ASTM E906/E906M-21

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: E906/E906M − 21 An American National Standard
Standard Test Method for
Heat and Visible Smoke Release Rates for Materials and
Products Using a Thermopile Method
This standard is issued under the fixed designation E906/E906M; 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* (DOT/FAA/AR-00/12), while configuration B is suitable, at
various incident heat fluxes, for research and development
1.1 This test method provides for determining the release
purposes.
rates of heat and visible smoke (Note 1) from materials,
products, or assemblies when exposed to different levels of
1.8 This test method does not provide information on the
radiant heat. fire performance of the test specimens under fire conditions
other than those conditions specified in this test method.
NOTE 1—Visible smoke is described in terms of the obscuration of
Known limitations of this test method are described in 1.8.1 –
transmitted light caused by combustion products released during the tests
1.8.5.
(see 14.2.1).
1.8.1 Heat and smoke release rates depend on a number of
1.2 Thisfire-test-responsemethodassessesheatreleasebya
factors, including the formation of surface char, the formation
thermal method, thermopile, using a radiant heat source
of an adherent ash, sample thickness, and the method of
composed of an array of four electrical resistance elements.
mounting.
1.3 This test method provides for radiant thermal exposure
1.8.2 Heat release values are a function of the specific
of a specimen both with and without a pilot. Piloted ignition
specimen size (exposed area) tested. Results are not directly
results from direct flame impingement on the specimen
scaleable to different exposed surface areas for some products.
(piloted, point ignition) or from use of the pilot to ignite gases
1.8.3 The test method is limited to the specified specimen
evolved by pyrolysis of the specimen.
sizesofmaterials,products,orassemblies.Ifproductsaretobe
tested, the test specimen shall be representative of the product
1.4 Heat and smoke release are measured from the moment
inactualuse.Thetestislimitedtoexposureofonesurface;the
the specimen is injected into a controlled exposure chamber.
options for exposed surface are vertical and horizontal facing
The measurements are continued during the period of ignition
up.
(and progressive flame involvement of the surface in the case
ofpointignition),andtosuchatimethatthetestisterminated.
1.8.4 At very high specimen heat release rates, it is possible
that flaming is observed above the stack, which makes the test
1.5 The apparatus described in this test method is often
invalid.
referred to as the Ohio State University (OSU) rate of heat
1.8.5 No general relationship has been established between
releaseapparatus.ConfigurationsAandBarevariationsonthe
heat release rate values obtained from horizontally and verti-
original design.
cally oriented specimens. Specimens that melt and drip in the
1.6 This test method is suitable for exposing essentially
vertical orientation shall be tested horizontally.
planarmaterials,productsorassembliestoaconstant,imposed
2 2
1.9 The values stated in either SI units or inch-pound units
external heat flux that ranges from 0kW⁄m to 80 kW/m .
are to be regarded separately as standard. The values stated in
1.7 The apparatus described in this test method has been
each system may not be exact equivalents; therefore, each
used in two configurations. Configuration A is that which is
system shall be used independently of the other. Combining
used by the Federal Aviation Administration for assessing
values from the two systems may result in non-conformance
materials for aircraft use, at an external heat flux of 35 kW/m
with the standard.
1.10 Fire testing involves hazardous materials, operations,
and equipment. See Section 6.
This test method is under the jurisdiction of ASTM Committee E05 on Fire
Standards and is the direct responsibility of Subcommittee E05.21 on Smoke and
1.11 This standard is used to measure and describe the
Combustion Products.
response or materials, products, or assemblies to heat and
Current edition approved Dec. 1, 2021. Published January 2022. Originally
flame under controlled conditions, but does not by itself
approved in 1983. Last previous edition approved in 2017 as E906–17. DOI:
10.1520/E0906-21. incorporate all factors required for fire hazard or fire risk
*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
E906/E906M − 21
assessment of the materials, products, or assemblies under 3.2.5 SMOKE unit, n—the concentration of smoke particu-
actual fire conditions. lates in a cubic metre of air that reduces the percent transmis-
sion of light through a 1m path to 10%. SMOKE = Standard
1.12 This standard does not purport to address all of the
Metric Optical Kinetic Emission.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.2.6 time to ignition, n—time between the start of the test
priate safety, health, and environmental practices and deter- and the presence of a flame on or over most of the specimen
mine the applicability of regulatory limitations prior to use. surface for a period of at least 4s.
1.13 Fire testing is inherently hazardous. Adequate safe-
4. Summary of Test Method
guards for personnel and property shall be employed in
4.1 The specimen to be tested is injected into an environ-
conducting these tests.
mental chamber through which a constant flow of air passes.
1.14 This international standard was developed in accor-
The specimen’s exposure is determined by a radiant heat
dance with internationally recognized principles on standard-
source adjusted to produce the desired total heat flux on the
ization established in the Decision on Principles for the
specimen. Exposure options include: horizontal or vertical
Development of International Standards, Guides and Recom-
orientations; nonpiloted ignition, piloted ignition of evolved
mendations issued by the World Trade Organization Technical
gases,orpointignitionofthesurface.Thechangesintempera-
Barriers to Trade (TBT) Committee.
ture and optical density of the gas leaving the chamber are
monitored, and from this data the release rates of heat and
2. Referenced Documents
visible smoke (see 14.2.1) are calculated.
