Janka Hardness Rating Of Malaysian Timbers

Janka hardness is one of the important mechanical properties of timber material. Janka hardness value indicates the capability of a timber to resist indentation force on its surface. The test to determine Janka hardness simulates the condition of a pointed loading, coerce on the surface of the timber perpendicular to the grain, or, in a few studies parallel to the grain. Janka hardness scale is the industry benchmark in evaluating the performance of timber for non-suspended flooring applications such as parquet and floor strip. It is a practical method in considering whether a timber floor can sustain dents, scratches, scuffs, impact forces, prolonged loading and other mechanical wear and tear.

Janka hardness value is not really an absolute value for design. Comparatively, it indicates which timbers are harder than others. Numerous other factors affect the mechanical performance of timber flooring, for example thickness, moisture content, inherent defects, biological deterioration, specific gravity, etc. It should be noted that the value is not appropriate for evaluating the hardness of engineered flooring products which compose of different types of materials. The value relates to the specific gravity of the timber, though special processes such as high temperature drying and chemical impregnation may increase the hardness of a timber material. Regardless of any hardness value a timber is rated, it will dent under certain degree of force or impact.

Although higher Janka value shows the harder the timber, it does not mean that it is the best preference. Beside timber hardness, there are other qualities to consider when choosing a timber for flooring material. Consumers' choice is normally based on the mechanical properties, aesthetic value as well as timber price. Timber with a suitable colour and grain texture will suit with the style, furniture, space and surrounding. The price of the timber flooring products is not necessarily based on Janka hardness or any other mechanical properties. Cost consideration should also be given to very hard timbers since they are more difficult to saw, drill, and nail, thus requiring more time and labour works to install. Principally, Janka hardness is used as part of the decision aspects, but not the only factor.