a constant flow rate of 0-50 cm /min, such that the concentra-
kilogram) samples in flame and fire tests.
tion of oxygen is between 20-50 % (60.1 %) by volume
6.3 Test results obtained from small (milligram) samples by entering the combustion chamber.
this method do not include extrinsic factors such as thickness,
7.10 A combustor (combustion chamber) capable of main-
sample orientation, external heat flux, ignition source, bound-
taining a constant temperature in the range of 1073-1273K
ary conditions, and ventilation rate that influence the results of
(800-1000°C). Typically, the residence time of the specimen
large (decagram/kilogram) samples in flame and fire tests.
gases in the combustor is 10 seconds and the combustor
6.4 The specific combustion rate and combustion tempera-
temperature is 1173K (900°C) in accordance with Ref. (5).
ture of Method B are not generally reproducible because
7.11 An in-line drier to remove moisture and acid gases
sample geometry can affect the rate of surface oxidation and
from the combustion stream to a dew point of 273K. Solid
gas phase ignition can o
...
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