2.1 ASTM Standards:
D618Practice for Conditioning Plastics for Testing
5. Significance and Use
E176Terminology of Fire Standards
5.1 This test method provides a description of the behavior
E1354Test Method for Heat and Visible Smoke Release
of material specimens under a specified fire exposure in terms
Rates for Materials and Products Using an Oxygen Con-
of the release rate of heat and visible smoke. It is possible to
sumption Calorimeter
determine the change in behavior of materials and products
2.2 ISO Standard:
with change in heat-flux exposure by testing specimens in a
ISO 13943Fire Safety-Vocabulary
series of exposures that cover a range of heat fluxes.
2.3 Federal Aviation Administration Standard:
5.2 The data obtained for a specific test describe the rate of
Aircraft Material Fire Test Handbook, DOT/FAA/AR-00/
heat and smoke release of the specimen when exposed to the
12, FAA Technical Center, April 2000
specific environmental conditions and procedures used in
performing that test.
3. Terminology
5.3 The entire exposed surface of the specimen will not be
3.1 Definitions—For definitions of terms used in this test
burning during the progressive involvement phase when
method refer to the terminology contained in Terminology
piloted, point ignition (impingement) procedures are used.
E176 and ISO 13943, Fire Safety-Vocabulary. In case of
During the period of progressive surface involvement, release
conflict, the definitions given in Terminology E176 shall
rates of heat and smoke are “per square metre of original
prevail.
exposed surface area” not “per square metre of flame involved
3.2 Definitions of Terms Specific to This Standard:
surface.”
3.2.1 continuous, as related to data acquisition, adj—
5.4 The rates of both heat and smoke release are calculated
conducted at data collection intervals of 5s or less.
per square metre of original surface area exposed. If a
3.2.2 exposed surface, n—that surface of the specimen
specimen swells, sags, delaminates, or otherwise deforms so
subjected to the incident heat.
that the exposed surface area changes, calculated release rates
3.2.3 gas phase ignition, n—ignition of pyrolysis products
correspond to the original area, not to the new surface area.
leaving a heated surface by a pilot flame or other ignition
5.5 Heat-release values depend on mode of ignition. Gas
source that does not impinge on, nor significantly affect, for
phase ignition gives a more dimensionally consistent measure
example, by reradiation, the heated surface.
of release rate when very rapid or immediate flame involve-
3.2.4 orientation, n—planeinwhichtheexposedfaceofthe
ment of the specimen surface occurs. However, piloted, point
specimen is located during testing, either vertical or horizon-
ignition allows release-rate information to be obtained at
tally face upwards.
external heat flux from zero up to that required for satisfactory
gas-phase ignition, usually over 20 kW/m external exposure.
No correlation between the two modes of piloted ignition has
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
been established.
Standards volume information, refer to the standard’s Document Summary page on
5.6 Release rates depend on many factors, some of which
the ASTM website.
Available from International Standardization Organization, P.O. Box 56,
cannot be controlled. It is possible that samples that produce a
CH-1211, Geneva 20, Switzerland.
surface char, a layer of adherent ash, or those that are
AvailablefromNationalTechnicalInformationService(NTIS),Springfield,VA
composites or laminates do not attain a steady-state release
22161.An electronic version of the handbook with the latest revisions can be found
at the FAA website: http://www.fire.tc.faa.gov/handbook.stm. rate. Thermally thin specimens, that is, specimens whose
E906/E906M − 21
unexposed surface changes temperature during period of test, by 5.94in. +0in., -0.06in.] exposed surface with thickness up
will not attain a steady-state release rate. Therefore, release to 100 mm [4.0in.]. The standard size for horizontally
ratesforagivenmaterialwilldepend,forexample,onhowthe mounted specimens is 150mm 6 2mm by 150mm 62mm
material is used, its thickness, and the method of mounting. [5.94in. +0in., -0.06in. by 5.94in. +0in., -0.06in.] exposed
surface, up to 45mm [1.75in.] thick. Mount thin specimens,
5.7 Heat-release values are for the specific specimen size
such as wall or floor coverings, in the same manner as used.
(exposed area) tested. Results are not directly scalable to
For example, test a wall covering to be glued to gypsum wall
different exposed surface areas for some products.
boardwhengluedtoasectionofgypsumboardusingthesame
5.8 The method is limited to specimen sizes of materials in
type of adhesive. The assembly shall be considered the
accordance with 7.1 and to products from which it is possible
specimen to be tested. Applications requiring thicknesses
toobtainatestspecimenrepresentativeoftheproductinactual
greater than 45mm [1.75in.] shall be tested at 45mm
use.Thetestislimitedtoexposureofonesurface;therearetwo
[1.75in.] thicknesses.
optionsforexposureorientation:eitherverticalorhorizontal.If
2 7.2 Conditioning—Condition the specimens at 23°C 6
a heat release rate of 8 kW, which is equivalent to 355 kW/m
3°C [70°F 6 5°F] and 50% 6 5% relative humidity for a
for 150mm [6-in.] by 150mm [6-in.] vertical specimens, or
2 minimum of 24h prior to test, or as described by ProcedureA
533kW⁄m for 100mm [4-in.] by 150mm [6-in.] horizontal
of Practice D618, if appropriate.
specimens is exceeded, there is danger of combustion occur-
ring above the stack. 7.3 Mounting—Expose only one surface of a specimen
duringatest.Insulate,onfivesides,specimensthathaveaslab
5.9 No general relationship between release rate values
geometry.Asinglelayerof0.03mm 60.01mm[0.0012-in. 6
obtained from horizontally and vertically oriented specimens
0.005-in.] aluminum foil shall be wrapped tightly on all
hasbeenestablished.Conducttestsonspecimensintheformin
unexposed sides with the dull side of the foil facing the
whichthematerialisorientedinenduseconditions.Toprovide
specimen surface. For products whose exposed surface is not a
additional information, conduct tests in the horizontal orienta-
plane, describe mounting and method of calculating surface
tion for those specimens that melt and drip in the vertical
area exposed when reporting results.
orientation.
