ASTM E1321-18

Standard Test Method for Determining Material Ignition and Flame Spread Properties

SIGNIFICANCE AND USE
5.1 This test method addresses the fundamental aspects of piloted ignition and flame spread. The procedure is suitable for the derivation of relevant material flammability parameters that include minimum exposure levels for ignition, thermal-inertia values, and flame-spread properties.  
5.2 This test method is used to measure some material-flammability properties that are scientifically constant and compatible and to derive specific properties that allow the prediction and explanation of the flame-spread characteristics of materials. They are considered effective properties that are dependent on the correlations used and when combined with theory can be used over a wide range of fire conditions for predicting material ignition and flame-spread behavior.  
5.3 Do not use this test method for products that do not have planar, or nearly planar, external surfaces and those products and assemblies in which physical performance such as joint separation and fastening methods has a significant influence on flame propagation in actual fire conditions.  
5.4 In this procedure, the specimens are subjected to one or more specific sets of laboratory test conditions. If different test conditions are substituted or the end-use conditions are changed, it is not always possible by or from this test method to predict changes in the fire-test-response characteristics measured. Therefore, the results are valid only for the fire test exposure conditions described in this procedure (see also 1.6).
SCOPE
1.1 This fire test response standard determines material properties related to piloted ignition of a vertically oriented sample under a constant and uniform heat flux and to lateral flame spread on a vertical surface due to an externally applied radiant-heat flux.  
1.2 The results of this test method provide a minimum surface flux and temperature necessary for ignition ( q˙"o,ig, Tig) and for lateral spread ( q˙"o,s, Ts,min), an effective material thermal inertia value (kρc), and a flame-heating parameter (Φ) pertinent to lateral flame spread.  
1.3 The results of this test method are potentially useful to predict the time to ignition, t ig, and the velocity, V, of lateral flame spread on a vertical surface under a specified external flux without forced lateral airflow. Use the equations in Appendix X1 that govern the ignition and flame-spread processes and which have been used to correlate the data.  
1.4 This test method is potentially useful to obtain results of ignition and flame spread for materials. Data are reported in units for convenient use in current fire growth models.  
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 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.  
1.7 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these tests.  
1.8 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 hazard statements, see Section 7.  
1.9 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: 31-Oct-2018
• ICS: 13.220.50 - Fire-resistance of building materials and elements
• ICS: 91.100.01 - Construction materials in general
• Technical Committee: E05 - Fire Standards
• Drafting Committee: E05.22 - Surface Burning

Relations

• Replaces: ASTM E1321-13 - Standard Test Method for Determining Material Ignition and Flame Spread Properties
• Effective Date: 01-Nov-2018
• Refers: ASTM E176-24 - Standard Terminology of Fire Standards
• Effective Date: 01-Jan-2024
• Refers: ASTM E84-23d - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Dec-2023
• Refers: ASTM E648-23 - Standard Test Method for Critical Radiant Flux of Floor-Covering Systems Using a Radiant Heat Energy Source
• Effective Date: 01-Nov-2023
• Refers: ASTM E970-23 - Standard Test Method for Critical Radiant Flux of Exposed Attic Floor Insulation Using a Radiant Heat Energy Source
• Effective Date: 01-Oct-2023
• Refers: ASTM E84-23c - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Sep-2023
• Refers: ASTM E648-19a - Standard Test Method for Critical Radiant Flux of Floor-Covering Systems Using a Radiant Heat Energy Source
• Effective Date: 01-Dec-2019
• Refers: ASTM E648-19ae1 - Standard Test Method for Critical Radiant Flux of Floor-Covering Systems Using a Radiant Heat Energy Source
• Effective Date: 01-Dec-2019
• Refers: ASTM E648-19 - Standard Test Method for Critical Radiant Flux of Floor-Covering Systems Using a Radiant Heat Energy Source
• Effective Date: 15-Jul-2019
• Refers: ASTM E84-19b - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Jul-2019
• Refers: ASTM E84-19a - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 15-Apr-2019
• Refers: ASTM E84-19 - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Mar-2019
• Refers: ASTM E176-18a - Standard Terminology of Fire Standards
• Effective Date: 15-Dec-2018
• Refers: ASTM E84-18b - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Oct-2018
• Refers: ASTM E84-18a - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Jul-2018

Overview

ASTM E1321-18: Standard Test Method for Determining Material Ignition and Flame Spread Properties is a critical fire test response standard developed by ASTM International. This standard specifies laboratory test methods to determine the ignition and flame spread characteristics of materials when exposed to an external radiant heat flux. Focusing on piloted ignition and lateral flame spread on vertical surfaces, ASTM E1321-18 provides essential flammability parameters that are widely used for predicting fire behavior in materials.

By delivering reliable data on minimum ignition flux, thermal inertia, ignition time, lateral flame spread, and related parameters, this standard supports the evaluation of material performance under fire exposure, helping to inform material selection, safety engineering, and regulatory compliance.

Key Topics

• Piloted Ignition Testing: Determines the minimum heat flux and temperature needed for ignition of a vertically oriented material sample under consistent conditions.
• Flame Spread Measurement: Assesses how flames propagate laterally across a vertical surface due to an applied radiant heat source.
• Material Flammability Parameters: Provides values such as minimum igniting surface flux, ignition temperature, lateral spread flux and temperature, effective thermal inertia, and flame-heating parameter.
• Applicability and Limitations: The method is suitable for planar or nearly-planar materials and is not appropriate for materials where joints or fastenings significantly affect fire propagation.
• Laboratory Conditions: Results are valid only for specified laboratory exposure conditions and should not be generalized to all real-world fire hazards or risk assessments.

Applications

The practical applications of ASTM E1321-18 include:

• Fire Safety Engineering: Supports the design and evaluation of buildings, transportation vehicles, and equipment by providing key data for fire modeling and fire growth predictions.
• Material Selection and Compliance: Helps manufacturers and specifiers determine suitable materials for use in environments where fire performance is regulated.
• Product Research and Development: Assists R&D teams in assessing the fire behavior of new composites, surface finishes, and construction materials.
• Fire Modeling: Supplies parameter values for use in predictive fire growth models, essential for risk analysis and safety simulation.
• Regulatory and Code Compliance: Facilitates adherence to building codes and fire safety regulations that reference material ignition and flame spread properties.

Important Note: ASTM E1321-18 should not be used in product testing involving complex assemblies where joint performance or fastening methods influence fire spread, or for materials without planar surfaces.

Related Standards

For comprehensive evaluation and determination of material flammability, refer also to these related ASTM fire test methods:

• ASTM E84 – Surface Burning Characteristics of Building Materials
• ASTM E162 – Surface Flammability of Materials Using Radiant Heat
• ASTM E176 – Terminology of Fire Standards
• ASTM E648 – Critical Radiant Flux of Floor-Covering Systems
• ASTM E970 – Critical Radiant Flux of Exposed Attic Floor Insulation
• ASTM E1317 – Flammability of Marine Surface Finishes

Summary

ASTM E1321-18 is a standardized test method essential for characterizing the ignition and flame spread properties of materials subjected to radiant heat. Its scientific approach under controlled laboratory conditions offers foundational data supporting fire safety engineering, materials development, and code compliance. For optimal safety and compliance, always use the latest edition of the standard and consult related test methods as needed.

