D7501_11

Place 300 milliliters of sample in a 500-milliliter glass bottle, and set it in a liquid or air chamber at 4.5 plus or minus 0.5 degrees Celsius or 40 plus or minus 1 degree Fahrenheit for 16 plus or minus 0.25 hours. A refrigerator is not suitable for this procedure. After the 16-hour cold soak at 4.5 plus or minus 0.5 degrees Celsius or 40 plus or minus 1 degree Fahrenheit is completed, remove the sample from bath, and place it in a circulating water bath with the temperature set to 25 plus or minus 0.5 degrees Celsius or 77 plus or minus 1 degree Fahrenheit, according to section 11.2.1 or 11.2.2 of the written standard. The sample shall be completely liquid before filtration. If the sample is completely liquid after the 16-hour cold soak, heat the sample at 25 plus or minus 0.5 degrees Celsius or 77 plus or minus 1 degree Fahrenheit for 2 plus or minus 0.25 hours. Otherwise, follow section 11.2.2 of the written standard. If the sample is solid or contains any solids or haze after the 16-hour cold soak, heat the sample at 25 plus or minus 0.5 degrees Celsius or 77 plus or minus 1 degree Fahrenheit for 4 plus or minus 0.25 hours. Verify that the sample is at 25 plus or minus 0.5 degrees Celsius or 77 plus or minus 1 degree Fahrenheit by dipping without stirring or agitating the sample with an RTD sensor or thermometer. Filter these samples as quickly as possible upon removal from the warming bath once the desired warming time has elapsed according to section 11.2.1 or 11.2.2 of the written standard, whichever applies. Complete assembly of the receiving flask, 0.7 micrometer glass fiber filter, and funnel as a unit-- see figure 1 of the written standard-- before swirling the sample. To minimize operator exposure to fumes, the filtering procedure may be performed in a fume hood. Start the vacuum system. The vacuum controls have to be preset to run the test correctly. Since vacuum cannot be achieved with an open filter, a dry run with biodiesel may be used to set the controls when manual needle valves and analog gauges are used. Automatic digital vacuum controllers can be used to preset the final vacuum pressure. Thoroughly clean the outside of the sample container in the region of the cap by wiping it with a damp, lint-free cloth. Swirl the container for about 2 to 3 seconds to dislodge any particles that might have adhered to the walls of the container. Take care not to shake the sample vigorously after the cold soak, as this could cause some of the solids to go back into solution. Immediately after swirling, remove cap and pour the entire contents of the sample container into the filtration funnel and simultaneously start the timer. The entire contents of the sample container shall be filtered through the glass fiber filter to ensure a correct measure of the contamination in the sample. The entire contents of the sample container is defined as everything that will flow out of the sample container when it is poured into the filtration funnel and held for 10 seconds after the bulk of the sample has been poured out. Record the vacuum in the system within 1 minute of starting the filtration. The vacuum shall be between 70 to 85 kilopascals or 21 to 25 inches of mercury. If the vacuum is not within the specified range, make adjustments to the vacuum system. When filtration is complete, as evidenced by no sample remaining on the filter, immediately turn off the vacuum system and record the duration of the filtration, rounding to the nearest second. If the filtration is not complete when 720 seconds or 12 minutes has elapsed, turn off the vacuum system, and record the duration of the filtration to the nearest second. Record the pressure in the system and the volume filtered just before the termination of the filtration.