7.4 Specimen Orientation—For specimens with anisotropic
5.10 Release rate measurements provide useful information
properties (meaning they have different properties in different
for product development by giving a quantitative measure of
directions such as machine and cross-machine directions for
specific changes in fire test performance caused by product
extrusions, wrap and fill for woven fabrics), the specimens
modifications.
shall be tested in the orientation giving the highest results. If
5.11 Thistestmethoddiffersinboththemethodofexposure
this orientation is not known prior to test, two sets of at least
and the calculation procedure from the techniques used inTest
threespecimenseachshallbepreparedandtested,withoneset
Method E1354, the cone calorimeter, which assesses heat
oriented in one direction and the second set oriented in the
release by oxygen consumption calorimetry, using a truncated
other direction.
cone as a radiant source.
8. Release Rate Apparatus—Configuration A
6. Operator Safety
8.1 The apparatus shown in Figs. 1 and 2 shall be used to
6.1 The test procedure involves high temperatures, and
determine heat release rates. All exterior surfaces of the
combustionprocesses.Therefore,itispossibleforeyeinjuries,
apparatus, except the holding chamber, shall be insulated with
burns,ignitionofextraneousobjectsorclothing,andinhalation
25mm 6 1mm [1in. 6 0.04in.] thick, low-density, high-
of smoke or combustion products to occur, unless proper
5,6
temperature, fiberglass board insulation. A gasketed door,
precautions are taken. To avoid accidental leakage of toxic
through which the sample injection rod slides, shall be pro-
combustion products into the surrounding atmosphere, it is
vided to form an airtight closure on the specimen hold
advisable to evacuate the chamber, at the end of a test, into an
chamber.
exhaust system with adequate capacity. The operator must use
8.2 Thermopile—The temperature difference between the
heavy gloves, safety tongs or other suitable protection for
air entering the environmental chamber and that leaving shall
removal of the specimen holder. The venting must be checked
bemonitoredbyathermopilehaving5hotand5cold24-gauge
periodically for proper operation. Care shall be taken not to
chromel-alumel junctions. The loop to be formed by the
touchthesparkigniterduringoperation,ifused,sinceitcarries
thermocouplejunctionshallbe1.3mm 60.3mm[0.050in. 6
a substantial potential. The exhaust system of the apparatus
0.010in.]indiameter.Thecoldjunctionsshallbelocatedinthe
shall be checked for proper operation before testing and shall
discharge into a building exhaust system with adequate capac-
ity. The possibility of the violent ejection of molten hot
3 3
Owens-Corning Flat Duct Board, Type 475-FR, density 65 kg/m [4 lb/ft ],
material or sharp fragments from some kinds of specimens
2 2
thermal conductivity 0.033 W/(m K) [10 Btu/(ft min)], 25 mm [1 in.] thick, or its
when irradiated must be taken into account.
equivalent.
The sole source of supply of the apparatus known to the committee at this time
7. Sample Preparation is Owens-Corning, Granville, OH. If you are aware of alternative suppliers, please
provide this information to ASTM Headquarters. Your comments will receive
7.1 The standard size for vertically mounted specimens is
careful consideration at a meeting of the responsible technical committee, which
150mm 62mmby150mm 62mm[5.94in.+0in.,-0.06in. you may attend.
E906/E906M − 21
FIG. 1 Rate of Heat Release Apparatus—Example 1
E906/E906M − 21
FIG. 2 Rate of Heat Release Apparatus—Example 2
E906/E906M − 21
panbelowtheairdistributionplate(see8.4).Thehotjunctions cross section, and 254mm 6 1 mm [10in. 6 0.04 in.] long,
shallbelocated10mm 61mm[0.38in. 60.04in.]belowthe fabricated from stainless steel, shall be mounted on the outlet
top of the chimney. One of the hot junctions shall be placed at ofthepyramidalsection(seeFigs.1and2).A25mm 61mm
the center of the chimney’s cross section, and the other four by 76mm 61mm[1in. 6 0.04in. by 3in. 6 0.04 in.] plate
shall be placed on the chimney diagonals 30mm 6 1mm of 0.46mm 6 0.05 mm [0.018in. 6 0.002 in.] stainless steel
[1.18in. 6 0.04in.] from the center thermocouple. shall be centered inside the stack, perpendicular to the airflow,
76mm 61mm[3in. 6 0.04 in.] above the base of the stack.
8.3 Radiant Heat Source—A radiant heat source for gener-
ating a heat flux of up to 80 kW/m , using four silicon carbide 8.6 Specimen Holders—Specimen holders shall be fabri-
cated of stainless steel sheet 0.46mm 6 0.05 mm [0.018in. 6
elements Type LL, 508mm 6 3 mm [20in. 6 0.1 in.] by
0.002 in.] thick as shown in Fig. 4. Specimen holders shall be
16mm 61mm[0.63in. 60.04in.],withanominalresistance
attached to the injection rod using the support shown in Fig. 4.
of 1.4Ω, as shown in Figs. 1-3, shall be used. The silicon
Each holder shall be provided with a “V”-shaped spring
carbide elements shall be mounted in the stainless steel panel
pressureplate.Thepositionofthespringpressureplateshallbe
box by inserting them through 16mm 6 1 mm [0.63in. 6
capable of being changed to accommodate different specimen
0.04in.] holes in 0.9mm 6 0.1mm [0.03-in. 6 0.004-in.]