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: E1321 − 18 An American National Standard
Standard Test Method for
Determining Material Ignition and Flame Spread Properties
This standard is issued under the fixed designation E1321; 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* priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 This fire test response standard determines material
For specific hazard statements, see Section 7.
properties related to piloted ignition of a vertically oriented
1.9 This international standard was developed in accor-
sample under a constant and uniform heat flux and to lateral
dance with internationally recognized principles on standard-
flame spread on a vertical surface due to an externally applied
ization established in the Decision on Principles for the
radiant-heat flux.
Development of International Standards, Guides and Recom-
1.2 The results of this test method provide a minimum
mendations issued by the World Trade Organization Technical
surface flux and temperature necessary for ignition (q˙" , T )
o,ig ig
Barriers to Trade (TBT) Committee.
and for lateral spread (q˙" , T ), an effective material
o,s s,min
2. Referenced Documents
thermal inertia value (kρc), and a flame-heating parameter (Φ)
pertinent to lateral flame spread.
2.1 ASTM Standards:
E84Test Method for Surface Burning Characteristics of
1.3 The results of this test method are potentially useful to
Building Materials
predict the time to ignition, t , and the velocity, V, of lateral
ig
E162Test Method for Surface Flammability of Materials
flame spread on a vertical surface under a specified external
Using a Radiant Heat Energy Source
flux without forced lateral airflow. Use the equations in
E176Terminology of Fire Standards
Appendix X1 that govern the ignition and flame-spread pro-
E286Test Method for Surface Flammability of Building
cesses and which have been used to correlate the data.
Materials Using an 8-ft (2.44-m) Tunnel Furnace (With-
1.4 Thistestmethodispotentiallyusefultoobtainresultsof
drawn 1991)
ignition and flame spread for materials. Data are reported in
E648Test Method for Critical Radiant Flux of Floor-
units for convenient use in current fire growth models.
Covering Systems Using a Radiant Heat Energy Source
1.5 The values stated in SI units are to be regarded as
E970TestMethodforCriticalRadiantFluxofExposedAttic
standard. No other units of measurement are included in this
Floor Insulation Using a Radiant Heat Energy Source
standard.
E1317Test Method for Flammability of Marine Surface
Finishes
1.6 This standard is used to measure and describe the
2.2 ASTM Adjuncts:
response of materials, products, or assemblies to heat and
Detaileddrawings(19),constructioninformation,andparts
flame under controlled conditions, but does not by itself
list (Adjunct to E1317)
incorporate all factors required for fire hazard or fire risk
assessment of the materials, products, or assemblies under
3. Terminology
actual fire conditions.
3.1 Definitions—For definitions of terms used in this test
1.7 Fire testing is inherently hazardous. Adequate safe-
method, refer to Terminology E176.
guards for personnel and property shall be employed in
3.2 Definitions of Terms Specific to This Standard:
conducting these tests.
3.2.1 backing board, n—anoncombustibleinsulatingboard,
1.8 This standard does not purport to address all of the
mounted behind the specimen during actual testing to satisfy
safety concerns, if any, associated with its use. It is the
the theoretical analysis assumption of no heat loss through the
responsibility of the user of this standard to establish appro-
specimen.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This test method is under the jurisdiction of ASTM Committee E05 on Fire contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards and is the direct responsibility of Subcommittee E05.22 on Surface Standards volume information, refer to the standard’s Document Summary page on
Burning. the ASTM website.
Current edition approved Nov. 1, 2018. Published November 2018. Originally The last approved version of this historical standard is referenced on
approved in 1990. Last previous edition approved in 2013 as E1321–13. DOI: www.astm.org.
10.1520/E1321-18. Available from ASTM Headquarters. Order ADJE1317.
*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
E1321 − 18
3.2.2 dummy specimen, n—a noncombustible insulating 4. Summary of Test Method
board used for stabilizing the operating condition of the
4.1 This test method consists of two procedures; one to
equipment.
measure ignition and one to measure lateral-flame spread.
3.2.2.1 Discussion—The dummy specimen is mounted in
Vertically mounted specimens are exposed to the heat from a
the apparatus in the position of the test specimen and removed vertical air-gas fueled radiant-heat energy source inclined at
only when a test specimen is to be inserted. 15° to the specimen (see Fig. 1).
4.1.1 For the ignition test, a series of 155,+0,−5 mm by
3.2.3 effective thermal property, n—thermal properties de-
155,+0,−5 mm specimens (see Fig. 1) are exposed to a
rived from heat-conduction theory applied to ignition/flame-
nearly uniform heat flux (see Fig. 2) and the time to flame
spread data treating the material as homogenous in structure.
attachment, using piloted ignition (see Fig. 3), is determined.
4.1.2 For the flame spread test, a 155,+0,−5 mm by
3.2.4 mirror assembly, n—a mirror, marked and aligned
800,+0,−5 mm specimen (see Fig. 1) is exposed to a
with the viewing rakes, used as an aid for quickly identifying
graduated heat flux (see Fig. 2) that is approximately 5 kW/m
and tracking the flame-front progress.
higher at the hot end than the minimum heat flux necessary for
3.2.5 special calibration board, n—a specially assembled
ignition; this flux being determined from the ignition test (see
noncombustible insulating board used for standardizing the
11.2). The specimen is preheated to thermal equilibrium; the
operating condition of the equipment which is used only to
preheat time being derived from the ignition test (see 12.1).
measure the flux distribution at specified intervals along the
After using piloted ignition, the pyrolyzing flame-front pro-
specimen surface.
gression along the horizontal length of the specimen as a
function of time is tracked. The data are correlated with a
3.2.6 thermally thick, n—the thickness of a medium that is
theory of ignition and flame spread for the derivation of
large enough to have the predominate thermal (temperature)
material flammability properties.
effects experienced within that distance, that is, negligible heat
is lost from its unexposed side.
5. Significance and Use
3.2.7 thermal operating level, n—the operating condition at
5.1 This test method addresses the fundamental aspects of
which the radiance of the heat source produces a specified
pilotedignitionandflamespread.Theprocedureissuitablefor
constant heat flux to some specified position at the specimen
thederivationofrelevantmaterialflammabilityparametersthat
surface.
include minimum exposure levels for ignition, thermal-inertia
values, and flame-spread properties.
3.2.8 viewing rakes, n—a set of bars with wires spaced at
50-mm intervals for the purpose of increasing the precision of
5.2 This test method is used to measure some material-
timing flame-front progress along the specimen.
flammability properties that are scientifically constant and
compatible and to derive specific properties that allow the
3.3 Symbols:
prediction and explanation of the flame-spread characteristics
−1/2
b = ignition correlation parameter, s .
of materials. They are considered effective properties that are
s/2 1/2
C = flame heat transfer factor, m /kW·s .
dependent on the correlations used and when combined with
CF = ratio of radiation pyrometer signal to flux incident
theory can be used over a wide range of fire conditions for
on dummy specimen as measured during calibra-
predicting material ignition and flame-spread behavior.
tion; a linear correlation is assumed, mV/(kW/m ).
5.3 Donotusethistestmethodforproductsthatdonothave
F(t) = specimen thermal response function.
planar, or nearly planar, external surfaces and those products
F(x) = surface flux configuration invariant, (kW/m )/mV.
and assemblies in which physical performance such as joint
h = heat loss coefficient, kW/m ·K.
q˙" = measured incident flux, kW/m .
e
q˙"o,ig = critical flux for ignition, kW/m .
q˙"o,s = critical flux for spread, kW/m .
t = time, s.
t* = characteristic equilibrium time, s.
t = time at sample insertion, s.
t = time at ignition, s.
t = ignition time under incident flux, s.
ig
T = ignition temperature, °C.
ig
T = minimum temperature for spread, °C.
s,min
T = ambient and initial temperature, °C.
∞
V = flame (pyrolysis front) velocity, m/s.
x = longitudinal position along centerline of specimen,
m.
2 3
Φ = flame heating parameter, (kW) /m .
2 2
kρc = thermal heating property, (kW/m ·K) s.
ε = surface emissivity.
2 4
σ = Stefan-Boltzmann constant, kW/m ·K .
FIG. 1 Schematic of Apparatus With Ignition Specimen
E1321 − 18
conditions are substituted or the end-use conditions are
changed, it is not always possible by or from this test method
to predict changes in the fire-test-response characteristics
measured. Therefore, the results are valid only for the fire test
exposure conditions described in this procedure (see also 1.6).
6. Apparatus
6.1 Dummy Specimens and Backing Boards:
6.1.1 This test method requires the use of a dummy speci-
men board in several instances during both calibration and
testing. The dummy specimen shall be a noncombustible
insulatingboard,20 65mminthickness,withadensityof750
6 100 kg/m .
6.1.2 Fortheignitiontests,thedummyspecimenboardshall
have a hole at the 50-mmposition, for mounting the fluxmeter.
FIG. 2 Normalized Flux Over Specimen
6.1.3 Forthepurposeofthistestmethod,backingboardsare
noncombustible insulating boards 25 6 5 mm thick with a
density no greater than 200 6 50 kg/m .
6.1.4 Useasaspecialcalibrationboardadummyspecimen,
as described in 6.1.1, for measuring the flux distribution along
the test specimen surface.
6.2 Test-Equipment Fabrication—Fig. 4 shows a photo-
graphoftheequipmentasassembledreadyfortest.Figs.5and
NOTE 1—All dimensions are in millimetres.
6 show schematics of the apparatus. These provide engineer-
FIG. 3 Pilot Configuration for Ignition Test
FIG. 4 General View of Apparatus
separationandfasteningmethodshasasignificantinfluenceon ing information necessary for the fabrication of the main
flame propagation in actual fire conditions.
frame, specimen holders, stack, and other necessary parts of
the equipment. Some commercially available units have added
5.4 In this procedure, the specimens are subjected to one or
safety features that are not described in the drawings.
more specific sets of laboratory test conditions. If different test
E1321 − 18
