Floor Finish Hardness Values – Knoop Versus Pencil Rating Methods

Knoop Hardness values relate resistance to indentation by a weighted wedge shaped diamond. A number is assigned to its hardness value. The larger the number, the harder the surface.

Pencil Hardness values measure floor finish resistance to indentation and tearing to the hardness of various grades of graphite. Pencil hardness values are as follows:

Very soft 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H, 7H, 8H Very Hard.