ASTM D3278-21

Standard Test Methods for Flash Point of Liquids by Small Scale Closed-Cup Apparatus

SIGNIFICANCE AND USE
5.1 Flash point measures the response of the test specimen to heat and ignition source under controlled laboratory conditions. It is only one of a number of properties that must be considered in assessing the overall flammability hazard of a material.  
5.2 Flash point is used in shipping and safety regulations by governmental regulatory agencies to define flammable and combustible materials and to classify them. Consult the particular regulation involved for precise definitions of these classes.  
5.3 Flash point can indicate the possible presence of highly volatile and flammable impurities or contaminants in a given liquid, such as the presence of residual solvents in solvent-refined drying oils.  
5.4 These equilibrium flash point test methods use a smaller specimen (2 mL) and a shorter test time (1 min) than traditional non-equilibrium test methods such as Test Method D56 and Test Methods D93.  
5.5 Test Methods D3828, Test Method D8174, and ISO 3679 are similar test methods and use the same apparatus.
SCOPE
1.1 These test methods cover procedures for determining whether a material does or does not flash at a specified temperature (flash/no flash Method A) or for determining the lowest finite temperature at which a material does flash (Method B), when using a small scale closed-cup apparatus. The test methods are applicable to paints, enamels, lacquers, varnishes, solvents, and related products having a flash point between 0 °C and 110 °C (32 °F and 230 °F) and viscosity lower than 15 000 mm2/s (cSt) at 25 °C (77 °F).
Note 1: Tests at higher or lower temperatures are possible however the precision has not been determined.
Note 2: More viscous materials can be tested in accordance with Annex A4.
Note 3: Organic peroxides can be tested in accordance with Annex A5, which describes the applicable safety precautions.
Note 4: The U.S. Department of Labor (OSHA, Hazard Communications), the U.S. Department of Transportation (RSPA), and the U.S. Environmental Protection Agency (EPA) have specified Test Methods D3278 as one of several acceptable methods for the determination of flash point of liquids in their regulations.  
1.2 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.  
1.3 This standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products, or assemblies under actual fire conditions.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 14-Jun-2021
• ICS: 13.220.40 - Ignitability and burning behaviour of materials and products
• ICS: 87.040 - Paints and varnishes
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.21 - Chemical Analysis of Paints and Paint Materials

Relations

• Refers: ASTM D6299-23a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Dec-2023
• Refers: ASTM D93-20 - Standard Test Methods for Flash Point by Pensky-Martens Closed Cup Tester
• Effective Date: 01-Aug-2020
• Refers: ASTM D8174-18 - Standard Test Method for Finite Flash Point Determination of Liquid Wastes by Small-Scale Closed Cup Tester
• Effective Date: 15-Mar-2018
• Refers: ASTM D6299-17b - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 15-Dec-2017
• Refers: ASTM D6299-17a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 15-Nov-2017
• Refers: ASTM D6299-17 - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Jan-2017
• Refers: ASTM D7236-16 - Standard Test Method for Flash Point by Small Scale Closed Cup Tester (Ramp Method)
• Effective Date: 01-Jun-2016
• Refers: ASTM D56-16 - Standard Test Method for Flash Point by Tag Closed Cup Tester
• Effective Date: 01-Jun-2016
• Refers: ASTM D3828-16 - Standard Test Methods for Flash Point by Small Scale Closed Cup Tester
• Effective Date: 01-Jun-2016
• Refers: ASTM D6299-13e1 - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Oct-2013
• Refers: ASTM D7236-07(2013) - Standard Test Method for Flash Point by Small Scale Closed Cup Tester (Ramp Method)
• Effective Date: 01-Oct-2013
• Refers: ASTM D93-13 - Standard Test Methods for Flash Point by Pensky-Martens Closed Cup Tester
• Effective Date: 15-Jul-2013
• Refers: ASTM D93-13e1 - Standard Test Methods for Flash Point by Pensky-Martens Closed Cup Tester
• Effective Date: 15-Jul-2013
• Refers: ASTM D93-12 - Standard Test Methods for Flash Point by Pensky-Martens Closed Cup Tester
• Effective Date: 01-Nov-2012
• Refers: ASTM D3828-12 - Standard Test Methods for Flash Point by Small Scale Closed Cup Tester
• Effective Date: 15-May-2012

Overview

ASTM D3278-21: Standard Test Methods for Flash Point of Liquids by Small Scale Closed-Cup Apparatus provides a robust, standardized procedure for determining the flash point of paints, enamels, lacquers, varnishes, solvents, and related liquid products. Developed by ASTM International, this standard is essential for industries working with flammable and combustible liquids, helping to assess the flammability hazard and ensure compliance with diverse regulatory requirements. ASTM D3278-21 applies to liquids with flash points between 0 °C and 110 °C (32 °F and 230 °F) and viscosities under 15,000 mm²/s at 25 °C (77 °F).

The standard consists of two core methods:

• Method A: Determines whether a flash occurs at a specified temperature (flash/no flash).
• Method B: Determines the lowest temperature at which a liquid will flash (finite flash point).

Key Topics

• Purpose of Flash Point Testing

  • Aids in classification of flammable and combustible liquids.
  • Identifies potential hazards during handling, storage, and transportation.
  • Detects highly volatile contaminants or impurities in liquids.

• Testing Approach

  • Utilizes a small-scale closed-cup apparatus with a 2 mL sample and 1-minute test time.
  • Offers faster and safer testing compared to traditional non-equilibrium methods.
  • Requires precise control of environmental factors such as temperature and barometric pressure.

• Regulatory Relevance

  • Recognized and referenced by OSHA (Hazard Communications), US EPA, and US Department of Transportation.
  • Used for compliance with shipping and safety regulations globally.

• Applicability

  • Suitable for paints, varnishes, solvents, and similar products.
  • Procedures for high-viscosity materials and organic peroxides are included via annexes.

• Safety Precautions

  • Emphasizes the need for careful handling of flammable samples and solvents.
  • Users are responsible for following health, safety, and environmental practices.

Applications

ASTM D3278-21 is widely used in multiple sectors where flammable liquid products are handled:

• Quality Control: Manufacturers of paints, coatings, varnishes, and solvents employ this standard to verify product safety and consistency.
• Regulatory Compliance: Meeting requirements from OSHA, EPA, and transportation authorities regarding the classification and labeling of hazardous materials.
• Shipment Classification: Used to determine whether products are classified as flammable or combustible under various national and international shipping regulations.
• Ingredient Screening: Detects unwanted volatile and flammable impurities, supporting product safety assessments.
• Research and Development: Laboratories use the standard to evaluate new formulations for safety and performance characteristics.

