D7321_10 V4

For fuels containing little particulate materials, only one filter is required, as a control filter is not required. If the fuel is highly contaminated, more than one filter may be required. See section 11 of the written standard. Clean all glassware used in preparation of glass fiber filter as described in section 9 of the written standard. Using forceps, place the glass fiber filter in a clean Petri dish to facilitate handling. The glass fiber filter should rest on clean glass support rods or watch glasses in the Petri dish. Place the Petri dish with its lid slightly ajar in a drying oven at 90 degrees Celsius, plus or minus 5 degrees Celsius, and leave it for 30 minutes. Remove the Petri dish from the drying oven and place it near the balance. Keep the Petri dish cover ajar, but such that the filter is still protected from contamination from the atmosphere. Allow 30 minutes for the filter to come to equilibrium with room air temperature and humidity. Remove the control glass fiber filter from the Petri dish with forceps, handling by the edge only, and place it centrally on the weighing pan of the balance. Weigh it. Record the initial mass to the nearest 0.0001 gram, and return it to the Petri dish. Place the filter on the funnel base. And then install the funnel and secure with locking ring or spring clip. Do not remove the plastic film from the funnel opening until ready to start filtration.