front of the radiating surface to enhance the combustion
efficiency and increase the radiant output.
6.3.4 Air and Fuel Supply, to support combustion of the
radiant panel. The appropriate air and fuel flow-metering
devices, gas control valves, pressure reducer, and safety
controls are all mounted on the panel support frame (see Fig.
5). Requirements are as follows:
−3 3
6.3.4.1 Aregulated air supply of about 8.33 by 10 m /s at
a pressure sufficient to overcome the friction loss through the
line, metering device, and radiant panel; the radiant-panel
pressure drop amounts to approximately 20 to 30 Pa. A
flowmetersuitableforindicatingairflowovertherangeof2to
−3 3
15 by 10 m /s shall be provided. A flowmeter suitable for
indicating methane flow rates over the range of 0.1 to 1.1 by
−3 3
10 m /s shall be provided.
6.3.4.2 The fuel gas used shall be either natural gas or
FIG. 5 Test Apparatus Main Frame, Front View
methane. A pressure regulator shall be provided to maintain a
constant supply pressure. Gas is controlled by either a manu-
allyadjustedneedlevalveoraventurimixer.Theventurimixer
willallowonetocontrolthefluxlevelofthepanelbyadjusting
only the air valve. The fuel gas-flow requirements are roughly
−3 3
0.26 to 1.03 by 10 m /s at a pressure sufficient to overcome
line pressure losses.
NOTE2—Ifaventurimixerisused,theregulatedairandfuelgassupply
shall be sufficient for efficient operation of the venturi mixer.
6.3.5 The Specimen Holder Support Frame Guides, Pilot
Flame Holder, Fume Stack (optional), Flame Front Viewing
Rakes, Radiation Pyrometer, and Mirror are all assembled on
the specimen support frame. The arrangement of parts on this
frame is shown in Figs. 4-6.
6.3.6 DummySpecimen,ofnoncombustibleinsulatingboard
of the thickness and density specified in the test procedure,
shall be mounted on the apparatus in the position of the
FIG. 6 Test Apparatus, Side View
specimen except during actual testing or calibration.
6.4 Instrumentation:
6.4.1 Total Radiation Pyrometer, compensated for its tem-
NOTE 1—The specimen fume stack available in some commercial
peraturevariationandhavinganominalsensitivitybetweenthe
models is not required for this test procedure.
thermal wavelengths of 1 and 9 µm that shall view a centrally
6.3 A brief parts list for the test-equipment assembly in- locatedareaontheradiantpanelofabout150by300mm.The
cludes: instrument shall be securely mounted on the specimen support
6.3.1 Main Frame (see Fig. 5), consisting of two separate frame in such a manner that it can view the radiant panel
sections, the radiant-panel support frame and the specimen surface oriented for specimens in the vertical position.
support frame. The two frame sections shall be joined in a 6.4.2 Heat Fluxmeters—Have available at least three flux-
manner that allows adjustments in the relative position of the
meters for this test method. One of these shall be retained as a
radiant panel to the specimen to be made easily. laboratory reference standard. The fluxmeters shall be of the
6.3.2 Specimen Holders, to provide for support of the thermopile type with a nominal range of 0 to 50 kW/m and
specimen during test; at least two of these are required, and have a sensitivity of approximately 10 mV at 50 kW/m . They
three prevent delays resulting from required cooling of holders shall have been calibrated to an accuracy of 5% over this
prior to mounting specimens. range.Thetimeconstantoftheseinstrumentsshallnotbemore
6.3.3 Radiant Panel, consisting of a radiation surface of than 290 ms (corresponding to a time to reach 95% of final
porous refractory tiles mounted at the front of a stainless steel outputofnotmorethan1s).Thetargetsensingtheappliedflux
plenum chamber to provide a flat radiating surface of approxi- shall occupy an area not more than 4 by 4 mm and be located
mately 280 by 483 mm. The plenum chamber shall include flushwithandatthecenterofthewater-cooled25-mmcircular
baffle plates and diffusers to distribute the gas/air mixture exposed metallic end of the fluxmeter. If fluxmeters of smaller
evenly over the radiation surface. The gas/air mixture enters diameters are to be used, these shall be inserted into a copper
the plenum chamber at one of the short sides to facilitate easy sleeve of 25-mm outside diameter in such a way that good
connection when the panel is mounted from the frame. A thermal contact is maintained between the sleeve and water-
reverberatory screen (see Fig. 6) is provided immediately in cooled fluxmeter body. The end of the sleeve and exposed
E1321 − 18
surface of the fluxmeter shall lie in the same plane. Radiation 8. Test Specimens
shall not pass through any window before reaching the target.
8.1 The specimens selected for testing shall be representa-
6.4.3 Timing Devices, such as a chronograph, a digital
tive of the product as it is intended for use.
clock,astopwatch,ataperecorder,adataacquisition/computer
8.2 Specimen Thickness—The requisite specimen shall be
system, or video camera shall be used to measure the times of
thermally thick. Materials and composites of normal thickness
ignition and flame-front advancement.
50 mm or less shall be tested using their full thickness.
6.4.4 Digital Millivoltmeter or Data Acquisition System,
capable of indicating signal changes of 10 µV or less, is
NOTE 3—Some commercially available units may be used for testing
suitable for monitoring changes in operating conditions of the specimens with thickness of 75,+0,−3 mm.
radiant panel.
8.2.1 Composites—Assemblies shall be as specified in 8.2.
6.5 Space for Conducting Tests: However, where thin materials or composites are used in the
fabricationofanassembly,itispossiblethatthepresenceofan
6.5.1 Test Area, at least 45-m volume with a ceiling height
air gap, or the nature of any underlying construction, or both,
of not less than 2.5 m. The floor area supporting the apparatus
significantly affects the flammability characteristics of the
shall be level.
exposed surface. Use the same substrate for testing as used
6.5.1.1 The apparatus shall be located with a clearance of at
during field installation. If that substrate cannot be used or if it
least 1-m separation between it and the walls of the test room.
isunknown,areferencesubstratemustbeusedinitsplace.The
No combustible finish material of ceiling, floor, or walls shall
standard reference substrate is fiber-reinforced cement board
be located within2mofthe radiant heat source.
with a nominal thickness of 6.3 mm, a density of 1762 6 80
6.5.2 Fume Exhaust System—An exhaust system shall be
kg/m , and uncoated. When testing a thin material or a
installed with a capacity for moving air and combustion
composite assembly, ensure that no air gap exists between the
products at a rate of 0.3 m /s 6 5%. Surround the exhaust
specimen and the substrate material.
system with a 1.3 by 1.3-m refractory fiber skirt hanging down
8.2.2 Specimens shall be tested in the form of intended use.
to1.7 60.1mfromtheflooroftheroom.Locatethespecimen
support frame and radiant panel beneath this hood in such a
8.3 Specimen Size:
way that all combustion fumes are withdrawn from the room.
8.3.1 Ignition Test—Thespecimensshallbe155,+0,−5by
6.5.3 Air Supply—Access to an exterior supply of air, to
155,+0,−5 mm and shall be representative of the product.
replace that removed by the exhaust system, is required. This
8.3.2 Flame Spread Test—The specimens shall be
shall be arranged in such a way that the ambient room
155,+0,−5 by 800,+0,−5 mm and shall be representative
temperature remains at 25 6 5°C.
of the product.
6.5.4 Room Drafts—Measurements shall be made of air
8.4 Number of Specimens:
speeds near a dummy specimen in the vertical position while
8.4.1 Ignition Test—Obtaining the ignition-flux profile re-
the fume exhaust system is operating but the radiant panel and
quires the testing of six to twelve specimens.
its air supply are turned off.At a distance of 100 mm from the
8.4.2 Flame Spread Test—Test three specimens for each
panel, perpendicular to the lower edge and at midlength of the
different exposed surface of the product tested.
panel, the air flow shall not exceed 0.2 m/s in any direction.
9. Calibration of Apparatus
7. Hazards
9.1 Perform mechanical, electrical, and thermal calibrations
7.1 Safeguards shall be installed in the panel fuel supply
as described in Annex A1. Perform these adjustments and
system to guard against a gas air fuel explosion in the test
calibrationsfollowinginitialinstallationoftheapparatusandat
chamber. The safeguards shall include, but are not limited to,
other times as the need arises.
oneormoreofthefollowing:agasfeedcut-offactivatedwhen
theairsupplyfails;aflamesensordirectedatthepanelsurface
9.2 Monthly Verification—In a continuous program of tests,
that stops fuel flow when the panel flame goes out; and a heat
the flux distribution shall be determined not less than once a
detector mounted in contact with the radiant panel plenum that
month. Where the time interval between tests is greater than
is activated when the panel temperature exceeds safe limits.
onemonth,thefluxdistributionshallbedeterminedatthestart
Manual reset is a requirement of any safeguard system used.
of the test series.
7.2 The exhaust system must be so designed and operated
9.3 Continuous Monitoring of Operation—Adummy speci-
that the laboratory environment is protected from smoke and
men shall remain mounted in the position normally occupied
gas. The operator shall be instructed on ways to minimize
by a specimen whenever the equipment is in stand-by opera-
exposure to combustion products by following sound safety
tion. This is a necessary condition of the continuous monitor-
and industrial hygiene practices. For example, ensure that the
ing procedure that is accomplished by measuring the follow-
exhaust system is working properly and wear appropriate
ing:
clothing including gloves, safety glasses, breathing apparatus
9.3.1 The millivolt signal from a heat fluxmeter positioned
(when hazardous fumes are expected), etc.
50 mm from the exposed end of a dummy specimen, and
7.3 Duringthistest,veryhighirradiancesaregeneratedthat 9.3.2 The millivolt signal from the radiation pyrometer
are capable of igniting some clothing following even brief mounted securely on the specimen holder frame facing the
exposures. Take precautions to avoid ignitions of this type. surface of the radiant panel.
E1321 − 18
9.3.3 Either of these measurement methods is satisfactory 11.2 Ignition Test Procedure:
for determining that the required thermal operating level has 11.2.1 Adjust the thermal operating level for an external
been achieved. Satisfactory results require that both signals flux {q˙" (x)} of 30 kW/m to the specimen surface at the
e
show no drift for 3 min prior to test. The observed operating 50-mm position.
level of the panel from either the radiation pyrometer or the 11.2.2 Ignite the pilot; adjust the air/acetylene control