Related Standards

Several standards complement ASTM D3278-21 in flash point determination and related testing:

• ASTM D56: Flash Point by Tag Closed Cup Tester
• ASTM D93: Flash Point by Pensky-Martens Closed Cup Tester
• ASTM D3828: Flash Point by Small Scale Closed Cup Tester
• ASTM D8174: Finite Flash Point Determination of Liquid Wastes by Small-Scale Closed Cup Tester
• ISO 3679: Determination of flash point - Rapid equilibrium closed cup method
• ISO 3680: Flash/no flash test - Rapid equilibrium method
• References to regulatory guidelines: US Department of Transportation, OSHA, EPA

Summary

ASTM D3278-21 provides essential, internationally recognized flash point test methods designed to enhance safety, quality, and regulatory compliance for liquid products. With its clear protocols, it supports manufacturers, regulators, and logistics professionals in making informed decisions around the handling, storage, and transport of flammable and combustible liquids. For industries working with paints, coatings, and solvents, leveraging ASTM D3278-21 is critical for hazard assessment and product compliance.

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: D3278 − 21
Standard Test Methods for
Flash Point of Liquids by Small Scale Closed-Cup
Apparatus
This standard is issued under the fixed designation D3278; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
INTRODUCTION
These small scale flash point methods test a sample at a specific temperature, where the specimen
being tested and the air-vapor mixture above it are close to thermal equilibrium.
Flash point values are a function of the apparatus design, the condition of the apparatus used, and
the operational procedure carried out. Flash point can therefore only be defined in terms of a standard
test method, and no general valid correlation can be guaranteed between results obtained by different
test methods, or with test apparatus different from that specified.
1. Scope under controlled conditions, but does not by itself incorporate
all factors required for fire hazard or fire risk assessment of the
1.1 These test methods cover procedures for determining
materials, products, or assemblies under actual fire conditions.
whether a material does or does not flash at a specified
1.4 This standard does not purport to address all of the
temperature (flash/no flash Method A) or for determining the
safety concerns, if any, associated with its use. It is the
lowest finite temperature at which a material does flash
responsibility of the user of this standard to establish appro-
(Method B), when using a small scale closed-cup apparatus.
priate safety, health, and environmental practices and deter-
The test methods are applicable to paints, enamels, lacquers,
mine the applicability of regulatory limitations prior to use.
varnishes, solvents, and related products having a flash point
1.5 This international standard was developed in accor-
between 0 °C and 110 °C (32 °F and 230 °F) and viscosity
dance with internationally recognized principles on standard-
lower than 15 000 mm /s (cSt) at 25 °C (77 °F).
ization established in the Decision on Principles for the
NOTE1—Testsathigherorlowertemperaturesarepossiblehoweverthe
Development of International Standards, Guides and Recom-
precision has not been determined.
mendations issued by the World Trade Organization Technical
NOTE 2—More viscous materials can be tested in accordance with
Annex A4. Barriers to Trade (TBT) Committee.
NOTE 3—Organic peroxides can be tested in accordance with Annex
A5, which describes the applicable safety precautions.
2. Referenced Documents
NOTE 4—The U.S. Department of Labor (OSHA, Hazard
2.1 ASTM Standards:
Communications),theU.S.DepartmentofTransportation(RSPA),andthe
U.S. Environmental Protection Agency (EPA) have specified Test Meth-
D56 Test Method for Flash Point by Tag Closed Cup Tester
ods D3278 as one of several acceptable methods for the determination of
D93 Test Methods for Flash Point by Pensky-Martens
flash point of liquids in their regulations.
Closed Cup Tester
1.2 The values stated in SI units are to be regarded as
D3828 Test Methods for Flash Point by Small Scale Closed
standard. The values given in parentheses after SI units are
Cup Tester
provided for information only and are not considered standard.
D3925 Practice for Sampling Liquid Paints and Related
Pigmented Coatings
1.3 This standard is used to measure and describe the
D6299 Practice for Applying Statistical Quality Assurance
responseofmaterials,products,orassembliestoheatandflame
and Control Charting Techniques to Evaluate Analytical
Measurement System Performance
These test methods are under the jurisdiction of ASTM Committee D01 on
Paint and Related Coatings, Materials, and Applications and are the direct
responsibility of Subcommittee D01.21 on Chemical Analysis of Paints and Paint
Materials. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved June 15, 2021. Published August 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1973. Last previous edition approved in 2020 as D3278 – 20. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D3278-21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3278 − 21
D7236 Test Method for Flash Point by Small Scale Closed flash occurred previously. A fresh test specimen is introduced
Cup Tester (Ramp Method) and tested. This procedure is repeated until the flash point is
D8174 Test Method for Finite Flash Point Determination of established within 5 °C.
Liquid Wastes by Small-Scale Closed Cup Tester 4.2.3 Theprocedureisthenrepeatedat0.5 °Cintervalsuntil
E1137/E1137M Specification for Industrial Platinum Resis- the flash point is determined to the nearest 0.5 °C.
tance Thermometers 4.2.4 A second determination is made in accordance with
2.2 ISO Standards: 4.2.3andtheaverageofthetwodeterminationsrecordedasthe
ISO 1513 Paints and varnishes — Examination and prepa- flash point.
ration of test samples for testing
5. Significance and Use
ISO 3679 Determination of flash no-flash and flash point—
Rapid equilibrium closed cup method 5.1 Flash point measures the response of the test specimen
ISO15528 Paints,varnishesandrawmaterialsforpaintsand to heat and ignition source under controlled laboratory condi-
varnishes — Sampling tions. It is only one of a number of properties that must be
ISO 17034 General requirements for the competence of considered in assessing the overall flammability hazard of a
reference material producers material.
ISO 17043 Conformity assessment – General requirements
5.2 Flash point is used in shipping and safety regulations by
for proficiency testing
governmental regulatory agencies to define flammable and
ISO 60751 Industrial platinum resistance thermometers and
combustible materials and to classify them. Consult the par-
platinum temperature sensors
ticular regulation involved for precise definitions of these
Guide 35 Certification of Reference Materials—General and
classes.
Statistical Principles
5.3 Flash point can indicate the possible presence of highly
3. Terminology
volatile and flammable impurities or contaminants in a given
liquid, such as the presence of residual solvents in solvent-
3.1 Definitions:
