ASTM E1678-21a

Standard Test Method for Measuring Smoke Toxicity for Use in Fire Hazard Analysis

SIGNIFICANCE AND USE
5.1 This test method has been designed to provide data for the mathematical modeling of fire hazard as a means for the evaluation of materials and products and to assist in their research and development.  
5.1.1 Test Method E1678 is functionally equivalent to NFPA 269-2017.  
5.2 This test method is used to predict, and subsequently confirm, the lethal toxic potency of smoke produced upon the exposure of a material or product to specific fire test conditions. Confirmation determines whether certain major gaseous toxicants account for the observed toxic effects and lethal toxic potency. If a predicted lethal toxic potency value is not confirmed adequately, indicating a potential for unusual or unexplained toxicity, the lethal toxic potency will need to be investigated using other methodology, such as conducting an experimental determination of the LC50 using the apparatus described. (See X1.3.1 and X1.3.2.)  
5.3 This test method produces lethal toxic potency values that are appropriate for use in the modeling of both pre-flashover and post-flashover fires. Most fire deaths due to smoke inhalation in the U.S. occur in areas other than the room of fire origin and are caused by fires that have proceeded beyond the room of fire origin. It is assumed that these are flashover fires. Therefore, the principal emphasis is placed on evaluating toxic hazard under these conditions. In post-flashover fires, large concentrations of carbon monoxide results from reduced air supply to the fire plume and other room-scale factors. Bench-scale tests do not have the capacity to simulate these phenomena. The lethal toxic potency values determined in this test method are obtained from fuel/air ratios more representative of pre-flashover, rather than post-flashover conditions. In cases where a pre-flashover fire representation is desired in fire hazard modeling, these LC50 values are appropriate. Lethal toxic potency and carbon monoxide yield values determined in this test method requi...
SCOPE
1.1 This fire-test-response standard covers a means for determining the lethal toxic potency of smoke produced from a material or product ignited while exposed to a radiant heat flux of 50 kW/m2 for 15 min.  
1.2 This test method is limited to test specimens no larger than 76 mm by 127 mm (3 in. by 5 in.), with a thickness no greater than 51 mm (2 in.). Specimens are intended to be representative of finished materials or products, including composite and combination systems.  
1.3 Lethal toxic potency values associated with 30-min exposures are predicted using calculations that use combustion atmosphere analytical data for carbon monoxide, carbon dioxide, oxygen (vitiation) and, if present, hydrogen cyanide, hydrogen chloride, and hydrogen bromide. The predictive equations are therefore limited to those materials and products whose smoke toxicity can be attributed to these toxicants. An animal check determines the extent to which additional toxicants contribute to the lethal toxic potency of the smoke.  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.5 This standard measures and describes the response of materials, products, or assemblies in response to heat under controlled conditions, but does not by itself incorporate all factors required for fire hazard of fire risk assessment of the materials, products, or assemblies under actual fire conditions.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations (particularly with regard to the care and use of experimental animals) prior to use. For specific hazards statements, see Section 7 and Note X1.1.  ...

General Information

• Status: Published
• Publication Date: 30-Nov-2021
• ICS: 13.220.50 - Fire-resistance of building materials and elements
• ICS: 91.040.01 - Buildings in general
• Technical Committee: E05 - Fire Standards
• Drafting Committee: E05.21 - Smoke and Combustion Products

Relations

• Refers: ASTM E176-24 - Standard Terminology of Fire Standards
• Effective Date: 01-Jan-2024
• Refers: ASTM E800-20 - Standard Guide for Measurement of Gases Present or Generated During Fires
• Effective Date: 01-Jul-2020
• Refers: ASTM E176-18a - Standard Terminology of Fire Standards
• Effective Date: 15-Dec-2018
• Refers: ASTM E176-18 - Standard Terminology of Fire Standards
• Effective Date: 01-Mar-2018
• Refers: ASTM E176-15a - Standard Terminology of Fire Standards
• Effective Date: 01-Aug-2015
• Refers: ASTM E176-15ae1 - Standard Terminology of Fire Standards
• Effective Date: 01-Aug-2015
• Refers: ASTM E176-15 - Standard Terminology of Fire Standards
• Effective Date: 01-Feb-2015
• Refers: ASTM E800-14 - Standard Guide for Measurement of Gases Present or Generated During Fires
• Effective Date: 15-Nov-2014
• Refers: ASTM E176-14c - Standard Terminology of Fire Standards
• Effective Date: 01-Oct-2014
• Refers: ASTM E176-14b - Standard Terminology of Fire Standards
• Effective Date: 15-Aug-2014
• Refers: ASTM E176-14a - Standard Terminology of Fire Standards
• Effective Date: 01-Aug-2014
• Refers: ASTM E176-14 - Standard Terminology of Fire Standards
• Effective Date: 01-Jul-2014
• Refers: ASTM E176-13 - Standard Terminology of Fire Standards
• Effective Date: 01-Apr-2013
• Refers: ASTM E176-12b - Standard Terminology of Fire Standards
• Effective Date: 15-Dec-2012
• Refers: ASTM E176-12a - Standard Terminology of Fire Standards
• Effective Date: 01-Nov-2012

Overview

ASTM E1678-21a is the Standard Test Method for Measuring Smoke Toxicity for Use in Fire Hazard Analysis, developed by ASTM Committee E05.21 on Smoke and Combustion Products. This international standard specifies a procedure for assessing the lethal toxic potency of smoke generated by materials or products exposed to fire conditions. The standard plays a critical role in fire hazard modeling by helping evaluate the potential health risks of smoke inhalation from different materials during fire scenarios.

ASTM E1678-21a is functionally equivalent to NFPA 269-2017, making it a recognized methodology for both research and regulatory applications. Its data outputs support product assessment, material selection, and engineering controls focused on minimizing life safety risks in building designs and product manufacturing.

Key Topics

• Smoke toxicity testing: This method evaluates the toxicity of smoke under controlled fire exposure, specifically a radiant heat flux of 50 kW/m² for 15 minutes.
• Measurement parameters: It predicts lethal toxic potency (LC50) using analysis of combustion gases such as carbon monoxide, carbon dioxide, oxygen, as well as hydrogen cyanide, hydrogen chloride, and hydrogen bromide if present.
• Bench-scale testing: Specimens tested are up to 76 mm × 127 mm and 51 mm thick, allowing assessment of finished products and composites representative of real-world end-use.
• Mathematical modeling: The data produced inform fire hazard models, especially for pre-flashover and post-flashover fire conditions.
• Animal confirmation: Use of rat exposure confirms whether major gases measured account for observed toxicity, ensuring comprehensiveness of the toxicological assessment.
• Limitations: The standard does not simulate all factors in real fires (e.g., particulate size, smoke transport) and does not directly assess incapacitation or sensory irritation.

Applications

ASTM E1678-21a is widely used in the following sectors:

• Building and construction: Assessing the fire hazard potential of construction materials, wall finishes, insulation, and coatings by measuring toxic gas emissions during fires.
• Transport and infrastructure: Used by manufacturers of transportation materials (rail, aviation, marine) to comply with safety requirements addressing smoke toxicity.
• Product development: Material scientists and engineers use this test for research and development, aiding the selection of safer material formulations.
• Regulatory compliance: Meeting safety regulations where demonstration of smoke toxicity characteristics is mandated for certain products.
• Fire safety engineering: Providing critical input data for fire models used by engineers to predict occupant exposure risks under different fire scenarios.

Related Standards

For a comprehensive approach to fire hazard analysis and smoke toxicity testing, users of ASTM E1678-21a should also consider:

• NFPA 269-2017: Functionally equivalent to ASTM E1678, and widely referenced for toxic potency data in fire hazard modeling.
• ASTM E176: Standard Terminology of Fire Standards, useful for consistent definitions across fire safety documents.
• ASTM E800: Guide for Measurement of Gases Present or Generated During Fires, outlining gas sampling and analysis protocols.
• ISO 19701: Methods for Sampling and Analysis of Fire Effluents, providing international alignment on analytical techniques.
• ISO 19702: Guidance on using Fourier Transform Infrared (FTIR) Spectroscopy for toxic gas analysis in fire effluents.

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Keywords: ASTM E1678-21a, smoke toxicity, fire hazard analysis, lethal toxic potency, LC50, combustion gases, bench-scale fire testing, building materials, fire safety standards, NFPA 269, regulatory compliance, combustible materials, fire modeling, toxic gas analysis.

