Table 2. The quality grade of fibers

Criteria	Grade of quality
	I		II		III
	Condition	Value	Condition	Value	Condition	Value
Fiber length (L; μm)	> 2,000	100	1,000–2,000	50	< 1,000	25
Runkel ratio (2 w / l)	< 0.25	100	0.25–0.50	50	0.50–1.00	25
Felting power (L / d)	> 90	100	50–90	50	< 50	25
Flexibility ratio (l / d)	> 0.80	100	0.50–0.80	50	< 0.50	25
Coefficient rigidity (W / d)	< 0.10	100	0.10–0.15	50	> 0.15	25
Muhlsteph ratio (%)	< 30	100	30–60	50	60–80	25
Score range	450–600		225–449		< 225

Data from Rachman and Siagian (1976).