Significance and Use
This test method is considered satisfactory for acceptance testing when the levels of the laboratories are controlled by the use of the same reference standard cotton samples because the current estimates of between-laboratory precision are acceptable under these conditions. In case of dispute, the statistical bias, if any, between the laboratory of the purchaser and the laboratory of the seller should be determined with each comparison being based on testing randomized specimens from one sample of material.
Fibrograph measurements provide a relatively fast method for determining the length and length uniformity of the fibers in a sample of cotton in a reproducible manner.
Results of the Fibrograph length tests do not necessarily agree with those obtained by other methods for measuring lengths of cotton fibers because of the effect of fiber crimp and other factors.
Fibrograph tests are more objective than commercial staple length classifications and also provide additional information on fiber length uniformity of cotton fibers. The cotton quality information provided by these results is used in research studies and quality surveys, in checking commercial staple length classifications, in assembling bales of cotton into uniform lots, and for other purposes.
Fibrograph measurements are based on the assumptions that a fiber is caught on the comb in proportion to its length as compared to total length of all fibers in the sample and that the point of catch for a fiber is at random along its length.
1.1 This test method covers the measurement of the length and length uniformity of cotton fibers by use of the Fibrograph. The test method is applicable to fibers taken from raw or partially processed cotton or some types of cotton waste, but not to fibers from blends of cotton with other fibers or to fibers recovered from cotton yarns or fabrics.
1.2 This test method covers procedures for all models of the Digital Fibrograph, hereafter referred to as Fibrograph.Note 1--Instructions for the use of Manual and Servo Fibrograph Models were included in the text of Test Method D1447 in 1971 and previous editions.
Note 2--For other methods covering the measurement of the length of cotton fibers refer to Test Method D1440.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.