Coefficient of friction testing

Coefficient of friction testing Coefficient of friction testing measures the ease with which two surfaces in contact can slide past one another, where two different values are associated with the coefficient of friction [...]

Slips, Trips, and Falls. Bad Design or Careless Behavior?

Randy Atlas, Ph.D., AIA, CPP


The paper and presentation address how much comparative negligence is contributed by bad architectural choices and environmental design compared to humans not being aware or “unconscious” of their surrounding environment. What is the role of the environment versus behavior? The architectural design process has critical steps in developing design criteria, but human factors and ergonomics are not typically given priority over aesthetics. Egress paths of travel are usually addressed in terms of accessibility and fire resistance but not in terms of walkability safety, including slip and trip resistance.
Various national and state codes and standards of care define safe travel paths, yet in 2007, more than 21,700 Americans died due to falls, and more than 7.9 million were injured. Falls are the leading cause of injury-related deaths among adults 73 years and older and 2nd leading cause of death for persons 60-72. Over Slips caused 275,000 occupational injuries, trips, and falls in 2008 (Scott, National Safety Council, 2009). Recommendations are made for improved architectural awareness and understanding of the human factors and ergonomics in preventing slip, trip, and fall accidents.


Form follows function. That was a familiar tenet of 20th-century architecture, initially expressed by the Bauhaus School of Design, which was popularized in America by architect Louis Sullivan and his student Frank Lloyd Wright. Yet, most architecture has focused on form rather than function. It is as if the structure, harmony with the site, and integrity of the materials have become the function. Less emphasis has been placed on the activities taking place inside the building. The profession continues to be dominated by the view that architecture is a matter of aesthetics and that form only follows form. (Wikipedia, Nov. 2006) “The intrinsic significance of our craft lies in the philosophical fact that we deal in nothing. We create emptiness through which certain physical bodies are to move – we shall designate these physical bodies for convenience as humans. By emptiness, I mean what is commonly known as rooms. Thus, it is only the crass layman who thinks that we put up stonewalls. We do nothing of the kind; we put up emptiness.” (Ayn Rand, The Fountainhead, 1943.) Most people are familiar with their home or apartment’s layout and environmental cues. When we venture into public spaces such as malls, airports, hotels, stadiums, etc., there is no familiarity with conditions. The frame of reference that protects us at home offers no protection from unfamiliar level changes, steps, holes, or slippery surfaces in public places. Consequently, falls and injuries often result. This paper will address the perception of level changes, design errors, and prevention strategies.
Identifying existing hazards entails a systematic appraisal or user analysis of all possible safety hazards. Those public use environments have a special duty of care to provide safe and easy access, egress, ingress, and walking surfaces. The first step in identifying existing hazards is where to look for the risks. The most logical starting point is observing the design and layout for obvious congestion points, code violations, and what features the architect provided for stairs, ramps, handrails, and floor surfaces. Managers or owners of publicly used spaces should review the history of user patterns. Understanding human factors and ergonomics provides clues on where and how people have accidents. Checking maintenance inspection and accident/incident reports indicates where problems exist.

The second step in identifying existing hazards is what to look for when looking for hazards. The following list is recognized design and construction failures that are contributing factors in stair fall accidents (Rosen, 1983:53):
• 1,2 or 3 winders
• Open risers
• Single steps
• Doors opening onto a stairway
• Low headroom
• Lack of intermediate landings
• Irregular riser heights,
• Tread depths of 10 inches or less
• Widths of stairs 60 to 66 inches
• Absence of nosing projections
• High door thresholds
• Excessive riser heights
• Low riser heights 6 inches or less
• Improperly elevated handrails
• Synthetic tread coverings
• Improper cross-sectional shape of handrail
• Open railings
• Handrails, which are not continuous
• Poor lighting
• Unmarked brick, terrazzo, waxed treads, and smooth marble surfaces
• Loose attachment of carpet or pad
• Walls or posts intruding into stairwell spaces

Thus, the significant areas for conscious observation are changes in elevation, stair and ramp geometry, handrail and guardrail design, lighting, the type of landing area in the event of a fall, physical barriers, and the coefficient of friction of adjacent surfaces. One of the critical issues in slips, trips, and falls is the lack of perception by the human brain to detect a change in elevation or a change in surface. The brain programs the human walk based on uniform distance. After the first step, the brain knows how far to extend the stride to duplicate the prior movement. Any variations from what the brain has learned to expect will result in improper placement of the foot and could result in a slip and fall. 85% of stair accidents occur on the first or last three steps. A one-step level change is particularly deadly as the brain does not expect or quickly perceive the change in geometry. As a result of the brain seeking uniformity, strong environmental cues must be given to increase awareness. Transition zones from one height to another or surface material to another need visual indicators. This
notice may be accomplished architecturally through texture, color, bordering, or signage. People walking are typically looking ahead in their field of vision and not looking at their feet. Thus, level changes or material changes with intense visual distractions or changes in light conditions (i.e., dark hallway into bright outdoor light) can create dangerous conditions for the building user. Another vital issue to look for while scoping the site for hazards is understanding the physical limitations of the walker. Many public use environments have an architectural feature known as monumental stairways. The Nation’s Capital, the State Capitals, and most of our downtown urban cities have governmental structures with grand entrances. Often, these monumental stairways have less than six-inch risers, have few or no handrails, are a marble material, and are usually taxing to climb. These design features are incredibly taxing to the elderly or handicapped (those not in a wheelchair). These features may be grandfathered into compliance with building codes if they exist. Arrangements must be made to accommodate the elderly or handicapped with compliant accessible ramps. Weather conditions should be evaluated as another critical variable in identifying hazards. The building environment will respond in changing ways to rain, snow, summer heat, ice, and wind. All egress points should be carefully designed to allow for water drainage and prevent water from entering the building. Door thresholds are one feature that accomplishes the prevention of water seepage. Most thresholds permit entry without incident. However, door thresholds that are improperly designed or are elevated too high create a significant tripping hazard.