refined drying oils.
3.1.1 equilibrium, n—in flash point test methods, the condi-
tion where the vapor above the test specimen, and the test 5.4 These equilibrium flash point test methods use a smaller
specimen are at the same temperature at the time the ignition
specimen(2 mL)andashortertesttime(1 min)thantraditional
source is applied. non-equilibrium test methods such as Test Method D56 and
3.1.1.1 Discussion—This condition may not be fully
Test Methods D93.
achieved in practice, since the temperature may not be uniform
5.5 Test Methods D3828, Test Method D8174, and ISO
throughout the test specimen, and the test cover and shutter on
3679 are similar test methods and use the same apparatus.
the apparatus can be cooler or warmer.
6. Apparatus
3.1.2 flash point, n—in flash point test methods, the lowest
temperature of the test specimen, adjusted to account for
6.1 Test Cup and Cover Assembly:
variations in atmospheric pressure from 101.3 kPa, at which
6.1.1 The essential dimensions and requirements of the
application of an ignition source causes the vapors of the test
apparatus are shown in Fig. A1.1 and described in Annex A1.
specimen to ignite under specified conditions of test.
6.1.2 The temperature range is from 0 °C to 110 °C.
6.1.2.1 Versions of the apparatus can cover a wider tem-
4. Summary of Test Methods
perature range.
4.1 Method A—Flash/No Flash Test—A2 mLtest specimen
6.1.3 Some apparatuses can automate temperature control
is introduced, by a syringe (6.5), into the test cup of the
downtosub-ambienttemperatures,timinganddipping,includ-
selected apparatus that is set and maintained at the specified
inghotwireignition,automaticallydetectingavalidflashpoint
testtemperature.Afteroneminute,anignitionsourceisapplied
and measuring barometric pressure.
andadeterminationmadeastowhetherornotaflashoccurred.
6.2 Barometer, accurate to 0.5 kPa. Barometers that have
4.2 Method B—Finite (or Actual) Flash Point—This
been pre-corrected for use at weather stations or airports are
methodessentiallyrepeatsMethodAanumberoftimes,andby
not suitable.
changing the test temperature and test specimen a number of
6.3 Draft Shield—A shield located at the back and on two
times, determines the flash point iteratively.
sides of the instrument, for use in circumstances where
4.2.1 A2 mLtest specimen is introduced into the test cup of
protection from drafts does not exist.
the selected apparatus that is maintained at the expected flash
6.4 Syringe (optional)—General purpose for use with very
point. After one minute, an ignition source is applied and a
viscous samples, to dispense 2 mL to 4 mL specimens (see
determination made whether or not a flash occurred.
Annex A4).
4.2.2 The test specimen is removed from the test cup; the
test cup and cover are cleaned, and the test temperature
6.5 Glass Syringe, 2mL 6 0.1 mL capacity at 25 °C
adjusted 5 °C lower or higher depending on whether or not a
(77 °F), to provide a means of taking a uniform specimen.
Check the capacity by discharging water into a weighing bottle
and weighing. Adjust plunger if necessary. A disposable
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. syringe of equal precision may be used.
D3278 − 21
7. Reagents and Materials tests made in a laboratory draft hood unless the extracted air
and vapors can be withdrawn without causing air currents over
7.1 Cleaning Solvent—Use only non-corrosive solvents ca-
the test cup during the ignition source application period.
pableofcleaningthetestcupandlidassembly.Twocommonly
used solvents are toluene and acetone. (Warning—Toluene,
9.2 Read the manufacturer’s instructions on the care and
acetone, and many other solvents are flammable and a health
servicing of the instrument and for the correct operation of any
hazard. Dispose of solvents and waste material in accordance
controls.
with local regulations.)
9.3 Prepare the apparatus for operation in accordance with
7.2 Butane, Propane, and Natural Gas—Optional for use as
the manufacturers’ instructions for calibrating, checking and
a pilot and ignition source. (Warning—Butane, propane, and
operating the equipment, especially the operation of the igni-
natural gases are flammable and a health hazard.)
tion source. (Warning—An incorrectly set test flame size or
7.3 Verification Fluids—See Annex A2.
setting of an electric ignitor can significantly affect the test
result.)
8. Sampling
9.4 Clean the test cup, cover, and its accessories with an
8.1 Obtain at least a 25 mL sample from a bulk test site in
appropriate solvent (7.1) to remove any traces of gum or
accordance with Practice D3925, ISO 1513, or ISO 15528, or
residue from the previous test. See Appendix X1 for detailed
a comparable sampling practice.
cleaning instructions.
8.2 Store samples in clean, tightly sealed containers, suit-
9.5 Measure and record the barometric pressure (6.2) before
able for the type of liquid being sampled, at normal room
commencing a test.
temperature (for example 20 °C to 25 °C (68 °F to 77 °F)) or
colder.
9.6 An optional electronic thermal flash detector may be
8.3 Do not store samples for an extended period of time in
used for all product types. It is essential where the ignition of
gas permeable containers, such as those made of plastic,
the vapors of the test specimen is not visible or when the
because volatile material can diffuse through the walls of the
apparatus is automated.
container. Samples in leaky containers are suspect and not a
9.7 For sub-ambient test temperatures see AnnexA3, unless
source of valid results.
the apparatus has integral test cup cooling facilities.
8.4 Erroneously high flash points can be obtained when
precautionsarenottakentoavoidlossofvolatilematerials.Do
10. Verification of Apparatus
not open containers unnecessarily. Do not make a transfer
10.1 Verify that the temperature measuring device is in
unless the sample temperature is at least 10 °C below the
accordance with A1.2.2 and Annex A6.
expectedflashpoint.Wherepossible,performtheflashpointas
the first test on the sample.
10.2 Verify the performance of the apparatus at least once
8.5 Decant any free water in the sample container.
per year by determining the flash point of a certified reference
material(CRM):suitablematerialsarelistedinAnnexA2.Use
8.6 Cool or adjust the temperature of the sample and its
a CRM that is reasonably close to the expected temperature
container to at least 10 °C below the expected flash point
range of the samples to be tested. The material shall be tested
beforeopeningtoremovethetestspecimen.Ifanaliquotofthe
accordingtoMethodB,Section12,andthedetectedflashpoint
original sample is to be stored prior to testing, ensure that the
obtained in 12.1.11 and 12.1.12 shall be corrected for baro-
container is filled to between 85 % and 95 % of its capacity.
metric pressure (see Section 13). The mean of the two
8.7 If sufficiently fluid, mix samples by gently shaking by
determined flash points shall be within the limits stated in
hand prior to removal of the test specimen, taking care to
Table A2.1 for the identified CRM or within the limits
minimize the loss of volatile components. If the sample is too
calculated for an unlisted CRM (see A2.1.1).
