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Standard

Methods, Locations and Criteria for System Sampling and Measuring the Solid Particle Contamination of Hydraulic Fluids

2021-05-06
CURRENT
ARP5376C
This Aerospace Recommended Practice (ARP) provides: Recommended methods for cleaning sample bottles, when used, and the solvents to be applied and how these solvents should be prepared. Recommendations for three measuring methods for determining the level of solid particle contamination of hydraulic fluids used in aerospace hydraulics. Recommendations for the selection of the sampling point, sampling method, and the sampling frequency.
Standard

Degradation Limits of MIL-PRF-5606, MIL-PRF-83282, and MIL-PRF-87257 Hydraulic Fluids Used in Hydraulic Test Stands

2020-10-14
CURRENT
AIR810E
This SAE Aerospace Information Report (AIR) presents data on normally accepted changes in physical properties and contamination levels for MIL-PRF-5606, MIL-PRF-83282, and MIL-PRF-87257 hydraulic fluids used in hydraulic test stands. This information is of importance to all users of hydraulic test stands to assure the performance data obtained on these test stands for specific components will not be adversely affected by excessive changes in fluid properties or contamination levels.
Standard

Filter Element Cleaning Methods

2020-10-09
CURRENT
AIR787B
This SAE Aerospace Information Report (AIR) provides technical information to assist the development of specific cleaning methods for those filter elements which are designated as "cleanable" and cannot be cleaned by simple and obvious procedures.
Standard

Aerospace - Evaluation of Particulate Contamination in Hydraulic Fluid - Membrane Procedure

2018-08-13
CURRENT
ARP4285A
This SAE Aerospace Recommended Practice (ARP) establishes a method for evaluating the particulate matter extracted from the working fluid of a hydraulic system or component using a membrane. The amount of particulate matter deposited on the membrane due to filtering a given quantity of fluid is visually compared against a standard membrane in order to provide an indication of the cleanliness level of the fluid.
Standard

Aerospace Microscopic Sizing and Counting of Particulate Contamination for Fluid Power Systems

2016-06-09
CURRENT
ARP598D
This SAE Aerospace Recommended Practice (ARP) defines the materials, apparatus and procedure for sizing and counting of particulate contamination, 5 μm or greater, in hydraulic fluid samples by membrane filtration iwth microscopic counting. It is capable of counting particulate matter in samples withdrawn from fluid power systems as identified by the 12 classes of SAE AS 4059 or NAS 1638 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.
Standard

Filter Element Cleaning Methods

2013-10-08
HISTORICAL
AIR787A
This SAE Aerospace Information Report (AIR) provides technical information to assist the development of specific cleaning methods for filter elements. Consideration is limited to filter elements which are designated as "cleanable" (not "disposable"), but which cannot be cleaned by simple and obvious procedures. Cleaning methods developed according to this report should be evaluated by the methods of ARP725. Satisfactory cleaning methods can be developed for most "cleanable" filter elements. Technical or economic feasibility of the cleaning method may be limited, however, by incompatibility of filter-element construction materials, by mechanical weakness or lack of corrosion resistance to withstand repeated or continued cleaning, or by the presence of unusually tenacious contamination. These factors must be considered when selecting approaches to the development of specific methods.
Standard

Aerospace - Chlorinated Solvent Contamination of MIL-H-5606/MIL-H-83282 Vehicle Hydraulic Systems

2013-06-18
CURRENT
AIR4713A
Although there is controversy regarding the chemical form of chlorine and its relation to harmful effects in the hydraulic fluid (i.e., chloride ions versus organic chloro-compounds versus total chlorine in all forms), it is generally agreed that total chlorine content should be measured and controlled. In the near future, the ban on the manufacture of chlorinated solvents, out of concern for depletion of the ozone layer, may in itself diminish or eliminate chlorine contamination related aircraft malfunctions. It is generally accepted that hydraulic fluid contamination should be held to a minimum under all conditions. The benefits of low contamination levels are improved performance, lower maintenance due to lower wear, corrosion and erosion, longer fluid life, longer component life, etc. Contaminants can be classified into two general types: those that are insoluble and those that are soluble in the hydraulic fluid.
Standard

Degradation Limits of Hydrocarbon-Based Hydraulic Fluids, MIL-PRF-5606, MIL-PRF-83282, and MIL-PRF-87257 Used in Hydraulic Test Stands

2013-04-22
HISTORICAL
AIR810D
This SAE Aerospace Information Report (AIR) presents data on normally accepted changes in physical properties and contamination levels for military hydraulic fluids used in hydraulic test stands. This information is of importance to all users of hydraulic test stands to assure the performance data obtained on these test stands for specific components will not be adversely affected by excessive changes in fluid properties or contamination levels. The data pertains to fluids conforming to specifications MIL-PRF-5606, MIL-PRF-83282, and MIL-PRF-87257. The guidelines incorporated in the AIR are the general consensus values of knowledgeable professionals. However, the experience and judgment of engineers and operators responsible for the equipment must be relied upon to determine when the hydraulic fluid is to be replaced.
Standard

