Safe walking requires a sufficient degree of friction between the shoe and walking surfaces.

New Standards Change the Landscape of Walkway Safety

Preventing slip, trip, and fall accidents is a risk management proposition.

Slip, trip and fall accidents result in more than 8 million emergency room visits and more than 21,000 deaths each year. They are second only to moving vehicle accidents as a source of death and injuries in the USA. The National Floor Safety Institute (NFSI) estimates that the financial impact exceeds $80 billion per year.

Often, these accidents become litigious. The grocery industry alone spends more than $450 million per year to defend slip, trip, and fall accidents. Most of these incidents are same-level accidents, where the pedestrian slips and falls on an even pathway. In 55 percent of these cases, the walkway is implicated as the cause.

Causes of Slip and Fall Accidents
Walking surfaces 55 %
Footwear 24 %
Hazard warning  1 %
Training 0.8 % 
Fraud 0.3 %

Managing the condition of walkways must be a priority for any risk and safety manager -– both to protect pedestrians from injury and to protect the organization against lawsuits for negligence. Up until recently, monitoring the condition of pedestrian walkways has been a largely subjective science. New standards issued by the American National Standards Institute and NFSI are changing that landscape. Welcome to the era of science and control in the management of walkway and pedestrian safety in the USA.

Safe walking requires a sufficient degree of friction between the shoe and walking surfaces. Some shoe materials offer more slip resistance than others; some flooring materials offer more slip resistance than others. Moreover, contaminants such as water, detergents, oil, dust, etc. serve as lubricants to reduce the coefficient of friction on walkway surfaces. Also, the condition of the floor can change over time due to wear or degradation of friction-enhancing coatings, etc.

As a risk manager, you may or may not have control over the selection and condition of pedestrian shoes. In a manufacturing plant, for instance, you can require the use of safety footwear. In a retail mall or restaurant, it's impossible to influence the footwear of the general public. At most, you can target the reduction of contaminant ingress onto walking surfaces and take action to clean spills when they occur, but this is not foolproof. Managing and monitoring the condition of pedestrian walkways offers you the greatest degree of control and must be a focal point in your efforts to ensure pedestrian safety.

New Walkway Monitoring Standards = A New Era for Walkway Safety
Three important new standards have been released that are game changers in your fight against pedestrian slip, trip, and fall accidents.

  • ANSI/NFSI B101.0: This new standard specifies the process by which walking surfaces shall be audited for slip resistance using an NFSI-approved walkway tribometer. A walkway tribometer is a device that measures the coefficient of friction (COF) or slip resistance of a hard-surface walkway, which is where most slip and fall accidents occur.
  • ANSI/NFSI B101.3: This standard specifies the process for measuring the dynamic coefficient of friction (DCOF), which is the classic definition of friction. It measures the pounds of pulling or pushing force required to slide a pound of mass across a surface. The higher the DCOF, the better -– as DCOF increases, slip resistance increases. This standard specifies action limit values, so you know when regular maintenance or more serious attention is required.
  • ANSI/NFSI B101.1: This standard specifies the process for measuring the static coefficient of friction (SCOF). SCOF differs from DCOF in that it measures the force required to initiate sliding. Typically, more force is required to initiate sliding than is required to perpetuate it.

One can technically argue the merits of measuring DCOF versus SCOF. The author personally prefers DCOF because it tends to be a more repeatable measure, and a significant body of research has been dedicated to determining the relationship between DCOF and walkway safety. Much of that study has been done in Germany, where the standards for pedestrian safety and technological research are highly advanced.

To support these standards, NFSI has created an interlaboratory study (ILS) process to confirm that walkway tribometers are valid, repeatable, and reproducible. Accompanying the ILS is a walkway tribometer approval process. Together, the NFSI ILS and tribometer approval process ensure that your walkway tribometer -- and the company that produces it -- are both dependable.

Executing Walkway Safety Monitoring
With the new auditing and walkway COF standards, your walkway safety management process fits neatly into the Plan-Do-Check-Act cycle with which you most likely are familiar.

1. Plan. Preventing slip, trip, and fall accidents is a risk management proposition. A variation on common tools for risk analysis, such as Failure Modes & Effects Analysis (FMEA), should be employed to evaluate a geographical space, such as a convenience store, for accident potential and to assign priority based upon the likelihood of an event, the magnitude of the consequences, and the effectiveness of your current controls. Utilize historical records on slip, trip, and fall accidents to evaluate your risk. Incorporate accident reporting, analysis, and corrective action protocols to continuously assess and improve your estimates of risk.

