Active Standard ASTM F312 | Developed by Subcommittee: E21.05
Book of Standards Volume: 15.03
Historical (view previous versions of standard)
Significance and Use
Reported particle size measurement is a function of both the actual particle dimension and shape factor as well as the particular physical or chemical properties of the particle being measured. Caution is required when comparing data from instruments operating on different physical or chemical parameters or with different particle size measurement ranges. Sample acquisition, handling and preparation can also affect the reported particle size results.
1.1 These 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:
1.1.1 Test Method A—Particle sizes are measured as the diameter of a circle whose area is equal to the projected area of the particle.
1.1.2 Test Method B—Particle sizes are measured by their longest dimension.
1.2 The test methods are intended for application to particle contamination determination of aerospace fluids, gases, surfaces, and environments.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 These 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.
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
F302 Practice for Field Sampling of Aerospace Fluids in Containers
F303 Practices for Sampling for Particles in Aerospace Fluids and Components
F311 Practice for Processing Aerospace Liquid Samples for Particulate Contamination Analysis Using Membrane Filters
F314 Methods of Test for Identification of Metallic and Fibrous Contaminants in Aerospace Fluids
F318 Practice for Sampling Airborne Particulate Contamination in Cleanrooms for Handling Aerospace Fluids