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: E1678 − 21a An American National Standard
Standard Test Method for
Measuring Smoke Toxicity for Use in Fire Hazard Analysis
This standard is issued under the fixed designation E1678; 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.
INTRODUCTION
Thepyrolysisorcombustionofeverycombustiblematerialorproductproducessmokethatistoxic.
It is, therefore, desirable to establish a test method for the development of data characterizing smoke
toxicity as an element of fire hazard analyses for both pre-flashover and post-flashover fires. The test
methodincludesquantificationofthetoxicityofthesmokeandascertainwhethertheobservedtoxicity
can be attributed to the major common toxicants.
1. Scope* 1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This fire-test-response standard covers a means for
responsibility of the user of this standard to establish appro-
determining the lethal toxic potency of smoke produced from
priate safety, health, and environmental practices and deter-
a material or product ignited while exposed to a radiant heat
mine the applicability of regulatory limitations (particularly
flux of 50 kW/m for 15 min.
with regard to the care and use of experimental animals) prior
1.2 This test method is limited to test specimens no larger
to use. For specific hazards statements, see Section 7 and Note
than 76mm by 127 mm (3in. by 5 in.), with a thickness no
X1.1.
greater than 51 mm (2 in.). Specimens are intended to be
1.7 This international standard was developed in accor-
representative of finished materials or products, including
dance with internationally recognized principles on standard-
composite and combination systems.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.3 Lethal toxic potency values associated with 30-min
mendations issued by the World Trade Organization Technical
exposures are predicted using calculations that use combustion
Barriers to Trade (TBT) Committee.
atmosphere analytical data for carbon monoxide, carbon
dioxide, oxygen (vitiation) and, if present, hydrogen cyanide,
2. Referenced Documents
hydrogen chloride, and hydrogen bromide. The predictive
2.1 ASTM Standards:
equations are therefore limited to those materials and products
E176Terminology of Fire Standards
whose smoke toxicity can be attributed to these toxicants. An
E800GuideforMeasurementofGasesPresentorGenerated
animal check determines the extent to which additional toxi-
During Fires
cants contribute to the lethal toxic potency of the smoke.
2.2 ISO Documents:
1.4 The values stated in SI units are to be regarded as
ISO 19701Methods for Sampling and Analysis of Fire
standard. The values given in parentheses after SI units are
Effluents
provided for information only and are not considered standard.
ISO 19702Guidance for Sampling and Analysis of Toxic
Gases and Vapours in Fire Effluents Using Fourier Trans-
1.5 This standard measures and describes the response of
form Infrared (FTIR) Spectroscopy
materials, products, or assemblies in response to heat under
2.3 NFPA Standard:
controlled conditions, but does not by itself incorporate all
NFPA269-2017StandardTestMethodforDevelopingToxic
factors required for fire hazard of fire risk assessment of the
Potency Data for Use in Fire Hazard Modeling
materials, products, or assemblies under actual fire conditions.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
This test method is under the jurisdiction of ASTM Committee E05 on Fire Standards volume information, refer to the standard’s Document Summary page on
Standards and is the direct responsibility of Subcommittee E05.21 on Smoke and the ASTM website.
Combustion Products. Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
Current edition approved Dec. 1, 2021. Published January 2022. Originally 4th Floor, New York, NY 10036, http://www.ansi.org.
approved in 1995. Last previous edition approved in 2021 as E1678–21. DOI: Available from National Fire Protection Association (NFPA), 1 Batterymarch
10.1520/E1678-21A. Park, Quincy, MA 02269, http://www.nfpa.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
E1678 − 21a
3. Terminology trations of the major gaseous toxicants are monitored over the
30-min period, with Ct products for each being determined
3.1 Definitions—For definitions of general terms used in
from integration of the areas under the respective
this test method, refer to Terminology E176.
concentration-time plots. The Ct product data, along with the
3.2 Definitions of Terms Specific to This Standard:
mass loss of the test specimen during the test, are then used in
3.2.1 carboxyhemoglobin saturation, n—the percent of
calculations to predict the 30-min LC of the test specimen.
blood hemoglobin predominately converted to carboxyhemo-
globin from reaction with inhaled carbon monoxide. 4.2 The predicted LC is then confirmed in comparable
3.2.1.1 Discussion—The chemical reaction between carbon
tests by exposing six rats, restrained for head-only exposure,
monoxide and hemoglobin in blood is reversible.The effect of for 30 min to the smoke produced from that mass of the test
carbonmonoxideontheexposedpersonmaynotbereversible.
specimen whose mass loss concentration during the 30-min
period is approximately (610%) equivalent to 70% and to
3.2.2 concentration-time curve, n—a plot of the concentra-
130% of its estimated LC . If no more than one rat dies
tion of a gaseous toxicant as a function of time.
during the 30-min exposure, or within 14-days post-exposure
3.2.2.1 Discussion—The concentration-time curve can also
to the mass loss concentration corresponding to 70% of the
be used to represent the sum total of all combustion products
LC , and at least five rats die during the 30-min exposure, or
instead of just a single one.
within 14-days post-exposure, to the mass loss concentration
3.2.3 Ct product, n—the concentration-time product in (µL/
corresponding to 130% of the LC , the predicted LC is
50 50
L)·min obtained by integration of the area under a
considered to be confirmed. Confirmation ensures that the
concentration-time curve.
monitored toxicants account for the observed toxic effects.
3.2.3.1 Discussion—Values expressed using this unit are
4.3 An animal test result that does not confirm the predic-
numericallyequaltothoseusingthepreviouslycitedunit,ppm,
tion indicates the presence of one or more additional toxicants
a term whose use is discouraged.
or toxicological antagonists, and the degree of disagreement
3.2.4 fractional exposure dose (FED), n—the ratio of the
indicates the importance of the unmeasured factors.
integrated area under the concentration-time curve for a
gaseous toxicant or the sum of all combustion products 4.4 For calculation of hazard from pre-flashover, flaming
produced in a given test to that integrated C(t) area which has fires, the toxicant gas yields and LC values are to be used as
been determined statistically from independent experimental experimentally determined. For calculation of hazard from
data to produce lethality in 50% of test animals within a post-flashover fires, the yields of carbon monoxide are aug-
specified exposure and postexposure time. mented to reflect the higher yields produced in such fires. The
experimental LC values are then adjusted using a specified
3.2.4.1 Discussion—When C is nearly constant over time,
thetimevaluesinthisrationumericallycancel,andtheFEDis calculation to produce LC (post-flashover) values.
simply the ratio of the average concentration of a gaseous
toxicant to its LC value for the same exposure time. When 5. Significance and Use
only a single measurement of C is made during a test, the
5.1 This test method has been designed to provide data for
accuracy of this simplification is not known. When not used
the mathematical modeling of fire hazard as a means for the
with reference to a specific toxicant, the term FED represents
evaluation of materials and products and to assist in their
the summation of FEDs for individual toxicants in a combus-
research and development.
tion atmosphere.
5.1.1 Test Method E1678 is functionally equivalent to
3.2.5 LC ,n—a measure of lethal toxic potency; the
50 NFPA 269-2017.
concentration of gas or smoke calculated statistically from
5.2 This test method is used to predict, and subsequently
concentration-responsedatatoproducelethalityin50%oftest
confirm, the lethal toxic potency of smoke produced upon the
animals within a specified exposure and postexposure time,
exposure of a material or product to specific fire test condi-
expressed in µL/L.
tions. Confirmation determines whether certain major gaseous
3.2.5.1 Discussion—Values expressed using this unit are
toxicantsaccountfortheobservedtoxiceffectsandlethaltoxic
numericallyequaltothoseusingthepreviouslycitedunit,ppm,
potency. If a predicted lethal toxic potency value is not
a term whose use is discouraged.
confirmed adequately, indicating a potential for unusual or
3.2.6 mass loss concentration, n—the mass loss of a test
unexplained toxicity, the lethal toxic potency will need to be
−3
specimen per unit exposure chamber volume in g·m .
investigated using other methodology, such as conducting an
3.2.7 post-flashover, n and adj—referring to the state of a experimental determination of the LC using the apparatus
fire after flashover. described. (See X1.3.1 and X1.3.2.)
5.3 This test method produces lethal toxic potency values
4. Summary of Test Method
that are appropriate for use in the modeling of both pre-
4.1 In this test method, a test specimen is subjected to flashover and post-flashover fires. Most fire deaths due to
ignition while it is exposed for 15 min to a radiant heat flux of smokeinhalationintheU.S.occurinareasotherthantheroom
50 kW/m . (See X1.2.2.) The smoke produced is collected for of fire origin and are caused by fires that have proceeded
30 min within a 200-L chamber communicating with the beyond the room of fire origin. It is assumed that these are
combustion assembly through a connecting chimney. Concen- flashover fires. Therefore, the principal emphasis is placed on
E1678 − 21a
evaluating toxic hazard under these conditions. In post-
flashoverfires,largeconcentrationsofcarbonmonoxideresults
from reduced air supply to the fire plume and other room-scale
factors. Bench-scale tests do not have the capacity to simulate
these phenomena. The lethal toxic potency values determined
in this test method are obtained from fuel/air ratios more
representative of pre-flashover, rather than post-flashover con-
ditions. In cases where a pre-flashover fire representation is
desired in fire hazard modeling, these LC values are appro-
priate. Lethal toxic potency and carbon monoxide yield values
determined in this test method require adjustment for use in
modeling of the hazard from post-flashover conditions. (See
X1.4.1.)
5.4 The lethal toxic potency values determined in this test
