Asking the right questions is vital to ensure you purchase hardwood flooring that best suits your needs. Key considerations include: How will the wood be used? Is it for a commercial space? Do you have young children or pets? Answering these questions will guide you to the optimal wood species for your flooring. Naturally, the harder the wood, the stronger it will be and the more impact it can withstand. A hardness scale known as the “Janka Hardness Test” classifies all wood species used in flooring. Here’s an example of this scale.
Janka hardness sscale
The Janka hardness test measures a wood’s resistance to denting; it quantifies the force required to embed a 11.284 mm (0.444 inch) steel ball to half its diameter. The resulting number indicates the pressure (in pounds-force) required to penetrate the wood. The harder the wood, the higher the pound-force value. This test, which leaves an indentation in the tested wood, was developed by Austrian dendrologist Gabriel Janka (1864-1932) in the early 20th century.
Source : Wikipedia