The floor material that transitions the outside to the inside should be carefully considered. Most major office towers, banks, and apartment towers have a concrete or granite outside surface, transitioning from marble to terrazzo or some slick, smooth, shiny floor material. On rainy or snowy days, shoes, dripping raincoats, and umbrellas create a significant safety hazard by bringing in water.
After conducting a safety audit of the public use environment for potential hazards, the next primary concern is what to do with these identified hazards. The designated person responsible for building upkeep and safety (guard service, maintenance, property manager, owner, tenant, or combination thereof) must notify the building management for corrective action. Once the building management or owners are notified that a safety hazard condition exists, the owners and management are put on notice, and further accidents are thus foreseeable, and they could be held legally liable.
The contribution of design to preventing stairway accidents lies mainly in directing attention to the presence of a stairway, level change, or change in surface materials. Design features can focus attention on the stairs and improve the user perception that the steps are clearly defined. Design can provide suitably
dimensioned steps. Design can provide handrails for support and assistance and balustrades to prevent falls from the stairs. Design can avoid features likely to lead to misuse of the stairway by children. Design can avoid creating decorating and maintenance hazards above the stairs. Careful planning and design can
provide the quality and quantity of light to ensure uniform light distribution and no glare to assist in perception. Injury to the user can be a liability issue for the architect and owner of public use spaces. Preventative steps should be taken to reduce or limit legal exposure. Stairs, ramps, and walkway surfaces should meet applicable building codes and national standards. Architects and owners may need to give more consideration to
operational directives regarding how materials specified should be used appropriately. Even if all foresight and
reasonable measures steps are taken, there is no guarantee that it will prevent injury or litigation. However, the issue of negligence and standard of care will be more favorable for the responsible architect and owner.


Thousands of people get injured yearly, and some are killed in the built environment by their careless behavior of not paying attention or faulty architectural features that contribute to the causal factors of these accidents. Most people walk in their daily lives in a swirl of distractions: cell phones, daydreaming, texting, drinking coffee, eating, carrying packages, pets, or children. Human beings in the 21st Century are unconscious of their surroundings and environment until something terrible happens (walking into a street and getting hit by a car for not paying attention to the street lights, misstepping off a curb or step, not observing contaminants on the ground or floor and slipping; tripping over a raised or buckling sidewalk; falling down stairs or steps, and not holding on to handrails, etc.). Accidents are a collateral consequence of behavior or lack thereof and the environment. We have more significant potential to control the environment than people’s behavior.


In achieving the goal of safe and secure buildings, the architect plays a critical role in making the decisions
that impact the selection of fixtures, finishes, and furniture. Most architects are not mindful of the factors contributing to slip, trip, and fall accidents.
Human factors, ergonomics, and premises liability are not topics taught in architectural colleges and schools
or in continuing education courses for practicing architects. The students and practitioners must be trained and
made aware of the consequences their unconscious decisions have on the impact of walking behavior. The
field of architecture is evolving because of litigation and the development of codes and standards to be more
aware and sensitive to the decisions and choices of materials, finishes, and circulation patterns of the users of
the built environment.
Education is critical in the evolution of architecture to be safer for its users. Introducing a course that teaches
human factors, ergonomics, and crime prevention through environmental design (CPTED) as part of their
professional practices development will yield future generations of architects and designers that are better
informed and equipped to make a safer living, working, and playing environment.

Atlas Security and Design will evaluate your property and provide a detailed report on its vulnerabilities. Call or Contact us today.


Heimsath, Clovis. 1977. Behavioral Architecture: Toward an Accountable Design Process. McGraw Hill, New
Rand, Ayn. 1943. The Fountainhead. New York, NY. Bobbs-Merrill Co.
Scott, W.E. 2009. The National Safety Council. Falls at Work: Protect Your Employees—statistics of Accidents.
Rosen, Stephen. 1983. The Slip and Fall Handbook. Harnow Press.
Wikipedia. Nov. 2006

Share This Story, Choose Your Platform!

Leave A Comment