thicknesses by inserting the retaining rod in different holes of
thick ceramic fiber or calcium-silicate millboard. Locations of
the specimen holder frame. Each holder shall also have two
the holes in the pads and stainless steel covered plates shall be
wiresattachedtothefrontoftheholdertosecurethefaceofthe
as shown in Fig. 3. A truncated diamond-shaped mask con-
specimen in the holder.
structed of 1.07mm 6 0.05 mm [0.042in. 6 0.002 in.]
stainless steel shall be added to provide uniform heat flux 8.6.1 Drip Pan—A drip pan shall be fabricated of stainless
density over the area occupied by the vertical specimen. An steel sheet 0.46mm 6 0.05 mm [0.018in. 6 0.002 in.] thick
adjustable power supply capable of producing 12.5kVA shall asshowninFig.4andbeattachedtothespecimenholderusing
be provided. The heat flux density over the specimen surface the flanges shown in Fig. 4. Line the drip pan with aluminum
when set at 35kW⁄m shall be uniform within 5%, and shall foil, to facilitate cleaning after a test.
becheckedperiodicallyandaftereachheatingelementchange.
NOTE 2—Drip pans are required to prevent melting specimens from
Uniformity of heat flux density shall be determined by calo-
dripping into the lower pilot burner.
rimeter measurements at the center and at the four corners of
8.7 Calorimeter—A water-cooled, total heat flux density,
the specimen surface.
foil-type Gardon gauge calorimeter shall be used to measure
8.4 Air Distribution System—The air entering the apparatus
the total heat flux density at a point where the center of the
shall be 21°C to 24°C [70°F to 75°F] in temperature and set
specimen surface is located at the start of the test. When
3 3 3 3
at approximately 0.04m /s 6 0.01m /s [85ft /min 6 20ft /
positioned to measure flux density, the sensing surface of the
min] using an orifice meter. The orifice meter shall be
meter shall be flush with the supporting device surface so that
comprised of a square-edged circular plate orifice, 0.5mm 6
air heated by such a support does not contact the sensing
0.1 mm [0.020in. 6 0.004 in.] thick, located in a circular pipe
surface of the meter.
with a diameter of 38mm 6 1 mm [1.50in. 6 0.04in.], with
8.8 Pilot Burners—Pilot burners shall be placed at the
two pressure measuring points located 38mm 6 1mm
bottom and top of the specimens. The burners shall be
[1.50in. 6 0.04 in.] above and 20mm 6 1 mm [0.75in. 6
constructed of stainless steel tubing with a 6mm 61mm
0.04 in.] below the orifice and connected to a mercury
[0.25in. 6 0.04 in.] outside diameter (OD) and 0.8mm 6
manometer. The inlet pipe shall remain 38mm 6 1mm
0.1mm [0.03in. 6 0.004 in.] wall thickness.
[1.50in. 6 0.04 in.] in diameter (Fig. 1).
8.8.1 Lower Pilot Burner—The lower pilot burner shall be
8.4.1 The air entering the environmental chamber shall be
locatedasshowninFig.1.Thelowerpilotburnershallhaveits
distributed by a 6.3mm 6 2 mm [0.25in. 6 0.04 in.] thick
centerline perpendicular to the surface of the specimen and
aluminum plate having eight 5.3mm 6 0.03mm [0.209-in. 6
5mm 6 1 mm [0.19in. 6 0.04 in.] above the specimen’s
0.001-in.]drillholes(ANSINo.4drillholes),51mm 61mm
lower exposed edge, and shall have its end 10mm 61mm
[2.0in. 6 0.04 in.] from the sides on 102mm 6 2 mm [4in.
[0.38in. 6 0.04 in.] from the specimen’s surface.Amethane-
6 0.08 in.] centers, mounted at the base of the environmental
3 3
air mixture shall be used consisting of 120cm /min 6 10cm /
chamber.Asecond plate having 120 evenly spaced, 3.6mm 6
3 3
min [0.0040ft /min 6 0.0003ft /min] (at standard tempera-
0.03mm [0.140-in. 6 0.001-in.] drill holes (ANSI No. 28 drill
ture and pressure) methane (99% minimum purity) and an air
holes) shall be mounted 152mm 62mm[6in. 6 0.08 in.]
supply, adjusted to produce a flame such that the inner cone is
above the aluminum plate (Fig. 2).
approximately the same length as the diameter of the flame.
8.4.2 The air supply manifold at the base of the pyramidal
8.8.2 Spark Igniter—A spark igniter shall be installed to
section shall have 48 evenly spaced, 3.7mm 6 0.03mm
ensure that the lower pilot burner remains burning. A test is
[0.147-in. 6 0.001-in.] drill holes (ANSI No. 26 drill holes)
invalidated if the lower pilot burner becomes extinguished for
10mm 61mm[0.38in. 60.04in.]fromtheinneredgeofthe
any period that exceeds 3 s.Acircuit for a satisfactory device
manifold,resultinginanairflowsplitofapproximatelythreeto
is sketched in Fig. 5.
one within the apparatus (Fig. 1).
8.8.3 Upper Pilot Burner—An upper pilot burner shall be
8.5 Exhaust Stack—An exhaust stack, 133mm 61mmby providedtoproduceflameletsabovethetestspecimentoignite
70mm 6 1 mm [5.25in. 6 0.04 in. by 2.75in. 6 0.04 in.] in flammable gases. If any of the flamelets on the upper pilot
E906/E906M − 21
FIG. 3 Side View—Globar Radiant Heat Panel
E906/E906M − 21
FIG. 4 Heat Release Specimen Holder, Mounting Bracket, and Drip Pan
E906/E906M − 21
6 0.04 in.] apart, with the first hole located 5mm 61mm
[0.19in. 60.04in.]fromtheclosedend,asisshowninFig.6.