viscous at ambient temperature, gently warm the sample in its
container to a temperature not warmer than 10 °C below the 10.3 Once the performance of the apparatus has been
test temperature, such that the sample can be mixed by gentle verified, the flash point of secondary working standards (SWS)
shaking. can then be utilized for more frequent performance checks (see
Annex A2).
NOTE 5—Results of flash point tests can be affected if the sample
volume falls below 50 % of the container’s capacity.
10.4 When the flash point obtained is not within the limits
8.8 If the sample is highly viscous and not sufficiently fluid
stated in 10.2 or 10.3, check the condition and operation of the
to be drawn into the 2 mL syringe and be introduced into the apparatus to ensure conformity with the details listed in Annex
test cup through the filler orifice, follow the procedure given in
A1, especially with regard to tightness of the cover (A1.2.1),
Annex A4. the action of the shutter, the size or intensity of the ignition
source, the position of the ignition source (A1.3), the operation
9. Preparation of Apparatus
of the flash detector (if fitted), and correct reading of the
9.1 Place the apparatus on a level, stable surface. Unless temperaturemeasuringdevice.Afteranyadjustment,repeatthe
tests are made in a draft-free area, surround the tester on three test in 10.2 or 10.3 using a fresh test specimen, with special
sides with a draft shield (see 6.3) for protection. Do not rely on attentiontotheproceduraldetailsprescribedinthetestmethod.
D3278 − 21
TEST METHOD A—FLASH/NO FLASH didnotresultinaflashwhilethehighertemperatureresultedin
a flash (the flash point).
12.1.1 Select the expected flash point of the sample as the
11. Procedure
initial test temperature.
11.1 Forspecificationpurposescarryoutaflash/noflashtest
12.1.1.1 If the expected flash point of the sample is
at a temperature (actual) that allows for a correction due to the
unknown, Appendix X2 may be used to obtain an approximate
ambient atmospheric pressure at the time of the test. Use the
flash point.
following equations to convert a specification flash point test
12.1.2 Follow the manufacturer’s instructions to set the test
requirement to the actual test temperature required for the test
temperature and the one minute test time.
and then round to the nearest 0.5 °C.
12.1.3 When the test cup is at the test temperature, fill the
o
Actual test temperature~ C! 5 S 2 0.25~101.3 2 A! (1)
c
syringe (6.5) with the sample to be tested; transfer the syringe
o
Actual test temperature~ C! 5 S 2 0.033~760 2 B! (2)
to the filling orifice, taking care not to lose any sample;
c
discharge the 2 mL test specimen into the test cup by fully
where:
depressing the syringe plunger; remove the syringe.
S = Specification, or uncorrected target test temperature,
c
12.1.3.1 If the sample is too viscous to be syringed through
°C,
the orifice, see Annex A4.
A = Ambient barometric pressure, kPa, and
12.1.4 Start the 60 s test timer; light the pilot light and
B = Ambient barometric pressure, mm Hg.
adjust the test flame (if used) to conform to the 4 mm ( ⁄32 in.)
Warning—Eq 1 and Eq 2 are only to be used when testing
gauge.
at a prescribed specification or target temperature is required.
12.1.5 When the end of the test time is indicated, apply the
11.1.1 Follow the manufacturer’s instructions to set the test
ignition source by slowly and uniformly opening the shutter
temperature and the test time.
and closing it completely over a period of 2 s to 3 s. Watch
11.1.2 When the test cup is at the test temperature, fill the
closely for a flash at the test cup openings.
syringe (6.5) with the sample to be tested; transfer the syringe
12.1.6 The test specimen is deemed to have flashed when a
to the filling orifice, taking care not to lose any sample;
large flame appears and instantaneously propagates itself over
discharge the 2 mL test specimen into the test cup by fully
the surface of the test specimen (see 3.1.2). Occasionally,
depressing the syringe plunger; remove the syringe.
particularly near the actual flash point, application of the
11.1.2.1 If the sample is too viscous to be syringed through
ignition source can cause a blue halo or an enlarged flame; this
the orifice, see Annex A4.
is not a flash and should be ignored.
11.1.3 Startthe60 stesttimer;lightthepilotlightandadjust
12.1.7 Note the test result as flash (or no flash) and the test
the test flame (if used) to conform to the 4 mm ( ⁄32 in.) gauge.
temperature.
11.1.4 When the end of the test time is indicated, apply the
12.1.8 If a flash is detected, repeat the procedure given in
ignition source by slowly and uniformly opening the shutter
12.1.3 to 12.1.7 testing a fresh specimen at a temperature 5 °C
and closing it completely over a period of 2 s to 3 s. Watch
lower each time until no flash is detected.
closely for a flash at the test cup openings.
12.1.8.1 Proceed to 12.1.10.
11.1.5 The test specimen is deemed to have flashed when a
12.1.9 When no flash was detected, repeat the procedure
large flame appears and instantaneously propagates itself over
given in 12.1.3 to 12.1.7 testing a fresh specimen at a
the surface of the test specimen (see 3.1.2). Occasionally,
temperature 5 °C higher each time until a flash is detected.
particularly near the actual flash point, application of the
12.1.10 Having established a flash within two temperatures
ignition source can cause a blue halo or an enlarged flame; this
5 °C apart, repeat the procedure testing a fresh specimen at
is not a flash and should be ignored.
0.5 °C intervals from the lower of the two temperatures until a
11.1.6 Record the test result as flash (or no flash), allowing
flash is detected.
for any known thermometer correction and the test tempera-
12.1.11 Record the temperature of the test when this de-
ture.
tected flash point occurs, allowing for any known thermometer
11.1.7 Turn off the pilot and test flames (if used). Remove
correction.
the test specimen and clean the test cup and cover (see
12.1.12 Repeat 12.1.10 and 12.1.11 to obtain and record a
Appendix X1). It may be necessary to allow the test cup
second detected flash point for the sample.
temperature to fall to a safe level before cleaning.
12.1.13 Turn off the pilot and test flames, if used. When the
cup temperature falls to a safe level, remove the test specimen
and clean the cup and cover (see Appendix X1).
TEST METHOD B—FINITE FLASH POINT
DETERMINATION
13. Calculations
12. Procedure
13.1 Method A—No further calculations are required if the
12.1 This procedure repeats the procedure of Method A a effects of barometric pressure were corrected for in Eq 1 or Eq
2 in 11.1.
number of times. Each test uses a fresh test specimen and a
different temperature. The changes of temperature allow the 13.1.1 If the effects of barometric pressure were not cor-
determination of two temperatures 5 °C apart and then two rected before the flash/no flash test, Eq 3 or Eq 4 shall be used
temperatures0.5 °Capartforwhichthefinallowertemperature to calculate the corrected test temperature.
D3278 − 21
o
Corrected test temperature C 5 C10.25 101.3 2 A (3) determinations on two different days on four solvents, three
~ ! ~ !
o resins, and
...

