What's the best way to prevent slips and falls? Based on the number of injuries in the workplace due to slippery floor conditions, there is no simple answer.
Any one solution -- be it slip-resistant shoes, mats or worker awareness -- will not eliminate the hazard. EHS professionals who want to implement, upgrade or review their slip-prevention programs need to ensure that they consider all aspects of what causes a slip and what can be done to reduce or eliminate one of the workplace's most common hazards.
Malcolm C. Robbins, a forensic engineer in San Diego who studies slip-and-fall accidents, said that unless someone can design a 100 percent slip-resistant environment and plan for the worst condition possible, the hazard cannot be eliminated. "If you say something is 90 percent effective, that still leaves 10 percent for an accident."
Slips and falls result in 15 percent of all accidental workplace deaths and 16 percent of accidents resulting in disability. Slips result in head or back injuries, lacerations, fractures, pulled muscles and deep contusions to the tune of $37 billion annually in health care costs.
Determining what aspects to include in a slip-prevention program is left up to employers because there is no slip-resistance standard. A portion of one OSHA regulation, 29 CFR 1910.22(a)(2), General Requirements for Walking-Working Surfaces, provides a place to start, albeit vague, when focusing on slip prevention:
"The floor of every workroom shall be maintained in a clean and, so far as possible, a dry condition. Where wet processes are used, drainage shall be maintained, and false floor, platforms, mats or other dry standing places should be provided where practicable."
Beyond that, OSHA recommends a minimum static coefficient of friction (SCOF), which measures friction between the footwear's outer sole and the floor, of 0.5 for a safe walking surface. Americans with Disabilities Act guidelines suggest a SCOF of 0.6 for level surfaces and 0.8 for ramps. As a point of reference, a wet, soapy bathtub has an SCOF of 0.4.
A comprehensive slip-prevention program should look at what Bill Markley of New Pig Corp. calls the "slip triangle" -- the contaminant, the floor and the person. Markley, a technical trainer/services specialist for the Tipton, Pa., manufacturer of contained absorbents for industrial facilities, said a program should include at least six elements: hazard identification, housekeeping, floor surfaces, matting, footwear and employee awareness.
A risk assessment approach can help illuminate slip hazards in your workplace. Look for hazards such as stairs, inclines, drop-offs and loose rugs or mats. Much of the focus, however, likely will be directed toward contaminants on the floor because those can be the hardest to control.
Determine the type of contaminant, whether it be water, grease, oil, a chemical or a dry substance such as metal shavings or dust. Sources of contamination can include lubricants from machinery, coolant overspray, water tracked in from outdoors, dust from sanding, newly mopped floors or metal chips in a machine shop.
Develop a checklist specific to your workplace and known problem areas where contaminants may accumulate. Review records and interview employees to pinpoint areas where slips and falls commonly occur.
With an inspection checklist in hand, walk through the workplace regularly. Take note of areas around workstations and locations where there is frequent pedestrian traffic. Look for uneven surfaces and obstructions in designated walkways. Frequent inspections of these areas will turn up accidents waiting to happen.
Keeping floors clean and clutter-free is one of the best ways to reduce hazards. "If you don't implement a continual housekeeping program, you may not be addressing the real problem," said Markley, whose company provides solutions and technical expertise to help maintain a cleaner, safer workplace.
Here are several common-sense tips to keeping floors clean and free of contaminants:
- Clean up spilled liquids or tracked-in water immediately by mopping or using an absorbent material.
- Sweep up loose debris.
- Inspect flooring surfaces for holes, chips or other trip hazards and make necessary repairs.
- Eliminate chronic hazards by implementing design changes, such as machine guards, and frequent equipment inspection and servicing.
- Select a floor cleaner that enhances slip resistance and does not leave a slippery residue.
Unless all floor surfaces can be inspected constantly, it is impractical to assume that contaminants will always be cleaned up immediately, said Robbins, the forensic engineer. Even hourly inspections, for example, may not be often enough. "What about the other 59 minutes?" he asked.
When leaks and spills are unavoidable, keep contaminants away from walkways by using absorbent materials, nonabsorbent barriers and containment decking. Once liquid is contained, retrieve it with a vacuum or pump for reuse or recycling.
Use warning signs, safety cones or barricade tape if you notice hazards such as broken, protruding or loose debris in walkways, or newly waxed or mopped floors not cordoned off.
A warning sign only is effective, Robbins said, if it warns of the danger, explains the consequence of the danger and tells a worker what to do. Otherwise, he added, it would be better to keep the worker away from the slippery area.
Not to be forgotten in a slip-prevention program is the floor.
Some surfaces are less slip-resistant than others, with or without contaminants. Types of slip-resistant floors to consider include brushed concrete, sheet vinyl with abrasive material, and seamless epoxy or urethane with surface aggregate. Porous surfaces tend to provide the most slip resistance because there are "nooks and crannies" that take up water, allowing the person to walk on the "peaks."
The same goes for floor coatings, which give the surface a profile, said Steve Feldman, director of sales and marketing for American Safety Technologies, a Roseland, N.J.-based manufacturer of anti-slip coatings. The more aggressive a profile, the higher its coefficient of friction.
While some floor surfaces will provide adequate slip protection, an anti-slip coating may be appropriate in many instances. Epoxy coatings with aluminum oxide, which is a hard, synthetic mineral, are preferred over sand and paint because sand becomes dislodged and paint is worn easily, Feldman said. Durable coatings can last several years between applications and reduce the frequency of stopping production for reapplication.