The burner shall be positioned above the specimen holder so
that the middle hole lies in the plane perpendicular to the
exposedsurfaceofthespecimenandpassesthroughitsvertical
centerline.Theburnerfuelshallbemethaneof99%minimum
purity.Thefuelflowrateshallbeadjustedtoproduceflamelets
25 mm [1 in.] in length that bend upwards slightly above the
burner tube.
8.8.5 Optional Fourteen-Hole Burner—An optional burner
that has been found satisfactory is as follows; this burner has a
greater probability of reigniting flamelets which become ex-
tinguishedduringatest.Fourteen1.04mm 60.01mm[0.041-
in. 6 0.0005-in.] drill holes (ANSI No. 59 drill holes), each
radiating in the same direction, shall be drilled into a 381mm
6 10mm [15in. 6 0.4in.] length of nominally 7mm
FIG. 5 Lower Pilot Burner Igniter Schematic
[0.25in.] tubing. The holes shall be spaced 13mm 6 1mm
[0.5in. 6 0.04 in.] apart with the first hole located 13mm 6
1mm[0.5in. 60.04in.]fromtheclosedend,asshowninFig.
burnerextinguishesforaperiodlongerthan3sduringthetest,
7.Theburnershallbepositionedabovethespecimenholderso
the test is invalidated. The upper pilot burner shall be con-
that the holes are placed above the specimen holder as shown
structed from a piece of stainless steel tubing with an OD of
in Fig. 7. The fuel fed to this burner shall be methane of 99%
6mm 6 1 mm [0.25in. 6 0.04 in.] and a wall thickness of
minimum purity mixed with air in a ratio of approximately
0.8mm 6 0.1 mm [0.03in. 6 0.004 in.]. The diameter hole
50/50 by volume. The total fuel flow shall be adjusted to
drilled 10mm 6 1 mm [0.38in. 6 0.04 in.] above the upper
provide flamelets 25mm [1 in.] long. When the gas/air ratio
edgeofthewindowframe,andbesupportedandpositionedby
and its fuel flow rate are properly adjusted, approximately
an adjustable Z-shaped bracket mounted outside the environ-
6mm [0.25 in.] of the flame length appears yellow in color.
mental chamber above the viewing window. The tubing shall
be located 20mm 6 1 mm [0.79in. 6 0.04 in.] above and
9. Calibration of Equipment—Configuration A
20mm 6 1 mm [0.79in. 6 0.04 in.] behind the upper front
edge of the specimen holder, and installed such that the holes
9.1 Calibration Burner—A calibration burner as shown in
are directed horizontally toward the radiant heat source. One
Fig. 8 shall be provided that fits over the end of the pilot flame
end of the tubing shall be closed with a silver solder plug or
tubing with a gas-tight connection.
equivalent.
9.2 Calibration Gas—Methane of at least 99% purity shall
8.8.4 Standard Three-Hole Burner—The standard three-
be used for calibration purposes.
hole upper pilot burner shall be constructed from a piece of
6mm 6 1 mm [0.25in. 6 0.04 in.] OD tubing 360mm 6 9.3 Wet Test Meter—Awet test meter accurate to 0.2 L/min
10mm [14in. 6 0.4 in.] long. Three 2.5mm 6 0.1 mm [0.007 ft /min] shall be provided to measure the gas flow rate
[0.098in. 6 0.004 in.] diameter drill holes (ANSI No. 40 drill tothecalibrationburner.Priortousage,thewettestmetershall
holes),eachradiatinginthesamedirection,shallbedrilledinto be leveled and filled with distilled water to the tip of the
the tubing. The holes shall be spaced 60mm 6 1 mm [2.4in. internal pointer.
FIG. 6 Upper Pilot Tube-Outlet Hole Sizes and Configurations
E906/E906M − 21
FIG. 7 Modification of the Upper Pilot Tube for the OSU Chamber
sothatthecalibrationgasflowratetothecalibrationburnercan
be set at either 1L⁄min, 4L⁄min, 6L⁄min, or 8 L/min
3 3 3 3
[0.035ft /min, 0.140ft /min, 0.210ft /min, or 0.280 ft /min].
9.4.2 Theactualcorrectedvalue, F,ofeachoftheflowrates
shall be determined to an accuracy of 0.2L⁄min [0.007ft /
mm], and these corrected values used for calibration calcula-
tions of heat release rate.
9.5 Calibration Procedure:
9.5.1 Replace the lower pilot burner with the calibration
burner shown in Fig. 8.
9.5.2 Installthewettestmeter.Ensureitisleveledandfilled
with distilled water. Ambient temperature and pressure of the
water are based on the internal wet test meter temperature.
9.5.3 Turn on the air distribution system.
9.5.4 Turn on the radiant heat source and ensure that the
2 2
heat flux density is 35.0kW⁄m 6 0.5 kW/m .
9.5.5 Using the calibration gas manifold, set the baseline
flow rate of 1 L/min [0.035 ft /min] of methane to the
FIG. 8 Calibration Burner—Configuration A
calibrationburner,andlighttheburner.Measurethethermopile
baseline voltage.
