The purpose of this technique is to provide a means of determining the severity of particulate contamination in fluid power systems. AS598 was prepared by SAE A6C1 panel and supersedes ARP598C. AS598 retained the technical content of ARP598C with more prescriptive requirements for the material used to carry out the analysis. The widely used technique has since been replaced in many instances with automatic particle counters (APC) but remains a proven, accurate and reliable technique. This SAE Aerospace Standard (AS) defines the materials, apparatus and procedure for sizing and counting of particulate contamination, 5 um or greater, in hydraulic fluid samples by membrane filtration with microscopic counting. The microscopic counting method is capable of counting particulate matter in samples withdrawn from fluid power systems as identified by the 12 classes of AS4059 and projected beyond these for the five standard ranges specified and can thus serve as the primary document to determine acceptability. It is also capable of revealing but not measuring evidence of abnormal amount of water, other fluids, fine particulate and other materials, especially fibers and metals. It is applicable to all military, civil, space vehicles and test equipment.
SAE AS598-2012 Referenced Document
SAE ARP4285-2001 Aerospace - Evaluation of Particulate Contamination in Hydraulic Fluid - Membrane Procedure
SAE ARP5376-1998 Methods@ Locations and Criteria for System Sampling and Measuring the Solid Particle Contamination of Hydraulic Fluids
SAE AS1241 AS1241 Shaft, Trim Control - Direct Drive
SAE AS4059 AEROSPACE-CLEANLINESS CLASSIFICATION FOR HYDRAULIC FLUIDS
SAE AS598-2012 history
1970SAE AS598A-2081 Aerospace Microscopic Sizing and Counting of Particulate Contamination for Fluid Power Systems
1970SAE AS598A-2024 Aerospace Microscopic Sizing and Counting of Particulate Contamination for Fluid Power Systems
2018SAE AS598A-2018 Aerospace Microscopic Sizing and Counting of Particulate Contamination for Fluid Power Systems
2012SAE AS598-2012 Aerospace Microscopic Sizing and Counting of Particulate Contamination for Fluid Power Systems