methodhavealevelofuncertaintyintheiraccuracywhenused
to predict real-scale toxic potencies. (See X1.4.2.)
FIG. 1 Overall View of the Apparatus
5.4.1 Theaccuracyofthebench-scaledataforpre-flashover
fires has not been established experimentally. The combustion
conditions in the apparatus are quite similar to real pre-
provided to monitor the temperature at the level of the animal
flashoverfires,althoughthemassburningratemaybehigherat
ports.Therearetwodoorsintheexposurechamber,inthefront
the 50 kW/m irradiance of the test method.
wall near the connection to the combustion cell and in the end
5.4.2 Comparison of the toxicant yields and LC (post-
wall nearest the animal ports. The purpose of the doors is to
flashover) values obtained using this method have been shown
allow for cleaning and maintenance of the chamber, chimney,
in limited tests (1) to reproduce the LC values from real-
andsmokeshutterandtoprovidefreshairduringcalibrationof
scale, post-flashover fires to within an accuracy of approxi-
the heat lamps and immediately prior to testing.
mately a factor of three. Therefore, LC (post-flashover)
6.2 Smoke Shutter, made of stainless steel plate and situated
values differing by less than a factor of three are indistinguish-
inside the animal exposure chamber. It is positioned so that it
able from each other. (See X1.4.2.)
will close over the chimney opening. It is hinged and provided
5.5 This test method does not attempt to address the
with a positive locking mechanism. The purpose of the shutter
toxicological significance of changes in particulate and aerosol
is to seal the combustion chamber and chimney from the
size, smoke transport, distribution, or deposition or changes in
exposure chamber at the end of irradiation.Awire attached to
the concentration of any smoke constituent as a function of
the shutter and a simple push rod are provided for gentle
time as may occur in a real fire.
closing of the shutter. A wire attached to a clamp locks the
5.6 The propensity for smoke from any material to have the
shutter in place. To produce a gas-tight seal, the underside of
same effects on humans in fire situations can be inferred only
the shutter is covered with a 12mm (0.5-in.) thick blanket of
to the extent that the rat is correlated with humans as a
low-densityceramicfiberinsulation(approximately65kg/m ),
biological system.
which is further covered with stainless steel foil.
5.7 This test method does not assess incapacitation. Inca-
6.3 Chimney (Fig. 3)—A stainless steel assembly approxi-
1 3
pacitation must be inferred from lethal toxic potency values.
mately 30mm by 300 mm (1 ⁄4in. by 11 ⁄4 in.), inside
dimensions, and 300 mm (11 ⁄4 in.) wide. It connects the
5.8 Theeffectsofsensoryirritationarenotaddressedbythis
combustion cell to the animal exposure chamber.The chimney
test method.
is divided into three channels by stainless steel dividers. The
6. Apparatus center channel is approximately 150 mm (6 in.) wide. The
purpose of the dividers is to induce smoke to travel up through
6.1 Animal Exposure Chamber—Shown in Figs. 1 and 2,a
the center portion of the chimney, while air from the animal
transparent polycarbonate or polymethylmethacrylate chamber
3 exposurechamberisdrawndownthroughtheoutsidechannels
with a nominal volume of 0.2 m (200 L). (See X1.2.5.) Its
toprovideairtothecombustioncell.Thechimneyisconnected
insidedimensionsare1220mmby370mmby450mm(48in.
to the underside of the animal exposure chamber by clamps,
1 3
by 14 ⁄2in. by 17 ⁄4 in.). The six animal ports, intended for
permitting its removal for cleaning. It is sealed to the animal
head-only exposure, are located in a horizontal row, approxi-
chamber by low-density ceramic fiber insulation (approxi-
mately half way from the bottom to the top of the chamber, in
mately65kg/m ).Theotherendofthechimneyissealedtothe
the front wall. A plastic bag with an approximate volume of
combustioncellbyanH-shapedtroughwithasmallquantityof
0.05 m (50 L or approximately 13 gal) is attached to the port
the same fiber insulation in the trough.
at the end of the chamber during a test to provide for gas
expansion. The exposure box is equipped with a gas sampling 6.4 Combustion Cell—Shown in Figs. 4-6, a horizontal
port at the animal nose level in the geometric center of the quartztubewitha127mm(5-in.)insidediameterandapproxi-
exposurechamberandwithaportforreturninggasesintheend mately 320 mm (12 ⁄2 in.) long. It is sealed at one end and has
wall closest to the gas analyzers. A thermocouple shall be alargestandardtaperouterjointattheotherend.Asealedinner
E1678 − 21a
FIG. 2 Schematic Drawing of the Apparatus
FIG. 3 Stainless Steel Chimney
joint serves as a removable plug for the open end (Fig. 6).The cell.Thesealedendofthecombustioncellisfittedwithaglass
combustioncellhasarectangularopeningonthetopparallelto collar to accommodate the electric sparker.
the axis of the cylinder with a “collar” that allows it to fit 6.4.1 Thecombustioncellissupportedbyametalframethat
securelyintothechimney.Thebottomofthecellhasaholefor also holds the load cell (Figs. 4 and 5). This entire frame is
the rod connecting the specimen support platform and load supported by a laboratory jack that holds the combustion cell
E1678 − 21a
FIG. 6 Combustion Cell
cell to be lowered for removal and cleaning. The load cell is
always at a fixed distance from the combustion cell.
6.5 Radiant Heaters:
6.5.1 Theactiveelementoftheheaterconsistsoffourquartz
infrared lamps (with tungsten filaments), rated at 2000 W at
240 V. The lamps (two on each side) are encased in water-
cooledholderswithparabolicreflectors.Theseholders(Fig.4)
FIG. 4 Front View of the Combustion Zone
are attached to adjustable metal frames, which allow the lamps
to be moved vertically and laterally and rotated in such a way
as to provide a uniform flux field across the sample surface.
Coolingwatermustbecirculatedthroughthelamps’respective
holders to keep them from overheating.The lamps must not be
operated without the cooling water.
6.5.2 The irradiance of the lamps must be held at a preset
level. One method entails a temperature controller and two
thermocouples(TypeK)thatareplacedbetweenthelampsand
the combustion cell and wired in parallel.
6.5.3 Theirradiancefromthelampsshallbeuniformwithin
the central area of the specimen holder to within 610%. Fig.
7showsthecalibrationholdertobeusedwhendeterminingthe
uniformityoftheradiantfieldfromthelamps.Thelampholders
must be repositioned, as necessary, if the field is found not to
be adequately uniform.
6.6 Temperature Controller (Optional)—When a tempera-
turecontrollerisusedformaintainingtherequiredradiantflux,
the quartz lamp output is controlled by a thermocouple signal
tothetemperaturecontroller.TheoutputsfromthetwoTypeK
thermocouples are averaged by means of a parallel-wired
connection, and this averaged value is used as the input to the
controller. The temperature controller must be a three-term
type and must provide an output signal suitable for driving the
power controller. The temperature controller must also incor-
porate a means for setting the maximum output to prevent the
FIG. 5 Side View of the Combustion Zone
power controller from being driven wide-open, if needed. The
power controller is selected to be compatible with the radiant
tightly to the chimney during experimentation and allows the heat lamps used.
E1678 − 21a
6.7.2 Thecalibrationoftheheatfluxmetermustbechecked
periodically. This is accomplished most readily by having two
flux meters, one used for routine testing and another used only
for calibration purposes.
6.7.3 The flux meter shall be used to calibrate the radiant
heater temperature controller. It shall be positioned in a rigid
supportdevicetoensurerepeatablereadings.Thesurfaceofthe
heat flux meter must be located at a position equivalent to the
center of the specimen face.
Fig. 7 indicates a calibration
bracket suitable for this purpose.
6.8 Ignitor—A spark ignitor is constructed of two 3.2mm
(0.125-in.) stainless steel rods. One of these two rods is bent at
90°, flattened on the end, and positioned to have the appear-
ance of the tip of an automotive spark plug. The gap between
the two rods shall be 2mm 6 0.5 mm. The two rods are
connected to the high-voltage spark system, which uses a
10kV transformer (Fig. 8). A 20000 Ω, 5W resistor is
FIG. 7 Calibration Jig
connected in series with one of the electrodes to reduce the
propagationofradiofrequencyinterferenceintotheinstrumen-
tation. The spark gap is positioned approximately 25 mm (1
6.7 Heat Flux Meter:
in.) above the center of the top surface of the specimen, inside
6.7.1 The total heat flux meter shall be of the Schmidt-
the combustion cell. In one operation method, the rods com-
Boelter (thermopile) type or equivalent, with a design range of
prising the spark igniter pass through a 29/42 male ground
at least 75 kW/m . The target receiving radiation shall be flat,
circular, approximately 12.5 mm in diameter, and coated with glass stopper, forming a gas-tight seal with a mating joint in
place of the collar on the combustion cell (Fig. 6). Otherwise,
durablematt-blackfinish.Thetargetshallbewatercooled.The
flux meter shall have an accuracy of within 63% and a the electrical leads shall be sealed in the glass collar in a
repeatability within 0.5%. gas-tight manner.
FIG. 8 Spark Igniter System
E1678 − 21a
6.9 Specimen Holder—A stainless steel assembly approxi- 6.11.2.3 The carbon monoxide analyzer shall have a range
mately 76mm by 127 mm (3in. by 5 in.), inside dimensions, from at least 0µL⁄L to 10000 µL/L.
and 50 mm (2 in.) deep (Fig. 9). The specimen is backed by a
NOTE 1—Most carbon monoxide analyzers display CO concentrations
−3
layer of ceramic fiber blanket of nominal 65-kg·m density.
inppm.Valuesexpressedinppmarenumericallyequaltothoseexpressed
The specimen holder is positioned for testing on the specimen
in µL/L.
platform, inside the combustion cell.
6.11.2.4 AdditionalgasanalysisforHCN,HCl,orHBrshall
6.10 Load Cell—The general arrangement of the load cell
beperformedwhenthenatureofthetestspecimenindicatesthe
and specimen holder is illustrated in Fig. 5. The load cell is
possibility of these gases being present in the combustion
installed under the combustion cell and is insulated against
products.Analysis for these gases shall follow the instructions
heating from the lamps. The specimen and holder are located
given in Guide E800. For any gases with which analysis
on a support plate and a rigid rod. The load cell shall have an
methodsareusedthatinvolvechemicalreaction,suchproducts
accuracy of 0.01 g, and it shall have a measuring range of at
are not returned to the animal exposure chamber but, rather,
least 100 g.
disposed of in an environmentally correct manner.
6.11 Gas Sampling:
6.12 Data Collection—The data collection system must