9.4 Calibration Gas Manifold:
9.5.6 Immediately prior to recording the thermopile outputs
9.4.1 Amanifold shall be provided upstream of the wet test
in 9.5.7, precondition the chamber at a methane flow rate of
meter to control calibration gas flow. The manifold shall have
8L⁄min [0.280ft /min]. Do not record the thermopile output
four flow orifices controlled by needle valves that are preset to
for this step as part of calibration.
provide calibration gas at approximate (uncorrected for the
9.5.7 Increasethegasflowtotheburnertoahigherflowrate
presence of water vapor) flow rates of 1L⁄min, 4L⁄min,
3 3 3
and then decrease to the baseline flow rate. After 2 mm of
6L⁄min, and 8 L/min [0.035ft /min, 0.140ft /min, 0.210ft /
burningateachrate,monitorthethermopileoutput(millivolts)
min, and 0.280 ft /min] as indicated by revolution rate (mea-
sured by a stop watch accurate to 1 s) of the wet test meter. for a 10-s period, and record the average reading and decrease
Output from each of the four flow orifices shall be controlled flow rate to the baseline flow of 1 L/min [0.035 ft /min]. This
byatoggleon/offvalve,andbeplumbedintoasingleflowline sequenceofincreasinganddecreasingthemethaneflowrateis
E906/E906M − 21
asfollows:1-4-1-6-1-8-1-6-1-4L/min[0.035-0.140 or during which at least one of the upper pilot flamelets was
- 0.035 - 0.210 - 0.035 - 0.280 - 0.035 - 0.210 - 0.035 - 0.140 extinguished for any period of time exceeding 3 s.
ft /min].
10.9 Calculate the heat release rate for any point of time
9.6 Computethecalibrationfactorforeachupwardratestep from the reading of the thermopile output voltage, V, at that
(that is: 1-4, 1-6, 1-8, 1-6, 1-4 L/min) according to the time as heat release rate by the following formula:
following formula:
RHR 5 k · V 2 V (2)
~ !
h 0
273 P 2 P F 2 F
~ ! ~ !
y 0
where k and V arethecalibrationfactorandthethermopile
k 5 25.31· · · ·@kWmV/m # (1)
h 0
h
T 760 ~V 2 V !
a 1 0
millivolt reading at the baseline, respectively.
where:
10.10 Determine and record the maximum heat release rate
F = corrected upper flow rate of calibration gas, L/min
during the 5-min test.
(either 4, 6, or 8),
10.11 Compute and record the total heat released after the
F = corrected baseline flow rate of methane, L/min (ap-
first 2 min of testing by integrating the heat release rate versus
proximately 1 L/min),
time curve during the first 2 min.
P = ambient atmospheric pressure, mm Hg,
P = water vapor pressure of wet test meter water
10.12 Clean the thermopile hot junctions to remove soot
y
temperature, mm Hg, after testing each specimen. Do not disturb the position of the
T = ambient temperature, K,
thermocouples. Ensure that the thermocouples are in their
a
V = thermopile voltage at upper flow rate, mV, and
1 proper position before proceeding with the next specimen.
V = thermopile voltage at baseline flow rate, mV.
NOTE 4—A small soft-bristled brush has been found satisfactory for
NOTE3—Theconstantusedintheaboveequationisderivedasfollows:
cleaning the thermocouple junctions. A template facilitates checking
25.31 = (Heat content of methane at STP, 31.176 Btu/L) × (conversion
thermocouple positioning.
factor of 0.0176 kW-min/Btu) / (area of a specimen, 0.02323 m ).
9.7 Averagethefiveresultsandcomputethepercentrelative
11. Release Rate Apparatus—Configuration B
standard deviation. If the percent relative standard deviation is
11.1 Release Rate Apparatus (Fig. 9) is used to determine
greaterthan5%,repeatthedetermination.Ifitislessthan5%,
releaseratesofheatandsmokebythistestmethod.Allexterior
use the average as the calibration factor.
surfaces of the apparatus, except the holding chamber, shall be
insulated with 25mm thick, low density, high-temperature,
10. Test Procedure and Calculations—Configuration A
fiber glass board insulation. A gasketed door, through which
10.1 Set the airflow to the equipment by adjusting the
thesampleinjectionrodslides,formsanairtightclosureonthe
pressure differential across the orifice plate to 200 mm
specimen hold chamber.
[7.87in.] mercury.
11.2 Thermopile—The temperature difference between the
10.2 Set the power supply to the Globars to produce a
air entering the environmental chamber and that leaving is
2 2
radiant flux density of 35.0kW⁄m 6 0.5kW⁄m at the point
monitored by a thermopile having five hot and five cold,
which the center of the front surface of the specimen will
24-gauge Chromel-Alumel Type K thermocouple junctions.
occupy when positioned for test.
The loop to be formed by the thermocouple junction shall be
1.4mm 60.3mm[0.050in. 60.010in.]indiameter.Thecold
10.3 Lightthepilotflamesandcheckthattheirpositionsare
junctions shall be located in the pan below the air distribution
asdescribedin10.8.Activatethesparkigniterifasparkigniter
plate. The hot junctions shall be located 10 mm [0.38 in.]
is used.
belowthetopofthechimney.Oneofthehotjunctionsshallbe
10.4 Place the specimen in the hold chamber with the
placed at the center of the chimney’s cross section, and the
radiation shield doors closed. Secure the airtight outer door,
other four shall be placed on the chimney diagonals 30 mm
and start the recording devices. Hold the specimen in the hold
[1.18 in.] from the center of the thermopile (see 11.5).The use
chamber for 60s 6 10 s.
of a compensator tab, as described in 11.2.2 through 11.2.5,is
10.5 Record, at least once per s, the thermopile millivolt
not needed if this thermopile is used.