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: D3278 − 20 D3278 − 21
Standard Test Methods for
Flash Point of Liquids by Small Scale Closed-Cup
Apparatus
This standard is issued under the fixed designation D3278; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
INTRODUCTION
These small scale flash point methods test a sample at a specific temperature, where the specimen
being tested and the air-vapor mixture above it are close to thermal equilibrium.
Flash point values are a function of the apparatus design, the condition of the apparatus used, and
the operational procedure carried out. Flash point can therefore only be defined in terms of a standard
test method, and no general valid correlation can be guaranteed between results obtained by different
test methods, or with test apparatus different from that specified.
1. Scope
1.1 These test methods cover procedures for determining whether a material does or does not flash at a specified temperature
(flash/no flash Method A) or for determining the lowest finite temperature at which a material does flash (Method B), when using
a small scale closed-cup apparatus. The test methods are applicable to paints, enamels, lacquers, varnishes, solvents, and related
products having a flash point between 00 °C and 110°C (32110 °C (32 °F and 230°F)230 °F) and viscosity lower than 150 St15 000
mm at 25°C (77°F). /s (cSt) at 25 °C (77 °F).
NOTE 1—Tests at higher or lower temperatures are possible.possible however the precision has not been determined.
NOTE 2—More viscous materials can be tested in accordance with Annex A4.
NOTE 3—Organic peroxides can be tested in accordance with Annex A5, which describes the applicable safety precautions.
NOTE 4—The U.S. Department of Labor (OSHA, Hazard Communications), the U.S. Department of Transportation (RSPA), and the U.S. Environmental
Protection Agency (EPA) have specified Test Methods D3278 as one of several acceptable methods for the determination of flash point of liquids in their
regulations.
NOTE 2—More viscous materials may be tested in accordance with Annex A4.
NOTE 3—Organic peroxides may be tested in accordance with Annex A5, which describes the applicable safety precautions.
NOTE 4—The U.S. Department of Labor (OSHA, Hazard Communications), the U.S. Department of Transportation (RSPA), and the U.S. Environmental
Protection Agency (EPA) have specified Test Methods D3278 as one of several acceptable methods for the determination of flash point of liquids in their
regulations.
These test methods are under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and are the direct responsibility of
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.
Current edition approved June 1, 2020June 15, 2021. Published June 2020August 2021. Originally approved in 1973. Last previous edition approved in 20112020 as
D3278 – 96 (2011)D3278 – 20. which was withdrawn January 2020 and reinstated in June 2020. DOI: 10.1520/D3278-20.DOI: 10.1520/D3278-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3278 − 21
NOTE 5—These test methods are similar to International Standards ISO 3679 and ISO 3680.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.after
SI units are provided for information only and are not considered standard.
1.3 This standard should be used to measure and describe the response of materials, products, or assemblies to heat and flame
under controlled conditions and should not be used to describe or appraise the fire-hazard or fire-risk of materials, products, or
assemblies under actual fire conditions. However, results of the test may be used as elements of a fire-hazard or a fire-risk
assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard or fire risk of a
particular end use. This standard is used to measure and describe the response of materials, products, or assemblies to heat and
flame under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of
the materials, products, or assemblies under actual fire conditions.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.For specific hazard statements, see 8.1 and 11.2.
1.5 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:
D56 Test Method for Flash Point by Tag Closed Cup Tester
D93 Test Methods for Flash Point by Pensky-Martens Closed Cup Tester
D850D3828 Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related MaterialsMethods for Flash Point by
Small Scale Closed Cup Tester
D3925 Practice for Sampling Liquid Paints and Related Pigmented Coatings
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D1015D7236 Test Method for Freezing Points of High-Purity HydrocarbonsFlash Point by Small Scale Closed Cup Tester
(Ramp Method) (Withdrawn 2019)
D1078D8174 Test Method for Distillation Range of Volatile Organic LiquidsFinite Flash Point Determination of Liquid Wastes
by Small-Scale Closed Cup Tester
E1137/E1137M Specification for Industrial Platinum Resistance Thermometers
2.2 ISO Standards:
ISO 1513 Paints and varnishes — Examination and preparation of test samples for testing
ISO 3679 Paints, varnishes, petroleum and related products—Determination of flash point—Rapid equilibrium Determination
of flash no-flash and flash point—Rapid equilibrium closed cup method
ISO 368015528 Paints, varnishes, petroleum and related products—Flash/no flash test—Rapid equilibrium methodvarnishes and
raw materials for paints and varnishes — Sampling
ISO 17034 General requirements for the competence of reference material producers
ISO 17043 Conformity assessment – General requirements for proficiency testing
ISO 60751 Industrial platinum resistance thermometers and platinum temperature sensors
Guide 35 Certification of Reference Materials—General and Statistical Principles
3. Terminology
3.1 Definitions:
3.1.1 equilibrium, n—in flash point test methods, the condition where the vapor above the test specimen, and the test specimen
are at the same temperature at the time the ignition source is applied.
3.1.1.1 Discussion—
This condition may not be fully achieved in practice, since the temperature may not be uniform throughout the test specimen, and
the test cover and shutter on the apparatus can be cooler or warmer.
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.
D3278 − 21
3.1.2 flash point, n—in flash point test methods, the lowest temperature, corrected to a pressure of 760 mm Hg (101.3 kPa, 1013
mbar), temperature of the test specimen, adjusted to account for variations in atmospheric pressure from 101.3 kPa, at which
application of an ignition source causes the vaporvapors of the test specimen to ignite under specified conditions of test.
4. Summary of Test Methods
4.1 Method A—Flash/No Flash Test—By means of a syringe, 2 mL of the sample is introduced through a leakproof entryA 2 mL
test specimen is introduced, by a syringe (6.5 port ), into the tightly closed small scale closed-cuptest cup of the selected apparatus
or directly into the cup that has been brought to the required test temperature. As a flash/no flash test, the expected flash point
temperature may be a specification or other operating requirement. After 1 min, a test flame is applied inside the cup and note is
taken that is set and maintained at the specified test temperature. After one minute, an ignition source is applied and a determination
made as to whether or not the test specimen flashes. A fresh specimen must be used if a repeat test is necessary.a flash occurred.
4.2 Method B—Finite (or Actual) Flash Point—For a finite flash point measurement, the temperature is sequentially increased
through the anticipated range, the test flame being applied at 5°C (9°F) intervals until a flash is observed. A true determination is
