Designation:D3278–96e1
Standard Test Methods for
Flash Point of Liquids by Small Scale Closed-Cup Apparatus1
This standard is issued under thefixed 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(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.
e1N OTE—Figures A1.1and A2.1were corrected editorially in October1997.
1.Scope
1.1These test methods cover procedures for determining whether a material does or does notflash at a specified temperature or for determining the lowestfinite temperature at which a material doesflash when using a small scale closed-cup apparatus.2The test methods are applicable to paints, enamels,lacquers,varnishes,and related products having a flash point between0and110°C(32and230°F)and viscosity lower than150St at25°C(77°F).
N OTE1—Tests at higher or lower temperatures are possible.
N OTE2—More viscous materials may be tested in accordance with Annex A4.
N OTE3—Organic peroxides may be tested in accordance with Annex A5,which describes the applicable safety precautions.
N OTE4—The U.S.Department of Labor(OSHA,Hazard Communica-tions),the U.S.Department of Transportation(RSPA),and the U.S. Environmental Protection Agency(EPA)have specified Test Methods D3278as one of several acceptable methods for the determination offlash point of liquids in th
eir regulations.
N OTE5—These test methods are similar to International Standards ISO 3679and ISO3680.
1.2This 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 thefire-hazard orfire-risk of materials, products,or assemblies under actualfire conditions.However, results of the test may be used as elements of afire-hazard or afire-risk assessment which takes into account all of the factors which are pertinent to an assessment of thefire hazard orfire risk of a particular end use.
1.3This 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 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For specific hazard statements,see Note7and Note1
2.
2.Referenced Documents
2.1ASTM Standards:
D56Test Method for Flash Point by Tag Closed Tester3 D93Test Methods for Flash Point by Pensky-Martens Closed Tester3
D850Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related Materials4
D1015Test Method for Freezing Points of High-Purity Hydrocarbons3
D1078Test Method for Distillation Range of V olatile Organic Liquids4
2.2ISO Standards:5
ISO3679Paints,varnishes,petroleum and related products—Determination offlash point—Rapid equilib-rium method
ISO3680Paints,varnishes,petroleum and related products—Flash/noflash test—Rapid equilibrium method 3.Terminology
3.1Definitions:
3.1.1flash point—the lowest temperature,corrected to a pressure of760mm Hg(101.3kPa,1013mbar),at which application of an ignition source causes the vapor of the specimen to ignite under specified conditions of test.
4.Summary of Test Methods
4.1By means of a syringe,2mL of the sample is introduced through a leakproof entry port into the tightly closed small scale closed-cup apparatus2or directly into the cup that has been brought to the required test temperature.As aflash/no flash test,the expectedflash point temperature may be a specification or other operating requirement.After1min,a test
1These test methods are under the jurisdiction of ASTM Committee D-1on Paint and Related Coatings,Materials,and Applications and are the direct responsibility
of Subcommittee D01.22on Health and Safety.
Current edition approved Jan.10,1996.Published April1996.Originally published as D3278–73.Last previous edition D3278–95.
2Small scale closed-cup apparatus has been found suitable for this purpose.
3Annual Book of ASTM Standards,V ol05.01.
4Annual Book of ASTM Standards,V ol06.04.
5Available from American National Standards Institute,13th Floor,11W.42nd St.,New York,NY10036.
1
Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.
flame is applied inside the cup and note is taken whether or not the test specimen flashes.A fresh specimen must be used if a repeat test is necessary.
4.2For 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.
5.Significance and Use
5.1Flash 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 impurities or contaminants in a given liquid,such as the presence of residual solvents in solvent-refined drying oils.See Test Methods D 56and D 93for alternate flash point testing.
6.Apparatus
6.1Test Cup and Cover Assembly 6—The essential dimen-sions and requirements of the apparatus are shown in Fig.A1.1and described in Annex A1.
6.2Thermometers,7low,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.
6.3Glass Syringe ,260.1-mL capacity at 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.
6.4Aluminum Cooling Block 8(describing in Annex A2),that fits snugly within the test cup used for rapid cooling of the sample cup.
6.5Barometer .
7.Reagents and Materials
7.1p-Xylene,9reference standard.7.2n-Butanol,10reference standard.
7.3Cooling Mixtures of ice and water or solid CO 2(dry ice)and acetone.
7.4Liquified Petroleum Gas .7.5Heat Transfer Paste.11
8.Sampling
8.1The specimen size for each test is 2mL.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.
N OTE 6—Caution: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 20°F (10°C)below the expected flash point.Discard samples in leaky containers.
