Nas 1638 pdf

Nas 1638 pdf

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revision history. nas 1638 was the forerunner of other contamination coding. the contamination levels selected are an extension and simplification of the widely accepted nas 1638. unless otherwise indicated, the issue on date of invitation of bids shall apply. if nas 1638 is used, the number of par - ticles in a 100 ml sample larger than 6 and/ or 14 microns must be within the range specified by the iso 4406 code. see the nas 1638 chart below for the various cleanliness levels: converting oil cleanliness standards - iso to nas to iso. nas 1638 represents the counts of particles in five size groups: 5 to 15 microns per 100 milliliters ( ml) 15 to 25 microns per 100 ml. cleanliness requirements of parts used in hydraulic systems. it is an old standard, originally employed in 1964 to classify the cleanliness levels in hydraulic components and systems within the us aerospace nas 1638 pdf industry. a particle count will show up to have almost the same nas class rating within the different particle ranges. iso 4406: 17/ : : 18/ : : 19/ : 10- 11 internal leakage many of our valves have a leak proof seat design: this means that the maximum allowed oil leakage value is 1 cc/ min ( about 15- 20 drops/ min) measured with 46cst oil at 40° c at the maximum permitted pressure. find out the cleanliness classes, the conversion table and the download links for the standards nas 1638 and iso 4406. example: nas> oooç cass 5, ( ref table l) ; or nasx) ooç gass 103, ( ref table il) appli cable docum ents bjþljcatjqns. the concept of the code can be seen in table 1 and it is based upon a fixed particle size distribution of the contaminant over a size range of > 5 to > 100 µm. the nas 1638 cleanliness standard was developed for aerospace components in the us and is still widely used for industrial and aerospace fluid power applications. nas 1638 the nas 1638 cleanliness standard was originally developed for aerospace components in the us but is still widely used for industrial and aerospace fluid power pdf applications. compared to the iso standard, nas 1638 also distinguishes particles larger than 15 μm. the first involves sending a fluid sample to a laboratory for analysis. contamination level classes according to nas 1638 ( january 1964) the contamination classes are defined by a number ( from 00 to 12) which indicates pdf the maximum number of particles per 100 ml, counted on a differential basis, in a given size bracket. ” * sae as4059 has been designed to replace nas/ 1964. when apc’ s came in to use this provided a method of analysing a sample much faster than the arp598 method. the nas 1638 reporting format pdf was developed for use where the principle means of counting particles was the optical microscope, with particles sized by the longest dimension per arp598. according to nas 1638, particles are counted in five size classes and nas 1638 pdf for each size range, a purity class from 00 to 12 is assigned accordingly. the figures are differential counts, and the nas class is usually reported as a single figure representing the maximum allowed. the nas system specifies different counts within each particle range to score a specific class. 50 to 100 microns per 100 ml. standard test methods for rockwell hardness of metallic materials. worst case) for designated particle inevitably, there is a requirement to be able to compare these cleanliness classification codes. sae i nternational arp598 arp743 arp785. learn about the encoding method of the level of contamination based on the number of particles per unit of volume in hydraulic systems, and how it has been replaced by the iso 4406 standard. the information normally included in a fluid condition report, along with typical targets or alarm limits, are shown in exhibit 1. 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. each class defines a range of counts. this sae aerospace standard defines cleanliness levels for particulate contamination of hydraulic fluids and includes methods of reporting data relating to the contamination levels. data is sorted into cumulative particle counter. a description is not available for this item. nas- 1638 cleanliness requirements of parts used in nas 1638 pdf hydraulic systems. the lab results contain pdf detailed information on the condition of the fluid. identification marking methods. nas 1638 contamination level according to nas 1638: the contamination classes are defined by a number ( fromwhich indicates the maximum number of particles per 100 ml, counted on a differential basis in a given size bracket. the figures are differential counts, and the nas class is usually reported as a single figure representing the maximum allowed particle counts ( i. nas 1638 is comprised of fluid cleanliness classes, each class defined in terms of maximum allowed particle. it is used widely in the uk north sea industries. although there is no guidance given in the standard on how to quote the levels, most industrial users quote a single code which is the highest recorded in all sizes. nas 1638 is a standard for classification of particle contamination in oils and fluids. see the nas vs iso cleanliness chart below for a good approximation. however, only the largest ( worst) of the 5 individual classes ( e. the nas 1638 coding system defines the maximum numbers permitted of 100ml volume at various size intervals ( differential counts) rather than using cumulative counts as in iso 4406. nas stands for national aerospace standard. both nas 1638 and iso 4406 focus on the methods for calculating particle counts or solid contamination levels within a fluid. nas 1638 table the nas 1638 cleanliness standard was developed for aerospace components in the us and is still widely used for industrial and aerospace fluid power applications and in the uk north sea industries. nas 1638 classes based on weight of particles are not. note - the comparisons relate to particle count data only. 25 to 50 microns per 100 ml. a contamination code has been added to describe the contamination levels of the fluid at the specified particle size ranges. nas1638 has been the most commonly used cleanliness. this distribution was based on particle contamination inside delivered aircraft hydraulic components in the 1960s. this specification establishes the acceptance cleanliness limits of hydraulic fluid wetting internal surfaces of parts, assemblies, lines and fittings for use in hydraulic systems prior to storage. most industrial users quote a single code which is the highest recorded in all sizes, e. the following documents form a part of this specification to the extent specified herein. a method of calibrating apc’ s. nas 1638 classes based on weight of particles are not applicable to these classes and are not included. nas 1638 ( national aerospace standard) the nas system divides particles in 5 particle size ranges. iso 4406 versus nas 1638 the recommended standard for defini- tion of oil cleanliness level is iso 4406. cleanliness level required for me- system - iso 4406 code xx/ 16/ 13. comparison of the nas 1638 classes to as4059 classes is defined and the differences explained ( appendix b). , 9) is reported as the nas class.