"The best way to have an anti-slip floor system is by altering the floor system more permanently," Feldman said.
A company that wants to turn its floors into anti-slip surfaces should ask three questions:
What is the nature of the traffic? The type of coating used will depend on whether the floor is for barefoot traffic in a plant's locker room or an area with heavy worker and forklift traffic. Areas designed for some types of heavy traffic require a more aggressive and durable surface.
What is the contamination? Determine common contaminants in a work area, then plan for a worst-case scenario so the surface can provide more protection than ordinarily necessary, Feldman said.
What is the surface? The type of surface will affect how a coating should be applied. For example, steel surfaces need a primer, while wood flooring calls for an undercoat to seal out moisture.
Before taking the time and expense to spread a floor coating over a large surface, Feldman said, apply it on a small area and test it to ensure that it is appropriate for the application.
Like spill containment systems, mats provide a way to reduce slip hazards when keeping floors free of contaminants is impractical or impossible.
One example is building entrance and exit areas where there can be constant traffic of wet shoes from rain or snow. Another example is machinery at a workstation that produces metal shavings. Both cases call for mats, said Lisa O'Dell, vice president of marketing for Tennessee Mat Co. Inc. in Nashville.
In the first example, an employer should use an absorbent walk-off mat large enough so that people can take three steps across it and get water off the bottom of their shoes, O'Dell said.
While an entrance is not the place for a 3-foot by 5-foot mat, that would be the correct size for most individual workstations. Mat manufacturers also can provide custom sizes and shapes. Runner matting works well for assembly lines and aisles.
In areas with contaminants, a mat should have holes in it to allow for drainage, said Bob Wood, director of sales for Superior Manufacturing Group, a Chicago-based maker of mats.
Mats with holes help increase production because continuous cleanup at workstations usually is not necessary, especially when dealing with metal shavings and dust, O'Dell said. "After enough particles have fallen through the holes, simply pick up the mat, sweep underneath it, and it's done."
Mats typically are made of styrene butadiene rubber, nitrile, natural rubber, vinyl/polyvinyl chloride or urethane. Some materials will not hold up well where certain chemical, greasy or oily contaminants are present. Use a low-profile, highly abrasive mat in these areas. Check with a mat manufacturer to determine which products work best with particular contaminants.
A mat should hold up to the elements if properly cared for, O'Dell said. "If you want a mat to last, you need to involve it in a regular maintenance program. At least hose it down, sweep it off or do something so it doesn't get nasty and will still work."
Do not adhere a mat to the floor, O'Dell said, because it will become hard to clean and may tear if it's pulled up.
To help avoid mats from becoming trip hazards, Wood recommends using matting with beveled, colored borders. "It alerts workers that they are approaching a different floor surface or level of flooring."
Borders should comply with OSHA's 29 CFR 1910.144 rule on safety color codes for marking physical hazards. A mat with a yellow border, for example, indicates caution and for marking physical hazards that can cause stumbling, falling and tripping.
While any slip-prevention program should include several elements, slip-resistant footwear is a key to making the program work.
To make sure that a shoe is truly slip-resistant, ask the manufacturer for test results, said J. Bryant Couey, TX Traction sales manager for Famous Footwear in Madison, Wis. Test results should come from an independent lab to ensure that results are valid.
The industry benchmark for testing footwear slip resistance, Couey said, is the American Society for Testing and Materials' F1677-96, Standard Test Method for Using a Portable Inclineable Articulated Strut Slip Tester. This test method determines the slip resistance of a shoe's sole against walkway surfaces in the laboratory or field under dry, wet or contaminated conditions.
The F1677-96 test will determine if a shoe will meet a 0.25 slip-resistance rating. This minimum acceptable rating measures the horizontal-to-vertical force exerted when the average person puts down his foot.
Couey lists two factors to achieving slip resistance with a shoe: the rubber compound and the tread pattern design, including the tread's surface-to-void ratio.
The rubber compound needs to be soft enough to provide slip resistance but hard enough to last and maintain its tread pattern after contact with floor surfaces and contaminants. The tread pattern design should have a grid pattern that channels water, grease and other residues away from the bottom of the shoe.
The tread's surface-to-void ratio measures how much of the sole's surface is in contact with the ground and how much void is available for contaminants to slide into and be channeled away from the shoe. While Couey indicated there is no clear-cut best ratio, Famous Footwear uses a 78-to-22 ratio, meaning that 78 percent of the sole is in contact with the ground and 22 percent has holes and ridges to make up the void.
No matter how slip-resistant a shoe may be, Couey points out, footwear is only one component of a slip-prevention program. "Just because you have footwear on doesn't mean you're invincible."
That's why Shoes for Crews carries a slip-resistant mat along with its shoe line. Matthew K. Smith, president and chief operating officer of the West Palm Beach, Fla., company, said other products like mats are needed because not all workers wear proper slip-resistant footwear.
Encourage employees by rewarding those who practice safe working habits and maintain a clean work environment. Workers can reduce the risk of slipping by:
- Taking their time and paying attention to where they are going;
- Adjusting their stride to a pace that is suitable for the walking surface and tasks being performed;
- Walking with feet pointed slightly outward;
- Making wide turns at corners; and
- Ensuring that items being carried or pushed do not prevent them from seeing spills.
New Pig's Markley advocates including employees in all phases of a slip-prevention program. "They're going to know best about the work areas, hazards and solutions."