ASTM D 7596:2023

1.1 This test method covers the determination of particle concentration, particle size distribution, particle shape, and soot content for new and in-service oils used for lubrication and hydraulic systems by a direct imaging integrated tester. 1.1.1 The test method is applicable to petroleum and synthetic based fluids. Samples from 2 mm²/s to 150 mm²/s at 40 °C may be processed directly. Samples of greater viscosity may be processed after solvent dilution. 1.1.2 Particles measured are in the range from 4 μm to ≥ 70 μm with the upper limit dependent upon passing through a 100 μm mesh inlet screen. 1.1.3 Particle concentration measured may be as high as 5 000 000 particles per mL without significant coincidence error. 1.1.4 Particle shape is determined for particles greater than approximately 20 µm in length. Particles are categorized into the following categories: sliding, cutting, fatigue, nonmetallic, fibers, water droplets, and air bubbles. 1.1.5 Soot is determined up to approximately 1.5 % by weight. 1.1.6 This test method uses objects of known linear dimension for calibration. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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. 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.

75.100, 75.120