fluxmeter shall correspond, within 2%, to the similarly mea- valvessothatalight-blueconicalflameextendsapproximately
suredconditionsduringthecalibrationprocedurementionedin 180mmlengthwiseacrossthecontiguouswallflangeatthetop
A1.3. of the specimen holder (see Fig. 3).
11.2.3 Check and, if necessary, readjust the apparatus to the
10. Conditioning
appropriate thermal operating level. Allow the apparatus to
stabilize for at least 3 min.
10.1 Specimen Conditioning—Before testing, condition the
11.2.4 Record the output of the radiation pyrometer for the
specimens to constant moisture content at a temperature of 23
purpose of monitoring the radiant panel operating level during
63°Candarelativehumidityof50 65%.Constantmoisture
testing. A sample data-log format is shown in Fig. 7.
content is considered to be reached when, following two
11.2.5 Recordtheexternalflux{q˙" (x)}asdeterminedfrom
e
successive weighings, carried out at 24-h intervals, the mea-
the output of the fluxmeter at the 50-mm position.
sured mass does not differ by more than 0.1% of the mass of
11.2.6 Record the ambient room temperature, T .
∞
the specimen.
11.2.7 Remove the fluxmeter from the dummy specimen.
10.2 Specimen Preparation—Prior to insertion in the speci-
11.2.8 Within a 10-s interval, remove the holder containing
men holder, wrap the back and edges of the specimen in a
the dummy specimen from the apparatus and insert the holder
single sheet of 0.2 mm thick aluminum foil. When inserted in
containing the test specimen. Using a suitable instrument such
the specimen holder, back each specimen with a 25-mm sheet
as a stopwatch, audiovisual instrument, data acquisition/
of noncombustible refractory insulating material of the same
computer system, chronograph, or strip chart recorder, or any
lateral dimensions, density, and thermal characteristics as the
combination thereof, record the time (t ) when the test speci-
backing board.
men is fully in place and the time (t ) of flame attachment to
10.2.1 Flame Spread Test—Using an appropriate marker
the specimen surface. Time of ignition (t ) is defined as the
ig
such as chalk, or a soft pencil, draw a line along the center
timeafterspecimeninsertiontothetimeofflameattachmentto
horizontal length of the exposed face of each specimen. Make
the specimen surface (t − t ). Terminate the test at 20 min if
2 1
vertical markings at 25-mm (or less) increments as an aid in
ignition does not occur.
tracking the flame-front progress.
11.2.9 Record the time to ignition, t .
ig
11.2.10 If ignition occurred, readjust the external flux {q˙"
e
11. Procedures
(x)} at the 50-mm position downward using increments of
11.1 General—This test method involves mounting condi-
approximately5kW/m andrepeatthetestuntilafluxatwhich
tioned specimens in a well defined flux field and measuring
ignitiontimes,spreadofflame,andpositionoffinalextinguish-
ment. Therefore, these procedures assume that the apparatus
hasbeenpreparedandcalibratedasdescribedinSection10and
Annex A1.
11.1.1 Start the fume exhaust system.
11.1.2 Slide the dummy specimen into the apparatus.
11.1.3 Turn on the regulated air supply to the radiant panel.
11.1.4 Position ignitor approximately 2 cm in front of the
radiant-panel surface.
11.1.5 Turn on the gas supply to ignite the radiant panel.
11.1.6 Adjust the air/gas flow for the appropriate thermal
operating level by referencing the millivolt signal from the
water cooled heat fluxmeter that monitors the irradiance at the
50-mmpositiononthedummyspecimenorthemillivoltsignal
from the total-radiation pyrometer that monitors the radiant-
panel surface, or both. Make the adjustments to the output of
the radiant panel by first adjusting the air supply and then, if
necessary, adjusting the gas supply. Allow at least 15 min for
the radiant panel to reach equilibrium.
11.1.7 Iftheheatfluxmetersignalisusedinestablishingthe
appropriate operating level, turn on the cooling water to the
fluxmeter prior to positioning the fluxmeter in the special
50-mm dummy specimen. The cooling water shall be within
63°C of room temperature. Use the dummy specimen fabri-
cated to accommodate the fluxmeter at the 50-mm position. FIG. 7 Data Logging Format Sample, Ignition Test
E1321 − 18
noignitionoccurshasbeenidentified.Ifignitiondidnotoccur, topreheatforthetime, t*,andignitethespecimenbymanually
readjust the external flux {q˙" (x)} at the 50-mm position moving a pilot along the bottom surface of the specimen in the
e
upward (using increments of approximately 5 kW/m ), and direction of decreasing irradiance.
repeat the test (using fresh specimen(s)) until a minimum flux
11.3.7 Record the time of ignition (t ).
ig
at which ignition occurs has been identified.
11.3.8 Visually track the flame-front progress along the
11.2.11 Determine a minimum flux for ignition (q˙" )by
o,ig longitudinal centerline of the specimen by using the mirror
bracketing within 62kW/m the fluxes for ignition/no igni-
assembly,theviewingrakes,orthemarkingsonthespecimens,
tion.
or combination thereof. Record the arrival time of the flame
11.2.12 Repeat 11.2.1 – 11.2.9 adjusting the external flux
front at 25-mm increments. As an alternate to the use of the
{q˙" (x)} at the 50-mm position upward (using increments of
mirror assembly for materials that propagate flame spread
e
approximately 10 kW/m ), until an ignition time flux profile
rapidlyfollowingignition,audiovisualequipmentshallbeused
(Fig. 8) has been determined for fluxes {q˙" (50)} between the
e to record the arrival time of the flame front at the incremented
minimum flux for ignition (q˙" ) and 65 kW/m . Depending
o,ig
positions.
onthenumberoftestsrequiredtobrackettheminimumfluxfor
11.3.9 Terminate the test if flaming reaches the end of the
ignition, it is possible that this will require up to twelve tests.
specimen or self-extinguishes and thus ceases progress along
11.3 Flame Spread Test Procedure: the specimen.
11.3.1 Remove the pilot flame so that it does not come in
11.3.10 Record both the time, t, (in seconds) and the
contact with the fuel gases emitted from the heated specimen.
position, x, (in millimetres) along the specimen at which the
11.3.2 With the dummy specimen in place, adjust the
flame-front progression ceases.
thermal operating level to the specimen surface, 50 mm from
11.3.11 Observations—In addition to recording experimen-
thehotend,foranirradiancethatisatroughly5kW/m higher
tal data, document observations on general behavior of the
than the minimum irradiance (q˙" ) necessary for ignition.
o,ig specimen including glowing, charring, melting, flaming drips,
Allow the apparatus to stabilize for 3 min.
disintegration of the specimen, etc.
11.3.12 Repeat operations 11.3.1 – 11.3.11 for two addi-
NOTE 4—Select this flux for ease in tracking the flame front. For most
materials this will be between 5 and 10 kW/m above the minimum
tional specimens.
ignition flux.
11.3.3 Record the external flux {q˙" (x)} to the specimen 12. Calculation
e
surfaceatthe50-mmposition.Ifapplicablefordatarecording,
12.1 Ignition Test Calculation:
start the data acquisition/computer system, the audiovisual
12.1.1 The theories used to develop correlation of ignition
instrument, or the strip chart recorder, or combination thereof.
test data are developed in Appendix X1 and Appendix X2.
11.3.4 Within a 10-s interval, remove the holder containing
12.1.2 Plottest-dataresults(q˙" )/(q˙" )versus =t; seeFig.
the dummy specimen from the apparatus and insert the holder o,ig e
X1.2 (a) and (b).
containing the test specimen. Immediately activate the timing
mechanism.
12.1.3 Fit straight line to data (solid line, see Fig. X1.2 (a)
11.3.5 Record the time when the test specimen is fully in
and (b)). See Appendix X1 for the rationale for using this
place by using the audio portion of the audiovisual instrument,
technique.
observing the stopwatch, or activating the event marker con-
12.1.4 Determine ignition parameters, b and t*, from the
nected to the computer, strip-chart recorder, or chronograph.A
respective slope of the line drawn through the data and the
sample flame spread data log format is shown in Fig. 9.
interceptofthislinewiththeline F(t)=1= q˙" / q˙" ;seeFig.
o,ig e
11.3.6 Allow the specimen to preheat for the time, t* (from
X1.2 (a).
correlated ignition-test data) and replace the pilot flame to the
12.1.5 Using the minimum flux required for ignition (q˙" )
o,ig
position shown in Fig. 3. If the specimen does not ignite,
(see 11.2.11), determine the surface ignition temperature (T )
ig
conductarepeattest(freshspecimen)usingamodifiedignition
(see Fig. 10 and Eq X1.9).
source,thatis,followsteps11.3.1–11.3.5,allowthespecimen
NOTE 5—Assuming a surface emissivity of one and steady conditions,
h depends only on the apparatus configuration (geometry) and operating
level.Heresteady-statesurfacetemperaturesweremeasuredforanumber
of real building materials over a range of heat-flux levels and also
calculatedfor h =15W/m ·k.Fig.10showsthetheoreticalandmeasured
c
data linking specimen-surface temperature to imposed heat flux. This
curvecanbeusedwithreasonableaccuracytoinfersurfacetemperatureat
ignition (T ) for the q˙" as a substitute to Eq X1.9 in Appendix X1.
ig o,ig
12.1.6 Determine effective thermal property (kρc) as fol-
lows (see also Eq X1.12 in Appendix X1):
4 h
kρc 5 (1)
S D
π b
where h =the heat-transfer coefficient at ignition, deter-
FIG. 8 Ignition Time as a Function of External Irradiance mined as follows (see also Eq X1.7 in Appendix X1):
E1321 − 18
FIG. 9 Data Logging Format Sample, Flame Spread Test
q˙" 12.2.1 The theory used to develop the correlation of flame-
o,ig
h 5 (2)
T 2 T spread test data are developed in Appendix X1 and Appendix
ig `
X2.
12.2 Flame Spread Test Calculation:
E1321 − 18
π
Φ 5 (8)
Cb
~ !
13. Report
13.1 Report the following information:
13.1.1 The date, the original ignition and flame spread data,
the observations made on each specimen, and the derived
ignition and flame spread parameters,
13.1.2 Name and address of the testing laboratory,
13.1.3 Identification of specimen including manufacturer
and code designation, thickness, density, and where known,
FIG. 10 Equilibrium Surface Temperature as a Function of Exter-
nal Radiant Heating composition of the specimen,
13.1.4 Identification of specimen backing material includ-
ingthickness,density,andwhereknown,thermalconductivity,
12.2.2 Using the flux-distribution values of Table 1, com-
13.1.5 Data from the ignition test including:
pute F(x)atthe x-positions corresponding to the flame-front
13.1.5.1 A table or graph, or both, showing ignition times
arrival times, t, as follows:
for external fluxes, and
q˙" x
~ !
e 13.1.5.2 Measured and derived ignition parameters, as fol-
F x 5 (3)
~ !
q˙" 50
~ !
e lows:
12.2.3 Calculate the surface flux at the measured flame-
q˙" = flux necessary for ignition, min,
o,ig
front positions from the flux q˙" (50) as recorded in 11.3.3,as
e