output during the final 20 s of the hold time before the
11.2.1 Thermopile for Research Configuration—
specimen is injected and report the average as the baseline
Alternatively, the temperature difference between the air enter-
thermopile reading (millivolts).
ing the environmental chamber and that leaving is monitored
by a thermopile having three hot and three cold, 24-gauge
10.6 After recording the baseline reading and within a time
Chromel-Alumel Type K junctions. The hot junctions are
frame not exceeding 3 s, open the radiation doors, inject the
spaced across the top of the exhaust stack. Two hot junctions
specimen into the burn chamber, and close the radiation doors.
are located 25 mm [1 in.] from each side on diagonally
Record thermopile millivolt outputs at least once per s for the
opposite corners and the third in the center of the chimney’s
duration for the test.
cross 14 mm [0.55 in.] below the top of the chimney.The cold
10.7 After the test has run for 5 min, terminate the test and
junctionsarelocatedinthepanbelowthelowerairdistribution
remove the sample.
plate (see 11.5). If this thermopile is used, the use of a thermal
10.8 Discarddatafromanytestduringwhichthelowerpilot inertia compensator, as described in 11.2.2 through 11.2.5,is
burner was extinguished for any period of time exceeding 3 s, recommended.
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FIG. 9 Release Rate Apparatus—Configuration B
E906/E906M − 21
11.2.2 Thermal Inertia Compensator—Acompensatortabis
made from 0.55mm [0.022-in.] stainless steel sheet, 10 mm
[0.4 in.] by 20 mm [0.8 in.]. An 800mm [31.5-in.] length of
24-gauge Chromel-Alumel Type K, glass-insulated duplex
thermocouplewireshallbeweldedorsilversolderedtothetab
asshowninFig.10,andthewirebentbacksoitisflushagainst
the metal surface.
11.2.3 Thecompensatortabshallbemountedontheexhaust
stack as shown in Fig. 11 using a 6/32-round head machine
screw, 12 mm [0.47-in.] long. Add small (approximately
4.5mm [0.177-in.] inside diameter, 9mm [0.354-in.] outside
diameter) washers between the head of the machine screw and
the compensator tab to give the best response to a square wave
input. One or two washers are likely to be adequate. The
FIG. 11 Compensator Tab Mount
sharpnessofthesquarewavecanbeincreasedbychangingthe
ratio of the output from the thermopile and compensator
thermocouple that is fed to the recorder. The ratio is changed
by adjusting the 1-KΩ variable resistor (R ) of the thermopile
bleeder shown in Fig. 12. When adjusting compensation keep
R assmallaspossible.Adjustmentofthecompensatorshallbe
made during calibration at a heat release rate of 7.0kW 6
0.5kW (see 12.1).
11.2.4 Adjust washers and variable resistor (R ) so that
FIG. 12 Wiring Diagram
90% full scale response is obtained in 8s to 10 s. There shall
be no overshoot as shown in Fig. 13(a). If an insufficient
number of washers is added or if R is too small, the output
with square wave input will look like Fig. 13(b). If too many
washers are added and if R is too large, the output will look
like Fig. 13(a).
11.2.5 Subtract the output of the compensator from the
thermopile. The junctions enclosed in the dotted circle of Fig.
12 are kept at the same constant temperature by electrically
insulating the junctions and placing them on the pipe carrying
air to the manifold, then covering them and the pipe with
FIG. 13 Square Wave Response
thermal insulation.
11.3 Smoke Monitor—Aphotometer (Fig. 14) measures the
shall be No. 82 miniature incandescent lamp operated at its
percent of light transmitted through the gases leaving the
recommended current, 1.0A.
apparatus.Aphotocell and circuitry shown in Fig. 15 shall be
11.3.1 The smoke monitor apparatus shall be mounted with
used and calibrated in accordance with 12.2. The light source
the center line 25 mm [1 in.] above the exhaust stack and
centered parallel to the length of the opening.The two parts of
the optical system shall be 130 mm [5.12 in.] apart. A
continuous flow of constant temperature air, approximately
The sole source of supply of the apparatus known to the committee at this time
0.004m /min, shall be maintained to the air lines to prevent
is Clairex, Plano, TX. If you are aware of alternative suppliers, please provide this
information to ASTM Headquarters. Your comments will receive careful consider- smoke from entering the smoke monitor.
ation at a meeting of the responsible technical committee, which you may attend.
11.4 RadiationSource—Aradiantheatsourceforgenerating
2 8
a flux up to 100 kW/m , using four silicon carbide elements,
Type LL, 20 by 12 by ⁄8, nominal resistance 1.6Ω, is shown
in Fig. 16 and Fig. 17. The silicon carbide elements are
mounted in the stainless steel panel box by inserting them
through 15.9mm [0.626-in.] holes in 0.8mm [0.03-in.] thick
ceramic fiber or asbestos board. Locations of the holes in the
pads and stainless steel cover plates are shown in Fig. 17. The
The sole source of supply of the apparatus known to the committee at this time
is Carborundum Co., Globar Div., Nigara Falls, NY. If you are aware of alternative
suppliers, please provide this information to ASTM Headquarters. Your comments
will receive careful consideration at a meeting of the responsible technical
FIG. 10 Compensator Tab committee, which you may attend.