then made using a fresh specimen, starting the test at the temperature of the last interval before the flash point of the material and
making tests at increasing 0.5°C (1°F) intervals.This method essentially repeats Method A a number of times, and by changing the
test temperature and test specimen a number of times, determines the flash point iteratively.
4.2.1 A 2 mL test specimen is introduced into the test cup of the selected apparatus that is maintained at the expected flash point.
After one minute, an ignition source is applied and a determination made whether or not a flash occurred.
4.2.2 The test specimen is removed from the test cup; the test cup and cover are cleaned, and the test temperature adjusted 5 °C
lower or higher depending on whether or not a flash occurred previously. A fresh test specimen is introduced and tested. This
procedure is repeated until the flash point is established within 5 °C.
4.2.3 The procedure is then repeated at 0.5 °C intervals until the flash point is determined to the nearest 0.5 °C.
4.2.4 A second determination is made in accordance with 4.2.3 and the average of the two determinations recorded as the flash
point.
5. Significance and Use
5.1 Flash point measures the response of the test specimen to heat and ignition source under controlled laboratory conditions. It
is only one of a number of properties that must be considered in assessing the overall flammability hazard of a material.
5.2 Flash point is used in shipping and safety regulations by governmental regulatory agencies to define flammable and
combustible materials and to classify them. Consult the particular regulation involved for precise definitions of these classes.
5.3 Flash point is one of the properties used to define the flammability of a liquid. It is used to classify liquids according to their
flammability by governmental regulatory agencies. It may also be used to determine the presence of can indicate the possible
presence of highly volatile and flammable impurities or contaminants in a given liquid, such as the presence of residual solvents
in solvent-refined drying oils. See Test Methods D56 and D93 for alternate flash point testing.
5.4 These equilibrium flash point test methods use a smaller specimen (2 mL) and a shorter test time (1 min) than traditional
non-equilibrium test methods such as Test Method D56 and Test Methods D93.
5.5 Test Methods D3828, Test Method D8174, and ISO 3679 are similar test methods and use the same apparatus.
6. Apparatus
6.1 Test Cup and Cover AssemblyAssembly: —
6.1.1 The essential dimensions and requirements of the apparatus are shown in Fig. A1.1 and described in Annex A1.
6.1.2 The temperature range is from 0 °C to 110 °C.
D3278 − 21
6.1.2.1 Versions of the apparatus can cover a wider temperature range.
6.1.3 Some apparatuses can automate temperature control down to sub-ambient temperatures, timing and dipping, including hot
wire ignition, automatically detecting a valid flash point and measuring barometric pressure.
6.2 Thermometers,Barometer, low, medium, high temperature small scale. Test to determine that the scale error does not exceed
0.25°C (0.5°F). The use of a magnifying lens assists in making temperature observations.accurate to 0.5 kPa. Barometers that have
been pre-corrected for use at weather stations or airports are not suitable.
6.3 Draft Shield—A shield located at the back and on two sides of the instrument, for use in circumstances where protection from
drafts does not exist.
6.4 Syringe (optional)—General purpose for use with very viscous samples, to dispense 2 mL to 4 mL specimens (see Annex A4).
6.5 Glass Syringe, 22 mL 6 0.1-mL0.1 mL capacity at 25°C (77°F),25 °C (77 °F), to provide a means of taking a uniform
specimen. Check the capacity by discharging water into a weighing bottle and weighing. Adjust plunger if necessary. A disposable
syringe of equal precision may be used.
6.4 Aluminum Cooling Block (describing in Annex A2), that fits snugly within the test cup used for rapid cooling of the sample
cup.
6.5 Barometer.
7. Reagents and Materials
7.1 p-Xylene,Cleaning Solvent—reference standard.Use only non-corrosive solvents capable of cleaning the test cup and lid
assembly. Two commonly used solvents are toluene and acetone. (Warning—Toluene, acetone, and many other solvents are
flammable and a health hazard. Dispose of solvents and waste material in accordance with local regulations.)
7.2 n-Butanol, reference standard.
7.2 Cooling Mixture Butane, Propane, and Natural Gas—of ice and water or solidOptional for use as a pilot and ignition source.
(Warning— COButane, propane, (dry ice) and acetone.and natural gases are flammable and a health hazard.)
7.3 Liquified Petroleum Gas. Verification Fluids—See Annex A2.
7.5 Heat Transfer Paste.
8. Sampling
8.1 Obtain at least a 25 mL sample from a bulk test site in accordance with Practice D3925, ISO 1513, or ISO 15528, or a
comparable sampling practice.
8.2 Store samples in clean, tightly sealed containers, suitable for the type of liquid being sampled, at normal room temperature
(for example 20 °C to 25 °C (68 °F to 77 °F)) or colder.
8.3 Do not store samples for an extended period of time in gas permeable containers, such as those made of plastic, because
volatile material can diffuse through the walls of the container. Samples in leaky containers are suspect and not a source of valid
results.
8.4 The specimen size for each test is 2 mL. Obtain at least a 25-mL sample from the bulk source and store in a nearly full, tightly
closed, clean glass container or in other container suitable for the type of liquid being sampled. (Erroneously high flash points can
be obtained when precautions are not taken to avoid loss of volatile materials. Do not open containers unnecessarily. Do not make
D3278 − 21
a transfer unless the sample temperature is at least 10 °C below the expected flash point. Where possible, perform the flash point
as the first testWarning—Erroneously high flash points may be obtained if precautions are not taken to avoid loss of volatile
material. Do not open sample containers unnecessarily and do not transfer the specimen to the cup unless the temperature of the
specimen is at least 10°C (20°F) below the expected flash point. Discard samples in leaky containers.) ( onWarning—Do not store
samples in plastic bottles (polyethylene, polypropylene, etc.), as volatile material may diffuse through the walls.) the sample.
8.5 Decant any free water in the sample container.
8.6 Cool or adjust the temperature of the sample and its container to at least 10 °C below the expected flash point before opening
to remove the test specimen. If an aliquot of the original sample is to be stored prior to testing, ensure that the container is filled
to between 85 % and 95 % of its capacity.
8.7 If sufficiently fluid, mix samples by gently shaking by hand prior to removal of the test specimen, taking care to minimize the
loss of volatile components. If the sample is too viscous at ambient temperature, gently warm the sample in its container to a
temperature not warmer than 10 °C below the test temperature, such that the sample can be mixed by gentle shaking.
NOTE 5—Results of flash point tests can be affected if the sample volume falls below 50 % of the container’s capacity.
8.8 If the sample is highly viscous and not sufficiently fluid to be drawn into the 2 mL syringe and be introduced into the test cup
through the filler orifice, follow the procedure given in Annex A4.
9. Preparation of Apparatus
9.1 Prior to initial use or after removal of the thermometer, insert the thermometer into its pocket (see Place the apparatus on a
