1.1These test methods cover the determination of the size distribution and quantity of particulate matter contamination from aerospace fluids isolated on a membrane filter. The microscopical techniques described may also be applied to other properly prepared samples of small particles. Two test methods are described for sizing particles as follows:

1.1.1Test Method A-Particle sizes are measured as the diameter of a circle whose area is equal to the projected area of the particle.

1.1.2Test Method B-Particle sizes are measured by their longest dimension.

1.2The test methods are intended for application to particle contamination determination of aerospace fluids, gases, surfaces, and environments.

1.3The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4These test methods do not provide for sizing particles smaller than 5 μm.

Note 1:Results of these methods are subject to variables inherent in any statistical method. The use of these methods as a standard for initially establishing limits should be avoided unless ample tolerances are permissible.

1.5This 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.

1.6This 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.