ASTM D3828 Test Methods for Flash Point by Small Scale Closed Cup Tester
METHOD B - FLASH POINT DETERMINATION
12. Procedure
12.1 This procedure repeats the procedures of Method A (11.3 through 11.8) a number of times. Each test uses a fresh test specimen and a different temperature. The change of temperature allows the determination of two temperatures 1°C (2°F) or 0.5°C (1°F) apart for which the lower temperature did not result in a flash while the higher temperature resulted in a flash (the flash point).
12.1.1 Select the expected flash point of the sample as the initial test temperature and follow the procedure 11.3 to 11.8.
12.1.2 If a flash is observed repeat the procedure given in 11.3 to 11.8 testing a fresh specimen at a temperature 5°C (9°F) lower each time until no flash is observed.
12.1.2.1 Proceed to 12.1.4.
12.1.3 When no flash was observed repeat the procedure given in 11.3 to 11.8 testing a fresh specimen at a temperature 5°C (9°F) higher each time until a flash is observed.
12.1.4 Having established a flash within two temperatures 5°C (9°F) apart, repeat the procedure at 1°C (2°F) intervals from the lower of the two temperatures until a flash is observed.
12.1.5 Record the temperature of the test when this flash occurs as the flash point, allowing for any known thermometer correction.
12.1.6 The flash point determined in 12.1.4 will be to the nearest 1°C (2°F).
12.1.6.1 If improved accuracy is desired (that is, to the nearest 0.5°C (1°F)) test a fresh test specimen at a temperature 0.5°C (1°F) below that at which the flash was observed in 12.1.4. If no flash is observed, the temperature recorded in 12.1.4 is the flash point to the nearest 0.5°C (1°F). If a flash is observed at the lower temperature (12.1.6), record this latter temperature as the flash point.
12.1.7 Turn off the pilot and test flmes, if used. When the cup temperature falls to a safe level, remove the test specimen and clean the cup and cover.
