ASTM D5452 Standard Test Method for Particulate Contamination in Aviation Fuels by Laboratory Filtration
8. Sampling
8.1 All containers and their closures shall be thoroughly cleaned in accordance with Practice D4306.
8.2 To obtain a representative sample from a fuel stream and to avoid external contamination, the sample may be drawn from the flushing fitting of a field sampling kit (see Test Method D2276). Ensure that the line is first flushed with the fuel to be sampled and that the line is externally clean.
8.3 Whether or not a sampling kit is available, suitable precautions shall be taken to avoid sample contamination by the use of a suitable sampling point in accordance with Test Method D2276. If the quick-disconnect sampling connection is not used, a stainless steel ball or plug type valve should be selected as its internal design avoids the possibility of trapping or generating solid contaminant. Samples that are collected for general laboratory or chemical analysis are not necessarily suitable for this test method because insufficient care may have been taken to avoid particulate contamination.
8.4 Where possible a 3.8 to 5-L (1-gal) fuel sample should be taken, preferably in the same container that will be used in the test to avoid the need to transfer from one container to another with increased possibility of contamination. Ideally, a sample to be tested should be collected in a single container and transferred to the laboratory for testing. If the sample is collected in small containers such as glass bottles and then shipped to the laboratory, the collection containers shall be handled in a way to flush particulates into the transport container which should be UN/ICAO approved for public transport. Results obtained by taking other sample volumes can have different precisions.
8.5 The sample volume shall be quoted with the results. If the sample was transferred from one container to another before the test was performed, this shall also be noted with the test results.
9. Preparation of Apparatus and Sample Containers
9.1 Clean all components of the filtration apparatus, including the funnels, filter base, forceps, petri dishes, dispensing cap or plug and tubing (from 6.12) as described in 9.1.2-9.1.6.
9.1.1 Remove any labels, tags, and so forth.
9.1.2 Wash with warm tap water containing detergent.
9.1.3 Rinse thoroughly with warm tap water.
9.1.4 Rinse thoroughly with reagent water. Container caps should be handled only externally with clean laboratory crucible tongs during this and subsequent washing.
9.1.5 Rinse thoroughly with filtered isopropyl alcohol.
9.1.6 Rinse thoroughly with filtered flushing fluid.
9.1.7 For special cleanliness procedures in facilities that can have airborne dust, see Appendix X4.
10. Preparation of Test and Control Membrane Filters
10.1 Two 47-mm membrane filters of nominal pore size 0.8-µm are required: a test and a control membrane filter. Matched-weight membrane filters may be used if so desired (see Note 1). Ifmatched-weight membrane filters are used, it is unnecessary to carry out the procedures detailed in this section because they had been carried out previously by the membrane filter supplier. The two membrane filters used for each individual test should be identified by marking the petri dishes used as containers. Clean glassware used in preparation of membrane filters must be cleaned as described in 9.1. Refer to Appendix X4.
10.1.1 Using forceps, place the test and control membrane filters side by side in a clean petri dish. To facilitate handling, the membrane filters should rest on clean glass support rods in the petri dish.
10.1.2 Place the petri dish with its lid slightly ajar, in an oven at 90 +/- 5°C and leave it for 30 min.
10.1.3 Remove the petri dish from the oven and place it near the balance. The petri dish cover should be ajar but still protecting the membrane filters from contamination from the atmosphere. Allow 30 min for the membrane filters to come to equilibrium with the ambient air temperature and humidity.
10.1.4 Remove the control membrane filter from the petri dish with forceps, handling by the edge only, and place it centrally on the weighing pan. Weigh it and return it to the petri dish.
10.1.5 Repeat 10.1.4 for the test membrane filter. Record the membrane filter masses.