6.11.1 The gas sampling system shall be designed in accor-
have the capability of recording the output from the gas
dance with the requirements specified in Guide E800. Gases
analyzers, thermocouple(s) in the chamber, and load cell and
that are removed for chemical analysis and that can be
shall have an accuracy corresponding to 0.01% of full-scale
recirculated to the animal exposure chamber are returned since
instrument output.
this is a closed system. A suitable gas sampling arrangement
6.13 Animal Restrainers—Animal restrainers made of alu-
includes a pump, glass wool filter at the sampling port, cold
minum and designed to permit head-only exposures shall be
traptoremovesootandmoisture,andpressurereliefvalvethat
used.Adetailedillustrationofananimalrestrainermeetingthis
returns all flow not required by the CO, CO , and O gas
2 2
requirement is shown in Fig. 10.
analyzers. The flow to these analyzers is also returned to the
animal exposure chamber through separate return lines. The
7. Hazards
return lines shall be closed during calibration of the instru-
ments to prevent the accumulation of calibration gases in the 7.1 This test method involves bright lights, high
animal exposure chamber. temperatures, and combustion processes. Hazards may,
6.11.2 Gas Analyzers: therefore, exist for eye injuries, burns, ignition of extraneous
6.11.2.1 The oxygen analyzer shall have a range from 0% objects, and inhalation of combustion products. To prevent the
to 21%. accidental leakage of toxic combustion products into the
6.11.2.2 The carbon dioxide analyzer shall have a range surrounding atmosphere, the entire exposure system should be
from at least 0% to 10%. placed into a chemical hood or under a canopy hood. If under
FIG. 9 Specimen Holder
E1678 − 21a
9.3 The animals shall be identified, weighed, and housed
upon receipt in a separate quarantine area for a minimum of
seven days prior to testing. The animals shall be weighed and
observed daily during the quarantine period. Animals that are
unsuitable by reason of size, health, or other criteria are not to
be used. Cage assignments shall be made according to a
randomization routine.
9.4 The animals shall be housed one to a cage. The
environment shall have proper ventilation and be controlled to
a temperature of 23°C 6 3 °C (73°F 6 5 °F) and have a
relativehumidityof50% 615%.Theanimalroomshallhave
a 12-h light/dark cycle.
9.5 Animals are to be weighed daily from the day of arrival
FIG. 10 Animal Restrainer
to the end of the 14-day postexposure observation period.
Normally, one rat in five are to be used as controls.
acanopyhood,anaccessoryexhausttrunkforanycombination
9.6 The animals shall be weighed prior to exposure and be
gases escaping through the load cell hole on the bottom of the
secured in individual restrainers for placement in the animal
combustion cell is required. An exhaust line to evacuate the
exposure chamber.
exposureboxattheendofatestisrecommended.Theoperator
9.7 After testing, surviving animals shall be housed in an
must use safety tongs for removal of the specimen holder.
animal room separate from the pretest animal room for the
While hot, the combustion cell must be touched only with
postexposure observation period.
protective gloves. Due to the intense light from the infrared
lamps used, dark safety glasses must be worn by the operator,
10. Calibration of Apparatus
or a darkened polymethylmethacrylate or polycarbonate shield
must be placed in front of the combustion cell.
10.1 The following parts of the test apparatus require
7.2 The venting system for the exposure chamber must be calibration: radiant heaters, gas analyzers, load cell, and
checkedforproperoperationbeforetestingandmustdischarge temperature controller (if used).
into an exhaust system with adequate capacity.
10.2 Heat Flux Calibration:
10.2.1 For heat flux calibration, secure the heat flux meter
8. Test Specimens
into the proper position. The target surface of the flux meter
8.1 Test specimens shall be cut to an appropriate area (see
must be centered at the location equivalent, both horizontally
Section 12), no larger than 76mm by 127 mm (3in. by 5 in.)
and vertically, to that of the top of the specimen when the
andnothickerthan50mm(2in.)(seeX1.2.3),representingthe
specimen holder is in place on the platform. (The ignitor shall
end-use product. Raw materials (for example, paints,
be removed from its position during this procedure.) If used,
adhesives, wall coverings, etc.) shall be tested on the substrate
set the temperature controller to the desired flux temperature
to which they are normally applied. Wrap the specimens for
and turn on the radiant heat lamps, adjusting the temperature
testingonallsidesexceptforthetopfacewitheitheraluminum
controller until the desired irradiance (that is, 50 kW/m 6
or stainless steel foil.
10%) is achieved. If one is using manual control of the heat
8.2 The test specimens shall be conditioned at an ambient
lamps, develop a calibration curve of heater controller setting
temperature of 23°C 6 3 °C (73°F 6 5 °F) and relative
asafunctionoftimerequiredtomaintainthedesiredfluxlevel.
humidity of 50% 6 10% for at least 24 h prior to testing.
10.2.2 Check the orientation of the radiant heat lamps
whenever the heaters have been moved or a lamp replaced,
9. Animals
using the following procedure. Install the heat flux calibration
9.1 The test animals shall be inbred 3 month to 4 month old
jig shown in Fig. 7. The top face of the calibration jig should
male rats obtained from a reputable supplier that certifies its
be at the same height where the top of a test specimen is
animals to be free of major respiratory pathogens.Appropriate
placed. Estimate a power setting for the lamps that will
weight ranges at the time of use are 225g to 325 g for Fischer
produce the desired level (for example, 50 kW/m)atthe
344 rats and 300g to 375 g for Sprague-Dawley rats.
center hole. Adjust the power, and allow at least 5 min for
equilibration. Adjust the orientation of the radiant heat lamps
9.2 Themaintenanceandcareofanimalsshallbeperformed
sothatnomeasurementatsevenlocationsacrossthefaceofthe
by qualified personnel in accordance with guidelines of the
specimen deviates by more than 10% from the average.
National Institutes of Health Guide for the Care and Use of
LaboratoryAnimals (2). Theanimalhousingfacilitiesshallbe
10.3 Gas Analyzer Calibration:
suitable for studies of this type.
10.3.1 At the beginning of each series of tests, the O,CO ,
2 2
and CO analyzers shall be calibrated by using nitrogen gas for
“zeroing”andanappropriategasmixturenearto,butlessthan,
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
this standard. the analyzer full-scale reading. The gas shall be set to flow at
E1678 − 21a
the same rate and pressure as the sample gas for all calibra- present, HCN, HCl, and HBr. The choice of specimen size for
tions. Ambient air shall be used for calibration of the O the initial tests is made with consideration of anticipated
analyzer,whilebottledgasescontainingCO andCOatknown toxicantyieldssuchthatFEDsfrom0.5to1.5areobtained(see
concentration are required for the CO and CO analyzers. A Section13).Intheabsenceofappropriateinformationforsuch
single mixture containing both CO and CO may be used. The choices, an area equal to one fourth of the maximum area of
gas return lines must be diverted during the calibration 96.5 cm is selected initially.Analytical data from at least two
procedure into an exhaust duct in order to prevent inadvertent initial tests are used for the prediction of an average LC for
accumulation of CO and CO in the exposure chamber. the test specimen (see Section 12).
11.1.1 Comparable tests are then conducted, but with the
NOTE 2—Air at 0 % relative humidity has 20.9 % oxygen.An increase
exposureofsixratstothesmokeproducedfromthatamountof
in relative humidity will lead to a decrease in oxygen percent.
the test material whose mass loss concentration during the
10.3.2 The calibration of devices used for analysis of other
30-min period is approximately (610%) equivalent to 70%
gases(forexample,HCN,HCl,andHBr)shallbeperformedin
and130%ofitsaveragepredictedLC .ThepredictedLC is
50 50
accordance with Guide E800.
considered to be confirmed if no more than one rat dies during
10.4 Load Cell Calibration:
the 30-min exposure, or within 14 days postexposure, to the
10.4.1 The load cell shall be calibrated with standard
masslossconcentrationcorrespondingto70%oftheLC and
weights in the range of the test specimens periodically and
at least five rats die during the 30-min exposure, or within
whenfirstsettinguptheapparatusoraftermakingadjustments
14-days postexposure to the mass loss concentration corre-
for sensitivity and range.
sponding to 130% of the LC . If the confirmation is not
10.4.2 The load cell is checked routinely before each test successful, or if unexplained or unusual toxicity is suspected,
with at least two analytical quality weights over the effective
other test methodology must be used to investigate the lethal
rangeofmeasurement.Anydeviationoftheloadcelloutput,as toxic potency of the test material. (See X1.3.1 and X1.3.2.)
compared to these weights, shall be recorded, and appropriate
11.2 Preparation for Tests:
compensation shall be made for the specimen mass loss
11.2.1 Turn on the coolant water for the heat flux meter (at
readings.
least 750mL⁄min) and for the tungsten lamps (at least
10.5 Calibration of Optional Temperature Controller—To
600mL⁄min).
set up the controller, first install the flux meter so that the
11.2.2 Verify that all lines, filters, and traps for the gas
sensing surface is at the exact center of where the top of the
analyzers have been serviced and that the flow rates are
specimen is placed in normal testing. Lamp adjustment to
satisfactory.
obtain a uniform flux field over the sample shall have been
11.2.2.1 Check the moisture trap in the gas analyzer stream.
completedpreviously.Next,connecttheoutputoftheheatflux
Dry the trap and replace the glass wool. The normal operating
meter to a strip chart recorder running at a trace speed
temperature of the moisture trap is 0 °C.
sufficiently fast to detect any changes in the flux. Using the
11.2.2.2 Place a glass-wool filter before the gas sampling
output from the heat flux meter, follow the instructions of the
port.
controller manufacturer for adjusting the controller in order to
11.2.3 Verify that the spark ignition circuit is operational.
obtain, as closely as possible, a square wave output from the
11.2.4 Performtherequiredcalibrationproceduresspecified
heat flux meter when the lamps are turned on and then turned
in Section 8.
off. Because the lamps respond quickly, while the temperature
11.2.5 Weigh the specimen on a laboratory balance capable
atthethermocouplesrisesmoreslowly,itisimportanttoavoid
of 60.01g.Wrapthespecimenineitheraluminumorstainless
