FLASH POINT BY MCCFP TESTER: ASTM D7094
EXPLANATION
The flash point measurement is one measure of the tendency of the test specimen to form a flammable mixture with air under controlled laboratory conditions. Flash point is used in shipping and safety regulations to define flammable and combustible materials and for classification purposes. This test method can be used to measure and describe the properties of materials in response to heat and an ignition source under controlled laboratory conditions and shall not be used to describe or appraise the fire hazard or fire risk of materials under actual fire conditions. Flash point can also indicate the possible presence of highly volatile and flammable materials in a relatively nonvolatile or nonflammable materials, such as the contamination of lubricating oils by small amounts of diesel fuel or gasoline. This test method was designed to be more sensitive to potential contamination than Test Method ASTM D6450.
This test method covers the determination of flash point of fuels, lube oils, solvents, and other liquids by a continuously closed cup tester utilizing a specimen size of 2 mL, a cup size of 7 mL, with a heating rate of 2.5° C per minute. Test Method ASTM D6450 uses a 1 mL sample, a cup size of 4 mL, and a heating rate of 5.5° C per minute.
No statistically significant bias was observed between this test method and Test Method ASTM D93 PMCC flash point method in the temperature range from 35 to 150° C.
This test method is a dynamic method and depends on definite rates of temperature increase. This test method utilizes a closed but unsealed cup with air injected into the test chamber. This test method is suitable for testing samples with a flash point from 35 to 225° C. If the user's specification requires a flash point method other than this method, neither this method or any other test method should be substituted for the prescribed test method without obtaining comparative data and an agreement from the specifier. This fact is valid for all flash point test methods.
TEST SUMMARY
The lid of the test chamber is regulated to a test temperature at least 18° C below the expected flash point. A 2 +/- 0.2 mL test specimen of a sample is introduced into the sample cup. The cup is then raised and pressed onto the lid of specified dimensions to form the continuously closed but unsealed test chamber with an overall volume of 7.0 +/- 0.3 mL. After closing the test chamber, the temperatures of the test specimen and the regulated lid are allowed to equilibrate to within 1 ° C. Then the lid is heated at a prescribed, constant rate. A high voltage arc of defined energy is discharged inside the test chamber at regular intervals. After each ignition, a variable amount of air is introduced into the test chamber to provide the necessary oxygen for the next flash test. The pressure inside the continuously closed but unsealed test chamber remains at ambient barometric pressure except for the short time during the air introduction and at a flash point. After each arc application, the instantaneous pressure increase above the ambient barometric pressure inside the test chamber is monitored. When the pressure increase exceeds 20 kPa, the temperature at that point is recorded as the uncorrected flash point, which is then corrected to barometric pressure.
TEST PRECISION
Repeatability: 4.1° C
Reproducibility: 5.5° C
These precision statements are valid in the flash point range between 35 and 225 ° C.
Since there is accepted reference materials suitable for determining bias for this test procedure, bias has not been determined.
