Slips, trips and falls
Detlef Mewes, Institute for Occupational Safety and Health of the German Social Accident Insurance, Germany
An inadequate slip resistance of flooring and/or footwear causes slipping accidents. Tripping is caused by the unevenness of the ground, obstacles on the flooring or poor coordination during stepping. Slipping or tripping can cause falls. Such accidents are summarized as falls on the same level, because they happen on level surfaces with no or only little change of incline. Accidents in which a person falls from a roof or scaffold are not included within the category of slip, trip and fall accidents. Such accidents are classified as "falls from a height". However, it is important to note that not all accident recording systems in EU Member States make this distinction
Slips, trips and falls are the biggest class of accidents in workplaces. In 2005 approximately 400,000 accidents leading to more than three days of absence from the workplace in the EU were due to slipping, tripping and falling. Slip, trip and fall accidents are not classified in any greater detail; it can be assumed however that the proportions of slip and trip accidents are approximately equal. The great majority of such accidents occur on the floor, followed by stairs.
European directive 89/106/EEC, section "Safety in use" states that unacceptable accident hazards caused by slipping, tripping or falling should not occur; the directive does not however state concrete requirements and measures by which this protection requirement may be attained. Regulation of this aspect remains the remit of the individual EU Member States. In addition, Directive 89/654 concerning workplace requirements states that floors ‘must have no dangerous bumps, holes or slopes and must be fixed, stable and not slippery’.
Factors affecting slip resistance
The main cause of slipping accidents is an inadequate slip resistance of flooring and footwear. Slip resistance depends on the friction between flooring and shoe: the higher the friction, the higher the slip resistance. Several different parameters can be assigned broadly to the four components; flooring, shoe, lubricant and human factors. These influence the frictional behaviour and thus the slip resistance.
- The type of floor can be assumed to be the most important factor in the avoidance of slip accidents. A correctly selected and installed floor may provide adequate slip resistance even where footwear with varying slip resistance properties is worn, and under wet conditions. In addition, floors generally remain installed in structures for many years and may not be replaced for decades. Besides the type of floor (such as ceramic tiles, natural stone, parquet, elastic surfacing), parameters such as the micro roughness and macro roughness, the profiling, the level of wear and the condition in which the floor is maintained all influence the slip resistance.
- The footwear selected also has an influence upon the slip resistance. Important footwear parameters include the type of sole material, its hardness, elasticity, roughness, tread, and level of wear.
- Liquid and solid lubricants increase the risk of slipping considerably, since they reduce the contact between shoe and floor covering. Typical examples are wet shoe soles, contamination by solids on the floor caused by production methods, and condensation.
- Human factors include parameters such as the walking behaviour, walking speed, weight, a person's physical fitness and attention, and also the ease with which slippery floors can be recognized as such.
Technical, organizational and personal measures enable the number of slip accidents to be reduced. The most suitable measures ultimately depend upon the circumstances in the case concerned.
Floors must have a sufficient slip resistance that depends on the working circumstances. For example a floor in a slaughterhouse requires a higher slip resistance capability than a floor in a finance company.
Shiny floors in particular often exhibit inadequate slip resistance, necessitating retrospective corrective measures. Chemical treatment in-situ of floors may be a suitable solution for existing mineral floor surfaces, such as natural stone floors, ceramic tiles, and concrete and screed floors. Components of the agent used to treat the floor covering react with the minerals within it, partially leaching them out. Such solutions are not suitable for floors made of wood or artificial materials. Chemical treatment of floors in situ is worthwhile only if it enhances the slip resistance of the floor without significantly impairing its visual appearance or the ease by which it can be cleaned. Mechanical treatment methods are also used on floors in situ. These include the grinding of existing surfaces.
Slip resistant mats and zones, for example at building entrances in which outdoor dirt is retained before it is carried into the building, are further engineered measures for increasing and ensuring slip resistance.
Slippery substances on floors should be eliminated if at all possible, for example by the use of suitable exhaust equipment on machinery. Projecting roofs outside buildings may provide effective protection against the weather (moisture, snow, rain, wet leaves).
If all these measures are not satisfactory, there may be no alternative but to remove an existing floor from a building and replace it with a new floor, despite this being the most expensive solution.