T = surface temperature necessary for ignition, min,
ig
follows:
b = ignition correlation parameter,
t* = time for specimen to reach thermal equilibrium, and
q˙" x 5 F x *q˙" 50 (4)
~ ! ~ ! ~ !
e e
kρc = thermal heating property,
12.2.4 Compute flame-front velocity by applying a running
13.1.6 Data from flame spread test including:
three-pointleastsquarefittothemeasuredflamefrontposition-
13.1.6.1 Surface flux at the 50-mm position,
time (x, t) data as follows:
13.1.6.2 Flame-front arrival time at 25-mm increments
t x
( (
along specimen surface, and
tx 2
(
13.1.6.3 Measured and derived flame spread parameters, as
V 5 (5)
~ t!
follows:
(
t 2
(
C = flame spread parameter,
12.2.5 Correlateandplotflame-spreaddataasshowninFig.
q˙" = flux necessary for ignition, min,
o,ig
X1.2 (see also Eq X1.10 in Appendix X1) as follows:
T = surface temperature necessary for ignition, min,
ig
21/2 q˙" = flux necessary for flame spread, min,
V versus q˙" x F t (6) o,s
~ ! ~ !
e
T = temperature necessary for flame spread, min, and
s,min
where:
Φ = flame heating parameter, and
= 13.1.7 Calibrated flux distribution along specimen surface
b t, t# t*
F t 5H (7)
~ !
at positions listed in Table 1.
1, t$ t*
NOTE 6—It is expected that the plotted velocity (V) and surface flux
(q˙" ) will represent values at the midpoint of the three points used for the 14. Precision and Bias
e
data fit.
14.1 Precision—The precision of this test method is under
12.2.6 Fit line to linear section of data (see solid line Fig.
consideration and is awaiting evaluation.
X1.2).SeeAppendixX2fortherationaleforweighingthedata
14.2 Bias—This test method for determining ignition and
points over the linear section of the data.
flame spread properties of materials has no bias because these
12.2.7 Obtain the following parameters:
valuesareeffectivepropertiesderivedfromthetestdata.While
C flame spread parameter (slope of straight line fitted to correlated flame
it is possible that these effective properties will have more
spread data (see Fig. X1.2))
precisely measurable physical counterparts, in this test method
q˙" x intercept of straight line (see Fig. X1.2)
o,ig
T from q˙" and theoretical curve for surface temperature (see Eq X1.9,
ig o,ig they are determined by a fit of the data to a model for flame
Fig. 10)
spread.
q˙" flux at position where flame stops (see Fig. X1.2)
o,s
T from q˙" and theoretical curve for surface temperature at thermal
s,min o,s
15. Keywords
equilibrium (see Eq X1.9 and Fig. 10)
12.2.8 Compute flame-spread parameter, Φ (see Eq X2.7 in 15.1 fire; flame spread; flammability; ignition; thermal
Appendix X2), as follows: intertia
E1321 − 18
TABLE 1 Calibration of Flux to the Specimen
NOTE 1—This table includes typical flux incident on the specimen and
specimenpositionsatwhichthecalibrationmeasurementsaretobemade.
Thefluxat50and350-mmpositionsshallbesetasaccuratelyaspossible.
Calibration data at other positions shall agree with typical values within
10%. This calibration shall be performed with the use of the special
dummyspecimen.Itispossibletomeasureallexceptthefirstofthefifteen
typical measurements listed.
Distance From Ex-
Typical Flux Levels at Calibration Position to be
posed End of the
2 2A
the Specimen, kW/m Used, kW/m
Specimen, mm
0 49.5
50 50.5 50.5
100 49.5
150 47.1 X
200 43.1
250 37.8 X
300 30.9
350 23.9 23.9
400 18.2
450 13.2 X
500 9.2
550 6.2 X
600 4.3
650 3.1 X
700 2.2
750 1.5 X
A
AnXindicatesthefluxesattheadditionalsixmeasuringpositionsrequiredbythe
standard. The seven empty spaces represent the fluxes at the additional measur-
ing positions recommended by the standard.
ANNEX
(Mandatory Information)
A1. ASSEMBLY OF APPARATUS
A1.1 Assembly and Adjustment
A1.1.1 The heat-flux measurement at the surface of the
specimen is the controlling criterion both in the original
adjustment of test operating conditions and periodic verifica-
tion of this adjustment. This heat flux shall be measured by a
fluxmeter inserted into holes in a special calibration board (see
Fig. A1.1).
A1.1.2 Monitorradiant-paneloperatinglevelsbetweencon-
secutivetestsbyuseofaheatfluxmetermountedatthe50-mm
position in a dummy specimen and during the test by use of a
radiation pyrometer calibrated on the basis of the readings of a
heat fluxmeter. Check the calibration periodically. This radia-
tion pyrometer shall be rigidly fixed to the specimen holder
frame in such a manner that it continuously views the
NOTE 1—All dimensions are in millimetres.
radiating-panel surface (see 6.4.1).
FIG. A1.1 Dummy Specimen for Flux Gradient Calibration
A1.2 Mechanical Alignment
A1.2.1 The position of the refractory surface of the radiant
panel with respect to the specimen must correspond with the A1.2.2 WiththeapparatusassembledasspecifiedinSection
angle and Dimension A shown in Fig. A1.2. These relation- 6, make the following mechanical alignments:
ships are achieved by adjustment between the panel and its A1.2.2.1 Check the rotating ring (see Fig. 6) with a level to
mounting bracket, the two main frames, and position of the ensure that it lies in a vertical plane. If the bearing does not lie
specimen holder guides. in the vertical plane, adjust the upper support bracket. If any
E1321 − 18
made to achieve the condition of no significant flaming from
the panel surface. In systems using a venturi valve, change the
flux levels by adjusting only the air valve. (Warning—Water
cooling of the fluxmeter is required to avoid damage to the
fluxmeter and erroneous signals at low flux levels. Control the
temperature of the cooling water in such a manner that the
fluxmeter body temperature remains within a few degrees of
room temperature. Make corrections of the flux measurement
for temperature differences between the fluxmeter body and
NOTE 1—All dimensions are in millimetres.
room temperature. It is possible that failure to supply water
FIG. A1.2 Specimen-Panel Arrangement
cooling will result in thermal damage to the sensing surface
and loss of calibration of the fluxmeter.)
nonvertical position is caused by excessive bearing roller
A1.3.2.1 The flux measured at both the 50 and 350-mm
clearance, install larger rollers.
positionshallmatchthevaluesinTable1toensurethatafixed
A1.2.2.2 With the radiant panel rotated into a vertical
configuration or view geometry between the panel and the
position (as checked with a level), the angle between the panel
specimen has been achieved. To meet these requirements,
and the longitudinal members of the specimen support frame
change the specimen longitudinal position shown by Dimen-
shall be 15 6 0.25° (see Fig. A1.2).
sion B in Fig. A1.2.
A1.2.2.3 With an empty specimen holder installed, adjust
A1.3.2.2 Developaplotandsmoothcurveonthebasisofat
the upper guide fork to ensure the holder lies in a vertical
least the eight required flux measurements shown in Table 1.
plane. Adjust the spacing between the radiant panel and the
Onthebasisofthenormalizedflux-distributioncurve(seeFig.
holder frame so that DimensionAin Fig.A1.2 is 125 62mm
2), the flux gradient along the specimen length is derived from
while still maintaining the 15 6 0.25° angular relationship.
a single flux measurement at the 50-mm position.
Dimension B must be adjusted to meet the flux distribution
NOTEA1.2—It is recommended that the 15 measured flux levels at the
requirements along the specimen.
positions shown in Table 1 be used to produce a smoother curve.
A1.2.2.4 Position the horizontal pilot as shown in Fig. 3.
A1.3.2.3 If the radiation pyrometer is to be used to set the
A1.2.2.5 Position the viewing rake so that the pins are
flux level at the 50-mm position, calibrate it over the operating
located at multiples of 50 6 2-mm distance from the closest
range of 20 to 65 kW/m , on the basis of the reading of a
end of the specimen exposed to the panel.
fluxmeterpositionedatthe50-mmpositionandtheslope(CF),
A1.3 Thermal Adjustment of Radiant Panel Operating
an apparatus constant, determined (see Fig. A1.3). Calculate
Level
A1.3.1 Thermal adjustment of the panel operating level is
achieved by first setting an air flow of about 0.26 m /s through
the panel. Gas is then supplied and the panel ignited and
allowed to come to thermal equilibrium with a dummy
specimen mounted before it. At proper operating condition
there shall be no visible flaming from the panel surface except
when viewed from one side parallel to the surface plane. From
this direction a thin blue flame very close to the panel surface
will be observed.An oblique view of the panel after a 15 min
warm up period shall show a bright orange radiating surface.
NOTEA1.1—Intheabsenceofacalibratedflowmeterintheairline,this
flow rate can be roughly set by holding a lighted match with its axis
FIG. A1.3 Typical Calibration of Panel Output to Specimen Sur-
horizontalandclosetotheburner-tileface.Theflamefromthematchshall
face as a Function of Total Radiation Pyrometer Signal
deviate from the vertical by about 10°.
A1.3.2 With a water-cooled fluxmeter mounted in the cali-
the flux distribution along the specimen using CF or a
brationboard(seeFig.A1.1),thefluxincidentonthespecimen fluxmeter reading at the 50-mm location (see 12.2.2 and
shall correspond to the values shown in Table 1. Compliance 12.2.3). Once the relationship between the pyrometer millivolt
with this requirement is achieved by adjustment of the air/gas output and the flux at 50 mm has been established, use either
flow rates.When required, changes in air and gas flow shall be way to set the heat flux level.
E1321 − 18
APPENDIXES
(Nonmandatory Information)
X1. IGNITION THEORY (1)
X1.1 The ignition theory is based on the following two X1.2.1 For common building materials, the surface
reasonable assumptions: emissivity, ε, is close to one and can be assumed to be one.
Also, the radiative part of the surface heat losses can be
X1.1.1 Most common organic solids, that is, those whose
−7 2 linearized. Thus, mathematically, the problem can be posed as
thermal diffusivity k/ρc fall in the range of 0 to 10 m /s, in
follows:
applications of construction can be treated as a semi-infinite
solid since the depth of heating for conditions of piloted ]T k ] T
5 (X1.1)
ignition is 2 to 5 mm. Even for materials of thickness smaller ]t ρc ]y
than this, the semi-infinite results apply if effective thermal
]T
4 4
y 50:2k 5 q˙" 2 h T 2 T 2 σ T 2 T (X1.2)
properties for the assembly of the material and its substrate are
e c~ `! ~ ` !
]y
considered. The same approach can be used for composite or
nonhomogenous materials.
>q˙" 2 h T 2 T
~ !
e `
X1.1.2 Pilotedignitioninanatmosphereofambient-oxygen
y→`:T 5 T (X1.3)
`
concentration occurs when the surface temperature of the
t 50:T 5 T (X1.4)
`
material reaches a threshold value, T , which depends on the
ig
materialitselfbutisrelativelyindependentofthewayinwhich
Thesolutionforthisproblemforthetemperatureaty=0can
the material is heated. In other words, a sample of a certain
be written as
...

