1、Designation: D 3941 90 (Reapproved 2007)Standard Test Method forFlash Point by the Equilibrium Method With a Closed-CupApparatus1This standard is issued under the fixed designation D 3941; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript 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.INTRODUCTIONTest Methods D56an
3、d D93describe procedures using the Tag Closed Tester and the Pensky-Martens Tester, respectively. Both test methods depend on a definite rate of temperature increase tocontrol the precision of the test method. The rate of heating may not in all cases give the accuracyexpected because of low thermal
4、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 inwhich the heating rate is considerably slower. This test method is similar to ISO 1523, but usesstandard ASTM cups, style, and format. Du
5、e to the slower heating rate, the time required to make adetermination of a flash point is considerably longer than for Test Methods D56and D93but theaccuracy is improved.1. Scope1.1 This test method covers the determination of the flashpoint of liquids in which the specimen and the air/vapormixture
6、 above it are approximately in temperature equilibrium.1.2 This test method is limited to a temperature range from0 to 110C (32 to 230F).1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard should be used to me
7、asure and describethe properties of material, products, or assemblies in responseto heat and flame under controlled laboratory conditions andshould not be used to describe or appraise the fire hazard orfire risk of materials, products or assemblies under actual fireconditions. However, results of th
8、is test may be used aselements of a fire risk assessment which takes into account allof the factors which are pertinent to an assessment of the firehazard of a particular end use.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespon
9、sibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D56 Test Method for Flash Point by Tag Closed Cup TesterD93 Test Methods for Flash Point by P
10、ensky-MartensClosed Cup TesterE1 Specification for ASTM Liquid-in-Glass Thermometers2.2 ISO Standard:ISO 1523 Paints, varnishes, petroleum, and relatedproductsDetermination of flash pointClosed cupequilibrium method33. Terminology3.1 Definitions:3.1.1 flash point, nthe lowest temperature corrected t
11、o apressure of 760 mm Hg (101.3 kPa) (1013 millibars) at whichapplication of an ignition source causes the vapor of thespecimen to ignite under specified conditions of test.4. Summary of Test Method4.1 A specimen is heated in a closed cup of standard designin a suitable liquid bath at the rate of 0.
12、5C (1.0F) in not lessthan 1.5 min so that the difference in temperature between the1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.22 on Flammability and Safety.Current edi
13、tion approved June 1, 2007. Published June 2007. Originallyapproved in 1980. Last previous edition approved in 2001 as D 3941 90 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume in
14、formation, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-295
15、9, United States.specimen in the cup and bath never exceeds 2.0C (3.5F).Flash determinations are made at intervals of not less than 1.5min.5. Significance and Use5.1 This test method, using a slow rate of heating, providesa uniform temperature throughout the specimen. The slow rateof heating is nece
16、ssary because of the low thermal conductivityof some liquids such as paints, resins, and related products, andalso because of the poor heat transfer by convection inhigh-viscosity products. Since the specimen is being heated ata reduced rate, the longer time interval between each determi-nation is n
17、ecessary to reestablish after each flash test thesaturation concentration of vapor in the air space above thespecimen.NOTE 1ISO 1523 is used in United Nations Recommendations forTransportation of Dangerous Goods and in the International CivilAviationOrganization (ICAO) regulations and for similar re
18、gulations in theInternational Maritime Dangerous Goods (IMDG) code. Test MethodD 3941, which is similar to ISO 1523, is used in the United StatesDepartment of Transportation (USDOT) regulations. The ICAO andIMDG codes are used for transshipment of hazardous materials throughthe United States to othe
19、r countries.6. Apparatus6.1 Test Cups, equipped with their lid as specified in TestMethods D56(Tag) and D 93 (Pensky-Martens). Remove thetest cup assembly (including lid and specimen thermometer)from the Tag and Pensky-Martens apparatus to permit either tobe used in a separate water bath.6.1.1 If a
20、stirrer is fitted to the test cup used, it shall operateduring the heating period but must be stopped during theflashing determination. If the stirrer originally fitted to the testcup is removed, the aperture in the cover shall be securelyplugged before starting the test.6.2 Liquid BathAny suitable
21、liquid bath capable of beingadjusted to the required temperature and of adequate heatcapacity to meet the requirements of the test. A bath fitted witha stirrer and an adjustable thermostat is convenient (see 4.1).NOTE 2The bath should be fitted with a cover, especially when thespecified temperature
22、is above 160F. At about this temperature theinerting effect of the water vapor may prevent or delay the flashing of theliquid under test.6.3 ThermometersStandard thermometers as specified inTest Methods D56and D93. One thermometer shall be usedto measure the temperature of the water bath and one sha
23、ll beused for measuring the temperature of the specimen in the cup.NOTE 3The thermometers for the water bath should be mounted at thecorrect level of immersion for which they are specified in SpecificationE1.6.4 Support, for holding the test cup in the liquid bath sothat the cover and upper edge are
24、 horizontal and the cup isimmersed in direct contact with the liquid in such a positionthat the level of the specimen in the cup is the same as that ofthe liquid in the bath.6.5 ShieldA three sided shield, open in front, each side460 mm (18 in. ) wide and 610 mm (24 in.) high, isrecommended.7. Reage
