Fall incidents result in over 12,000 deaths and over 2 million disabling injuries each year. In this article we will discuss pedestrian falls, which include falls on walking surfaces, falls from stairs, and falls from ramps. It is necessary to reconstruct the conditions and events leading up to any fall incident in order to identify the hazard(s) and cause(s). The two primary classification types of falls are Slips and Trips.
SLIPS:
A slip occurs when a person's foot or feet unexpectedly slide on a walking surface resulting in a loss of balance and subsequent fall. Common slipping hazards include liquids on walking surfaces, slippery objects such as food items left on walking surfaces, excessive slope on ramps, slippery shoe sole materials, changes in levels, etc. The Coefficient of Friction (COF) measures the slipperiness of surfaces. COF is the ratio of the friction force to the total force that is normal or perpendicular to the sliding surface; the higher the COF, the greater the traction. Representative values of COF are: book on a table, 0.3, brake material on brake drum, 1.2, dry tire on dry road, 1, and good walking surface with proper shoes, .5.
TRIPS:
A trip occurs when the motion of a person's foot or feet is interrupted by contact with an object resulting in a loss of balance and subsequent fall. Common tripping hazards include obstructions protruding into walkways or from the walking surface, loose carpeting, tile or other floor covering material, uneven or raised surfaces, irregular walking surfaces, holes, objects laying on a surface, non uniform steps, etc.
CODES AND STANDARDS APPLICABILITY:
The American Society of Testing Materials (ASTM) Standard D-2047 Static Coefficient of Friction of Polish-Coated Floor Surfaces as Measured by the James Machine states that a surface with a coefficient of friction of minimally 0.50 or greater is safe for walking. The .50 coefficient of friction standard is generally accepted and referenced in other voluntary codes such as Americans With Disabilities Act (ADA) and Underwriters Laboratories (UL). OSHA has adopted this standard as well. The building codes have not established a requirement for what constitutes a non-slip floor for either materials or anti-slip coefficient of friction.
Building codes do contain construction and safety requirements that are relevant to fall prevention. ASTM Standard F-1637 Safe Practice for Safe Walking Surfaces covers design and construction guidelines and minimum maintenance criteria for new and existing buildings and structures. The National Fire Protection Association (NFPA) codes address egress in and out of buildings for both a normal and an emergency basis. The American National Standards Institute (ANSI) publishes applicable minimum standards for various safety topics including making buildings accessible to the disabled and some of these contain relevant information to pedestrian fall hazards.