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: E1321 − 13 E1321 − 18 An American National Standard
Standard Test Method for
Determining Material Ignition and Flame Spread Properties
This standard is issued under the fixed designation E1321; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Scope*
1.1 This fire test response standard determines material properties related to piloted ignition of a vertically oriented sample
under a constant and uniform heat flux and to lateral flame spread on a vertical surface due to an externally applied radiant-heat
flux.
1.2 The results of this test method provide a minimum surface flux and temperature necessary for ignition (q˙" , T ) and for
o,ig ig
lateral spread (q˙" , T ), an effective material thermal inertia value (kρc), and a flame-heating parameter (Φ) pertinent to lateral
o,s s,min
flame spread.
1.3 The results of this test method are potentially useful to predict the time to ignition, t , and the velocity, V, of lateral flame
ig
spread on a vertical surface under a specified external flux without forced lateral airflow. Use the equations in Appendix X1 that
govern the ignition and flame-spread processes and which have been used to correlate the data.
1.4 This test method is potentially useful to obtain results of ignition and flame spread for materials. Data are reported in units
for convenient use in current fire growth models.
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 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.
1.7 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these
tests.
1.8 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 hazard statements, see Section 7.
1.8 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these
tests.
1.9 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:
E84 Test Method for Surface Burning Characteristics of Building Materials
E162 Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source
E176 Terminology of Fire Standards
E286 Test Method for Surface Flammability of Building Materials Using an 8-ft (2.44-m) Tunnel Furnace (Withdrawn 1991)
E648 Test Method for Critical Radiant Flux of Floor-Covering Systems Using a Radiant Heat Energy Source
E970 Test Method for Critical Radiant Flux of Exposed Attic Floor Insulation Using a Radiant Heat Energy Source
E1317 Test Method for Flammability of Marine Surface Finishes
This test method is under the jurisdiction of ASTM Committee E05 on Fire Standards and is the direct responsibility of Subcommittee E05.22 on Surface Burning.
Current edition approved Oct. 1, 2013Nov. 1, 2018. Published October 2013November 2018. Originally approved in 1990. Last previous edition approved in 20092013
as E1321 – 09.E1321 – 13. DOI: 10.1520/E1321-13.10.1520/E1321-18.
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.
The last approved version of this historical standard is referenced on www.astm.org.
*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
E1321 − 18
2.2 ASTM Adjuncts:ASTM
Detailed drawings (19), construction information, and parts list (Adjunct to E1317)
3. Terminology
3.1 Definitions—For definitions of terms used in this test method, refer to Terminology E176.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 backing board, n—a noncombustible insulating board, mounted behind the specimen during actual testing to satisfy the
theoretical analysis assumption of no heat loss through the specimen. It shall be roughly 25 6 5 mm thick with a density no greater
than 200 6 50 kg/m .
3.2.2 dummy specimen, n—a noncombustible insulating board used for stabilizing the operating condition of the equipment,
roughly 20 6 5 mm in thickness with a density of 750 6 100 kg/mequipment. .
3.2.2.1 Discussion—
The dummy specimen is mounted in the apparatus in the position of the test specimen and removed only when a test specimen
is to be inserted. For the ignition tests, the dummy specimen board shall have a hole at the 50-mm position, for mounting the
fluxmeter.
3.2.3 effective thermal property, n—thermal properties derived from heat-conduction theory applied to ignition/ flame-spread
ignition/flame-spread data treating the material as homogenous in structure.
3.2.4 mirror assembly, n—a mirror, marked and aligned with the viewing rakes, used as an aid for quickly identifying and
tracking the flame-front progress.
3.2.5 special calibration board, n—a specially assembled noncombustible insulating board used for standardizing the operating
condition of the equipment which is used only to measure the flux distribution at specified intervals along the specimen surface.
It shall be roughly 206 5 mm in thickness with a density of 750 6 100 kg/m .
3.2.6 thermally thick, n—the thickness of a medium that is large enough to have the predominate thermal (temperature) effects
experienced within that distance, that is, negligible heat is lost from its unexposed side.
3.2.7 thermal operating level, n—the operating condition at which the radiance of the heat source produces a specified constant
heat flux to some specified position at the specimen surface.
3.2.8 viewing rakes, n—a set of bars with wires spaced at 50-mm intervals for the purpose of increasing the precision of timing
flame-front progress along the specimen.
3.3 Symbols:
−1/2
b = ignition correlation parameter, s .
s/2 1/2
C = flame heat transfer factor, m /kW·s .
CF = ratio of radiation pyrometer signal to flux incident on dummy specimen as measured during calibration; a linear
correlation is assumed, mV/(kW/m ).
F(t) = specimen thermal response function.
F(x) = surface flux configuration invariant, (kW/m )/mV.
h = heat loss coefficient, kW/m ·K.
q˙" = measured incident flux, kW/m .
e
q˙"o,ig = critical flux for ignition, kW/m .
q˙"o,s = critical flux for spread, kW/m .
t = time, s.
t* = characteristic equilibrium time, s.
t = time at sample insertion, s.
t = time at ignition, s.
t = ignition time under incident flux, s.
ig
T = ignition temperature, °C.
ig
T = minimum temperature for spread, °C.
s, min
T = ambient and initial temperature, °C.
∞
V = flame (pyrolysis front) velocity, m/s.
x = longitudinal position along centerline of specimen, m.
2 3
Φ = flame heating parameter, (kW) /m .
2 2
kρc = thermal heating property, (kW/m ·K) s.
ε = surface emissivity.
Available from ASTM Headquarters. Order ADJE1317.
E1321 − 18
2 4
σ = Stefan-Boltzmann constant, kW/m ·K .
4. Summary of Test Method
4.1 This test method consists of two procedures; one to measure ignition and one to measure lateral-flame spread. Vertically
mounted specimens are exposed to the heat from a vertical air-gas fueled radiant-heat energy source inclined at 15° to the specimen
(see Fig. 1).
4.1.1 For the ignition test, a series of 155, + 0, − 5 mm by 155, + 0, − 5 mm specimens (see Fig. 1) are exposed to a nearly
uniform heat flux (see Fig. 2) and the time to flame attachment, using piloted ignition (see Fig. 3), is determined.
4.1.2 For the flame spread test, a 155, + 0, − 5 mm by 800, + 0, − 5 mm specimen (see Fig. 1) is exposed to a graduated heat
flux (see Fig. 2) that is approximately 5 kW/m higher at the hot end than the minimum heat flux necessary for ignition; this flux
being determined from the ignition test (see 11.2). The specimen is preheated to thermal equilibrium; the preheat time being
derived from the ignition test (see 12.1). After using piloted ignition, the pyrolyzing flame-front progression along the horizontal
length of the specimen as a function of time is tracked. The data are correlated with a theory of ignition and flame spread for the
derivation of material flammability properties.
5. Significance and Use
5.1 This test method addresses the fundamental aspects of piloted ignition and flame spread. The procedure is suitable for the
derivation of relevant material flammability parameters that include minimum exposure levels for ignition, thermal-inertia values,
and flame-spread properties.
5.2 This test method is used to measure some material-flammability properties that are scientifically constant and compatible
and to derive specific properties that allow the prediction and explanation of the flame-spread characteristics of materials. They
are considered effective properties that are dependent on the correlations used and when combined with theory can be used over
a wide range of fire conditions for predicting material ignition and flame-spread behavior.
5.3 Do not use this test method for products that do not have planar, or nearly planar, external surfaces and those products and
assemblies in which physical performance such as joint separation and fastening methods has a significant influence on flame
propagation in actual fire conditions.
5.4 In this procedure, the specimens are subjected to one or more specific sets of laboratory test conditions. If different test
conditions are substituted or the end-use conditions are changed, it is not always possible by or from this test method to predict
changes in the fire-test-response characteristics measured. Therefore, the results are valid only for the fire test exposure conditions
described in this procedure (see also 1.6).
6. Apparatus
6.1 Dummy Specimens and Backing Boards:
6.1.1 This test method requires the use of a dummy specimen board in several instances during both calibration and testing. The
dummy specimen shall be a noncombustible insulating board, 20 6 5 mm in thickness, with a density of 750 6 100 kg/m .
6.1.2 For the ignition tests, the dummy specimen board shall have a hole at the 50-mm position, for mounting the fluxmeter.
6.1.3 For the purpose of this test method, backing boards are noncombustible insulating boards 25 6 5 mm thick with a density
no greater than 200 6 50 kg/m .
6.1.4 Use as a special calibration board a dummy specimen, as described in 6.1.1, for measuring the flux distribution along the
test specimen surface.
FIG. 1 Schematic of Apparatus With Ignition Specimen
E1321 − 18
FIG. 2 Normalized Flux Over Specimen
NOTE 1—All dimensions are in millimetres.
FIG. 3 Pilot Configuration for Ignition Test
FIG. 4 General View of Apparatus
6.2 Test-Equipment Fabrication—Fig. 4 shows a photograph of the equipment as assembled ready for test. Figs. 5 and 6 show
schematics of the apparatus. These provide engineering information necessary for the fabrication of the main frame, specimen
holders, stack, and other necessary parts of the equipment. Some commercially available units have added safety features that are
not described in the drawings.
E1321 − 18
FIG. 5 Test Apparatus Main Frame, Front View
FIG. 6 Test Apparatus, Side View
NOTE 1—The specimen fume stack available in some commercial models is not required for this test procedure.
6.3 A brief parts list for the test-equipment assembly includes:
6.3.1 Main Frame (see Fig. 5), consisting of two separate sections, the radiant-panel support frame and the specimen support
frame. The two frame sections shall be joined in a manner that allows adjustments in the relative position of the radiant panel to
the specimen to be made easily.
6.3.2 Specimen Holders, to provide for support of the specimen during test; at least two of these are required, and three prevent
delays resulting from required cooling of holders prior to mounting specimens.
6.3.3 Radiant Panel, consisting of a radiation surface of porous refractory tiles mounted at the front of a stainless steel plenum
chamber to provide a flat radiating surface of approximately 280 by 483 mm. The plenum chamber shall include baffle plates and
diffusers to distribute the gas/air mixture evenly over the radiation surface. The gas/air mixture enters the plenum chamber at one
of the short sides to facilitate easy connection when the panel is mounted from the frame. A reverberatory screen (see Fig. 6) is
provided immediately in front of the radiating surface to enhance the combustion efficiency and increase the radiant output.
6.3.4 Air and Fuel Supply, to support combustion of the radiant panel. The appropriate air and fuel flow-metering devices, gas
control valves, pressure reducer, and safety controls are all mounted on the panel support frame (see Fig. 5). Requirements are as
follows:
−3 3
6.3.4.1 A regulated air supply of about 8.33 by 10 m /s at a pressure sufficient to overcome the friction loss through the line,
metering device, and radiant panel; the radiant-panel pressure drop amounts to approximately 20 to 30 Pa. A flowmeter suitable
−3 3
for indicating air flow over the range of 2 to 15 by 10 m /s shall be provided. A flowmeter suitable for indicating methane flow
−3 3
rates over the range of 0.1 to 1.1 by 10 m /s shall be provided.
6.3.4.2 The fuel gas used shall be either natural gas or methane. A pressure regulator shall be provided to maintain a constant
supply pressure. Gas is controlled by either a manually adjusted needle valve or a venturi mixer. The venturi mixer will allow one
to control the flux level of the panel by adjusting only the air valve. The fuel gas-flow requirements are roughly 0.26 to 1.03 by
−3 3
10 m /s at a pressure sufficient to overcome line pressure losses.
E1321 − 18
NOTE 2—If a venturi mixer is used, the regulated air and fuel gas supply shall be sufficient for efficient operation of the venturi mixer.
6.3.5 The Specimen Holder Support Frame Guides, Pilot Flame Holder, Fume Stack (optional), Flame Front Viewing Rakes,
Radiation Pyrometer, and Mirror are all assembled on the specimen support frame. The arrangement of parts on this frame is
shown in Figs. 4-6.
6.3.6 Dummy Specimen, of noncombustible insulating board of the thickness and density specified in the test procedure, shall
be mounted on the apparatus in the position of the specimen except during actual testing or calibration.
6.4 Instrumentation:
6.4.1 Total Radiation Pyrometer, compensated for its temperature variation and having a nominal sensitivity between the
thermal wavelengths of 1 and 9 μm that shall view a centrally located area on the radiant panel of about 150 by 300 mm. The
instrument shall be securely mounted on the specimen support frame in such a manner that it can view the radiant panel surface
