Slip Resistance Test Standards: ASTM F2913 and SATRA TM144 Explained

Why slip resistance standards matter

Slip resistant shoes are often advertised with a lab result, but the result only means something if you know which standard produced it. Two common standards, ASTM F2913 and SATRA TM144, measure traction differently, and the difference affects how you should read the rating.

Health and safety organizations, including the American Podiatric Medical Association, the American Academy of Orthopaedic Surgeons, and the National Institute for Occupational Safety and Health, emphasize choosing footwear that reduces fall risk. A slip resistant outsole is one part of that equation, and standardized testing helps you compare shoes with confidence. Before buying, check whether the brand publishes the test method, the contaminant used, and the coefficient of friction. Without those details, a "slip resistant" claim is not comparable across shoes. For more on how tread design affects grip, see tread pattern and slip resistance and outsole rubber types.

ASTM F2913: measuring the whole shoe

ASTM F2913 is a whole shoe test method. It places a complete shoe on a test surface, applies a controlled vertical force, and slides the shoe horizontally while measuring the force needed to keep it moving. The ratio of horizontal force to vertical force is expressed as a coefficient of friction.

Because the test uses an entire shoe, it accounts for the outsole pattern, the hardness of the sole, and the way the shoe contacts the ground. This makes ASTM F2913 useful for comparing one finished shoe against another. A higher coefficient of friction means more grip on the contaminant used during the test. It does not automatically guarantee real-world performance, but it gives you a consistent way to rank shoes tested under the same conditions.

SATRA TM144: testing the outsole material

SATRA TM144 is a material-level test. It measures the slip resistance of a sample cut from a shoe outsole, rather than the whole shoe. The sample is pressed against a specified floor surface and pulled under a known load. The result is again a coefficient of friction.

Because only the outsole material is tested, SATRA TM144 cannot capture how tread depth, lug shape, or heel geometry affect traction. Two outsoles made from the same compound may behave differently when built into shoes with different sole patterns. Brands often cite SATRA TM144 for work boots and safety shoes because it is a fast, repeatable way to compare compounds. When you see a TM144 rating, pair it with a whole shoe result like ASTM F2913 whenever possible. This gives you a fuller picture of how the shoe might perform in use.

What coefficient of friction means

All of these tests report a coefficient of friction, a unitless number that compares the force of friction to the load pressing the shoe onto the floor. A higher value indicates more resistance to sliding, while a lower value indicates a slipperier interface.

You will rarely see a pass or fail threshold marked on a shoe box. Instead, manufacturers may state a coefficient or a minimum value achieved under one contaminant, such as water or a diluted cleaning solution. The scale is relative, so what matters most is how one shoe compares to another under the identical protocol.

When comparing ratings, only compare values from the same standard and the same contaminant. A result from ASTM F2913 on wet ceramic tile is not directly comparable to a result from SATRA TM144 on a dry steel plate. To understand the surface and pattern effects, review shoe outsole contact patch and outsole lug depth guide.

Wet versus oily surfaces: how the contaminant changes the result

The same shoe can produce very different slip ratings depending on the liquid used. Water is a common contaminant, but many restaurant and industrial floors are covered in oil, grease, or diluted food residue. Slip resistant soles designed for water may not perform as well on oily surfaces.

ASTM F2913 and SATRA TM144 can both be run with different contaminants. When a brand publishes a rating, check whether it was obtained on wet tile, wet steel, oily ceramic, or another surface. The contaminant matters more than the raw number. If you spend most of your day in a commercial kitchen, choose a shoe with an outsole expressly developed for oil resistance. For wet outdoor surfaces, deeper treads and wider channels help channel water away. You can also check tread pattern and slip resistance and shoe outsole contact patch for design details.

How to compare slip resistance ratings

Start by confirming the test method. If a brand uses ASTM F2913, that is a whole shoe test; if it uses SATRA TM144, that is an outsole material test. Know which one you are looking at.

Next, check the contaminant. Ratings on water and ratings on oil are not interchangeable. Ask the brand for the exact surface and liquid used. Finally, look at the coefficient of friction value. A higher value indicates more slip resistance under that specific protocol, so use the same protocol to compare two shoes.

Points to keep in mind:

• Confirm the standard name, either ASTM F2913 or SATRA TM144.
• Match the contaminant: water, oil, or diluted detergent.
• Look for a coefficient number, not just the words "slip resistant."
• Prefer brands that also state the test surface.
• Remember that a shoe tested on a smooth tile may behave differently on concrete or carpet.

What you should look for in slip resistant shoes

For wet floors, a shoe with a broad contact patch and shallow, wide lugs will typically evacuate water better than one with narrow, sharp treads. For oily floors, a softer outsole compound with a matte finish often gives more bite. See outsole rubber types for a closer look at material properties.

Work shoes and boots that are marketed for hospitality, healthcare, or industrial settings often include the standard and contaminant in their specifications. If they do not, treat the claim with caution. You may want to compare options in our best work shoes guide or best shoes for rain or snow.

Remember that slip resistance changes as the outsole wears. A smooth, worn sole can lose grip even if it passed a lab test when new. Replace slip resistant shoes when the tread depth looks shallow. You can learn how to extend the life of your shoes in how to keep slip resistant shoes slip resistant and outsole lug depth guide.

What to pick for your use

Questions

What is the difference between ASTM F2913 and SATRA TM144?

ASTM F2913 tests a whole finished shoe, while SATRA TM144 tests a sample of the outsole material. The whole shoe test accounts for tread pattern and geometry, whereas the material test isolates the outsole compound's grip.

Which slip resistance standard is better?

Neither is universally better. ASTM F2913 gives a more complete result for working shoes because it tests the final product. SATRA TM144 is more useful for comparing outsole compounds during development. For purchasing, prefer a whole shoe standard like ASTM F2913.

How do I know if a shoe is slip resistant on oil and grease?

Look for a rating that explicitly says the test was done with an oily contaminant. If the brand only mentions a water test, you cannot assume the outsole will grip well on oil.

Can I compare ASTM F2913 and SATRA TM144 results directly?

No. The standards are not directly comparable because they test different specimens. Always compare values from the same standard and the same contaminant, such as wet tile or oily steel.

Why do some shoes have a higher coefficient of friction than others?

The outsole material, tread pattern, contact patch, and the contaminant used all affect the coefficient of friction. A higher value in the same test protocol means more grip under those specific conditions.

Does a slip resistant rating last for the life of the shoe?

No. Wear gradually smooths the outsole and reduces traction, especially on water and oil. When the tread depth becomes shallow or the sole feels polished, it is time to replace the shoes.

Do I need slip resistant shoes for everyday walking?

For regular indoor walking on dry floors, most shoes provide adequate grip. Slip resistant soles become important for wet, oily, or professionally demanding environments where the risk of falling is higher.