Side Hardness (or janka hardness)

Side hardness (or janka hardness) is a strength property for wood used in flooring applications. It represents the resistance of the wood to wear, denting and marring. It is measured by a load required to embed a 0.444 inch (11.3mm) steel ball to ½ its diameter in wood (see ASTM D143). The higher the number, the harder the wood species.