oriented for specimens in the vertical position.
6.4.2 Heat Fluxmeters—Have available at least three fluxmeters for this test method. One of these shall be retained as a
laboratory reference standard. The fluxmeters shall be of the thermopile type with a nominal range of 0 to 50 kW/m and have a
sensitivity of approximately 10 mV at 50 kW/m . They shall have been calibrated to an accuracy of 5 % over this range. The time
constant of these instruments shall not be more than 290 ms (corresponding to a time to reach 95 % of final output of not more
than 1 s). The target sensing the applied flux shall occupy an area not more than 4 by 4 mm and be located flush with and at the
center of the water-cooled 25-mm circular exposed metallic end of the fluxmeter. If fluxmeters of smaller diameters are to be used,
these shall be inserted into a copper sleeve of 25-mm outside diameter in such a way that good thermal contact is maintained
between the sleeve and water-cooled fluxmeter body. The end of the sleeve and exposed surface of the fluxmeter shall lie in the
same plane. Radiation shall not pass through any window before reaching the target.
6.4.3 Timing Devices, such as a chronograph, a digital clock, a stopwatch, a tape recorder, a data acquisition/computer system,
or video camera shall be used to measure the times of ignition and flame-front advancement.
6.4.4 Digital Millivoltmeter or Data Acquisition System, capable of indicating signal changes of 10 μV or less, is suitable for
monitoring changes in operating conditions of the radiant panel.
6.5 Space for Conducting Tests:
6.5.1 Test Area, at least 45-m volume with a ceiling height of not less than 2.5 m. The floor area supporting the apparatus shall
be level.
6.5.1.1 The apparatus shall be located with a clearance of at least 1-m separation between it and the walls of the test room. No
combustible finish material of ceiling, floor, or walls shall be located within 2 m of the radiant heat source.
6.5.2 Fume Exhaust System—An exhaust system shall be installed with a capacity for moving air and combustion products at
a rate of 0.3 m /s 6 5 %. Surround the exhaust system with a 1.3 by 1.3-m refractory fiber skirt hanging down to 1.7 6 0.1 m
from the floor of the room. Locate the specimen support frame and radiant panel beneath this hood in such a way that all
combustion fumes are withdrawn from the room.
6.5.3 Air Supply—Access to an exterior supply of air, to replace that removed by the exhaust system, is required. This shall be
arranged in such a way that the ambient room temperature remains at 25 6 5°C.
6.5.4 Room Drafts—Measurements shall be made of air speeds near a dummy specimen in the vertical position while the fume
exhaust system is operating but the radiant panel and its air supply are turned off. At a distance of 100 mm from the panel,
perpendicular to the lower edge and at midlength of the panel, the air flow shall not exceed 0.2 m/s in any direction.
7. Hazards
7.1 Safeguards shall be installed in the panel fuel supply system to guard against a gas air fuel explosion in the test chamber.
The safeguards shall include, but are not limited to, one or more of the following: a gas feed cut-off activated when the air supply
fails; a flame sensor directed at the panel surface that stops fuel flow when the panel flame goes out; and a heat detector mounted
in contact with the radiant panel plenum that is activated when the panel temperature exceeds safe limits. Manual reset is a
requirement of any safeguard system used.
7.2 The exhaust system must be so designed and operated that the laboratory environment is protected from smoke and gas. The
operator shall be instructed on ways to minimize exposure to combustion products by following sound safety and industrial
hygiene practices. For example, ensure that the exhaust system is working properly and wear appropriate clothing including gloves,
safety glasses, breathing apparatus (when hazardous fumes are expected), etc.
7.3 During this test, very high irradiances are generated that are capable of igniting some clothing following even brief
exposures. Take precautions to avoid ignitions of this type.
8. Test Specimens
8.1 The specimens selected for testing shall be representative of the product as it is intended for use.
8.2 Specimen Thickness—The requisite specimen shall be thermally thick. Materials and composites of normal thickness 50 mm
or less shall be tested using their full thickness.
E1321 − 18
NOTE 3—Some commercially available units may be used for testing specimens with thickness of 75, + 0, − 3 mm.
8.2.1 Composites—Assemblies shall be as specified in 8.2. However, where thin materials or composites are used in the
fabrication of an assembly, it is possible that the presence of an air gap, or the nature of any underlying construction, or both,
significantly affects the flammability characteristics of the exposed surface. Use the same substrate for testing as used during field
installation. If that substrate cannot be used or if it is unknown, a reference substrate must be used in its place. The standard
reference substrate is fiber-reinforced cement board with a nominal thickness of 6.3 mm, a density of 1762 6 80 kg/m , and
uncoated. When testing a thin material or a composite assembly, ensure that no air gap exists between the specimen and the
substrate material.
8.2.2 Specimens shall be tested in the form of intended use.
8.3 Specimen Size:
8.3.1 Ignition Test—The specimens shall be 155, + 0, − 5 by 155, + 0, − 5 mm and shall be representative of the product.
8.3.2 Flame Spread Test—The specimens shall be 155, + 0, − 5 by 800, + 0, − 5 mm and shall be representative of the product.
8.4 Number of Specimens:
8.4.1 Ignition Test—Obtaining the ignition-flux profile requires the testing of six to twelve specimens.
8.4.2 Flame Spread Test—Test three specimens for each different exposed surface of the product tested.
9. Calibration of Apparatus
9.1 Perform mechanical, electrical, and thermal calibrations as described in Annex A1. Perform these adjustments and
calibrations following initial installation of the apparatus and at other times as the need arises.
9.2 Monthly Verification—In a continuous program of tests, the flux distribution shall be determined not less than once a month.
Where the time interval between tests is greater than one month, the flux distribution shall be determined at the start of the test
series.
9.3 Continuous Monitoring of Operation—A dummy specimen shall remain mounted in the position normally occupied by a
specimen whenever the equipment is in stand-by operation. This is a necessary condition of the continuous monitoring procedure
that is accomplished by measuring the following:
9.3.1 The millivolt signal from a heat fluxmeter positioned 50 mm from the exposed end of a dummy specimen, and
9.3.2 The millivolt signal from the radiation pyrometer mounted securely on the specimen holder frame facing the surface of
the radiant panel.
9.3.3 Either of these measurement methods is satisfactory for determining that the required thermal operating level has been
achieved. Satisfactory results require that both signals show no drift for 3 min prior to test. The observed operating level of the
panel from either the radiation pyrometer or the fluxmeter shall correspond, within 2 %, to the similarly measured conditions
during the calibration procedure mentioned in A1.3.
10. Conditioning
10.1 Specimen Conditioning—Before testing, condition the specimens to constant moisture content at a temperature of 236 23
6 3°C and a relative humidity of 50 6 5 %. Constant moisture content is considered to be reached when, following two successive
weighings, carried out at 24-h intervals, the measured mass does not differ by more than 0.1 % of the mass of the specimen.
10.2 Specimen Preparation—Prior to insertion in the specimen holder, wrap the back and edges of the specimen in a single sheet
of 0.2 mm thick aluminum foil. When inserted in the specimen holder, back each specimen with a 25-mm sheet of noncombustible
refractory insulating material of the same lateral dimensions, density, and thermal characteristics as the backing board.
10.2.1 Flame Spread Test—Using an appropriate marker such as chalk, or a soft pencil, draw a line along the center horizontal
length of the exposed face of each specimen. Make vertical markings at 25-mm (or less) increments as an aid in tracking the
flame-front progress.
11. Procedures
11.1 General—This test method involves mounting conditioned specimens in a well defined flux field and measuring ignition
times, spread of flame, and position of final extinguishment. Therefore, these procedures assume that the apparatus has been
prepared and calibrated as described in Section 10 and Annex A1.
11.1.1 Start the fume exhaust system.
11.1.2 Slide the dummy specimen into the apparatus.
11.1.3 Turn on the regulated air supply to the radiant panel.
11.1.4 Position ignitor approximately 2 cm in front of the radiant-panel surface.
11.1.5 Turn on the gas supply to ignite the radiant panel.
11.1.6 Adjust the air/gas flow for the appropriate thermal operating level by referencing the millivolt signal from the water
cooled heat fluxmeter that monitors the irradiance at the 50-mm position on the dummy specimen or the millivolt signal from the
E1321 − 18
total-radiation pyrometer that monitors the radiant-panel surface, or both. Make the adjustments to the output of the radiant panel
by first adjusting the air supply and then, if necessary, adjusting the gas supply. Allow at least 15 min for the radiant panel to reach
equilibrium.
11.1.7 If the heat fluxmeter signal is used in establishing the appropriate operating level, turn on the cooling water to the
fluxmeter prior to positioning the fluxmeter in the special 50-mm dummy specimen. The cooling water shall be within 63°C of
room temperature. Use the dummy specimen fabricated to accommodate the fluxmeter at the 50-mm position.
11.2 Ignition Test Procedure:
11.2.1 Adjust the thermal operating level for an external flux {q˙" (x)} of 30 kW/m to the specimen surface at the 50-mm
e
position.
11.2.2 Ignite the pilot; adjust the air/acetylene control valves so that a light-blue conical flame extends approximately 180 mm
lengthwise across the contiguous wall flange at the top of the specimen holder (see Fig. 3).
11.2.3 Check and, if necessary, readjust the apparatus to the appropriate thermal operating level. Allow the apparatus to stabilize
for at least 3 min.
11.2.4 Record the output of the radiation pyrometer for the purpose of monitoring the radiant panel operating level during
testing. A sample data-log format is shown in Fig. 7.
11.2.5 Record the external flux {q˙" (x)} as determined from the output of the fluxmeter at the 50-mm position.
e
11.2.6 Record the ambient room temperature, T .
∞
11.2.7 Remove the fluxmeter from the dummy specimen.
11.2.8 Within a 10-s interval, remove the holder containing the dummy specimen from the apparatus and insert the holder
containing the test specimen. Using a suitable instrument such as a stopwatch, audiovisual instrument, data acquisition/computer
system, chronograph, or strip chart recorder, or any combination thereof, record the time (t ) when the test specimen is fully in
place and the time (t ) of flame attachment to the specimen surface. Time of ignition (t ) is defined as the time after specimen
2 ig
insertion to the time of flame attachment to the specimen surface (t − t ). Terminate the test at 20 min if ignition does not occur.
2 1
11.2.9 Record the time to ignition, t .
ig
11.2.10 If ignition occurred, readjust the external flux {q˙" (x)} at the 50-mm position downward using increments of
e
approximately 5 kW/m and repeat the test until a flux at which no ignition occurs has been identified. If ignition did not occur,
readjust the external flux {q˙" (x)} at the 50-mm position upward (using increments of approximately 5 kW/m ), and repeat the
e
test (using fresh specimen(s)) until a minimum flux at which ignition occurs has been identified.
11.2.11 Determine a minimum flux for ignition (q˙" ) by bracketing within 62 kW/m the fluxes for ignition/no ignition.
o,ig
11.2.12 Repeat 11.2.1 – 11.2.9 adjusting the external flux {q˙" (x)} at the 50-mm position upward (using increments of
e
approximately 10 kW/m ), until an ignition time flux profile (Fig. 8) has been determined for fluxes {q˙" (50)} between the
e
FIG. 7 Data Logging Format Sample, Ignition Test
E1321 − 18
FIG. 8 Ignition Time as a Function of External Irradiance
minimum flux for ignition (q˙" ) and 65 kW/m . Depending on the number of tests required to bracket the minimum flux for
o,ig
ignition, it is possible that this will require up to twelve tests.
11.3 Flame Spread Test Procedure:
11.3.1 Remove the pilot flame so that it does not come in contact with the fuel gases emitted from the heated specimen.
11.3.2 With the dummy specimen in place, adjust the thermal operating level to the specimen surface, 50 mm from the hot end,
for an irradiance that is at roughly 5 kW/m higher than the minimum irradiance (q˙" ) necessary for ignition. Allow the
o,ig
apparatus to stabilize for 3 min.
NOTE 4—Select this flux for ease in tracking the flame front. For most materials this will be between 5 and 10 kW/m above the minimum ignition
flux.
11.3.3 Record the external flux {q˙" (x)} to the specimen surface at the 50-mm position. If applicable for data recording, start
e
the data acquisition/computer system, the audiovisual instrument, or the strip chart recorder, or combination thereof.
11.3.4 Within a 10-s interval, remove the holder containing the dummy specimen from the apparatus and insert the holder
containing the test specimen. Immediately activate the timing mechanism.
11.3.5 Record the time when the test specimen is fully in place by using the audio portion of the audiovisual instrument,
observing the stopwatch, or activating the event marker connected to the computer, strip-chart recorder, or chronograph. A sample
flame spread data log format is shown in Fig. 9.
