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All About: Durometer


Rubber floor protectors are often used under heavy objects such as treadmills in residential gyms or machinery in industrial warehouses. Rubber flooring, however, must be the correct hardness to ensure that they can work effectively as rubber padding. A rubber floor company will generally list this information labeled as the durometer of their wholesale rubber flooring. Durometer refers to the hardness of a rubber. In fact, the word durometer is derived from the latin word “duro” which refers to hard or tough. Mr. Elasticity explains that durometer is a measurement to test the materials resistance to permanent indentation, or its ability to succumb to pressurized points while retaining its original shape. Durometer is the official measurement for polymers, elastomers, and rubber padding.

In a name synonymous with durometer, Albert F. Shore discovered the proper method of measuring hardness in elastomers and rubbers by studying the process of measuring metal hardness. To measure metal, the depth of penetration of a ball was pressed into a metal under certain amounts of pressure and then measured to see how much the metal warped. This was ineffective, however, for rubber padding because rubber indentation was not permanent like metal, but rather transient. Shore and his son then created the instrument that is still in use today to properly measure durometer, the Shore Durometer.

To accurately measure wholesale rubber flooring, you must use 1/4-inch thick piece of rubber flooring. Place this material on a hard subsurface and press the Shore Durometer into the rubber for ten seconds. The instrument will point to a value in between 0 and 100. A zero reading on the scale means that the indenter was pushed to the maximum amount and the material is very soft. A 100 indicates that the indenter was unable to penetrate the material at all. Although the difference will not be very much, it is important when comparing rubber floor protectors to test them in the same environment as rubber hardens when in colder temperatures. Often, a rubber floor company will show the number as a range, such as 55-65, to allow for tolerance, or small variations, that must be expected with wholesale rubber flooring.

Durometer is usually recorded using two scales, Shore A and Shore D. Shore A refers to the original measurement that Albert Shore pioneered. This test uses a blunt indenter and a moderate spring force. These instruments are not as accurate with any readings that are above 90. Generally for rubber flooring, the material will not exceed 90 as it is a softer material than rubber so the Shore A test is used most commonly. On the other hand, Shore D instruments use a sharper indenter and stronger spring to penetrate a greater depth for harder materials. The Shore D scale was created after new harder plastic materials were invented. This scale is more accurate for harder plastics with smaller intervals than the Shore A test. A rubber floor company will most likely show the durometer of its products using the Shore A scale, but if you have any questions a sales representative will always verify which scale was used.

When deciding which rubber floor protectors to use for your personal requirements, it is always important to check the durometer of the particular rubber flooring products that you are interested in. While this information should be prominently displayed with each product, a sales representative will always be able to help you determine what the durometer is of each product and what durometer is necessary for your needs. As Mr. Elasticity dubs it, with this “basic durometerology” information you are one step closer to finding the perfect rubber padding for your home or office!