ASTM D3941-90(2001)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
Designation:D3941–90(Reapproved2001)
Standard Test Method for
Flash Point by the Equilibrium Method With a Closed-Cup
Apparatus
This standard is issued under the fixed designation D 3941; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
INTRODUCTION
Test Methods D56 and D93 describe procedures using the Tag Closed Tester and the Pensky-
Martens Tester, respectively. Both test methods depend on a definite rate of temperature increase to
control the precision of the test method. The rate of heating may not in all cases give the accuracy
expected because of low thermal conductivity of certain materials. To reduce this effect, ISO/TC 35,
Paints and Varnishes, and ISO/TC 28, Petroleum Products and Lubricants, have issued ISO 1523 in
which the heating rate is considerably slower. This test method is similar to ISO 1523, but uses
standard ASTM cups, style, and format. Due to the slower heating rate, the time required to make a
determination of a flash point is considerably longer than for Test Methods D56 and D93 but the
accuracy is improved.
1. Scope 2. Referenced Documents
1.1 This test method covers the determination of the flash 2.1 ASTM Standards:
point of liquids in which the specimen and the air/vapor D56 Test Method for Flash Point by Tag Closed Tester
mixture above it are approximately in temperature equilibrium. D93 Test Methods for Flash Point by Pensky-Martens
1.2 This test method is limited to a temperature range from Closed Tester
32 to 230°F (0 to 110°C). E1 Specification for ASTM Thermometers
1.3 The values stated in inch-pound units are to be regarded 2.2 ISO Standard:
as the standard. The values given in parentheses are for ISO 1523 Paints, varnishes, petroleum, and related
information only. products—Determination of flash point—Closed cup
1.4 This standard should be used to measure and describe equilibrium method
the properties of material, products, or assemblies in response
3. Terminology
to heat and flame under controlled laboratory conditions and
3.1 Definitions:
should not be used to describe or appraise the fire hazard or
fire risk of materials, products or assemblies under actual fire 3.1.1 flash point, n—the lowest temperature corrected to a
pressure of 760 mm Hg (101.3 kPa) (1013 millibars) at which
conditions. However, results of this test may be used as
elements of a fire risk assessment which takes into account all application of an ignition source causes the vapor of the
of the factors which are pertinent to an assessment of the fire specimen to ignite under specified conditions of test.
hazard of a particular end use.
4. Summary of Test Method
1.5 This standard does not purport to address all of the
4.1 Aspecimen is heated in a closed cup of standard design
safety concerns, if any, associated with its use. It is the
in a suitable liquid bath at the rate of 1.0°F (0.5°C) in not less
responsibility of the user of this standard to establish appro-
than 1.5 min so that the difference in temperature between the
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of Annual Book of ASTM Standards, Vol 05.01.
Subcommittee D01.22 on Health and Safety. Annual Book of ASTM Standards, Vol 14.03.
Current edition approved May 25, 1990. Published July 1990. Originally Available from American National Standards Institute, 13th Floor, 11 W. 42nd
e1
published as D 3941 – 80. Last previous edition D 3941 – 84 . St., New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
D3941–90 (2001)
specimen in the cup and bath never exceeds 3.5°F (2.0°C). 7. Reagents and Materials
Flash determinations are made at intervals of not less than 1.5
7.1 Water or Mixture of Water and Ethylene Glycol
min.
(1+1) may be used as a bath liquid.
5. Significance and Use
8. Preparation of Sample
5.1 This test method, using a slow rate of heating, provides
8.1 Obtain a representative sample of the product under test
a uniform temperature throughout the specimen. The slow rate and keep in an air-tight container.
ofheatingisnecessarybecauseofthelowthermalconductivity
8.2 Because of the possibility of loss of volatile constitu-
of some liquids such as paints, resins, and related products, and ents, the sample should receive only the minimum treatment to
also because of the poor heat transfer by convection in
ensure uniformity. After removing the specimen, immediately
high-viscosity products. Since the specimen is being heated at close the sample container tightly to ensure that no volatile
a reduced rate, the longer time interval between each determi-
flammable components escape from the container (otherwise a
nation is necessary to reestablish after each flash test the new sample may be necessary if further testing is required).
saturation concentration of vapor in the air space above the
8.3 Do not open containers unnecessarily. Do not make
specimen. transfers unless the sample temperature is at least 20°F (10°C)
below the expected flash point, except for materials that are too
NOTE 1—ISO 1523 is used in United Nations Recommendations for
viscous to be handled at that temperature. In these cases,
TransportationofDangerousGoodsandintheInternationalCivilAviation
transfer the specimens at the lowest possible temperature at
Organization (ICAO) regulations and for similar regulations in the
which the material can be accurately measured into the cup.
International Maritime Dangerous Goods (IMDG) code. Test Method
D 3941, which is similar to ISO 1523, is used in the United States
8.4 Discard samples in leaky containers.
Department of Transportation (USDOT) regulations. The ICAO and
8.5 Do not store samples in plastic (polyethylene, polypro-
IMDG codes are used for transshipment of hazardous materials through
pylene, etc.) bottles, since volatile material may diffuse
the United States to other countries.
through the walls of the bottles.
6. Apparatus
9. Preparation of Apparatus
6.1 Test Cups, equipped with their lid as specified in Test
9.1 Support the cup and liquid bath on a level steady table.
MethodsD56 (Tag) and D 93 (Pensky-Martens). Remove the
Unless tests are made in a draft-free room or compartment,
test cup assembly (including lid and specimen thermometer)
surround the tester on three sides by the shield for protection
from the Tag and Pensky-Martens apparatus to permit either to
from drafts. Tests made in a laboratory draft hood or near
be used in a separate water bath.
ventilators are not reliable.
6.1.1 If a stirrer is fitted to the test cup used, it shall operate
9.2 Adjust the temperature of the bath to 10°F (5°C) below
during the heating period but must be stopped during the
the
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