Standard Specifications for
The fineness of Wool or Mohair and Assignment of Grade1
This standard is issued under the fixed designation D 3991; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of the last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 These specifications cover the classification, by the fineness
grade, of wool or mohair that is in the grease, pulled, washed,
or scoured state, or in the form of card sliver.
1.2 These specifications are applicable also to the assignment of
the grade for wool or mohair in spun materials or products
processed beyond carding on the woolen system but not on the
a worsted system that involves a combing process.
NOTE 1—For fineness specifications for wool top, mohair top, and
alpaca, refer to Specifications D 39922 and D 2252.3
2. Referenced Documents
2.1 ASTM Standards:
D 123 Terminology Relating to Textiles3
D 2130 Test Method for Diameter of Wool and Other
Animal Fibers by Microprojection3
D 2252 Specification for Fineness of Types of Alpaca3
D 3992 Specification for Fineness of Wool Top or Mohair
Top and Assignments of Grade2
2.2 Federal Standards:
Official Standards of the United States for Grades of Wool,
Section 31.04
Measurement Method for Determining Grade of Wool,
Section 31.2044
Official Standards of the United States for Grades of Grease
Mohair, Section 32.15
Measurement Method for Determining Grade of Grease
Mohair, Section 32.2045
NOTE 2—A discussion on the development of grease mohair standards
can be found in the literature.6,7
Click below to download Astm D 3991 – 94 (Reapproved 2000) pdf free