N OTE 7—Precaution:Do not store samples in plastic bottles (polyeth-ylene,polypropylene,etc.),as volatile material may diffuse through the walls.
9.Preparation of Apparatus
9.1Prior to initial use or after removal of the thermometer,insert the thermometer into its pocket (see Fig.A1.1)with a good heat transfer paste.
9.2To 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 9°F (5°C)throughout the scale range of the heater.9.3Place the tester in a subdued light and in a position not exposed to disturbing drafts.Provide a black-coated shield,if necessary.
9.4Read 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.
9.5Check the accuracy of the tester by duplicate determi-nation of the flash point of the p -xylene reference standard (Annex A3).The mean of the results should be 8161.5°F (27.260.8°C).An additional reference standard,n -butanol (Annex A3),may be used to check the accuracy at approxi-mately the te
mperature specified by ulatory agencies in defining flammable liquids.The mean of duplicates should be 36.760.8°C (9861.5°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.
TEST METHOD A—FLASH/NO FLASH
10.Procedure—Ambient to 110°C (230°F)
10.1Inspect 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.
10.2Switch 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 8)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 9).
N OTE 8—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.
6
Closed-cup flash point testers and their accessories meeting the requirements of the unit shown in Fig.A1.1are available from ERDCO Engineering Corp.,721Custer Ave.,Evanston,IL 60202or Stanhope-Seta Ltd.,Park Close Englefield Green,Engham,Surrey,TW20OXD,England.7
Thermometers may be obtained from the suppliers of the Small Scale Tester.8
Cooling blocks may be obtained from ERDCO Engineering Corp.9
p -Xylene is available as “Flash Point Check Fluid”from Special Products Div.,Chemical Dept.,Phillips Petroleum Co.,Borger,TX 25303.10
n -Butanol may be obtained from chemical supply companies.11
Heat transfer paste is available from the suppliers of the Small Scale Tester.No.340Silicone is available from Dow Corning Corp.,2030Willard H.Dow Center,Midland,MI 48674.G641Heat Transfer Compound is available from General Electric Co.,Products Div.,12Corporate Woods Blvd.,Albany,NY
12211.
N OTE9—The test cup temperature is stable when the signal light slowly cycles on and off.
10.3Determine the barometric pressure to determine the corrected specification temperature at that barometric pressure (see15.1).
10.4After the test-cup temperature has stabilized at the specification or targetflash 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 than45SUS at38°C(100°F)or equivalent of9.5cSt at25°C(77°F),raise the lid and discharge the contents of the syringe directly into the cup.Immediately close the lid tightly.
10.5Set the1-min timing device.In the meantime,open the gas control valve and light the pilot and testfl
ames.Adjust the testflame size with the pinch valve to match the size of the 5⁄32-in.(4-mm)diameterflame gage.
10.6After1min has elapsed,observe the temperature.If at the specification temperature(accounting for the differences of the barometer reading from760mm),apply the testflame by slowly and uniformly opening the slide fully and closing completely over a period of approximately21⁄2s(Note10), watching for aflash(Note11)while theflame is inserted.
N OTE10—When inserted,the nozzle of the ignition device should intersect the plane of the underside of the cover(see A1.1).
N OTE11—The material is considered to haveflashed only if a com-paratively large blueflame appears and propagates itself over the surface of the liquid.Occasionally,particularly near the actualflash-point tem-perature,application of the testflame may give rise to a halo;this effect should be ignored.
10.7Turn off the test and pilotflame.Clean the apparatus in preparation for the next test.
11.Procedure—0°C(32°F)to Ambient
11.1If the specification or targetflash point is at or below ambient temperature,cool the sample to5to10°
C(10to20°F) below that point by some convenient means.
11.2Cool the tester to approximately the temperature of the sample by inserting the cooling block(Fig.A2.1)filled with a cooling mixture(Note12and Note13)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.
N OTE12—Precaution: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.
N OTE13—Caution:Be careful when inserting the cooling block into the tester cup to prevent damage to the cup.
11.3Introduce the specimen as in10.4.Allow the tempera-ture to rise under ambient conditions or increase the tempera-ture of the cup by rotating the heater controller clockwise slowly until the specification temperature adjusted for baro-metric pressure is reached.Determine whether the material flashes as in10.5and10.6.
11.4Turn off the test and pilotflames.Clean the apparatus.
TEST METHOD B—FINITE FLASH POINT
12.Procedure—Ambient to110°C(230°F)
12.1Preliminary or Trial Test:
12.1.1Follow steps10.1-10.5,omitting the barometric read-ing and using an estimatedfiniteflash point instead of specificationflash-point temperature.