a significant overshoot, which can occur if the controller is not
steel foil, leaving the top surface exposed, and determine the
tunedoptimally.Itisalsoimportanttoavoidusingsettingsthat
combined weight of the specimen with the foil and after
result in an unstable, oscillating output. If such a problem is
mounting in the specimen holder. Verify that the load cell
noted, the solution is to limit the maximum output from the
readout corresponds to the appropriate weight of the specimen
slave controller. This can be accomplished by either using the
plus holder.
“load line out” function of the temperature controller, if so
equipped, or by installing a voltage divider at the output of the
11.3 Test Procedure:
temperaturecontroller.Whensettingupthecontrollerwiththis
11.3.1 If the animals are to be exposed, they shall be
function, it is always necessary to have the thermocouples
weighed and placed in their restrainers.
reading room air temperature and not some elevated tempera-
11.3.2 Insertthespecimen,mountedinthespecimenholder,
ture.Bycorrectadjustmentofthetemperaturecontroller,90%
into the combustion cell, and replace the standard taper plug
ofthedesiredfluxcanbereachedwithin2s,with100%being
(use no grease or sealant on the ground glass). Secure the plug
reachedwithin20sandadeviationofwithin 65%fortherest
with wire or springs. Place the animals into the ports in the
of the test.
exposure chamber immediately prior to the beginning of an
animal exposure test. Close all exposure chamber doors and
11. Procedure
ports, if not used for animals.Ascertain that the smoke shutter
is open.
11.1 General—Test procedures for smoke toxicity data are
initially to be followed without the exposure of test animals in 11.3.3 Turnonthesparker.Activatethepowertotheradiant
order to produce analytical data for CO, O,CO and, if heat lamps simultaneous with the start of data collection.
2 2
E1678 − 21a
11.3.4 Record the time at which ignition of the specimen thevaluesareinµL/LexceptO ,whichisin%byvolume.The
occurs and turn off the sparker. Record the time of flameout. valuesofmandbdependontheconcentrationofCO .If[CO ]
2 2
For specimens that have a tendency to self-extinguish soon ≤ 5% by volume, m =−18 and b =122000. If [CO]>5%
after ignition, the sparker shall be left on until flaming ceases. by volume, m =23 and b =−38600. For each individual
11.3.5 Switch off the power to the radiant heat lamps and toxicant, the LC values shown were determined statistically
close the smoke shutter at the end of 15 min. from independent experimental data to produce lethality in
11.3.6 Collect data for a total of 30 min from initiation of 50% of the test animals (rats) within a 30-min exposure plus
the test. 14-days postexposure.
11.3.7 Ceasecollectingdataattheendof30min.Ifanimals
12.3 The30-minLC foratestspecimeniscalculatedfrom
were exposed, they are to be removed from the exposure
Eq 2:
chamber. Vent the exposure chamber with a high capacity
specimenmassloss
exhaust system.
LC 5 (2)
FED 3chambervolume
11.3.8 Blood samples should be taken from any dead
animals and analyzed for carboxyhemoglobin saturation in
where the specimen mass loss is in g and the chamber
tests using the exposure of animals. Blood sampling and 3 −3
volume is 0.2 m . The resulting LC has the units of g·m .
analyses are to be conducted in accordance with generally
12.4 The yields of gases produced (mass of gas per mass of
accepted methodologies.
fuel consumed) at 25 °C are calculated from Eq 3:
11.3.9 In tests using the exposure of animals, those surviv-
ing shall be checked daily for any signs of toxic effects (for
@X#·8.2·MW
x
Y 5 (3)
x 6
example, difficulty in breathing and convulsions), exploratory
10 @m #
behavior,andeyeandrightingreflexes.Thestatusandweights
where [X] is the concentration of gas X in µL/L, MW is its
x
(at 7days and 14 days) of the animals shall be followed for a
gram molecular weight, and m is the mass of sample
14-day postexposure period. Any deaths during this time
consumed, also in grams.
period shall be recorded.
11.3.10 Remove the sample holder from the combustion
12.5 The lethal toxic potency value for hazard analysis of
chamber, and cool it to ambient temperature in an exhaust
post-flashover fires is calculated from Eq 4:
hood. Disassemble the specimen holder and determine the
weight of the stainless steel foil and residue after the specimen LC post 2 flashover 5 (4)
~ !
1 CO
@ #
23 25
has cooled. 144 310 2 5.0 310
LC m
50 100
11.3.11 Remove and clean the combustion chamber and
−3
chimneyaftereachtest.Cleantheexposurechamberaftereach where:LC (g·m )isthevaluedeterminedfromEq2,m
50 100
test. Ethyl alcohol is a satisfactory solvent. There must be no is the mass (g) of specimen lost during the test at the FED=1
residue on the inside of any of the pieces of the apparatus. condition, and [CO] (µL/L) is the concentration of CO at the
FED=1 condition. This equation is based on a post-flashover
12. Calculation
CO yield of 0.2 g/g of fuel burned. (See Appendix X1.4.1.)
12.1 General—The lethal toxic potency (LC ) of the test
50 12.6 The post-flashover CO yield for the specific product
specimen is predicted from the combustion atmosphere ana-
under evaluation may also be obtained from an appropriate
lytical data for CO, CO,O , and, if present, HCN, HCl, and
2 2 full-scale test. A value of LC (post-flashover) is then deter-
−2 −3
HBr. (See X1.2.6.) This is accomplished for a given specimen
mined by substituting 22 × 10 Y for 44 × 10 in Eq 4,
CO
mass loss by first calculating the FED for the test. The LC is
50 resulting in Eq 5:
then calculated as that specimen mass loss which would yield
a FED=1 within a chamber volume of 1 m .
LC post 2 flashover 5 (5)
~ !
1 @CO#
10.22Y 2 5.0 310
CO
NOTE 3—Although the theoretical value of the FED associated with
LC m
50 100
50%lethalityis1.0,amedianvalueof1.1hasbeenfoundexperimentally
(3).
13. Report
12.2 The 30-min FED for a given specimen mass loss is
13.1 Report the following information:
calculated from Eq 1:
13.1.1 Laboratory.
m@CO# 21 2 @O # @HCN#
FED 5 1 1 (1) 13.1.2 Test identification and date.
CO 2 b 21 2 LC O LC HCN
@ #
2 50 2 50
13.1.3 Laboratory ambient conditions (temperature and hu-
midity).
HCl HBr m CO 21 2 O
@ # @ # @ # @ #
1 1 5 1
13.1.4 Description of specimen, including how the test
LC HCl LC HBr @CO # 2 b ~21 2 5.4!%
50 50 2
specimen was derived from the full-scale product and how the
@HCN# @HCl# @HBr#
specimen was configured in the specimen holder.
1 1 1
150 µL/L 3700 µL/L 3000 µL/L
13.1.5 Specimen dimensions.
13.1.6 Irradiation time and heat flux conditions.
where the values of all gas concentrations are the integrated
Ct product values under their respective concentration-time 13.1.7 Maximum exposure chamber temperature and time
curves taken over the 30-min test period divided by 30.All of when attained (see X1.2.5).
E1678 − 21a
13.1.8 Initialspecimenmassandmasslossduringthetestin 13.2 Includethefollowinginformationinthereportforeach
−3
g·m of chamber volume (see X1.3.3). test using the exposure of animals:
13.2.1 Strain of rat and identity of supplier.
13.1.9 Time to ignition and flame out.
13.2.2 Weight of each animal when received, prior to test,
13.1.10 Observations of Specimen—Required observations
and at 7-days and 14-days postexposure for surviving animals.
are times to smoke evolution, ignition, and flame out. Other
13.2.3 Number of animals dying during the test (including
observations would include melting, char formation, spalling,
up to 10-min posttest) and number of animals that die up to
unusually vigorous burning, and reignition.
14days posttest.
13.1.11 Gas Analysis Data—Required exposure chamber
13.2.4 Blood carboxyhemoglobin saturation values for ani-
data include integrated Ct product values over the 30-min test
mals dying during the test.
for CO, O , HCN, HCl, and HBr; minimum O concentration
2 2
13.2.5 Animal observations, for example, unusual behavior
andmaximumCO concentration;andtimestoreachminimum
duringthetest;immediateposttestobservationsofliveanimals
O and maximum CO . The methods used for analyses are to
2 2
suchastremors,convulsions,difficultyinbreathing,severeeye
be identified.
irritation, etc.
13.1.12 Calculation:
13.3 State in the report whether the animal tests did or did
13.1.12.1 Ctproductforeachanalyzedtoxicantineachtest,
not confirm the value of the LC obtained from Eq 2.
13.1.12.2 Yield of each analyzed toxicant in each test.
13.1.12.3 FED value for each test, 14. Precision and Bias
13.1.12.4 Predicted LC value for pre-flashover use, for
50 14.1 Precision—The precision of this test method has not
each test, and
yet been established. A precision statement will be prepared
13.1.12.5 Best Overall Predicted LC Value to one signifi-
and included in the test method after the completion of an
cant figure—Aleast squares regression analysis of FED versus
interlaboratory test series.
mass loss values for all tests is used to determine the best
14.2 Bias—The bias of this test method has not been
overall predicted LC value.
measured since there is no accepted reference material for use
13.1.12.6 Calculated value of LC (post-flashover) to one
50 in making such measurements.
significant figure.
15. Keywords
13.1.13 Optional plots are those of individual toxicant
concentrations, specimen mass loss, and temperature as func- 15.1 combustiontoxicity;fire-hazardanalysis;firetests;fire
tions of time. toxicity
APPENDIX
(Nonmandatory Information)
X1. COMMENTARY
X1.1 Introduction—This commentary is provided to give tute of Standards and Technology (NIST) and SwRI for the
insightintothedevelopmentofthistestmethod,todescribethe developmentofthistestmethod (1).Itsmainfeaturesisthatof
rationale for the unique features of this test method, and to providing for combustion of a test specimen under the realistic
describe the proper use of the data provided. NIST Special
conditions of radiant heat within an apparatus designed espe-
Publication827isrecommended (3)foramorecomprehensive cially for ruggedness and ease of operation.
treatment, along with the presentation of data and results
X1.2.2 For a small, developing fire, the bench scale speci-
obtained on typical materials.
men in the radiant apparatus is a reasonable representation of
the full-scale fire. The thermal boundary conditions are
X1.2 Development of the Test Method—A test method for
appropriate, being radiative and from one face only. A small
assessing the acute inhalation toxicity of combustion products
fire will impose approximately 35 kW/m on an adjacent
has three basic components: a combustion system, a chemical
unburned surface (6, 7), although values around 48 kW/m are
analysis system, and an animal exposure system (4).
common and values over 100 kW/m can be measured. Thus,
Additionally,theremustbearationalandacceptedstrategyfor
while an irradiance of 50 kW/m for a pre
...

