ASTM standards to measure wool fiber diameter

An average fiber diameter is an important factor in determining the quality of wool. With a finer diameter wool is generally softer and more valuable than wool with a coarser diameter. ASTM has established two major standards to measure the diameter of wool and other animal fibers:

1. ASTM D2130-22- Standard test method to measure wool and other animal fibers’ diameter by micro projection

This test method uses a micro projector to measure the diameter of wool fibers. The micro projector is a microscope that projects an enlarged image of the fiber onto a screen. The diameter of the fiber is then measured using a scale on the screen.

2. ASTM D6510-18- Standard test method to determine wool fiber diameter by optical diffraction

This test method uses a laser to measure the diameter of wool fibers. The laser light is diffracted by the fiber, and the diffraction pattern is used to calculate the diameter of the fiber.