Cleaning is probably the most important organizational measure for retention of the slip resistance. Cleaning can help to reduce the likelihood of slip accidents by keeping floors free of contamination. However, the cleaning process itself often introduces contamination to the surface, such as water or detergent solution. After cleaning, any improvement in slip resistance will not take full effect until the surface has dried. Occasional testing of floor surfaces is recommended to monitor slip resistance levels and to determine the effectiveness of the cleaning procedure.
The cleaning methods and products used must be suitable for the floor covering. In general, floor coverings with a high slip resistance are also more difficult to clean. Cleaning machines with rotating brushes and jet streams have proved effective for the cleaning of floors with deep profiles or rough surfaces. Their use may pay off economically even on relatively small floor areas. When using jet-stream cleaning equipment it is important that the pressure and temperature of the liquid and the mixture ratio of the cleaning agent and water do not damage the floor covering and, where applicable, the joints.
In some cases, the use of cleaning and care products may even reduce the slip resistance of floor coverings. This possibility must be considered when cleaning and care products and their concentration are selected. Such products are often used at too high a concentration in practice. Where care products with slip resistant additives are used, the concentration must be mixed precisely in order to assure the slip resistant property. Moisture renders slip resistant care products ineffective, making the floor even smoother than it would have been had the product not been used. Following the use of floor-wipe products with slip resistant additives, the floor covering should not be polished again, as this negates the slip resistant property.
The organizational measures also include regular checks of the slip resistance by means of mobile equipment that can be used on site. In areas that can be controlled, such as company premises, the use of slip resistant footwear should be ensured. In areas presenting a particular risk of slipping, warning signs should draw attention to the hazard. If necessary, access to these areas should be controlled.
The regular provision of instruction to employees is a particularly important personal measure. Instructions should be given among other things to wear suitable footwear. Footwear should be tested in real workplace environment, as this is the best way to find out whether the slip resistance of a shoe is high enough for a specific working environment. To rely on laboratory test data alone is not sufficient. Shoe soles should be checked regularly as these wear out with time.
Furthermore instructions should be given to remove slippery contamination from the floor immediately, and to walk in a safe manner. The handrail should always be used on steps. The cleaning personnel should also receive regular instruction; if appropriate, multilingual work instructions should be provided.
Trip accidents are caused by elevations or recesses in floors such as steps, inclines, gutters and gaps, or trip hazards of any kind. In general, height intervals of over 4 mm are considered trip hazards, and on the surfaces of steps, height differences of over 2 mm. Pipes and cables, loose floor edging, or objects left lying on the floor act as trip hazards. Approximately 50% of all tripping accidents are related to bad housekeeping.
A range of measures, can be taken to avoid trip hazards:
- the floor must be laid properly and maintained in a good condition;
- the surface must be level and free of holes;
- if necessary, elevations on the floor must be bridged, and recesses covered or filled;
- the traffic area must be free of door bumpers and stops, pipes and cables, and drops, inclines and openings;
- should an area be identified as hazardous, access to it must be prevented, at least until the hazard has been eliminated;
- there must be sufficient lighting, coloured or high-contrast markings or warning signs in order to draw attention to the hazard point.
The risk of tripping can also be influenced substantially by individual behaviour. Fast walking or running, distraction by the use of mobile telephones and the carrying of large packages which obscure the view of the ground increase the risk of tripping and the associated injury.
The handrail on stairs has the sole function of assuring safety during ascent and descent. The design of the handrail must permit grasping, during both ascent and descent and during the carrying of objects, ideally with the same hand.
Links for further reading
DGUV – Deutsche Gesetzliche Unfallversicherung. Fußböden, Rampen, Treppen. Retrieved 9 June 2011, from: 
Bergische Universität Wuppertal. Fachgebiets Sicherheitstechnik/Arbeitssicherheit. Retrieved 9 June 2011, from: 
HSE – Health and Safety Executive. Slips and Trips. Retrieved 9 June 2011, from: 
EU-OSHA – European Agency for Safety and Health at Work Fact Sheet 14: Preventing Work-Related Slips Trips and Falls, 2001. Available on: