What Do Shore D Hardness and Taber Abrasion Tell You?

In epoxy technical documents, two figures often appear side by side: Shore D hardness and Taber abrasion. Many readers treat them as two ways of saying the same thing — “is the floor durable” — but in fact they measure two different properties, and a hard floor is not necessarily less worn in real use.

This article explains what each figure measures, how to read it, and why two figures measured under different conditions should not be compared. This article does not record a Shore D or Taber figure for any Kadier product, because no product-specific Kadier figures are published in a confirmed technical data sheet (TDS) yet. Any figure used to select a product must come from the TDS of the specific product, together with its test conditions.

What does Shore D hardness measure?

Shore D hardness measures resistance to indentation when a probe is pressed into the surface, on the Shore D scale commonly used for hard materials. The higher the value, the harder the surface and the harder it is to dent. In practice, hardness relates to surface feel, resistance to marks from heavy objects left in place, and partly to resistance to light scratching.

Hardness, however, is not the same as toughness. A very hard but brittle surface can crack or chip under impact, while a slightly softer but more flexible surface may withstand impact better. Shore D should therefore only be read together with other figures such as adhesion strength, impact resistance and conditions of use, never alone as proof that a floor is durable.

What does Taber abrasion measure?

In the Taber abrasion test, a sample rotates under grinding wheels for a set number of cycles, and the amount of material lost is measured, usually as weight loss. The lower the loss, the better the surface withstands abrasion under those test conditions. This figure is closer to real use than Shore D in one respect: it simulates repeated wear from wheels, footwear and objects dragged across the floor.

The key point is that test conditions determine what the figure means. Wheel type, load, number of cycles and test environment all affect the result. Two Taber figures can only be compared with each other when they were measured under the same conditions. A low Taber figure measured under mild conditions proves nothing when the real floor must carry heavy forklifts running continuously.

How to read the two figures together

Place both figures against the real conditions of use of the project: what vehicles run on the floor, wheel loads, traffic density, whether pallets are dragged, and whether sand and abrasive dust are present. Pedestrian walkways and heavy forklift areas need two different levels of requirement, and the same threshold should not be used for every area.

When receiving a TDS, check four things: what the measured value is, which standard it was measured to, under what conditions, and whether the test sample used the same coating system and the same thickness as the system to be applied. If a document gives only a figure without conditions, ask for the missing information before comparing it with another product.

Common misunderstandings

The first misunderstanding: the higher the Shore D, the better in every case. In practice, for impact-bearing floors, flexibility and adhesion can matter more than absolute hardness. The second misunderstanding: a low Taber figure guarantees service life. Service life also depends on the substrate, application, cleaning and actual loads. The third misunderstanding: a good figure in one property compensates for the other. There is no automatic compensation of that kind; each figure answers a different question.

See Kadier’s coating systems to compare system build-up and general scope of application: RollCoat and LevelFlow. Shore D and Taber figures for each system, if available, must be taken from the TDS of the specific product.

Request a consultation — describe the actual loads and traffic on the floor so they can be checked against the TDS of a suitable product.

Illustration photo: Pexels, photographer ELEVATE. General reference framework: TCVN 9014:2011 and TCVN 12574-2018 on paints and coatings; product-specific figures are to be checked against the TDS of the specific product.