level, stable surface. Unless tests are made in a draft-free area, surround the tester on three sides Fig. A1.1) with a good heat
transferdraft shield (see 6.3paste.) for protection. Do not rely on tests made in a laboratory draft hood unless the extracted air and
vapors can be withdrawn without causing air currents over the test cup during the ignition source application period.
9.2 To help in making the necessary settings during a test, before the initial use determine the relationship between the temperature
control dial and thermometer readings at intervals not over 5°C (9°F) throughout the scale range of the heater.
9.3 Place the tester in a subdued light and in a position not exposed to disturbing drafts. Provide a black-coated shield, if necessary.
9.2 Read the manufacturer’s operating and maintenance instructions on the care and servicing of the tester. Observe the specific
suggestions regarding the operation of the various controls.instrument and for the correct operation of any controls.
9.3 Prepare the apparatus for operation in accordance with the manufacturers’ instructions for calibrating, checking and operating
the equipment, especially the operation of the ignition source. (Warning—An incorrectly set test flame size or setting of an electric
ignitor can significantly affect the test result.)
9.4 Clean the test cup, cover, and its accessories with an appropriate solvent (7.1) to remove any traces of gum or residue from
the previous test. See Appendix X1 for detailed cleaning instructions.
9.5 Measure and record the barometric pressure (6.2) before commencing a test.
9.6 An optional electronic thermal flash detector may be used for all product types. It is essential where the ignition of the vapors
of the test specimen is not visible or when the apparatus is automated.
9.7 Check the accuracy of the tester by duplicate determination of the flash point of the For sub-ambient test temperatures see
p-xylene reference standard (Annex A3). The mean of the results should be 27.2 6 0.8°C (81 6 1.5°F). An additional reference
standard, , unless the apparatus has integral test n-butanol (Annex A3), may be used to check the accuracy at approximately the
temperature specified by U.S. regulatory agencies in defining flammable liquids. The mean of duplicates should be 36.7 6 0.8°C
(98 6 1.5°F). If not, remove the thermometer and observe whether sufficient heat transfer paste surrounds the thermometer to
provide good heat transfer from the cup to the thermometer.cup cooling facilities.
D3278 − 21
10. Verification of Apparatus
10.1 Verify that the temperature measuring device is in accordance with A1.2.2 and Annex A6.
10.2 Verify the performance of the apparatus at least once per year by determining the flash point of a certified reference material
(CRM): suitable materials are listed in Annex A2. Use a CRM that is reasonably close to the expected temperature range of the
samples to be tested. The material shall be tested according to Method B, Section 12, and the detected flash point obtained in
12.1.11 and 12.1.12 shall be corrected for barometric pressure (see Section 13). The mean of the two determined flash points shall
be within the limits stated in Table A2.1 for the identified CRM or within the limits calculated for an unlisted CRM (see A2.1.1).
10.3 Once the performance of the apparatus has been verified, the flash point of secondary working standards (SWS) can then be
utilized for more frequent performance checks (see Annex A2).
10.4 When the flash point obtained is not within the limits stated in 10.2 or 10.3, check the condition and operation of the
apparatus to ensure conformity with the details listed in Annex A1, especially with regard to tightness of the cover (A1.2.1), the
action of the shutter, the size or intensity of the ignition source, the position of the ignition source (A1.3), the operation of the flash
detector (if fitted), and correct reading of the temperature measuring device. After any adjustment, repeat the test in 10.2 or 10.3
using a fresh test specimen, with special attention to the procedural details prescribed in the test method.
TEST METHOD A—FLASH/NO FLASH
10. Procedure—Ambient to 110°C (230°F)
10.1 Inspect the inside of the test cup, lid, and shutter mechanism for cleanliness and freedom from contamination. Use an
absorbent tissue to wipe clean, if necessary. Lock the cover lid tightly in place.
10.2 Switch the heater on, if not already at stand-by. To rapidly approach the specification flash temperature of the material under
test, turn the heater dial fully clockwise (Note 6) causing the heater signal (red) light to glow. When the thermometer indicates a
temperature of about 3°C (5°F) below the specification or target flash-point temperature, reduce the heat input to the test cup by
slowly turning the heater control dial counter clockwise until the signal light goes out (Note 7).
NOTE 6—When a desired temperature is dialed on the controller, the elapsed time to reach this temperature may be greater than if the controller is turned“
full on,” but less attention is required.
NOTE 7—The test cup temperature is stable when the signal light slowly cycles on and off.
10.3 Determine the barometric pressure to determine the corrected specification temperature at that barometric pressure (see 15.1).
10.4 After the test-cup temperature has stabilized at the specification or target flash point, charge the syringe with the sample being
tested and insert the tip of the syringe into the filling orifice (Fig. A1.1), taking care not to lose any material. Discharge the
specimen into the test cup by completely depressing the syringe plunger, then remove the syringe. If the material has a viscosity
greater than 45 SUS at 38°C (100°F) or equivalent of 9.5 cSt at 25°C (77°F), raise the lid and discharge the contents of the syringe
directly into the cup. Immediately close the lid tightly.
10.5 Set the 1-min timing device. In the meantime, open the gas control valve and light the pilot and test flames. Adjust the test
flame size with the pinch valve to match the size of the ⁄32-in. (4-mm) diameter flame gage.
10.6 After 1 min has elapsed, observe the temperature. If at the specification temperature (accounting for the differences of the
barometer reading from 760 mm), apply the test flame by slowly and uniformly opening the slide fully and closing completely over
a period of approximately 2 ⁄2 s (Note 8), watching for a flash (Note 9) while the flame is inserted.
NOTE 8—When inserted, the nozzle of the ignition device should intersect the plane of the underside of the cover (see A1.1).
NOTE 9—The material is considered to have flashed only if a comparatively large blue flame appears and propagates itself over the surface of the liquid.
Occasionally, particularly near the actual flash-point temperature, application of the test flame may give rise to a halo; this effect should be ignored.
D3278 − 21
10.7 Turn off the test and pilot flame. Clean the apparatus in preparation for the next test.
11. Procedure—0°C (32°F) to Ambient
11.1 If the specification or target flash point is at or below ambient temperature, cool the sample to 5 to 10°C (10 to 20°F) below
that point by some convenient means.
11.2 Cool the tester to approximately the temperature of the sample by inserting the cooling block (Fig. A2.1) filled with a cooling
mixture into the sample well. Dry the cup with a paper tissue to remove any collected moisture prior to adding the specimen using
a precooled syringe. (Warning—Be careful in handling the cooling mixture and cooling block; wear gloves and goggles. Mixtures