11.3.6 Allow the specimen to preheat for the time, t* (from correlated ignition-test data) and replace the pilot flame to the
position shown in Fig. 3. If the specimen does not ignite, conduct a repeat test (fresh specimen) using a modified ignition source,
that is, follow steps 11.3.1 – 11.3.5, allow the specimen to preheat for the time, t*, and ignite the specimen by manually moving
a pilot along the bottom surface of the specimen in the direction of decreasing irradiance.
11.3.7 Record the time of ignition (t ).
ig
11.3.8 Visually track the flame-front progress along the longitudinal centerline of the specimen by using the mirror assembly,
the viewing rakes, or the markings on the specimens, or combination thereof. Record the arrival time of the flame front at 25-mm
increments. As an alternate to the use of the mirror assembly for materials that propagate flame spread rapidly following ignition,
audiovisual equipment shall be used to record the arrival time of the flame front at the incremented positions.
11.3.9 Terminate the test if flaming reaches the end of the specimen or self-extinguishes and thus ceases progress along the
specimen.
11.3.10 Record both the time, t, (in seconds) and the position, x, (in millimetres) along the specimen at which the flame-front
progression ceases.
11.3.11 Observations—In addition to recording experimental data, document observations on general behavior of the specimen
including glowing, charring, melting, flaming drips, disintegration of the specimen, etc.
11.3.12 Repeat operations 11.3.1 – 11.3.11 for two additional specimens.
12. Calculation
12.1 Ignition Test Calculation:
12.1.1 The theories used to develop correlation of ignition test data are developed in Appendix X1 and Appendix X2.
12.1.2 Plot test-data results (q˙" )/(q˙" ) versus =t; see Fig. X1.2 (a) and (b).
o,ig e
12.1.3 Fit straight line to data (solid line, see Fig. X1.2 (a) and (b)). See Appendix X1 for the rationale for using this technique.
12.1.4 Determine ignition parameters, b and t*, from the respective slope of the line drawn through the data and the intercept
of this line with the line F(t) = 1 = q˙" / q˙" ; see Fig. X1.2 (a).
o,ig e
12.1.5 Using the minimum flux required for ignition (q˙" ) (see 11.2.11), determine the surface ignition temperature (T ) (see
o,ig ig
Fig. 10 and Eq X1.9).
NOTE 5—Assuming a surface emissivity of one and steady conditions, h depends only on the apparatus configuration (geometry) and operating level.
E1321 − 18
FIG. 9 Data Logging Format Sample, Flame Spread Test
Here steady-state surface temperatures were measured for a number of real building materials over a range of heat-flux levels and also calculated for
h = 15 W/m ·k. Fig. 10 shows the theoretical and measured data linking specimen-surface temperature to imposed heat flux. This curve can be used with
c
reasonable accuracy to infer surface temperature at ignition (T ) for the q˙" as a substitute to Eq X1.9 in Appendix X1.
ig o,ig
12.1.6 Determine effective thermal property (kρc) as follows (see also Eq X1.12 in Appendix X1):
4 h
kρc 5 (1)
S D
π b
where h = the heat-transfer coefficient at ignition, determined as follows (see also Eq X1.7 in Appendix X1):
q˙ "
o,ig
h 5 (2)
T 2 T
ig `
E1321 − 18
FIG. 10 Equilibrium Surface Temperature as a Function of External Radiant Heating
12.2 Flame Spread Test Calculation:
12.2.1 The theory used to develop the correlation of flame-spread test data are developed in Appendix X1 and Appendix X2.
12.2.2 Using the flux-distribution values of Table 1, compute F(x) at the x-positions corresponding to the flame-front arrival
times, t, as follows:
q˙ " x
~ !
e
F~x! 5 (3)
q˙ " ~50!
e
12.2.3 Calculate the surface flux at the measured flame-front positions from the flux q˙" (50) as recorded in 11.3.3, as follows:
e
q˙ " ~x! 5 F~x!*q˙ " ~50! (4)
e e
12.2.4 Compute flame-front velocity by applying a running three-point least square fit to the measured flame front position-time
(x, t) data as follows:
t x
( (
tx 2
(
V 5 (5)
~ t!
(
t 2
(
12.2.5 Correlate and plot flame-spread data as shown in Fig. X1.2 (see also Eq X1.10 in Appendix X1) as follows:
21/2
V versus q˙ " ~x! F~t! (6)
e
where:
b =t, t # t*
F t 5H (7)
~ !
1, t $ t*
NOTE 6—It is expected that the plotted velocity (V) and surface flux (q˙" ) will represent values at the midpoint of the three points used for the data
e
fit.
12.2.6 Fit line to linear section of data (see solid line Fig. X1.2). See Appendix X2 for the rationale for weighing the data points
over the linear section of the data.
12.2.7 Obtain the following parameters:
C flame spread
q˙9
o,ig
q˙"
o,ig
T
ig
T
ig
q˙9
o,s
q˙"
o,s
T
s,min
T
s,min
12.2.8 Compute flame-spread parameter, Φ (see Eq X2.7 in Appendix X2), as follows:
π
Φ5 (8)
~Cb!
13. Report
13.1 Report the following information:
E1321 − 18
13.1.1 The date, the original ignition and flame spread data, the observations made on each specimen, and the derived ignition
and flame spread parameters,
13.1.2 Name and address of the testing laboratory,
13.1.3 Identification of specimen including manufacturer and code designation, thickness, density, and where known,
composition of the specimen,
13.1.4 Identification of specimen backing material including thickness, density, and where known, thermal conductivity,
13.1.5 Data from the ignition test including:
13.1.5.1 A table or graph, or both, showing ignition times for external fluxes, and
13.1.5.2 Measured and derived ignition parameters, as follows:
q˙" = flux necessary for ignition, min,
o,ig
T = surface temperature necessary for ignition, min,
ig
b = ignition correlation parameter,
t* = time for specimen to reach thermal equilibrium, and
kρc = thermal heating property,
13.1.6 Data from flame spread test including:
13.1.6.1 Surface flux at the 50-mm position,
13.1.6.2 Flame-front arrival time at 25-mm increments along specimen surface, and
13.1.6.3 Measured and derived flame spread parameters, as follows:
C = flame spread parameter,
q˙" = flux necessary for ignition, min,
o,ig
T = surface temperature necessary for ignition, min,
ig
q˙" = flux necessary for flame spread, min,
o,s
T = temperature necessary for flame spread, min, and
s,min
Φ = flame heating parameter, and
13.1.7 Calibrated flux distribution along specimen surface at positions listed in Table 1.
TABLE 1 Calibration of Flux to the Specimen
NOTE 1—This table includes typical flux incident on the specimen and
specimen positions at which the calibration measurements are to be made.
The flux at 50 and 350-mm positions shall be set as accurately as possible.
Calibration data at other positions shall agree with typical values within
10 %. This calibration shall be performed with the use of the special
dummy specimen. It is possible to measure all except the first of the fifteen
typical measurements listed.
Distance From Ex-
Typical Flux Levels at Calibration Position to be
posed End of the
2 2A
the Specimen, kW/m Used, kW/m
Specimen, mm
0 49.5
50 50.5 50.5
100 49.5
150 47.1 X
200 43.1
250 37.8 X
300 30.9
350 23.9 23.9
400 18.2
450 13.2 X
500 9.2
550 6.2 X
600 4.3
650 3.1 X
700 2.2
750 1.5 X
A
An X indicates the fluxes at the additional six measuring positions required by the
standard. The seven empty spaces represent the fluxes at the additional measur-
ing positions recommended by the standard.
14. Precision and Bias
14.1 Precision—The precision of this test method is under consideration and is awaiting evaluation.
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14.2 Bias—This test method for determining ignition and flame spread properties of materials has no bias because these values
are effective properties derived from the test data. While it is possible that these effective properties will have more precisely
measurable physical counterparts, in this test method they are determined by a fit of the data to a model for flame spread.
15. Keywords
15.1 fire; flame spread; flammability; ignition; thermal intertia
ANNEX
(Mandatory Information)
A1. ASSEMBLY OF APPARATUS
A1.1 Assembly and Adjustment
A1.1.1 The heat-flux measurement at the surface of the specimen is the controlling criterion both in the original adjustment of test
operating conditions and periodic verification of this adjustment. This heat flux shall be measured by a fluxmeter inserted into holes
in a special calibration board (see Fig. A1.1).
A1.1.2 Monitor radiant-panel operating levels between consecutive tests by use of a heat fluxmeter mounted at the 50-mm position
in a dummy specimen and during the test by use of a radiation pyrometer calibrated on the basis of the readings of a heat fluxmeter.
Check the calibration periodically. This radiation pyrometer shall be rigidly fixed to the specimen holder frame in such a manner
that it continuously views the radiating-panel surface (see 6.3.16.4.1).
A1.2 Mechanical Alignment
A1.2.1 The position of the refractory surface of the radiant panel with respect to the specimen must correspond with the angle and
Dimension A shown in Fig. A1.2. These relationships are achieved by adjustment between the panel and its mounting bracket, the
two main frames, and position of the specimen holder guides.
A1.2.2 With the apparatus assembled as specified in Section 6, make the following mechanical alignments:
A1.2.2.1 Check the rotating ring (see Fig. 6) with a level to ensure that it lies in a vertical plane. If the bearing does not lie in
the vertical plane, adjust the upper support bracket. If any nonvertical position is caused by excessive bearing roller clearance,
install larger rollers.
A1.2.2.2 With the radiant panel rotated into a vertical position (as checked with a level), the angle between the panel and the
longitudinal members of the specimen support frame shall be 15 6 0.25° (see Fig. A1.2).
NOTE 1—All dimensions are in millimetres.
FIG. A1.1 Dummy Specimen for Flux Gradient Calibration
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NOTE 1—All dimensions are in millimetres.
FIG. A1.2 Specimen-Panel Arrangement
A1.2.2.3 With an empty specimen holder installed, adjust the upper guide fork to ensure the holder lies in a vertical plane. Adjust
the spacing between the radiant panel and the holder frame so that Dimension A in Fig. A1.2 is 125 6 2 mm while still maintaining
the 15 6 0.25° angular relationship. Dimension B must be adjusted to meet the flux distribution requirements along the specimen.
A1.2.2.4 Position the horizontal pilot as shown in Fig. 3.
A1.2.2.5 Position the viewing rake so that the pins are located at multiples of 50 6 2-mm distance from the closest end of the
specimen exposed to the panel.
A1.3 Thermal Adjustment of Radiant Panel Operating Level
A1.3.1 Thermal adjustment of the panel operating level is achieved by first setting an air flow of about 0.26 m /s through the panel.
Gas is then supplied and the panel ignited and allowed to come to thermal equilibrium with a dummy specimen mounted before
it. At proper operating condition there shall be no visible flaming from the panel surface except when viewed from one side parallel
to the surface plane. From this direction a thin blue flame very close to the panel surface will be observed. An oblique view of
the panel after a 15 min warm up period shall show a bright orange radiating surface.
NOTE A1.1—In the absence of a calibrated flowmeter in the air line, this flow rate can be roughly set by holding a lighted match with its axis horizontal
and close to the burner-tile face. The flame from the match shall deviate from the vertical by about 10°.
A1.3.2 With a water-cooled fluxmeter mounted in the calibration board (see Fig. A1.1), the flux incident on the specimen shall
correspond to the values shown in Table 1. Compliance with this requirement is achieved by adjustment of the air/gas flow rates.
When required, changes in air and gas flow shall be made to achieve the condition of no significant flaming from the panel surface.
In systems using a venturi valve, change the flux levels by adjusting only the air valve. (Warning—Water cooling of the fluxmeter
is required to avoid damage to the fluxmeter and erroneous signals at low flux levels. Control the temperature of the cooling water
in such a manner that the fluxmeter body temperature remains within a few degrees of room temperature. Make corrections of the
flux measurement for temperature differences between the fluxmeter body and room temperature. It is possible that failure to
supply water cooling will result in thermal damage to the sensing surface and loss of calibration of the fluxmeter.)
A1.3.2.1 The flux measured at both the 50 and 350-mm position shall match the values in Table 1 to ensure that a fixed
configuration or view geometry between the panel and the specimen has been achieved. To meet these requirements, change the
specimen longitudinal position shown by Dimension B in Fig. A1.2.
A1.3.2.2 Develop a plot and smooth curve on the basis of at least the eight required flux measurements shown in Table 1. On the
basis of the normalized flux-distribution curve (see Fig. 2), the flux gradient along the specimen length is derived from a single
flux measurement at the 50-mm position.
NOTE A1.2—It is recommended that the 15 measured flux levels at the positions shown in Table 1 be used to produce a smoother curve.
A1.3.2.3 If the radiation pyrometer is to be used to set the flux level at the 50-mm position, calibrate it over the operating range
of 20 to 65 kW/m , on the basis of the reading of a fluxmeter positioned at the 50-mm position and the slope (CF), an apparatus
constant, determined (see Fig. A1.3). Calculate the flux distribution along the specimen using CF or a fluxmeter reading at the
50-mm location (see 12.2.2 and 12.2.3). Once the relationship between the pyrometer millivolt output and the flux at 50 mm has
been established, use either way to set the heat flux level.
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FIG. A1.3 Typical Calibration of Panel Output to Specimen Surface as a Function of Total Radiation Pyrometer Signal
APPENDIXES
(Nonmandatory Information)
X1. IGNITION THEORY (1)
X1.1 The ignition theory is based on the following two rea
...