This SAE Aerospace Recommended Practice (ARP) delineates two complementary filter element performance ratings: (1) dirt capacity, and (2) filtration efficiency, and corresponding test procedures. It is intended for non-cleanable (disposable), fine fuel filter elements used in aviation gas turbine engine fuel systems.
The document is being revised as follows: (1) Clarification of test fluids in 1.4. (2) Addition of a footnote in references that ISO 4402 has been withdrawn. (3) In 4.1.1, addition of a requirement for test fuel integrity. IFT requirement for test fuel changed to a minimum of 27 dynes/cm which can be more realistically achieved without impacting test results significantly. The IFT requirement has been clarified to be reflective of how the testing is actually performed. (4) In 4.1.1, addition of kinematic viscosity and density measurement, since this is necessary information when comparing the results for different test fluids. (5) Filter element rating in Table 1 changed from 1000 to 200 to be more reflective of filter element efficiency ratings utilized in aerospace. (6) Paragraph 6.5.4 specifies a new level of cleanliness since the reference to the cleanliness level stated in 6.3.5 was not applicable to this step. (7) Validation counts in Table 2 updated based upon the results of the ‘ISO Fine Test Dust (ISO FTD) Particle Count Mini-Round Robin’ conducted by ISO, which is more representative of recent lots of ISO FTD. (8) Volume changed in 220.127.116.11 from 500 mL to 100 mL since the larger volume is not necessary, given the high gravimetric levels. (9) New 18.104.22.168 inserted which requires a gravimetric analysis be performed on the injection fluid sample collected in 22.214.171.124, prior to performing the multi-pass test, in order to confirm the concentration of the contaminant in the contaminant injection system prior to the test. (10) Volume changed in the newly numbered 126.96.36.199 from 500 mL to 100 mL as the larger volume is not necessary, given the high gravimetric levels. (11) Update of references and addition of references ASTM D445, ASTM D1298, and ASTM D7566. (12) Editorial changes for clarity throughout the document.