such as dry ice and acetone can produce severe frost bite.)(Warning—Be careful when inserting the cooling block into the tester
cup to prevent damage to the cup.)
11.3 Introduce the specimen as in 10.4. Allow the temperature to rise under ambient conditions or increase the temperature of the
cup by rotating the heater controller clockwise slowly until the specification temperature adjusted for barometric pressure is
reached. Determine whether the material flashes as in 10.5 and 10.6.
11.4 Turn off the test and pilot flames. Clean the apparatus.
TEST METHOD B—FINITE FLASH POINT
11. Procedure—Ambient to 110°C (230°F) Procedure
11.1 Preliminary or Trial Test: For specification purposes carry out a flash/no flash test at a temperature (actual) that allows for
a correction due to the ambient atmospheric pressure at the time of the test. Use the following equations to convert a specification
flash point test requirement to the actual test temperature required for the test and then round to the nearest 0.5 °C.
o
Actual test temperature C 5 S 2 0.25 101.3 2 A (1)
~ ! ~ !
c
o
Actual test temperature C 5 S 2 0.033 760 2 B (2)
~ ! ~ !
c
where:
S = Specification, or uncorrected target test temperature, °C,
c
A = Ambient barometric pressure, kPa, and
B = Ambient barometric pressure, mm Hg.
Warning—Eq 1 and Eq 2 are only to be used when testing at a prescribed specification or target temperature is required.
11.1.1 Follow steps 10.1 – 10.5, omitting the barometric reading and using an estimated finite flash point instead of specification
flash-point temperature.the manufacturer’s instructions to set the test temperature and the test time.
11.1.2 When the test cup is at the test temperature, fill the syringe (6.5) with the sample to be tested; transfer the syringe to the
filling orifice, taking care not to lose any sample; discharge the 2 mL test specimen into the test cup by fully depressing the syringe
plunger; remove the syringe.
11.1.2.1 If the sample is too viscous to be syringed through the orifice, see Annex A4.
11.1.3 Start the 60 s test timer; light the pilot light and adjust the test flame (if used) to conform to the 4 mm ( ⁄32 in.) gauge.
11.1.4 After 1 min has elapsed, observe the temperature. Apply the test flame When the end of the test time is indicated, apply
the ignition source by slowly and uniformly opening the slide fully shutter and closing it completely over a period of 22 s ⁄2 s (to
3 s.Note 8), watching Watch closely for a flash (atNote 9) while the flame is inserted. the test cup openings.
11.1.5 The test specimen is deemed to have flashed when a large flame appears and instantaneously propagates itself over the
surface of the test specimen (see 3.1.2). Occasionally, particularly near the actual flash point, application of the ignition source can
cause a blue halo or an enlarged flame; this is not a flash and should be ignored.
D3278 − 21
11.1.6 Record the test result as flash (or no flash), allowing for any known thermometer correction and the test temperature.
11.1.7 Turn off the pilot and test flames (if used). Remove the test specimen and clean the test cup and cover (see Appendix X1).
It may be necessary to allow the test cup temperature to fall to a safe level before cleaning.
12.2 If a flash is observed, proceed as in 12.3. If no flash is observed, proceed as in 12.4.
12.3 Using a temperature 5°C (9°F) lower than the temperature observed in 12.1.2, repeat 12.1 (Note 4). If a flash is still observed,
repeat at 5°C lower intervals until no flash is observed.
NOTE 10—Never make a repeat test on the same specimen. Always take a fresh portion for each test.
12.3.1 After establishing the approximate flash point, repeat 12.1 with a new specimen, but stabilizing the test temperature at
which no flash occurred previously. Observe if a flash occurs at this temperature. If not, increase the temperature by making a small
adjustment to the temperature controller so that an increase of 0.5°C (1°F) occurs within 1 min. Test for a flash at each 0.5°C
interval, recording the temperature at which the flash actually occurs. Record the barometric pressure. Clean the tester.
12.3.1.1 Repeat 12.3.1 with a new specimen. Calculate the corrected mean temperature in accordance with 15.2. Turn off pilot and
test flames and clean the tester.
12.4 Using a test temperature 5°C (9°F) higher than the temperature observed in 12.2, repeat 12.1 (Note 10). If no flash is
observed, repeat at 5°C higher intervals until a flash is observed.
12.4.1 After establishing the approximate flash point (12.4) with new specimens, make two determinations of the flash point in
accordance with 12.3.1 and calculate the corrected mean temperature in accordance with 15.2.
13. Procedure—0°C (32°F) to Ambient Temperature
13.1 Preliminary or Trial Test:
13.1.1 Cool the sample to 3 to 5°C (5 to 10°F) below the expected flash point.
13.1.2 Cool the tester to approximately the temperature of the sample by inserting the cooling block filled with a cooling medium
into the sample well. (Warning—See 11.2.)
13.1.3 Introduce the specimen using a precooled syringe as in 10.4. Set the 1-min timing device. After 1 min observe the
temperature, then apply the test flame by slowly and uniformly opening the slide fully and closing completely over a period of 2 ⁄2
s, watching for a flash (Note 9) while the flame is inserted. Record the temperature.
13.2 If a flash is observed, proceed as in 13.3. If no flash is observed, proceed as in 13.4.
13.3 Take a new specimen and recool the sample cup to 5°C (9°F) below the previous temperature (13.1.3). After 1 min, check
for a flash as in 13.1.3. If the material flashes, repeat at 5°C lower intervals until no flash is observed.
13.3.1 After establishing the approximate flash point, repeat 13.1.1 and 13.1.3 with a new specimen but stabilizing the test
temperature at which no flash occurred previously. Observe if a flash occurs at this temperature. If not, increase the temperature
by making a small adjustment to the temperature controller so that an increase of 0.5° C (1°F) occurs within 1 min. Test for a flash
at each 0.5°C interval, recording the temperature at which the flash actually occurs. Record the barometric pressure.
13.3.1.1 Repeat 13.3.1 with a new specimen. Calculate the corrected mean in accordance with 15.2. Turn off pilot and test flames
and clean the tester.
13.4 Using a test temperature 5°C (9°F) higher than the temperature observed in 13.1.3, repeat 13.1.3 (Note 10). If no flash is
observed, repeat at 5°C higher intervals until a flash is observed.
D3278 − 21
13.4.1 After establishing the approximate flash point (13.4), make the determinations of the flash point in accordance with 13.3
and calculate the corrected mean in accordance with 15.2.
TEST METHOD B—FINITE FLASH POINT DETERMINATION
14. Clean-up of Apparatus and Preparation for Next Test
14.1 Unlock the lid assembly of the tester and raise to the hinge stop. Soak up liquid with an absorbent paper tissue and wipe dry.
Clean the underside of the lid and filling orifice. A pipe cleaner may be of assistance in cleaning the orifice.
14.2 If the material is a viscous liquid or contains dispersed solids, after soaking up most of the specimen add a small amount of
a solvent suitable for the sample to the cup. Then soak up the solvent and wipe clean the interior surfaces of the cup with an
absorbent tissue paper.
NOTE 11—If necessary to remove residual high boiling solvent residues, moisten tissue with acetone and wipe dry.
NOTE 12—If any further cleaning is necessary, remove the lid and shutter assembly. Disconnect the silicone rubber hose and slide the
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