ASTM D6795 Standard Test Method for Measuring the Effect on Filterability of Engine Oils After Treatment with Water and Dry Ice and a Short (30 min) Heating Time
10. Procedure
10.1 Assemble apparatus as shown in Fig. 1 with filter installed in proper orientation (25 µm smooth side up).
10.2 Determine the new oil flow rate by placing a sample of the new oil in the burette. Pressurize the system and force at least 10 mL of oil through the filter to saturate the filter with oil and remove any air bubbles. Disconnect the air line and fill the burette with new oil to a level (1 to 2) cm above the 0 mark. Pressurize the system to (69 +/- 2) kPa, open the stopcock, and measure the flow time for each successive 5 mL of oil between the (0 and 25) mL graduations.
10.3 To determine the test oil flow rate, the flow times of the new oil are first determined in accordance with 10.2. Using the same filter disc, filter holder, and burette, reduce the new oil level in the burette to the lowest level that allows no air bubbles below the stopcock. Disconnect the air line and fill the burette with a well-mixed sample of test oil to a level (1 to 2) cm above the 0 mark. Pressurize the system to (69 +/- 2) kPa, open the stopcock, and measure the flow time for each successive 5 mL of oil between the (0 and 25) mL graduations.
10.4 Run each non-reference and reference oil in duplicate; repeat Section 9 and 10.1 to 10.4 for each non-reference and each reference oil.
10.5 For TMC-monitored tests, run the TMC reference oil on the same day as the non-reference oil.
10.6 For tests not monitored by the TMC, an in-house quality assurance oil can be used in place of the TMC reference.
11. Calculation
11.1 Calculate the flow rate for the new oil and the test oil for each 5 mL portion of oil using Eq 1:
flow rate = A/B
where:
A = volume of oil, and
B = flow time.
11.2 Calculate the percent change in flow rate of the test oil relative to the new oil with the final oil flow rates (between 20 mL and 25 mL measured with the same filter disc) using Eq 2:
percent change in flow rate = (E - D)/D x 100
where:
D = final new oil flow rate, and
E = final test oil flow rate.
12. TMC Reference Oil Testing
12.1 Test a TMC-coded reference oil along with each batch of non-reference oil tests. Run the reference oil simultaneously with, and in the same batch as, the non-reference oils.
NOTE 2 - Annex A1 discusses the involvement of the ASTM TMC with respect to the reference test-monitoring program.
12.1.1 Prior to conducting a reference oil test, procure a supply ofreference oils directly from the TMC. These oils have been formulated or selected to represent specific chemistry types, or performance levels, or both. Each reference oil sample is identified using a unique set of identification codes on the container labels. The coded reference samples provide for a blind reference-testing program to protect against the possibility of bias in the results.
12.1.1.1 The testing laboratory tacitly agrees to use the TMC reference oils exclusively in accordance with the TMC's published Policies for Use and Analysis of ASTM Reference Oils, and to run and report the reference oil test according to TMC guidelines.
NOTE 3 - Policies for the Use and Analysis of ASTM Reference Oils are available from the TMC.
12.1.2 Request a reference oil assignment from the TMC for this test method. The TMC determines the specific reference oil to be tested by the laboratory. Assignments are made by the unique identifying codes on the reference oil container labels.
12.1.3 Run the TMC reference oil test according to the test method and in the same manner as the non-reference oil test(s). Run the reference oil simultaneously with, and in the same batch as, the non-reference oils. Reference oils and non-reference oils in the same batch shall be run within the same 4 h time frame.
12.1.4 Reporting ofReference Oil Test Results - Report the results of all reference oil tests to the TMC according to the following directives:
12.1.4.1 The data report forms are available from the TMC for reporting all TMC reference oil test data to the TMC. Report only the reference oil results to the TMC. Do not include any non-reference test data. Complete all of the required blank fields on the forms.
12.1.4.2 Transmit reference test data to the TMC by electronic means or by telephone facsimile immediately upon completion of the test analysis. Include all of the reporting forms in the transmission.
NOTE 4 - Specific protocols for the electronic transmission of test data to the TMC are available from the TMC.
12.1.5 Evaluation of Reference Test Oil Results - Upon receipt of the transmitted TMC reference oil test results, the TMC reviews the test for operational adherence to the published test method. Ifthe test is found to be operationally valid, the reference oil results are evaluated using acceptance criteria established by the governing surveillance panel. The reference oil acceptance criteria are subject to change at the discretion of the surveillance panel.
12.1.5.1 If the transmitted test is found to be both operationally valid and statistically acceptable, the testing laboratory is notified of the acceptable status of the reference test. The uncoded TMC reference oil identification is also disclosed to the testing laboratory.
12.1.5.2 In the event that a TMC reference oil test is found to be unacceptable, an explanation of the problem relating to the failure is provided to the testing laboratory. If there is an obvious operational reason for the failed test, the problem shall be corrected before requesting another TMC reference oil assignment. If the reason for failure is not obvious, all test-related equipment shall be rechecked for compliance to the test method and good laboratory practice. Following this recheck, the TMC assigns another TMC reference oil for testing.
12.1.6 Status of Non-Reference Oil Tests Relative to TMC Reference Oil Tests - The batch of non-reference tests is considered valid only if the results of the TMC reference oil test meet the predetermined acceptance specifications for the particular reference oil tested.
