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Slip And Fall

Slip And Fall

By: Dr. Nicholas Propes, PhD (Electrical Engineering)
Dr. Ash Thakker, PhD, P.E., FASM, CMfgE
Dr. Jyoti Ajitsaria, PhD (Mechanical Engineering)
Global Technology Experts, Inc.
Tel: (770) 803-3001
Email Dr. Propes

A "slip and fall" or "trip and fall" is the generic term for an injury which occurs when someone slips, trips or falls as a result of a dangerous or hazardous condition on someone else's property. It includes falls as a result of water, ice or snow, as well as abrupt changes in flooring, poor lighting, or a hidden hazard, such as a gap or hard to see hole in the ground. The National Center for Injury Prevention and Control estimates that in 2004, more than 8 million people were injured in falls. Fall related injuries are of large concern, mostly to older individuals. According to the Center for Disease Control, in 2005, 15,800 people age 65 and older died from fall-related injuries, 1.8 million age 65 and older were treated in emergency rooms for fall-related injuries, and over 433,000 of these people were hospitalized. If you are on someone else's property and injure yourself as a result of a dangerous condition on the property, the landowner or business proprietor may be liable for your injuries.

Slip and Fall Statistics:

  • The #2 leading cause of injuries throughout the United States. (Auto accidents are #1)
  • The #2 cause for Workers Compensation and Liability claims. (40% of all claims paid out)
  • The #1 cause of accidents in homes, hotels, restaurants, and public buildings. (70% occur on flat and level surfaces)

There are four major causes for slip and fall accidents:

  • Lack of slip resistance on walking surfaces
  • Poor walking surface conditions
  • Poor visibility
  • Lack or poor condition of handrails and guardrails
  • Lack of slip resistance on walking surfaces
  • Friction between walking surfaces and shoes is necessary to prevent slipping. Slip resistance refers to the likelihood of footwear slipping on walking surfaces, especially those that are wet or have a buildup of wax, dirt, or other substance between the floor and shoe soles. Property owners have a legal responsibility to ensure walking surfaces are safe for pedestrians under conditions reasonably expected according to the walking surface's purpose and are not negligent in the care or maintenance of the surface. Installation of appropriate flooring materials may be the property owner's duty to ensure safe walking by pedestrians.
  • Poor walking surface conditions
  • Aside from lack of slip resistance, walking surfaces can be in poor condition due to other deficiencies. Mats present a trip hazard, especially those in a deteriorated condition with loose threads and curling corners, mats with edges greater than ½ inch or without a slip resistant liner between mat bottom and floor surface. Concrete surfaces which are buckled and cracked, have uneven joins, loose pieces and holes or missing or damaged manhole and services covers pose a potential slip and fall danger. Unmarked raised doorsills can cause trips. Spills that are not marked with signage or mopped up promptly and properly create a poor walking surface, even on floors that are structurally sound. Some or all of these conditions, depending on the circumstances, may give rise to a claim of negligence.

  • Poor Visibility
  • Proper lighting is an obligation of a property owner. All areas should be well lit, including inside the building, the outside perimeter, stairways and parking areas. Lighting should be adequate for all seasons of the year, weather conditions and times of the day people are reasonably expected to use the premises. A situation involving improper lighting may also give rise to negligence claims.

  • Lack or poor condition of handrails and guardrails
  • Handrails must be within reach across the entirety of a stair (i.e. both sides and the middle) and optimally placed between 34 and 38 inches to reduce the possibility of a person falling over the handrail. The handrail should also be easily graspable by the average person. Handrails must be anchored in accordance with building regulations.

    Slip and falls can entail a variety of injuries, most commonly affecting the lower back, coccyx, knees, ankles, wrists and hands. Occasionally, neck injuries or head injuries are reported and may make the case that much more serious. The way a person falls and the surface on which they land will have substantial effects on the injuries they may receive.

    Slip and fall, in United States tort law, is a claim or case based on a person slipping (or tripping) and falling. It is a tort, and based on a claim that the property owner was negligent in allowing some dangerous condition to exist that caused the slip or trip. Because of a general perception that slip and falls are at least partly the fault of the person injured, slip and fall injuries are usually worth less than injuries from other types of torts. This is a difficult area of the law for the layman to understand and for the attorney to explain liability rationale to her client.