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: E1678 − 21 E1678 − 21a An American National Standard
Standard Test Method for
Measuring Smoke Toxicity for Use in Fire Hazard Analysis
This standard is issued under the fixed designation E1678; 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.
INTRODUCTION
The pyrolysis or combustion of every combustible material or product produces smoke that is toxic.
It is, therefore, desirable to establish a test method for the development of data characterizing smoke
toxicity as an element of fire hazard analyses for both pre-flashover and post-flashover fires. The test
method includes quantification of the toxicity of the smoke and ascertain whether the observed toxicity
can be attributed to the major common toxicants.
1. Scope*
1.1 This fire-test-response standard covers a means for determining the lethal toxic potency of smoke produced from a material
or product ignited while exposed to a radiant heat flux of 50 kW/m for 15 min.
1.2 This test method is limited to test specimens no larger than 7676 mm by 127 mm (3(3 in. by 5 in.), with a thickness no greater
than 51 mm (2 in.). Specimens are intended to be representative of finished materials or products, including composite and
combination systems.
1.3 Lethal toxic potency values associated with 30-min exposures are predicted using calculations that use combustion atmosphere
analytical data for carbon monoxide, carbon dioxide, oxygen (vitiation) and, if present, hydrogen cyanide, hydrogen chloride, and
hydrogen bromide. The predictive equations are therefore limited to those materials and products whose smoke toxicity can be
attributed to these toxicants. An animal check determines the extent to which additional toxicants contribute to the lethal toxic
potency of the smoke.
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for
information only and are not considered standard.
1.5 This standard measures and describes the response of materials, products, or assemblies in response to heat under controlled
conditions, but does not by itself incorporate all factors required for fire hazard of fire risk assessment of the materials, products,
or assemblies under actual fire conditions.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations (particularly with regard to the care and use of experimental animals) prior to use. For specific hazards
statements, see Section 7 and Note X1.1.
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 Combustion
Products.
Current edition approved July 1, 2021Dec. 1, 2021. Published August 2021January 2022. Originally approved in 1995. Last previous edition approved in 20152021 as
E1678 – 15.E1678 – 21. DOI: 10.1520/E1678-21.10.1520/E1678-21A.
*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
E1678 − 21a
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E176 Terminology of Fire Standards
E800 Guide for Measurement of Gases Present or Generated During Fires
2.2 ISO Documents:
ISO 19701 Methods for Sampling and Analysis of Fire Effluents
ISO 19702 Guidance for Sampling and Analysis of Toxic Gases and Vapours in Fire Effluents Using Fourier Transform Infrared
(FTIR) Spectroscopy
2.3 NFPA Standard:
NFPA 269-2017 Standard Test Method for Developing Toxic Potency Data for Use in Fire Hazard Modeling
3. Terminology
3.1 Definitions—For definitions of general terms used in this test method, refer to Terminology E176.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 carboxyhemoglobin saturation, n—the percent of blood hemoglobin predominately converted to carboxyhemoglobin from
reaction with inhaled carbon monoxide.
3.2.1.1 Discussion—
The chemical reaction between carbon monoxide and hemoglobin in blood is reversible. The effect of carbon monoxide on the
exposed person may not be reversible.
3.2.2 concentration-time curve, n—a plot of the concentration of a gaseous toxicant as a function of time.
3.2.2.1 Discussion—
The concentration-time curve can also be used to represent the sum total of all combustion products instead of just a single one.
3.2.3 Ct product, n—the concentration-time product in (μL/L)·min obtained by integration of the area under a concentration-time
curve.
3.2.3.1 Discussion—
Values expressed using this unit are numerically equal to those using the previously cited unit, ppm, a term whose use is
discouraged.
3.2.4 fractional exposure dose (FED), n—the ratio of the integrated area under the concentration-time curve for a gaseous toxicant
or the sum of all combustion products produced in a given test to that integrated C(t) area which has been determined statistically
from independent experimental data to produce lethality in 50 % of test animals within a specified exposure and postexposure time.
3.2.4.1 Discussion—
When C is nearly constant over time, the time values in this ratio numerically cancel, and the FED is simply the ratio of the average
concentration of a gaseous toxicant to its LC value for the same exposure time. When only a single measurement of C is made
during a test, the accuracy of this simplification is not known. When not used with reference to a specific toxicant, the term FED
represents the summation of FEDs for individual toxicants in a combustion atmosphere.
3.2.5 LC , n—a measure of lethal toxic potency; the concentration of gas or smoke calculated statistically from concentration-
response data to produce lethality in 50 % of test animals within a specified exposure and postexposure time, expressed in μL/L.
3.2.5.1 Discussion—
Values expressed using this unit are numerically equal to those using the previously cited unit, ppm, a term whose use is
discouraged.
−3
3.2.6 mass loss concentration, n—the mass loss of a test specimen per unit exposure chamber volume in g·m .
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.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Available from National Fire Protection Association (NFPA), 1 Batterymarch Park, Quincy, MA 02269, http://www.nfpa.org.
E1678 − 21a
3.2.7 post-flashover, n and adj—referring to the state of a fire after flashover.
4. Summary of Test Method
4.1 In this test method, a test specimen is subjected to ignition while it is exposed for 15 min to a radiant heat flux of 50 kW/m .
(See X1.2.2.) The smoke produced is collected for 30 min within a 200-L chamber communicating with the combustion assembly
through a connecting chimney. Concentrations of the major gaseous toxicants are monitored over the 30-min period, with Ct
products for each being determined from integration of the areas under the respective concentration-time plots. The Ct product
data, along with the mass loss of the test specimen during the test, are then used in calculations to predict the 30-min LC of the
test specimen.
4.2 The predicted LC is then confirmed in comparable tests by exposing six rats, restrained for head-only exposure, for 30 min
to the smoke produced from that mass of the test specimen whose mass loss concentration during the 30-min period is
approximately (610 %) equivalent to 70 % and to 130 % of its estimated LC . If no more than one rat dies during the 30-min
exposure, or within 14-days postexposurepost-exposure to the mass loss concentration corresponding to 70 % of the LC , and at
least five rats die during the 30-min exposure, or within 14-days postexposurepost-exposure, to the mass loss concentration
corresponding to 130 % of the LC , the predicted LC is considered to be confirmed. Confirmation ensures that the monitored
50 50
toxicants account for the observed toxic effects.
4.3 An animal test result that does not confirm the prediction indicates the presence of one or more additional toxicants or
toxicological antagonists, and the degree of disagreement indicates the importance of the unmeasured factors.
4.4 For calculation of hazard from pre-flashover, flaming fires, the toxicant gas yields and LC values are to be used as
experimentally determined. For calculation of hazard from post-flashover fires, the yields of carbon monoxide are augmented to
reflect the higher yields produced in such fires. The experimental LC values are then adjusted using a specified calculation to
produce LC (post-flashover) values.
5. Significance and Use
5.1 This test method has been designed to provide data for the mathematical modeling of fire hazard as a means for the evaluation
of materials and products and to assist in their research and development.
5.1.1 Test Method E1678 is functionally equivalent to NFPA 269-2017.
5.2 This test method is used to predict, and subsequently confirm, the lethal toxic potency of smoke produced upon the exposure
of a material or product to specific fire test conditions. Confirmation determines whether certain major gaseous toxicants account
for the observed toxic effects and lethal toxic potency. If a predicted lethal toxic potency value is not confirmed adequately,
indicating a potential for unusual or unexplained toxicity, the lethal toxic potency will need to be investigated using other
methodology, such as conducting an experimental determination of the LC using the apparatus described. (See X1.3.1 and
X1.3.2.)
5.3 This test method produces lethal toxic potency values that are appropriate for use in the modeling of both pre-flashover and
post-flashover fires. Most fire deaths due to smoke inhalation in the U.S. occur in areas other than the room of fire origin and are
caused by fires that have proceeded beyond the room of fire origin. It is assumed that these are flashover fires. Therefore, the
principal emphasis is placed on evaluating toxic hazard under these conditions. In post-flashover fires, large concentrations of
carbon monoxide results from reduced air supply to the fire plume and other room-scale factors. Bench-scale tests do not have the
capacity to simulate these phenomena. The lethal toxic potency values determined in this test method are obtained from fuel/air
ratios more representative of pre-flashover, rather than post-flashover conditions. In cases where a pre-flashover fire representation
is desired in fire hazard modeling, these LC values are appropriate. Lethal toxic potency and carbon monoxide yield values
determined in this test method require adjustment for use in modeling of the hazard from post-flashover conditions. (See X1.4.1.)
5.4 The lethal toxic potency values determined in this test method have a level of uncertainty in their accuracy when used to
predict real-scale toxic potencies. (See X1.4.2.)
E1678 − 21a
5.4.1 The accuracy of the bench-scale data for pre-flashover fires has not been established experimentally. The combustion
conditions in the apparatus are quite similar to real pre-flashover fires, although the mass burning rate may be higher at the 50
kW/m irradiance of the test method.
5.4.2 Comparison of the toxicant yields and LC (post-flashover) values obtained using this method have been shown in limited
tests (1) to reproduce the LC values from real-scale, post-flashover fires to within an accuracy of approximately a factor of three.
Therefore, LC (post-flashover) values differing by less than a factor of three are indistinguishable from each other. (See X1.4.2.)
5.5 This test method does not attempt to address the toxicological significance of changes in particulate and aerosol size, smoke
transport, distribution, or deposition or changes in the concentration of any smoke constituent as a function of time as may occur
in a real fire.
5.6 The propensity for smoke from any material to have the same effects on humans in fire situations can be inferred only to the
extent that the rat is correlated with humans as a biological system.
5.7 This test method does not assess incapacitation. Incapacitation must be inferred from lethal toxic potency values.
5.8 The effects of sensory irritation are not addressed by this test method.
6. Apparatus
6.1 Animal Exposure Chamber—Shown in Figs. 1 and 2, a transparent polycarbonate or polymethylmethacrylate chamber with a
nominal volume of 0.2 m (200 L). (See X1.2.5.) Its inside dimensions are 12201220 mm by 370370 mm by 450 mm (48(48 in.
1 3
by 14 ⁄2 in. by 17 ⁄4 in.). The six animal ports, intended for head-only exposure, are located in a horizontal row, approximately half
way from the bottom to the top of the chamber, in the front wall. A plastic bag with an approximate volume of 0.05 m (50 L or
approximately 13 gal) is attached to the port at the end of the chamber during a test to provide for gas expansion. The exposure
box is equipped with a gas sampling port at the animal nose level in the geometric center of the exposure chamber and with a port
for returning gases in the end wall closest to the gas analyzers. A thermocouple shall be provided to monitor the temperature at
the level of the animal ports. There are two doors in the exposure chamber, in the front wall near the connection to the combustion
cell and in the end wall nearest the animal ports. The purpose of the doors is to allow for cleaning and maintenance of the chamber,
chimney, and smoke shutter and to provide fresh air during calibration of the heat lamps and immediately prior to testing.
6.2 Smoke Shutter, made of stainless steel plate and situated inside the animal exposure chamber. It is positioned so that it will
close over the chimney opening. It is hinged and provided with a positive locking mechanism. The purpose of the shutter is to seal
the combustion chamber and chimney from the exposure chamber at the end of irradiation. A wire attached to the shutter and a
simple push rod are provided for gentle closing of the shutter. A wire attached to a clamp locks the shutter in place. To produce
FIG. 1 Overall View of the Apparatus
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FIG. 2 Schematic Drawing of the Apparatus
a gas-tight seal, the underside of the shutter is covered with a 12-mm12 mm (0.5-in.) thick blanket of low-density ceramic fiber
insulation (approximately 65 kg/m ), which is further covered with stainless steel foil.
1 3
6.3 Chimney (Fig. 3)—A stainless steel assembly approximately 3030 mm by 300 mm (1 ⁄4 in. by 11 ⁄4 in.), inside dimensions, and
300 mm (11 ⁄4 in.) wide. It connects the combustion cell to the animal exposure chamber. The chimney is divided into three