2. Do. Once you have analyzed the risks associated with slip, trip, and fall accidents for a geographical space, you may need to take some actions to adjust the risk in high-priority walkway spaces to tolerable levels. These actions could be as simple as putting down mats or installing warning signs. In other instances, it may be necessary to adjust the specification for acceptable footwear, when that is within your control. Sometimes it's necessary to modify the COF of the walkway itself with treatments or, where serious deficiencies exist, replace the flooring itself.

3. Check. To create a control system, you need a feedback loop to check and verify the effectiveness of your efforts. Conduct routine inspections to look for damage, buckling, curling, or other deficiencies in mats and rugs. Confirm that warning signs are up and very visible. Look for spills or other contaminants that increase the risk of a slip, trip and fall accident. Regularly monitor the COF of your hard surface walkways using ANSI/NFSI B101-standardized test methods and approved tribometers.

4. Act. If inspections and walkway condition monitoring of the COF reveal deficiencies, take proactive steps to correct whatever condition fell out of control. For hard surfaces, if the COF falls below acceptable limits, action is required to clean, treat, maintain, or replace the surfaces. ANSI/NFSI B101.3, the standard for measuring the wet DCOF for a hard-surface walkway, provides specific value limits. Based upon decades of research in Germany, these DCOF value limits and the related guidelines tell you when walkway maintenance action is required.

Actions could include cleaning, degreasing, treatment or, in extreme cases, replacement of the affected walkway surface.

Wet DCOF Value Slip Resistance Potential Action
>0.45 (inclines), .0.42 (level) High -- lower probability of slipping Monitor DCOF regularly and maintain cleanliness.
0.30 - 0.45 (inclines), 0.30 - 0.42 (level) Acceptable -- increased probability of slipping Monitor DCOF regularly and maintain cleanliness. Consider traction-enhancing products and practices where applicable for intended use.
<0.30 Low -- higher probability of slipping Seek professional intervention. Consider replacing flooring and/or coating with high-traction products.

Figure 3. DCOF action limits published in the ANSI/NFSI B101.3 standard.

Monitoring Walkways Couldn't Be Easier
Historically, monitoring the COF of a walkway was cumbersome and imprecise. New, microprocessor-based technology makes it a breeze today. Modern walkway tribometers are fast (a test can be completed in a matter of seconds), easy to use, and portable. Many have on-board printers and the ability to upload data to a computer for trending and/or inclusion in a report.

Moreover, they are inexpensive to purchase and maintain. Be sure that your tribometer can measure both DCOF and SCOF, can comply with ANSI/NFSI B101.3 and B101.1 standards, has passed the challenging NFSI ILS test for validity, repeatability, and reproducibility, and is on the NFSI approved tribometer list. Your supplier should offer training on the use of the tribometer and be able to support the deployment of your walkway safety monitoring program.

Slip, trip, and fall accidents are commonly used as fodder to entertain people in movies, comedy acts, and cartoons. In real life, falls aren't funny. Rather, they're very costly to individuals, organizations, and society at large.

With a little focus on risk management, which includes routine monitoring of the slip resistance of walkways – the cause of more than 55 percent of all slip-and-fall accidents -- we can take dead aim at the root of the problem. New standards from ANSI/NFSI, coupled with modern walkway tribometery technology, makes the process fast, easy, and cost effective. Let's usher in the new era of managed walkway safety!

1. Kendzior, R.J. (2010) "Falls Aren't Funny: America's Multi-Billion Dollar Slip and Fall Crisis," Government Institutes: The Scarecrow Press, Toronto. ISBN #978-1-60590-696-6. 2. ASTM F2508 (2011) Standard Practice for Validation and Calibration of Walkway Tribometers Using Reference Surfaces, the American Society for Standards and Materials, West Conshohocken, PA, USA.
3. ANSI/NFSI B101.0 (2012) Walkway Surface Auditing Guideline for the Measurements of Walkway Slip Resistance, American National Standards Institute, New York, NY, USA.
4. ANSI/NFSI B101.1 (2009) Test Method for Measuring the SCOF of Common Hard Surface Floor Materials, American National Standards Institute, New York, NY, USA.
5. ANSI/NFSI B101.3 (2012) Test Method for Measuring the SCOF of Common Hard Surface Floor Materials, American National Standards Institute, New York, NY, USA.
6. DIN 51131 (2008) Method for the Measurement of the Dynamic Coefficient of Friction, the German Institute of Standardization (DIN), Berlin, Germany.
7. DIN 51130 (1992) Determination of Anti-Slip Properties: The Ramp Test, the German Institute of Standardization (DIN), Berlin, Germany.
8. Troyer, D. (2012) "Risk Analysis System for Preventing Slip, Trip and Fall Accidents," working paper under peer review for publication in Quality Progress magazine.

This article originally appeared in the September 2012 issue of Occupational Health & Safety.

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