25、nts and Materials7.1 Water or Mixture of Water and Ethylene Glycol(1+1) may be used as a bath liquid.8. Preparation of Sample8.1 Obtain a representative sample of the product under testand keep in an airtight container.8.2 Because of the possibility of loss of volatile constitu-ents, the sample shou
26、ld receive only the minimum treatment toensure uniformity. After removing the specimen, immediatelyclose the sample container tightly to ensure that no volatileflammable components escape from the container (otherwise anew sample may be necessary if further testing is required).8.3 Do not open conta
27、iners unnecessarily. Do not maketransfers unless the sample temperature is at least 10C (20F)below the expected flash point, except for materials that are tooviscous to be handled at that temperature. In these cases,transfer the specimens at the lowest possible temperature atwhich the material can b
28、e accurately measured into the cup.8.4 Discard samples in leaky containers.8.5 Do not store samples in plastic (polyethylene, polypro-pylene, etc.) bottles, since volatile material may diffusethrough the walls of the bottles.9. Preparation of Apparatus9.1 Support the cup and liquid bath on a level s
29、teady table.Unless tests are made in a draft-free room or compartment,surround the tester on three sides by the shield for protectionfrom drafts. Tests made in a laboratory draft hood or nearventilators are not reliable.9.2 Adjust the temperature of the bath to 5C (10F) belowthe approximate flash po
30、int determined by Section 10.9.3 Carefully clean and dry the test cup, the cover, and thecup thermometer, and bring them to approximately the sametemperature as the bath liquid.10. Procedure10.1 Preliminary TestDetermine the approximate flashpoint of the material by one or more preliminary tests. Se
31、e 10.2through 10.7.10.2 Fill the test cup with the appropriate amount ofspecimen for the cup being used at a temperature that is at least10C (20F) below the approximate flash point (10.1). (See 8.3for viscous materials.) Remove any bubbles on the surface ofthe specimen. Wipe the inside of the cover
32、with a clean clothor absorbent tissue paper.10.3 Immediately after filling the test cup, place the cover inposition and support the cup in the bath so that the cover ishorizontal and the cup is immersed in direct contact with thebath liquid and with the surface of the specimen at the samelevel as or
33、 below that of the liquid in the bath. Confirm that thebath is at a temperature 5C (10F) below the approximateflash point.10.4 Light the flame of the ignition device and adjust it tothe size of a bead of diameter 4.0 mm (532 in.).10.5 As soon as the specimen has attained the same tem-perature as the
34、 bath (that is, the starting temperature of thedefinitive tests), perform a flash point test by opening the slide,D 3941 90 (2007)2inserting and removing the test flame, and closing the slideagain, over a period of 2.5 6 0.5 s. While the test flame isinserted, observe whether there is a flash.10.6 I
35、f ignition occurs (Note 4), the initial temperatureselected was too high. Repeat the complete procedure from10.2 with a fresh specimen at a temperature about 5C (10F)lower.NOTE 4When the vapor mixture under test is near the flash-pointtemperature, application of the test flame may give rise to a hal
36、o; however,the product is only deemed to have flashed if a comparatively large flameappears and propagates itself over the surface of the liquid. If a large blueflame does not appear as a flash, but instead a continuous luminous flameburns in the orifice when the slide is opened and the ignition fla
37、meintroduced, then the flash point of the product is much lower than the testtemperature.10.7 If no ignition occurs (Note 4), heat the bath at a ratesuch that the difference in temperature between the bath andthe specimen never exceeds 2C (3.5F). When the specimenhas increased in temperature by 0.5C
38、 (1F) (that is, after notless than 1.5 min nor more than 5 min), repeat the ignition test,and if no ignition occurs, repeat the procedure until a tempera-ture is reached at which ignition occurs. Read to the nearest0.5C (1F) the temperature indicated by the cup thermometer.10.8 Make two determinatio
39、ns repeating the procedure from10.2, using the flash point temperature determined in 10.7 asthe initial temperature. Correct each temperature reading forany known thermometer correction and record the result as theflash point temperature at the barometric pressure prevailingduring the test. Record a
40、lso the barometric pressure in milli-metres of mercury or kilopascals. Correct each flash pointreading when the barometric pressure differs from 760 mm Hg(101.3 kPa). (see 11.1). Determine the mean of the correctedresults of the two determinations.NOTE 5As volatile components are liable to be presen
41、t in the productsbeing tested, the total duration of the test should not exceed 1 h.11. Calculation of Correction for Barometric Pressure11.1 When the barometric pressure differs from 760 mm Hg(101.3 kPa) calculate the corrected flash point temperature T bymeans of the following equation:T 5 F 1 0.0
42、6 760 2 P! (1)5 C 1 0.03 760 2 P!5 F 1 0.42 101.3 2 B!5 C 1 0.23 101.3 2 B!where:F (C) = observed flash point, F (C) andP (B) = barometric pressure, mm of Hg (kPa).12. Report12.1 Report the flash point (the mean of two results) to thenearest 0.5C (1F) and the cup used in the test.13. Precision and B
43、ias13.1 PrecisionISO reported the following:13.1.1 RepeatabilityTwo results, each the mean of twodeterminations, obtained by the same operator using the sameapparatus should be considered suspect if they differ by morethan 2C (3.5F).13.1.2 ReproducibilityTwo results, each the mean of twodeterminatio
44、ns, obtained by operators in different laboratoriesshould be considered suspect if they differ by more than 3C(5F).13.2 BiasThe procedure for measuring flash point in thistest method has no bias because the value of the flash point canbe defined only in terms of a test method.14. Keywords14.1 closed
45、 cup; equilibrium method; flash point; Pensky-Martens; TagASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such pate
46、nt rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited eith
47、er for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair h
48、earing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 3941 90 (2007)3
