How do falls happen

Slips 

Slips happen where there is too little friction or traction between the footwear and the walking surface. Common causes of slips are:

• wet or oily surfaces

• occasional spills

• weather hazards

• loose, unanchored rugs or mats

• flooring or other walking surfaces that do not have the same degree of traction in all areas

• distractions while walking

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Dynamic Coefficient of Friction (DCOF)

DCOF is the ratio of the force necessary to keep a surface in motion sliding over another surface, divided by the weight (or normal force) of the sliding object. Different contaminants such as dirt, water, soap, oil, or grease can change this value.

There are many factors that affect the possibility of a slip occurring on a surface, including, by way of example, but not in limitation, the following: the material of the shoe sole and the degree of its wear; the presence and nature of surface contaminants; the speed and length of stride at the time of a slip; the physical and mental condition of the individual at the time of a slip; whether the floor is flat or inclined; how the hard surface flooring material is used and maintained; and the DCOF of the material, how the flooring surface is structured, and how drainage takes place if liquids are involved. Because many variables affect the risk of a slip occurring, the measured DCOF value shall not be the only factor in determining the appropriateness of a hard surface flooring material for a particular application

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ANSI A137.1  Regulations

The American National Standards Institute (ANSI) A326.3 standard was revised, balloted and approved in 2021 with a product use classification system, where products are classified into one or more of five categories based on their slip resistance properties: Interior, Dry; Interior, Wet; Interior, Wet Plus; Exterior, Wet; and Oils/Greases.

Product Use Classification

Classification / Reference Category / Criteria

Interior Dry                ID                          ≥ 0.42 dry DCOF*

Interior, Wet              IW                         ≥ 0.42 wet DCOF*  or Manufacturer- Declared

Interior, Wet Plus     IW+                       Manufacturer-  Declared

Exterior, Wet             EW                        Manufacturer-Declared

Oils/Greases              O/G                       Manufacturer-Declared

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Manufacturer-declared” refers to Section 3.4 of the ANSI A326.3 standard which states the following:

Manufacturer shall declare product use classification based on manufacturing parameters, internal quality control criteria, their experience with similar surfaces, and the criteria in this standard for all surfaces classified under Sections 4.1.3, 4.1.4, and 4.1.5 [respectively, “Interior, Wet Plus,” “Exterior, Wet,” and “Oils/Greases,”], mosaic surfaces, and flooring where surface structure (e.g. three-dimensionally patterned or profiled surfaces) results in misleading DCOF measurements due to test device constraints. Optionally, surfaces classified under Section 4.1.2 [“Interior, Wet”] shall also be permitted to be manufacturer- declared. Hard surface flooring manufacturer shall define internal product selection criteria (for example, but not in limitation, DCOF limit values established using this test method or other test methods, internal reference standards and practices, and/or the presence of abrasive grain and/or surface structure) for each product where the manufacturer-declared product use classification is not based on DCOF criteria developed per this standard. Regardless of declared product use classification, specifier shall determine materials appropriate for specific project conditions, considering by way of example, but not in limitation, type of use, traffic, expected contaminants, expected maintenance, expected wear3, and manufacturers’ guidelines and recommendations. [Text in brackets is not part of the standard and has been added for clarity. For footnotes, see the A326.3 standard.]

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What about surfaces that have been coated with another material?

From the A326.3 standard:

Hard surface flooring materials which have a coating applied after firing (for ceramic manufactured products), after fabrication (for non-ceramic manufactured products), or after installation of flooring materials onsite shall only be used in areas that can be kept dry, unless otherwise declared by the coating’s manufacturer. If testing data is required after a coating is applied, use the test method specified by the manufacturer, or the dry testing procedure in this standard [A326.3] if no test method is specified by the manufacturer of the coating.

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Flooring Considerations​

• Ceramic and porcelain tiles should not be used in floor applications where there is a consistent surface presence of water, oil, or grease. This includes outdoor areas.

• Proper maintenance is critical. Improper maintenance and improper maintenance products can result in a build-up on the surface of the tile causing the tile to be slippery.  

• No floor tile is "slip proof."

• Slippery conditions can be reduced by limiting foot traffic in contaminated conditions, use of appropriate footwear, prompt removal of contaminants, effective drainage, and proper maintenance. Installations and end use conditions can vary. The end user must evaluate the tile to be used with their specific end use conditions, maintenance program(s), and footwear selection to determine compatibility.

• Tile size can be a factor for slip resistance in wet areas. Smaller sizes allow for more drainage through an increased number of grout joints and easier sloping. Planar variations on larger formats could result in a higher probability of standing water and increase the risk for hydroplaning.

• Polished and semi polished surfaces create a very smooth surface. Maximum Floor Safety does not recommend polished surfaces in any areas that may be subjected to water, oil, or grease exposures.