Mean fibre length: After ginning the mean fibre length is determine. Using bare sorter and boll sorter mean length is determined. This length is ideally measured in millimeter (mm) or in inch.

Classification of mean fibre length

Category

Mean fibre length (mm)

Short

Less than 19

Medium

20.0 to 21.5

Superior medium

22.0 to 24.0

Long

24.5 to 26.0

Superior long

More than 27.0

Span length: Span length is measured with the help of digital fibograph 2.5% span length and 50% span length is determined. Span length is considered as standard in international market

Classification of 2.5% span length

Category

2.5% Span length (mm)

Short-B

Less than 20

Short-A

20.5 to 24.5

Medium

25.0 to 29.0

Long

29.5 to 32.5

Extra long

More than 33.0

Fibre fineness: Fibre fineness is a weight of one-inch fibre. If weight is more then fibre fineness is less and if weight of one-inch fibre is less then fineness is more. To determine the fibre fineness micronaire: fineness tester, air perimeter, aerialometer is used. In international market unit of fibre fineness is militex. Militex is 37.39 times more than micronaire. Fibre fineness is classified based on micronaire as follows and unit of fibre fineness is (microgram/inch)

Classification of Fibre fineness

Category

Fibre fineness
(microgram/inch)

Very fine

Less than 3.0

Fine

3.0 to 3.9

Average

4.0 to 4.9

Coarse

5.0 to 5.9

Very coarse

More than 6.0

Fibre maturity-coefficient: Fibre maturity depends on quantity of cellulose. Maturity of fibre is determined with the help of compound microscope. On a slide 100-200 fibre are taken and wet by solution of 18% caustic soda. After evaluation it is classified in matured, 1/2 mature and immature fibre. Using this classification maturity coefficient is determined. Classification of maturity-coefficient as follows

Classification of maturity-coefficient

Category

Maturity-coefficient

Very emature

Less than 0.60

Emature

0.60 to 0.70

Average emature

0.71 to 0.80

Good emature

0.81 to 0.90

Very high emature

More than 0.90

Fibre tenacity: Tenacity is the strength of fibre. It is determine by stelometer, strength tester. For this fibre tuft is taken between strength tester and forceps and strength required for breaking load of fibre is the tenacity and it is measure in kg and then wet of fibre is taken in milligram. When fibre strength is determine without keeping distant in fibre strength tester or forceps. It is known as 0" gauge and if there is 3.2mm distant then it is 1/8 gauge fibre strength. On stelometer elongation of fibre can be determine. The unit of tenacity determination is gram per Tex

Classification of Fibre tenacity

Category

Fibre tenacity
(gram/Tex)

P.S.I.

Very low

Less than 34.5

Less than 6.5

Low

34.5 to 37.4

6.5-6.9

Average

37.5 to 43.0

7.0-7.9

Good

43.1 to 47.7

8.0-8.9

Very good

More than 47.5

More than 9.0

Uniformity Ratio: Uniformity ratio of cotton fibre is determined by the formula:

Uniformity ratio = 50% span length / 2.5% span length x 100

Uniformity ratio is determined in percentage. If it less than 47% there is increasing short fibres.

Classification of uniformity ratio

Category

Uniformity ratio percentage

Poor

Less than 42%

Fair

42-43%

Average

44-45%

Good

46-47%

Very good

More than 47%