FIG. 3 Stainless Steel Chimney
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channels by stainless steel dividers. The center channel is approximately 150 mm (6 in.) wide. The purpose of the dividers is to
induce smoke to travel up through the center portion of the chimney, while air from the animal exposure chamber is drawn down
through the outside channels to provide air to the combustion cell. The chimney is connected to the underside of the animal
exposure chamber by clamps, permitting its removal for cleaning. It is sealed to the animal chamber by low-density ceramic fiber
insulation (approximately 65 kg/m ). The other end of the chimney is sealed to the combustion cell by an H-shaped trough with
a small quantity of the same fiber insulation in the trough.
6.4 Combustion Cell—Shown in Figs. 4-6, a horizontal quartz tube with a 127-mm127 mm (5-in.) inside diameter and
approximately 320 mm (12 ⁄2 in.) long. It is sealed at one end and has a large standard taper outer joint at the other end. A sealed
inner joint serves as a removable plug for the open end (Fig. 6). The combustion cell has a rectangular opening on the top parallel
to the axis of the cylinder with a “collar” that allows it to fit securely into the chimney. The bottom of the cell has a hole for the
rod connecting the specimen support platform and load cell. The sealed end of the combustion cell is fitted with a glass collar to
accommodate the electric sparker.
6.4.1 The combustion cell is supported by a metal frame that also holds the load cell (Figs. 4 and 5). This entire frame is supported
by a laboratory jack that holds the combustion cell tightly to the chimney during experimentation and allows the cell to be lowered
for removal and cleaning. The load cell is always at a fixed distance from the combustion cell.
6.5 Radiant Heaters:
6.5.1 The active element of the heater consists of four quartz infrared lamps (with tungsten filaments), rated at 2000 W at 240 V.
The lamps (two on each side) are encased in water-cooled holders with parabolic reflectors. These holders (Fig. 4) are attached
to adjustable metal frames, which allow the lamps to be moved vertically and laterally and rotated in such a way as to provide a
uniform flux field across the sample surface. Cooling water must be circulated through the lamps’ respective holders to keep them
from overheating. The lamps must not be operated without the cooling water.
FIG. 4 Front View of the Combustion Zone
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FIG. 5 Side View of the Combustion Zone
FIG. 6 Combustion Cell
6.5.2 The irradiance of the lamps must be held at a preset level. One method entails a temperature controller and two
thermocouples (Type K) that are placed between the lamps and the combustion cell and wired in parallel.
6.5.3 The irradiance from the lamps shall be uniform within the central area of the specimen holder to within 610 %. Fig. 7 shows
the calibration holder to be used when determining the uniformity of the radiant field from the lamps. The lampholders must be
repositioned, as necessary, if the field is found not to be adequately uniform.
6.6 Temperature Controller (Optional)—When a temperature controller is used for maintaining the required radiant flux, the quartz
lamp output is controlled by a thermocouple signal to the temperature controller. The outputs from the two Type K thermocouples
E1678 − 21a
FIG. 7 Calibration Jig
are averaged by means of a parallel-wired connection, and this averaged value is used as the input to the controller. The temperature
controller must be a three-term type and must provide an output signal suitable for driving the power controller. The temperature
controller must also incorporate a means for setting the maximum output to prevent the power controller from being driven
wide-open, if needed. The power controller is selected to be compatible with the radiant heat lamps used.
6.7 Heat Flux Meter:
6.7.1 The total heat flux meter shall be of the Schmidt-Boelter (thermopile) type or equivalent, with a design range of at least 75
kW/m . The target receiving radiation shall be flat, circular, approximately 12.5 mm in diameter, and coated with durable
matt-black finish. The target shall be water cooled. The flux meter shall have an accuracy of within 63 % and a repeatability within
0.5 %.
6.7.2 The calibration of the heat flux meter must be checked periodically. This is accomplished most readily by having two flux
meters, one used for routine testing and another used only for calibration purposes.
6.7.3 The flux meter shall be used to calibrate the radiant heater temperature controller. It shall be positioned in a rigid support
device to ensure repeatable readings. The surface of the heat flux meter must be located at a position equivalent to the center of
the specimen face. Fig. 7 indicates a calibration bracket suitable for this purpose.
6.8 Ignitor—A spark ignitor is constructed of two 3.2-mm3.2 mm (0.125-in.) stainless steel rods. One of these two rods is bent
at 90°, flattened on the end, and positioned to have the appearance of the tip of an automotive spark plug. The gap between the
two rods shall be 22 mm 6 0.5 mm. The two rods are connected to the high-voltage spark system, which uses a 10-kV10 kV
transformer (Fig. 8). A20 000-Ω, 5-W A 20 000 Ω, 5 W resistor is connected in series with one of the electrodes to reduce the
propagation of radio frequency interference into the instrumentation. The spark gap is positioned approximately 25 mm (1 in.)
above the center of the top surface of the specimen, inside the combustion cell. In one operation method, the rods comprising the
spark igniter pass through a 29/42 male ground glass stopper, forming a gas-tight seal with a mating joint in place of the collar
on the combustion cell (Fig. 6). Otherwise, the electrical leads shall be sealed in the glass collar in a gas-tight manner.
6.9 Specimen Holder—A stainless steel assembly approximately 7676 mm by 127 mm (3(3 in. by 5 in.), inside dimensions, and
−3
50 mm (2 in.) deep (Fig. 9). The specimen is backed by a layer of ceramic fiber blanket of nominal 65-kg·m density. The
specimen holder is positioned for testing on the specimen platform, inside the combustion cell.
6.10 Load Cell—The general arrangement of the load cell and specimen holder is illustrated in Fig. 5. The load cell is installed
under the combustion cell and is insulated against heating from the lamps. The specimen and holder are located on a support plate
and a rigid rod. The load cell shall have an accuracy of 0.01 g, and it shall have a measuring range of at least 100 g.
6.11 Gas Sampling:
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FIG. 8 Spark Igniter System
FIG. 9 Specimen Holder
6.11.1 The gas sampling system shall be designed in accordance with the requirements specified in Guide E800. Gases that are
removed for chemical analysis and that can be recirculated to the animal exposure chamber are returned since this is a closed
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system. A suitable gas sampling arrangement includes a pump, glass wool filter at the sampling port, cold trap to remove soot and
moisture, and pressure relief valve that returns all flow not required by the CO, CO , and O gas analyzers. The flow to these
2 2
analyzers is also returned to the animal exposure chamber through separate return lines. The return lines shall be closed during
calibration of the instruments to prevent the accumulation of calibration gases in the animal exposure chamber.
6.11.2 Gas Analyzers:
6.11.2.1 The oxygen analyzer shall have a range from 00 % to 21 %.
6.11.2.2 The carbon dioxide analyzer shall have a range from at least 00 % to 10 %.
6.11.2.3 The carbon monoxide analyzer shall have a range from at least 00 μL ⁄L to 10 000 μL/L.
NOTE 1—Most carbon monoxide analyzers display CO concentrations in ppm. Values expressed in ppm are numerically equal to those expressed in μL/L.
6.11.2.4 Additional gas analysis for HCN, HCl, or HBr shall be performed when the nature of the test specimen indicates the
possibility of these gases being present in the combustion products. Analysis for these gases shall follow the instructions given in
Guide E800. For any gases with which analysis methods are used that involve chemical reaction, such products are not returned
to the animal exposure chamber but, rather, disposed of in an environmentally correct manner.
6.12 Data Collection—The data collection system must have the capability of recording the output from the gas analyzers,
thermocouple(s) in the chamber, and load cell and shall have an accuracy corresponding to 0.01 % of full-scale instrument output.
6.13 Animal Restrainers—Animal restrainers made of aluminum and designed to permit head-only exposures shall be used. A
detailed illustration of an animal restrainer meeting this requirement is shown in Fig. 10.
7. Hazards
7.1 This test method involves bright lights, high temperatures, and combustion processes. Hazards may, therefore, exist for eye
injuries, burns, ignition of extraneous objects, and inhalation of combustion products. To prevent the accidental leakage of toxic
combustion products into the surrounding atmosphere, the entire exposure system should be placed into a chemical hood or under
a canopy hood. If under a canopy hood, an accessory exhaust trunk for any combination gases escaping through the load cell hole
on the bottom of the combustion cell is required. An exhaust line to evacuate the exposure box at the end of a test is recommended.
The operator must use safety tongs for removal of the specimen holder. While hot, the combustion cell must be touched only with
protective gloves. Due to the intense light from the infrared lamps used, dark safety glasses must be worn by the operator, or a
darkened polymethylmethacrylate or polycarbonate shield must be placed in front of the combustion cell.
7.2 The venting system for the exposure chamber must be checked for proper operation before testing and must discharge into
an exhaust system with adequate capacity.
FIG. 10 Animal Restrainer
E1678 − 21a
8. Test Specimens
8.1 Test specimens shall be cut to an appropriate area (see Section 12), no larger than 7676 mm by 127 mm (3(3 in. by 5 in.) and
no thicker than 50 mm (2 in.) (see X1.2.3), representing the end-use product. Raw materials (for example, paints, adhesives, wall
coverings, etc.) shall be tested on the substrate to which they are normally applied. Wrap the specimens for testing on all sides
except for the top face with either aluminum or stainless steel foil.
8.2 The test specimens shall be conditioned at an ambient temperature of 2323 °C 6 3 °C (73(73 °F 6 5 °F) and relative humidity
of 5050 % 6 10 % for at least 24 h prior to testing.
9. Animals
9.1 The test animals shall be inbred 3 month to 4 month old male rats obtained from a reputable supplier that certifies its animals
to be free of major respiratory pathogens. Appropriate weight ranges at the time of use are 225225 g to 325 g for Fischer 344 rats
and 300300 g to 375 g for Sprague-Dawley rats.
9.2 The maintenance and care of animals shall be performed by qualified personnel in accordance with guidelines of the National
Institutes of Health Guide for the Care and Use of Laboratory Animals (2). The animal housing facilities shall be suitable for
studies of this type.
9.3 The animals shall be identified, weighed, and housed upon receipt in a separate quarantine area for a minimum of seven days
prior to testing. The animals shall be weighed and observed daily during the quarantine period. Animals that are unsuitable by
reason of size, health, or other criteria are not to be used. Cage assignments shall be made according to a randomization routine.
9.4 The animals shall be housed one to a cage. The environment shall have proper ventilation and be controlled to a temperature
of 2323 °C 6 3 °C (73(73 °F 6 5 °F) and have a relative humidity of 5050 % 6 15 %. The animal room shall have a 12-h
light/dark cycle.
9.5 Animals are to be weighed daily from the day of arrival to the end of the 14-day postexposure observation period. Normally,
one rat in five are to be used as controls.
9.6 The animals shall be weighed prior to exposure and be secured in individual restrainers for placement in the animal exposure
chamber.
9.7 After testing, surviving animals shall be housed in an animal room separate from the pretest animal room for the postexposure
observation period.
10. Calibration of Apparatus
10.1 The following parts of the test apparatus require calibration: radiant heaters, gas analyzers, load cell, and temperature
controller (if used).
10.2 Heat Flux Calibration:
10.2.1 For heat flux calibration, secure the heat flux meter into the proper position. The target surface of the flux meter must be
centered at the location equivalent, both horizontally and vertically, to that of the top of the specimen when the specimen holder
is in place on the platform. (The ignitor shall be removed from its position during this procedure.) If used, set the temperature
controller to the desired flux temperature and turn on the radiant heat lamps, adjusting the temperature controller until the desired
irradiance (that is, 50 kW/m 6 10 %) is achieved. If one is using manual control of the heat lamps, develop a calibration curve
of heater controller setting as a function of time required to maintain the desired flux level.
10.2.2 Check the orientation of the radiant heat lamps whenever the heaters have been moved or a lamp replaced, using the
following procedure. Install the heat flux calibration jig shown in Fig. 7. The top face of the calibration jig should be at the same
The boldface numbers in parentheses refer to the list of references at the end of this standard.
E1678 − 21a
height where the top of a test specimen is placed. Estimate a power setting for the lamps that will produce the desired level (for
example, 50 kW/m ) at the center hole. Adjust the power, and allow at least 5 min for equilibration. Adjust the orientation of the
radiant heat lamps so that no measurement at seven locations across the face of the specimen deviates by more than 10 % from