12.1.2After1min has elapsed,observe the temperature. Apply the testflame by slowly and uniformly opening the slide fully and closing completely over a period of21⁄2s(Note10), watching for aflash(Note11)while theflame is inserted. 12.2If aflash is observed,proceed as in12.3.If noflash is observed,proceed as in12.4.
12.3Using a temperature5°C(9°F)lower than the tempera-ture observed in12.1.2,repeat12.1(Note4).If aflash is still observed,repeat at5°C lower intervals until noflash is observed.
N OTE14—Never make a repeat test on the same specimen.Always take
a fresh portion for each test.
12.3.1After establishing the approximateflash point,repeat 12.1with a new specimen,but stabilizing the
test temperature at which noflash occurred previously.Observe if aflash occurs at this temperature.If not,increase the temperature by making a small adjustment to the temperature controller so that an increase of0.5°C(1°F)occurs within1min.Test for aflash at each0.5°C interval,recording the temperature at which the flash actually occurs.Record the barometric pressure.Clean the tester.
12.3.1.1Repeat12.3.1with a new specimen.Calculate the corrected mean temperature in accordance with15.2.Turn off pilot and testflames and clean the tester.
12.4Using a test temperature5°C(9°F)higher than the temperature observed in12.2,repeat12.1(Note14).If noflash is observed,repeat at5°C higher intervals until aflash is observed.
12.4.1After establishing the approximateflash point(12.4) with new specimens,make two determinations of theflash point in accordance with12.3.1and calculate the corrected mean temperature in accordance with15.2.
13.Procedure—0°C(32°F)to Ambient Temperature 13.1Preliminary or Trial Test:
13.1.1Cool the sample to3to5°C(5to10°F)below the expectedflash point.
13.1.2Cool the tester to approximately the temperature of the sample by inserting the cooling blockfille
d with a cooling medium into the sample well.(Precaution—See Note12and Note13.)
13.1.3Introduce the specimen using a precooled syringe as in10.4.Set the1-min timing device.After1min observe the temperature,then apply the testflame by slowly and uniformly opening the slide fully and closing completely over a period of 21⁄2s,watching for aflash(Note11)while theflame is inserted. Record the temperature.
13.2If aflash is observed,proceed as in13.3.If noflash is observed,proceed as in13.4.
13.3Take a new specimen and recool the sample cup to5°C (9°F)below the previous temperature(13.1.3).After1
editorially
min,
check for aflash as in13.1.3.If the materialflashes,repeat at 5°C lower intervals until noflash is observed.
13.3.1After establishing the approximateflash point,repeat 13.1.1and13.1.3with a new specimen but stabilizing the test temperature at which noflash occurred previously.Observe if aflash occurs at this temperature.If not,increase the tempera-ture by making a small adjustment to the temperature controller so that an increase of0.5°C(1°F)occurs within1min.Test for aflash at each0.5°C interval,recording the temperature at which theflash actually occurs.Record the barometric pres-sure.
13.3.1.1Repeat13.3.1with a new specimen.Calculate the corrected mean in accordance with15.2.Turn off pilot and test flames and clean the tester.
13.4Using a test temperature5°C(9°F)higher than the temperature observed in13.1.3,repeat13.1.3(Note14).If no flash is observed,repeat at5°C higher intervals until aflash is observed.
13.4.1After establishing the approximateflash point(13.4), make the determinations of theflash point in accordance with
13.3and calculate the corrected mean in accordance with15.2.
14.Clean-up of Apparatus and Preparation for Next Test 14.1Unlock the lid assembly of the tester and r
aise to the hinge stop.Soak up liquid with an absorbent paper tissue and wipe dry.Clean the underside of the lid andfilling orifice.A pipe cleaner may be of assistance in cleaning the orifice. 14.2If 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.
N OTE15—If necessary to remove residual high boiling solvent resi-dues,moisten tissue with acetone and wipe dry.
N OTE16—If any further cleaning is necessary,remove the lid and shutter assembly.Disconnect the silicone rubber hose and slide the lid assembly to the right to remove.If warm,handle carefully.
14.3After the cup has been cleaned,its temperature may be rapidly increased to some stand-by value by turning the temperature control dial to an appropriate point.
N OTE17—It is convenient to hold the test cup at some stand-by temperature(depending on planned usage)to conserve time in bringing the cup within the test temperature range.The cup temperature may be quickly lowered by inserting the aluminum cooling blockfilled with an appropriate cooling mixture into the cup.
14.4The syringe is easily cleaned byfilling it several times with acetone or other compatible solvent,discharging the solvent each time,and allowing the syringe to air dry with the plunger removed.Replace the plunger,and pump several times to displace any solvent vapor with air.