    Because of the seriousness of the “slip and fall” problem a great many researchers have focused on devising tools to analyze this event. Concentrating only on slips, there is general agreement that they may be abated by controlling the friction coefficients of floors. Slippery surfaces, improper footwear, inadequate hazard identification, inattentiveness, construction deficiencies, and physiology are among the many underlying reasons for slip and fall. To initiate the investigation, analysis of the premises is a cost-effective first step. Measurements of critical dimensions, frictional aspects of the stairs or floors and lighting levels, yield factual information that acts as a basis for accepting or denying a claim. Three major ingredients of the slip and fall accident investigation revolve around the friction between the floor and the shoe, physical configuration of the accident scene, and/or lighting of the scene.

    It is generally considered in the industry that a walkway surface with a coefficient of friction higher than 0.5 is non-hazardous. Federal regulations from the Americans with Disabilities Act recommend a coefficient of friction of 0.6 or higher. The coefficient of friction is a measure of the slipperiness of a surface, the lower the coefficient, the more slippery the surface. The coefficient of friction is the ratio of the weight of an object to the frictional force required to just move the object. Human locomotion involves acceleration during start-up, slowdown, steady movement, and maneuvers. These accelerations are associated with tangential forces transferred from a walker's footwear to the walking surface. To accomplish desired ambulation the tangential forces must be resisted by ground reaction forces. On uncontaminated dry floors, ground reaction forces are developed through friction.

    If a claim of a slippery surface arises, determination of the coefficient of friction or slip resistance through testing may help in the evaluation of the claim. For slip and fall investigations, the incident walking surface slip resistance can be measured using a tribometer/slipmeter. The surface can be tested to identify if it is above or below accepted levels of slip resistance thresholds. Special instruments are available to measure slip resistance. There are many distinct type of tribometers developed in the late twentieth century, but there is still wide disparity among the results. Due to publications of various sets of guidelines for development of a valid meter, there is less controversy about the threshold of safety then about how to measure it. The table below list some of the tribometers developed in the early twentieth century.

    Table 1: List of Tribometers



    ASTM Standard

    Horizontal Dynamometer

    Ceramic Tile Institute


    Horizontal Pull Slipmeter

    Charles Irvine


    James Machine

    Sidney James

    D2047, F489

    MK I Slipmeter

    Robert Brungraber

    F462, F1678

    MK II Slipmeter

    Robert Brungraber

    F462, F1677

    Universal Slip Tester

    William English


    Single Pendulum Tester

    Percy Sigler



    CERAM Research


    English XL

    William English


    Slip resistance is related but is not the same as coefficient of static or dynamic friction.  Slip resistance is typically referenced in the cases of slip and fall accidents because it includes surfaces contaminated with liquids such as water/lubricant etc.  The American Society of Testing and Material (ASTM) and the American National Standards Institute (ANSI) refer to a slip resistance measure defined as “…the relative force that resists the tendency of the shoe or foot to slide along the walkway surface”. ASTM has created the F1679 standard specifically for the English XL Variable Incidence Tribometer (VIT).  It is one of only two standards approved in the United States for measuring under wet surface conditions. 

    The English XL VIT (Figure 1) is the most widely accepted slipmeter of choice among US insurance companies, and it is widely accepted in the courts. It is a portable "slip tester", designed to test the “slip index" on various walking surfaces, level or incline (even steps), under dry and wet (or otherwise contaminated) conditions by mimicking certain pedestrian bio-mechanical parameters. It can measure the slipperiness of any walking surface and is recognized by ASTM/ANSI F1679, ANSI A1264.2, and other specialized test standards for its use by ASTM, NFPA and ANSI committees as well as OSHA and ADA compliance. The English XL VIT is designed primarily for valid measurement on wet surfaces, incorporating dynamics that mimic certain parameters of a pedestrian's gait. It is the only tribometer equipped with a stair fixture that enables the metering of traction on step nosings parallel to the direction of pedestrian travel. It is considered by many to be the most precise tribometer in the market currently for wet surface slip resistance measurements.

    Slip and Fall - Figure 1

    The English XL Slip Meter measures slip resistance index (SRI) on a scale of 0.0 to 1.0. The values in the lower end indicate danger of slip and fall and values in the upper range is an indication of increased degree of safety. It has long been accepted among researchers, as well as in the courts, that a slip index of .50 is the threshold of safety. That is, lower numbers are either hazardous or marginal, while higher numbers are recognized as adequate for normal walking and normal pedestrian activities.

    Global Technology Connection, Inc. has extensively used the English XL to expose slippery floors and to give their clients their due compensation.

    Global Technology Experts, Inc. (founded 1996) has investigated 350+ failures that included slip and fall, lift trucks, bicycle failures, electrical failures, battery failures, construction defects, automotive bumpers, airplane and engine component failures, automotive axle, weld joints, aluminum, titanium, polymers, ceramics and composite materials. Life assessment and durability of prototype components etc.

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