the average.
10.3 Gas Analyzer Calibration:
10.3.1 At the beginning of each series of tests, the O , CO , and CO analyzers shall be calibrated by using nitrogen gas for
2 2
“zeroing” and an appropriate gas mixture near to, but less than, the analyzer full-scale reading. The gas shall be set to flow at the
same rate and pressure as the sample gas for all calibrations. Ambient air shall be used for calibration of the O analyzer, while
bottled gases containing CO and CO at known concentration are required for the CO and CO analyzers. A single mixture
2 2
containing both CO and CO may be used. The gas return lines must be diverted during the calibration procedure into an exhaust
duct in order to prevent inadvertent accumulation of CO and CO in the exposure chamber.
NOTE 2—Air at 0 % relative humidity has 20.9 % oxygen. An increase in relative humidity will lead to a decrease in oxygen percent.
10.3.2 The calibration of devices used for analysis of other gases (for example, HCN, HCl, and HBr) shall be performed in
accordance with Guide E800.
10.4 Load Cell Calibration:
10.4.1 The load cell shall be calibrated with standard weights in the range of the test specimens periodically and when first setting
up the apparatus or after making adjustments for sensitivity and range.
10.4.2 The load cell is checked routinely before each test with at least two analytical quality weights over the effective range of
measurement. Any deviation of the load cell output, as compared to these weights, shall be recorded, and appropriate compensation
shall be made for the specimen mass loss readings.
10.5 Calibration of Optional Temperature Controller—To set up the controller, first install the flux meter so that the sensing
surface is at the exact center of where the top of the specimen is placed in normal testing. Lamp adjustment to obtain a uniform
flux field over the sample shall have been completed previously. Next, connect the output of the heat flux meter to a strip chart
recorder running at a trace speed sufficiently fast to detect any changes in the flux. Using the output from the heat flux meter, follow
the instructions of the controller manufacturer for adjusting the controller in order to obtain, as closely as possible, a square wave
output from the heat flux meter when the lamps are turned on and then turned off. Because the lamps respond quickly, while the
temperature at the thermocouples rises more slowly, it is important to avoid a significant overshoot, which can occur if the
controller is not tuned optimally. It is also important to avoid using settings that result in an unstable, oscillating output. If such
a problem is noted, the solution is to limit the maximum output from the slave controller. This can be accomplished by either using
the “load line out” function of the temperature controller, if so equipped, or by installing a voltage divider at the output of the
temperature controller. When setting up the controller with this function, it is always necessary to have the thermocouples reading
room air temperature and not some elevated temperature. By correct adjustment of the temperature controller, 90 % of the desired
flux can be reached within 2 s, with 100 % being reached within 20 s and a deviation of within 65 % for the rest of the test.
11. Procedure
11.1 General—Test procedures for smoke toxicity data are initially to be followed without the exposure of test animals in order
to produce analytical data for CO, O , CO and, if present, HCN, HCl, and HBr. The choice of specimen size for the initial tests
2 2
is made with consideration of anticipated toxicant yields such that FEDs from 0.5 to 1.5 are obtained (see Section 13). In the
absence of appropriate information for such choices, an area equal to one fourth of the maximum area of 96.5 cm is selected
initially. Analytical data from at least two initial tests are used for the prediction of an average LC for the test specimen (see
Section 12).
11.1.1 Comparable tests are then conducted, but with the exposure of six rats to the smoke produced from that amount of the test
material whose mass loss concentration during the 30-min period is approximately (610 %) equivalent to 7070 % and 130 % of
its average predicted LC . The predicted LC is considered to be confirmed if no more than one rat dies during the 30-min
50 50
exposure, or within 14 days postexposure, to the mass loss concentration corresponding to 70 % of the LC and at least five rats
die during the 30-min exposure, or within 14-days postexposure to the mass loss concentration corresponding to 130 % of the
E1678 − 21a
LC . If the confirmation is not successful, or if unexplained or unusual toxicity is suspected, other test methodology must be used
to investigate the lethal toxic potency of the test material. (See X1.3.1 and X1.3.2.)
11.2 Preparation for Tests:
11.2.1 Turn on the coolant water for the heat flux meter (at least 750750 mL mL/min) ⁄min) and for the tungsten lamps (at least
600 600 mL mL/min).⁄min).
11.2.2 Verify that all lines, filters, and traps for the gas analyzers have been serviced and that the flow rates are satisfactory.
11.2.2.1 Check the moisture trap in the gas analyzer stream. Dry the trap and replace the glass wool. The normal operating
temperature of the moisture trap is 0 °C.
11.2.2.2 Place a glass-wool filter before the gas sampling port.
11.2.3 Verify that the spark ignition circuit is operational.
11.2.4 Perform the required calibration procedures specified in Section 8.
11.2.5 Weigh the specimen on a laboratory balance capable of 60.01 g. Wrap the specimen in either aluminum or stainless steel
foil, leaving the top surface exposed, and determine the combined weight of the specimen with the foil and after mounting in the
specimen holder. Verify that the load cell readout corresponds to the appropriate weight of the specimen plus holder.
11.3 Test Procedure:
11.3.1 If the animals are to be exposed, they shall be weighed and placed in their restrainers.
11.3.2 Insert the specimen, mounted in the specimen holder, into the combustion cell, and replace the standard taper plug (use no
grease or sealant on the ground glass). Secure the plug with wire or springs. Place the animals into the ports in the exposure
chamber immediately prior to the beginning of an animal exposure test. Close all exposure chamber doors and ports, if not used
for animals. Ascertain that the smoke shutter is open.
11.3.3 Turn on the sparker. Activate the power to the radiant heat lamps simultaneous with the start of data collection.
11.3.4 Record the time at which ignition of the specimen occurs and turn off the sparker. Record the time of flameout. For
specimens that have a tendency to self-extinguish soon after ignition, the sparker shall be left on until flaming ceases.
11.3.5 Switch off the power to the radiant heat lamps and close the smoke shutter at the end of 15 min.
11.3.6 Collect data for a total of 30 min from initiation of the test.
11.3.7 Cease collecting data at the end of 30 min. If animals were exposed, they are to be removed from the exposure chamber.
Vent the exposure chamber with a high capacity exhaust system.
11.3.8 Blood samples should be taken from any dead animals and analyzed for carboxyhemoglobin saturation in tests using the
exposure of animals. Blood sampling and analyses are to be conducted in accordance with generally accepted methodologies.
11.3.9 In tests using the exposure of animals, those surviving shall be checked daily for any signs of toxic effects (for example,
difficulty in breathing and convulsions), exploratory behavior, and eye and righting reflexes. The status and weights (at 77 days
and 14 days) of the animals shall be followed for a 14-day postexposure period. Any deaths during this time period shall be
recorded.
11.3.10 Remove the sample holder from the combustion chamber, and cool it to ambient temperature in an exhaust hood.
Disassemble the specimen holder and determine the weight of the stainless steel foil and residue after the specimen has cooled.
11.3.11 Remove and clean the combustion chamber and chimney after each test. Clean the exposure chamber after each test. Ethyl
alcohol is a satisfactory solvent. There must be no residue on the inside of any of the pieces of the apparatus.
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12. Calculation
12.1 General—The lethal toxic potency (LC ) of the test specimen is predicted from the combustion atmosphere analytical data
for CO, CO , O , and, if present, HCN, HCl, and HBr. (See X1.2.6.) This is accomplished for a given specimen mass loss by first
2 2
calculating the FED for the test. The LC is then calculated as that specimen mass loss which would yield a FED = 1 within a
chamber volume of 1 m .
NOTE 3—Although the theoretical value of the FED associated with 50 % lethality is 1.0, a median value of 1.1 has been found experimentally (3).
12.2 The 30-min FED for a given specimen mass loss is calculated from Eq 1:
m CO 21 2 O HCN
@ # @ # @ #
FED 5 1 1 (1)
@CO # 2 b 21 2 LC O LC HCN
2 50 2 50
@HCl# @HBr# m@CO# 21 2 @O #
1 1 5 1
LC HCl LC HBr CO 2 b 21 2 5.4 %
@ # ~ !
50 50 2
HCN HCl HBr
@ # @ # @ #
1 1 1
150 µL/L 3700 µL/L 3000 µL/L
where the values of all gas concentrations are the integrated Ct product values under their respective concentration-time curves
taken over the 30-min test period divided by 30. All of the values are in μL/L except O , which is in % by volume. The values
of m and b depend on the concentration of CO . If [CO ] ≤ 5 % by volume, m = −18 and b = 122 000. If [CO ] > 5 % by volume,
2 2 2
m = 23 and b = −38 600. For each individual toxicant, the LC values shown were determined statistically from independent
experimental data to produce lethality in 50 % of the test animals (rats) within a 30-min exposure plus 14-days postexposure.
12.3 The 30-min LC for a test specimen is calculated from Eq 2:
specimen mass loss
LC 5 (2)
FED 3chamber volume
3 −3
where the specimen mass loss is in g and the chamber volume is 0.2 m . The resulting LC has the units of g·m .
12.4 The yields of gases produced (mass of gas per mass of fuel consumed) at 25 °C are calculated from Eq 3:
@X#·8.2·MW
x
Y 5 (3)
x 6
10 m
@ #
where [X] is the concentration of gas X in μL/L, MW is its gram molecular weight, and m is the mass of sample consumed,
x 100
also in grams.
12.5 The lethal toxic potency value for hazard analysis of post-flashover fires is calculated from Eq 4:
LC ~post 2 flashover! 5 (4)
1 @CO#
23 25
144 310 2 5.0 310
LC m
50 100
−3
where: LC (g·m ) is the value determined from Eq 2, m is the mass (g) of specimen lost during the test at the FED=1
50 100
condition, and [CO] (μL/L) is the concentration of CO at the FED=1 condition. This equation is based on a post-flashover CO yield
of 0.2 g/g of fuel burned. (See Appendix X1.4.1.)
12.6 The post-flashover CO yield for the specific product under evaluation may also be obtained from an appropriate full-scale
−2 −3
test. A value of LC (post-flashover) is then determined by substituting 22 × 10 Y for 44 × 10 in Eq 4, resulting in Eq 5:
50 CO
LC ~post 2 flashover! 5 (5)
1 @CO#
10.22Y 2 5.0 310
CO
LC m
50 100
13. Report
13.1 Report the following information:
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13.1.1 Laboratory.
13.1.2 Test identification and date.
13.1.3 Laboratory ambient conditions (temperature and humidity).
13.1.4 Description of specimen, including how the test specimen was derived from the full-scale product and how the specimen
was configured in the specimen holder.
13.1.5 Specimen dimensions.
13.1.6 Irradiation time and heat flux conditions.
13.1.7 Maximum exposure chamber temperature and time when attained (see X1.2.5).
−3
13.1.8 Initial specimen mass and mass loss during the test in g·m of chamber volume (see X1.3.3).
13.1.9 Time to ignition and flame out.
13.1.10 Observations of Specimen—Required observations are times to smoke evolution, ignition, and flame out. Other
observations would include melting, char formation, spalling, unusually vigorous burning, and reignition.
13.1.11 Gas Analysis Data—Required exposure chamber data include integrated Ct product values over the 30-min test for CO,
O , HCN, HCl, and HBr; minimum O concentration and maximum CO concentration; and times to reach minimum O and
2 2 2 2
maximum CO . The methods used for analyses are to be identified.
13.1.12 Calculation:
13.1.12.1 Ct product for each analyzed toxicant in each test,
13.1.12.2 Yield of each analyzed toxicant in each test.
13.1.12.3 FED value for each test,
13.1.12.4 Predicted LC value for pre-flashover use, for each test, and
13.1.12.5 Best Overall Predicted LC Value to one significant figure—A least squares regression analysis of FED versus mass loss
values for all tests is used to determine the best overall predicted LC value.
13.1.12.6 Calculated value of LC (post-flashover) to one significant figure.
13.1.13 Optional plots are those of individual toxicant concentrations, specimen mass loss, and temperature as functions of time.
13.2 Include the following information in the report for each test using the exposure of animals:
13.2.1 Strain of rat and identity of supplier.
13.2.2 Weight of each animal when received, prior to test, and at 77-days and 14-days postexposure for surviving animals.
13.2.3 Number of animals dying during the test (including up to 10-min posttest) and number of animals that die up to 14 days
14 days posttest.
13.2.4 Blood carboxyhemoglobin saturation values for animals dying during the test.
13.2.5 Animal observations, for example, unusual behavior during the test; immediate posttest observations of live animals such
as tremors, convulsions, difficulty in breathing, severe eye irritation, etc.
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13.3 State in the report whether the animal tests did or did not confirm the value of the LC obtained from Eq 2.
14. Precision and Bias
14.1 Precision—The precision of this test method has not yet been established. A precision statement will be prepared and included
in the test method after the completion of an interlaboratory test series.
14.2 Bias—The bias of this test me
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