ASTM D 7109:2025

1.1 This test method covers the evaluation of the shear stability of polymer-containing fluids. The test method measures the viscosity loss, in mm²/s and percent, at 100 °C of polymer-containing fluids when evaluated by a diesel injector apparatus procedure that uses European diesel injector test equipment. The viscosity loss reflects polymer degradation due to shear at the nozzle. Viscosity loss is evaluated after both 30 cycles and 90 cycles of shearing. Note 1: This test method evaluates the shear stability of oils after both 30 cycles and 90 cycles of shearing. For most oils, there is a correlation between results after 30 cycles and results after 90 cycles of shearing, but this is not universal. Note 2: Test Method D6278 uses essentially the same procedure with 30 cycles but without the 90 cycles portion of the test. The correlation between results from this test method at 30 cycles and results from Test Method D6278 has been established and shown in Research Report RR:D02-2041 to be equivalent. Note 3: Test Method CEC L-014 uses the same equipment with the procedure eliminating the 30 cycle sampling during the test. In an ILS study performed by the Coordinating European Counsil in collaboration with ASTM, it was shown that the protocols produce similar results. Note 4: Test Method D2603 has been used for similar evaluation of shear stability; limitations are as indicated in the significance statement. No detailed attempt has been undertaken to correlate the results of this test method with those of the sonic shear test method. Note 5: This test method uses test apparatus as defined in CEC L-14-A-93. This test method differs from CEC-L-14-A-93 in the period of time required for calibration. Note 6: Test Method D5275 also shears oils in a diesel injector apparatus but may give different results. Note 7: This test method has different calibration and operational requirements than withdrawn Test Method D3945 . 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific warning statements are given in Section 8 . 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

17.060