wool,By: sky ID:1131300043,U.S standards for grades of wool.,average fiber diameter,standard deviation in fiber diameter,Determining grade of wool,Measurement method,Procedure for determining average and standard deviation of fiber diameter.,scope,Principle of procedure,and material,apparatus,calibration,sampling,Test specimens of grease wool, pulled wool, scoured,Test condition,Wool, and card sliver,Preparation of slides,Measurement of fibers,Nature of test,Number of fibers,Calculation,calculation,The average diameter of fiber (X):,A=Midpoint of cell containing the smallest measurement,m=Cell interval,The standard deviation (y),Official grades,Finer than grade 80’s Wool with an average fiber diameter of 17.69 microns or less and a standard deviation in fiber diameter of 3.59 microns or less.,Grade 80’s,Grade 70’s,Grade 60’s,Grade 64’s,Grade 62’s,Grade 58’s,Grade 56’s,Grade 54’s,Grade 50’s,Grade 48’s,Grade 46’s,Grade 44’s,Grade 40’s,Grade 36’s,Coarser than grade 36’s Wool with an average fiber diameter of 40.21 microns or more.,Wool top,Terms defined,Wool top ---- A continuous untwisted strand of scoured wool fibers from which the shorter fibers or noils have been removed by combing.,Determining grade of wool top,Average fiber diameterA fiber diameter dispersion,Procedure for determining average fiber diameter and fiber diameter dispersion,Principle of procedure,Apparatus and material,calibration,sampling,Test condition,Preparation of slides,Measurement of fibers,Nature of test,Number of slides and fibers,calculation,calculations,The average diameter of fiber (X),Official grades,Finer than grade 80’s Wool top with an average fiber diameter of 18.09 microns or less and a fiber diameter dispersion that meets the following requirements: 25 microns and under-not less than 95 percent. 25.1 microns and over-not more than 5 percent. 30.1 microns and over-not more than 1 percent.,Grade 70’s,Grade 64’s,Grade 80’s,Grade 62’s,Grade 60’s,Grade 58’s,Grade 56’s,Grade 54’s,Grade 50’s,Grade 48’s,Grade 44’s Grade 40’s Grade 36’s Coarser that grade 36’s Wool top with an average fiber diameter of 41.30 microns or over.,。