Note that the comparison to ISO 4406 is necessarily an approximation. The contamination classes are defined by a number (from 00 to 12) which indicates the maximum number of particles per 100 mL, counted on a differential basis, in a given size bracket. Oil cleanliness is critical to the reliability of your machinery. Contamination level classes according to NAS 1638 (January 1964) Particle Contamination ISO And NAS Cleanliness Codes. This convention is employed with laser particle size analyzers. 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.Īlthough 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. If NAS 1638 is used, the number of particles in a 100 ml sample larger than 6 and/or 14 microns must be within the range specified by the ISO 4406 code. Nevertheless, in many areas of industry, NAS 1638 has largely been outpaced by the ISO 4406 standard in recent years. It is still referred to in some industries, although the ISO 4406 cleanliness codes are more commonly found. Iso 4406 To Nas 1638 Conversion Islamic Will Template South Africa Tiesto Club Life Volume Two Miami Zip Spore Galactic Adventures 5. definition of oil cleanliness level is ISO 4406. The application of this standard was extended to industrial hydraulic systems as nothing else existed at the time. The NAS system was originally developed in 1964 to define contamination classes for contamination contained in aircraft components. A Comparison of NAS 1638 and ISO 4406 Cleanliness Codes

Iso 4406 to nas 1638 conversion