E906/E906M − 21
FIG. 14 Smoke Monitor
FIG. 15 Constant Current Lamp Supply and Photocell Bridge Circuit
diamond shaped mask of 24-gauge stainless steel is added to 11.5 Air Distribution System—The air entering the environ-
provide uniform heat flux over the area occupied by the mental chamber is distributed by a 6.3mm [0.24-in.] thick
150mm by 150mm [6in. by 6 in.] vertical sample. A power
aluminum plate having eight 5.3mm 6 0.03mm [0.209-in. 6
supplyof16.5kVA,adjustablefrom0Vto270V isrequired. 0.001-in.] drill holes (ANSI No. 4 drill holes), 51 mm [2 in.]
from sides on 102mm [4-in.] centers, mounted at the base of
9 2 the environmental chamber. A second plate of 18-gauge steel
If a heat flux of up to 100 kW/m is desired, a separate power supply for each
pair of elements can be used where maximum voltage is less than 270 V. having 120 evenly spaced 3.6mm 6 0.03mm [0.140-in. 6
E906/E906M − 21
FIG. 16 Globar Radiant Panel
0.001-in.] drill holes (ANSI No. 28 drill holes) is mounted
150mm [6in.] above the aluminum plate.Awell regulated air
supply is required.
11.5.1 The air supply manifold at the base of the pyramidal
section has 48 evenly spaced 3.7mm 6 0.03mm [0.147-in 6
0.001-in] drill holes (ANSI No. 26 drill holes) 10 mm [0.4 in.]
3 3
fromtheinneredgeofthemanifoldso0.03m /s[1ft /s]ofair
3 3
flowsbetweenthepyramidalsectionsand0.01m /s[0.35ft /s]
flows through the environmental chamber when total air flow
3 3
to apparatus is controlled at 0.04m /s [1.4ft /s ].
11.6 Exhaust Stack—An exhaust stack, 133mm by 70 mm
[5.2in. by 2.8 in.] in cross section and 254 mm [10 in.] long,
fabricated from 28-gauge stainless steel is mounted on the
outlet of the pyramidal section. A 25mm by 76mm [1-in. by
3-in.] plate of 31-gauge stainless steel is centered inside the
stack, perpendicular to the air flow, 75 mm [3 in.] above the
base of the stack.
11.7 Specimen Holders—Vertical specimen holders shall be
attachedtotheinjectionrodusingtheverticalsupportshownin
Fig. 18. Two different types of specimen holders shall be
provided, one for 150mm by 150mm [6-in. by 6-in.] speci-
mens to be tested in vertical orientation (Fig. 19) and the other
for 110mm by 150mm [4.3-in. by 6.0-in.] specimens in
horizontalorientation(Fig.20).Eachholderisprovidedwitha
V-shaped spring pressure plate and 12.7mm [0.5-in.] backing
10 3
plate of rigid insulation board having a density of 320kg⁄m
3 3 3
FIG. 17 Locations of Holes in Globar Radiant Panel
6 80 kg/m [20lb⁄ft 6 5 lb/ft ] and thermal conductivity of
2 2
0.08W⁄m·K 6 0.01W⁄m·K [24Btu/ft min 6 3 Btu/ft min].
It is acceptable to change the position of the spring pressure
11.7.1 The unexposed surfaces of the specimen shall be
platetoaccommodatedifferentspecimenthicknessbyinserting
covered with two thicknesses of 0.025mm [0.001-in.] alumi-
a retaining rod in different holes of the specimen holder frame.
num foil pressed tightly to sides and back. This foil shall be
carried out and over the lip on the horizontal holder to form a
Thesolesourceofsupplyoftheapparatusknowntothecommitteeatthistime
8mm 63mmhighshieldfromradiantheatimmediatelytothe
is Babcock/Wilcox Refractories, Augusta, GA. If you are aware of alternative
side (see Fig. 20).
suppliers, please provide this information to ASTM Headquarters. Your comments
11.7.2 Pans or plates for supporting specimens that cannot
will receive careful consideration at a meeting of the responsible technical
committee, which you may attend. be mounted in the holders (see 11.7) or are to be tested in an
E906/E906M − 21
FIG. 18 Vertical Holder Mount
unrestrainedconditionshallbeconstructedsotheweightofthe the radiation doors are in their open position and the specimen
holder is minimized to reduce heat capacity of the supporting
is inserted, is adjusted to position the front surface of the
structure.Forhorizontalspecimensthatmelt,andforthermally
specimen 100 mm from the entrance of the environmental
thinspecimens,thealuminumfoilboat(see11.7.1)shallbeset
chamber.
on or backed by the 12mm [0.47-in.] rigid insulation board
11.7.4 The frame for the horizontal radiation reflector is
described in 11.7.
shown in Fig. 21, and the horizontal assembly in the burn
11.7.3 The adjustable radiation shield (see Fig. 9)onthe
position is shown in Fig. 22.
verticalspecimenholder,whichcoverstheopeningmadewhen
E906/E906M − 21
FIG. 19 Vertical Specimen Holder
11.8 Radiation Reflector for Horizontally Mounted 11.11 Pilot-Flame Positions—In addition to piloted and
Specimens—A new 320mm by 225mm [12.6-in. by 8.9-in.] nonpilotedmodeofoperation,itispossibletoaccomplishpilot
sheet of 0.025mm [0.001-in.] aluminum foil shall be placed ignition of a specimen by locating the pilot flame at different
over the rod supports before each test with bright side toward positionsrelativetothesamplesurfacesothattheflamewillor
the panel. The foil shall be supported by crimping around all will not impinge on the specimen surface.The location chosen
edges with a 2mm [1-in.] overlap. dependsonthenatureofignitiontobesimulatedbythetest.In
all piloted ignitions, the lower pilot flame size shall be in
11.9 Radiometers—Total-flux meters (calorimeters) shall
accordance with 11.10. Pilot positions are described in 11.11.1
be used to measure the total heat flux
...