Secondary Filters for Fluid System Reliability

2012-09-24
CURRENT
AIR4057B
This SAE Aerospace Information Report (AIR) discusses the design choices and engineering trade-offs available to the system designer in the efficient selection and application of Last-Chance filters in contrast to main or primary system filters.
Standard

Aerospace-Particle Count Data Conversion and Extrapolation

2012-09-24
CURRENT
AIR877C
This SAE Aerospace Information Report (AIR) describes a mathematical model that can be used to analyze particle count data. Particle counts that fit the model can be graphically displayed, converted from one counting size-frequency range to another, and extrapolated to estimate counts beyond the measured range. Derivation, applications, and calculations are described.
Standard

Aerospace Microscopic Sizing and Counting of Particulate Contamination for Fluid Power Systems

2012-01-19
HISTORICAL
AS598
This SAE Aerospace Standard (AS) defines the materials, apparatus and procedure for sizing and counting of particulate contamination, 5 µm 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.
Standard

LIQUID FILTER RATINGS, PARAMETERS AND TESTS

2011-08-10
HISTORICAL
AIR887A
This AIR identifies and explains the meaning of various ratings and terms used to describe the physical characteristics of liquid filter elements. The significance of various filter parameters are discussed. In addition, a number of filter test methods are briefly described. This AIR and the data presented are only applicable to filters in which the system liquid wets the filter elements.
Standard

Aerospace Fluid Power - Cleanliness Classification for Hydraulic Fluids

2011-03-18
HISTORICAL
AS4059E
This SAE Aerospace Standard (AS) defines cleanliness classes for particulate contamination of hydraulic fluids and includes methods of reporting related data (Appendix A). The contamination classes selected are based on the widely accepted NAS 1638 cleanliness classes. Conversion from NAS 1638 cleanliness class specifications to AS4059 class specifications is defined. Comparison of the NAS 1638 classes to AS4059 classes is defined and the differences explained (Appendix B). This document provides versatility in identifying a maximum class in multiple size ranges, total number of particles larger than a specific size or designating a class for each size. NAS 1638 classes based on weight of particles are not applicable to either of these classes and are not included.
Standard

Procedure for the Determination of Particulate Contamination of Air in Dust Controlled Spaces By the Particle Count Method

2010-05-26
CURRENT
ARP743C
This document has been decalred "CANCELLED" as of May 2010. By this action, this document will remain listed in the Numercial Section of the Aerospace Standards Index. This SAE Aerospace Recommended Practice (ARP) describes two procedures for sampling particles in dust controlled spaces. One procedure covers airborne dust above 5 μm. The other (and newly added procedure) covers particles of 25 μm and larger that "fall out" of the environment onto surfaces. In each case the particles are sized in the longest dimension and counted. Airborne particles are reported as particles per cubic meter (cubic foot) whereas particles collected in fall out samples are reported as particles per 0.1 square meter (square foot). This document includes English units in parentheses as referenced information to the SI units where meaningful.
Standard

Methods, Locations And Criteria For System Sampling And Measuring The Solid Particle Contamination Of Hydraulic Fluids

2010-03-08
HISTORICAL
ARP5376B
This SAE Aerospace Recommended Practice (ARP) provides procedures for assuring cleanliness of sampling equipment, for performing the sampling process, and for measuring and reporting the sample particle count. The ARP gives procedures for cleaning sample bottles, when used, and recommends the solvents to be applied and how these solvents should be prepared. Requirements for the selection of the sampling point, sampling method, and sampling frequency are also specified. This ARP also recommends three measuring methods for determining the level of solid particle contamination of hydraulic fluids used in aerospace hydraulics. These are: a on-line automatic particle counting; b automatic particle counting method using bottle samples; c microscopic particle count method using bottle samples.
Standard

Aerospace - Evaluation of Particulate Contamination in Hydraulic Fluid - Membrane Procedure

2008-06-04
HISTORICAL
ARP4285
This SAE Aerospace Recommended Practice (ARP) establishes a method for evaluating the particulate matter extracted from the working fluid of a hydraulic system or component using a membrane. The amount of particulate matter deposited on the membrane due to filtering a given quantity of fluid is visually compared against a standard membrane in order to provide an indication of the cleanliness level of the fluid. A particular feature of this method is the membrane preparation to achieve an even particulate distribution on the membrane suitable for other applications. Membrane evaluation using standard membranes, described in this document, is an alternative technique to counting with either an optical microscope (ARP598) or an automatic particle counter (ISO 11500). The latter particle counting procedures are considered more precise.
Standard

Secondary Filters for Fluid System Reliability

2004-12-01
HISTORICAL
AIR4057A
This SAE Aerospace Information Report (AIR) discusses the design choices and engineering trade-offs available to the system designer in the efficient selection and application of Last-Chance filters in contrast to main or primary system filters.
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