ASTM D56 standard test method for flash point by Tag closed cup tester
10. Apparatus (Automated Instrument)
10.1 An automated flash point instrument is used that is capable of performing the test in accordance with Section 9. The apparatus can use a gas test flame or electric ignitor. The dimensions for the test cup and test cover are shown in Fig. A1.1 and Fig. A1.2.
10.2 Samples with low flash point may require a source of cooling for the heating area.
11. Preparation of Apparatus (Automated Instrument)
11.1 Support the automated apparatus on a level, steady surface, such as a table. Unless tests are made in a draft-free compartment, it is a good practice, but not required, to surround the tester with a shield to prevent draft.
11.2 The user of the automatic instrument must be sure that all of the manufacturer's instructions for calibrating, checking, and operating the equipment are followed.
11.2.1 Adjust the detection system per manufacturer's instructions.
11.2.2 Calibrate the temperature measuring device per manufacturer's instructions.
11.2.3 Verify the performance of the automated apparatus at least once per year by determining the flash point of a certified reference material (CRM) such as those listed in Annex A2, which is reasonably close to the expected temperature range of the samples to be tested. The material shall be tested according to the procedure of this test method and the observed flash point obtained in 9.5 shall be corrected for barometric pressure (see Section 13). The flash point obtained shall be within the limits stated in Table A2.1 for the identified CRM or within the limits calculated for an unlisted CRM (see Annex A2).
11.2.4 Once the performance of the apparatus has been verified, the flash point of secondary working standards (SWSs) can be determined along with their control limits. These secondary materials can then be utilized for more frequent performance checks (see Annex A2).
11.2.5 When the flash point obtained is not within the limits stated in 11.2.3 or 11.2.4, check the condition and operation of the apparatus to ensure conformity with the details listed in Annex A1, especially with regard to tightness of the lid (see A1.1.3), the action of the shutter, the position of the ignition source (see A1.1.3.3), and the angle and position of the temperature measuring device (see A1.1.3.4). After any adjustment, repeat the test in 11.2.3 using fresh test specimen, with special attention to the procedural details prescribed in the test method.
12. Procedure (Automated)
12.1 Adjust the external cooling system, if required, to a temperature necessary to cool the heating area 10°C below the expected flash point.
12.2 Place the test cup in position in the instrument.
12.3 Enter the Expected Flash Point; this will allow the heating area to be cooled to the required minimum starting temperature.
NOTE 4 - To avoid an abnormal heating rate when the specimen is at a low temperature, it is recommended to precool the test cup and cover. This may be accomplished by placing the assembly into position in the instrument while it is cooling to 10°C (18°F) below the programmed Expected Flash Point.
NOTE 5 - Flash Point results determined in an "unknown Expected Flash Point mode" should be considered approximate. This value can be used as the Expected Flash Point when a fresh specimen is tested in the standard mode of operation.
12.4 Using a graduated cylinder and taking care to avoid wetting the cup above the final liquid level, measure 50 more or less 0.5 mL of the sample into the cup, both the sample and the graduated cylinder being precooled, when necessary, so that the specimen temperature at the time of the measurement is 27 more or less 5°C (80 more or less 10°F) or at least 10°C (18°F) below the expected flash point, whichever is lower. It is essential that the sample temperature be maintained at least 10°C (18°F) below the expected flash point during the transfers from the sample container to the cylinder and from the cylinder to the test cup. Destroy air bubbles on the surface of the specimen by use of knife point or other suitable device. Wipe the inside of the cover with a clean cloth or absorbent tissue paper; then attach the cover, with the temperature measuring device in place, to the bath collar. Connect the shutter and ignition source activator, if so equipped, into the lid housing. When using a gas test flame, light the pilot flame and adjust the test flame to 4 mm (5/32 in.) in diameter. If the instrument is equipped with an electrical ignition device, adjust according to the manufacturer's instructions. Test the ignition source dipping action, if so equipped, and observe if the apparatus functions correctly. Press the start key. If a flash is observed upon initial operation, discontinue the test and discard the result. In this case a fresh specimen shall be cooled to an additional 10°C (18°F) below the original specimen installation temperature.
NOTE 6 - Care should be taken when cleaning and positioning the lid assembly so as not to damage or dislocate the flash detection system or temperature measuring device. See manufacturer's instructions for proper care and maintenance.
12.5 The apparatus shall automatically control the test procedure as described in this test method. When the flash point is detected, the apparatus will record the temperature and automatically discontinue the test. If a flash is detected on the first application, the test should be discontinued, the result shall be discarded and the test repeated with a fresh specimen. (Warning - For certain mixtures containing halogenated hydrocarbons, such as, methylene chloride or trichloroethylene, no distinct flash, as defined, is observed. Instead a significant enlargement of the test flame (not halo effect) and change in color of the test flame from blue to yellowish-orange occurs. Continued heating and testing of these samples above ambient temperature can result in significant burning of vapors outside the test cup, and can be a potential fire hazard. See Appendix X1 and Appendix X2 for more information.)
12.6 When the apparatus has cooled down to a safe handling temperature (less than 55°C (130°F)) remove the cover and the test cup and clean the apparatus as recommended by the manufacturer.