15.Correction for Barometric Pressure
15.1Determine the corrected specificationflash point to be used in Test Method A by the following equations:
F5S20.06~7602P!
C5T20.03~7602P!
F5S20.42~101.32B!
C5T20.23~101.32B!
where:
F C=flash point to be observed to obtain the specifica-
tionflash point at standard pressure,°C(°F),
S(T)=specificationflash point,°C(°F),and
P(B)=ambient barometric pressure,mm Hg(kPa).
N OTE18—The barometric pressure used in this calculation must be the ambient pressure for the laboratory at the time of test.Many aneroid barometers,such as those used at weather stations and airports,are precorrected to give sea-level readings.These must not be used.
15.2When the barometric pressure in Test Method B differs from760mm Hg,correct theflash point temperature,A,by means of the following equations:
A5F10.06~7602P!
5C10.03~7602P!
5F10.42~101.32B!
5C10.23~101.32B!
where:
F(C)=observedflash point,°C(°F),and
P(B)=ambient barometric pressure,mm Hg(kPa).
16.Report
16.1When using theflash/noflash method,report whether or not the sampleflashed at the requiredflash point and that Test Method A was used.
16.2If an actualflash point was determined,report the mean of duplicate determinations to the nearest0.5°C(1°F),pro-vided the difference between the values does not exceed1°C (2°F)and that Test Method B was used.
17.Precision and Bias12
17.1No statement is made about either the precision or bias of Test Method A-Flash/No Flash,since the result merely states whether there is conformance to the criteria for success specified in the procedure.
17.2On the basis of an interlaboratory study of Test Method
B in which one operator in each offive laboratories made two determinations on two different days on four solvents,three resins and two paints of differentflash points,the intralabora-tory and interlaboratory standard deviations were found to be:
Standard Deviation
Within-Between-
Materials Laboratory Laboratory Solvents(viscosity below45SUS at20°C
(100°F)),°F
0.98  1.55
Resins and Paints(viscosity above45
SUS at
20°C(100°F)),°F
1.89
2.41
Based on these standard deviations,the following criteria should be used for judging the acceptability of results at the 95%confidence level:
17.3Liquids at or Below45SUS at20°C(100°F)or Equivalent Viscosity:
12Supporting data are available from ASTM Headquarters.Request RR:D01-1000.These data are also reported in the Journal of Paint Technology,V ol45,No. 581,p.
44.
17.3.1Repeatability—Two results,each the mean of two determinations,obtained by the same operator on different days should be considered suspect if they differ by more than 1.7°C(3°F).
17.3.2Reproducibility—Two results,each the mean of two measurements,obtained by different laboratories,should be considered suspect if they differ by more than3.3°C(6°F).
17.4Viscous Liquid Above45SUS at20°C(100°F)or Liquids With Dispersed Solids:
17.4.1Repeatability—Two results,each the mean of two determinations,obtained by the same operator on different days should be considered suspect if they differ by more than 3.3°C(6°F).
17.4.2Reproducibility—Two results,each the mean of two measurements,obtained by different laboratories should be considered suspect if they differ by more than5°C(9°F).
17.5A study to determine the precision for materials with a viscosity greater than150St has not been made.
17.6The precision for liquid peroxides has not been deter-mined,but the precision of liquid peroxides should be similar to that of other liquids.
17.7Bias—No estimate of the bias offlash-point tests can be determined as no absolute values are available.In addition, the results are equipment and method dependent.
18.Keywords
18.1flash/noflash;flash point;organic peroxides;organic solvents;small scale closed-cup apparatus
ANNEXES
(Mandatory Information)
A1.APPARATUS SPECIFICATIONS
A1.1A typical apparatus is shown in Fig.A1.1.Electrical heaters are fastened to the cup in a way as to provide for efficient transfer of heat.The tester includes a variable heater control device with a scaled dial and a visible signal to indicate when energy is or is not being applied.Energy may be supplied from a100to250V50/60Hz(for stationary use)or by a12-V d-c battery service(forfield use).An adjustable testflame and a pilotflame to maintain the testflame are provided.These flames may be fueled by piped gas service(fixed location)or by a self-contained tank of liquefied petroleum gas(7.4)(for portability).A testflame measuring5⁄32in.(4mm)in diameter may be checked against a gage ring on the surface of the tester. Never recharge the gas tank with the pilot or testflames lighted,nor in the vicinity of other nakedflames.A1-min audible signal is a desirable accessory.The cover isfitted with an opening slide device capable of inserting the ignitionflame into the well when the slide is open.When inserted the nozzle of the ignition device shall intersect the plane of the underside of the
cover.

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