ASTM D3278 test method for flash point of liquids
ASTM D3278 standard test methods for flash point of liquids by small scale closed-cup apparatus
6. Apparatus
6.1 Test Cup and Cover Assembly - The essential dimensions and requirements of the apparatus are shown in Fig. A1.1 and described in Annex A1.
6.2 Thermometers, low, 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.
6.3 Glass Syringe, 2 +/- 0.1-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.
6.4 Aluminum Cooling Block (describing in Annex A2), that fits snugly within the test cup used for rapid cooling of the sample cup.
6.5 Barometer.
7. Reagents and Materials
7.1 p-Xylene, reference standard.
7.2 n-Butanol, reference standard.
7.3 Cooling Mixtures of ice and water or solid CO2 (dry ice) and acetone.
7.4 Liquified Petroleum Gas.
7.5 Heat Transfer Paste.
8. Sampling
8.1 The specimen size for each test is 2 mL. 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.
NOTE 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.
NOTE 7 - Precaution: Do not store samples in plastic bottles (polyethylene, polypropylene, etc.), as volatile material may diffuse through the walls.
9. Preparation of Apparatus
9.1 Prior 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.
9.2 To 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.
9.3 Place the tester in a subdued light and in a position not exposed to disturbing drafts. Provide a black-coated shield, if necessary.
9.4 Read 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.
9.5 Check the accuracy of the tester by duplicate determination of the flash point of the p-xylene reference standard (Annex A3). The mean of the results should be 81 +/- 1.5°F (27.2 +/- 0.8°C). An additional reference standard, n-butanol (Annex A3), may be used to check the accuracy at approximately the temperature specified by U.S. regulatory agencies in deifning flammable liquids. The mean of duplicates should be 36.7 +/- 0.8°C (98 +/- 1.5°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.
