Employee safety is one of the most important requirements for any workplace. Slips and falls are among the most common injuries at work. They account for about 86% of total injuries, and 90% of these happen because the floor is wet.

These injuries are particularly prevalent in the food industry, where they occur four times more often than the average in other industries. Injuries can create significant impacts to all involved. Most significant is the suffering and possible disabling of the person injured. Next is impact on the company—financial, loss of key staff, loss of productivity, and liability.

 

MINIMIZING TRIPS AND FALLS

There are four main contributing factors that can cause a worker to slip and fall down. These include: environment, organization, individual, and footwear (Table 1).

Causative Factor Control measure

Environment

  • Contamination of the floor (spillages, debris, wet cleaning)

 

  • Slip resistance of the floor not maintained properly (incorrect or inadequate cleaning)

 

  • Slip resistance of the floor is too low (inadequate floor roughness)

 

  •  Steps and slopes—steps are too sudden and not well marked; slopes are too steep

 

  • Adverse conditions hiding floor conditions

 

  • The nature of the task and  movement on the floor (need to carry heavy loads, turn and move quickly, pull loads)

 

  • Eliminate the contaminants

 

  • Remove debris and clean more thoroughly

 

  • Increase slip resistance or lay a more slip resistant floor

 

  • Ensure that steps and slopes are  well marked and provide  adequate foot and hand hold and stability

 

  •  Remove hidden obstacles;  provide adequate lighting

 

  • Encourage more care walking  in slip areas

Organization 

  • Layout of work premises and general traffic flow

 

  • Safety culture

 

  • Supervision

 

  •  Identify slip potential areas and encourage safer behavior and vigilance

 

  • Education and promote positive, proactive attitudes to safety in general; measure and communicate safety progress on continual basis

 

  • Monitor risks and behavior and correct accordingly

Footwear

  • Shoes and slip resistance must match

 

  • Suitable shoes. Right kind of sole material and texture for the floor surface

Individual

  • Safety is everyone’s responsibility
  • Provide adequate training; reward individuals who introduce better, safer ways of working

It goes without saying that to reduce slips and falls the floor should be kept clean and dry.  In food and beverage production environments, this may not always be possible.  Striking the optimum balance between safety and production realities is not always an easy task.

 

Often, for instance, there is a conflict between cleaning and surface roughness of a floor. While the supervisor of the facility may be looking for a rough, anti-slip floor for safety’s sake, the maintenance manager may prefer a smooth surface that is easy to clean instead. The solution usually involves a trade-off between the two.

 

REGULATIONS AND MEASUREMENT

Regulations regarding slip-resistance vary widely between countries.  In the EU, for instance, some regulations exist, but there are no common requirements that companies have to follow.   In countries such as the UK, USA, and Australia, there are, and these may be linked to a higher incidence of litigation. 

 

The most widely used method of measuring the slip resistance of a floor worldwide is the Pendulum Tester, also known as the Portable Skid Resistance Tester, the British Pendulum, and the TRRL Pendulum (figure 1).  It is currently a standard in 49 countries on five continents.

 

The American ASTM E303-93 and UK BS EN 13036-4-2011 slip-resistance standards are what define the Pendulum Tester as a measuring device.  Australia uses it as well and its HB 197:1999 standard is known to provide the most detailed information for wet Pendulum Tester values in different situations.

 

The TRRL test method uses a dummy foot that swings down and makes glancing contact with the floor surface being tested.  The unit measures the coefficient of friction (CoF) between the two surfaces (the floor and the bottom of the foot) at the moment of impact.  The test equipment is portable allowing “in situ” use while a facility is in full operation.  The test can be executed on wet or dry floors, and slip-resistance results are expressed as low, moderate or high.

 

The EU uses a variable-angle ramp test (see figure 2) that is based on the DIN 50197 and DIN 51130 anti-slip standards.   In this test, flooring strips are mounted on a movable ramp, and an operator wearing safety boots walks on them in one direction, and then back again in the other. The ramp is then slightly inclined in stages until the operator slips. The angle at which slippage occurs is recorded as the “R value” of the floor.  Variable-angle ramp tests done in the food and beverage industry often include oil contaminants added to the to the floor strips to simulate real-life conditions. These types of tests are well suited to heavily textured or profiled surfaces.

 

Two other dynamic “in-situ” test methods use the Tribometer (Figure 3) and SlipAlert (Figure 4) testers.  Each provides a practical and fast method of defining the surface coefficient of friction. These methods can be used on both wet and dry floors. SlipAlert is also adopted by the British BS 8204-6: Synthetic Resin Flooring standard, and is used mainly in the UK as a more practical method than the TRRL Pendulum.

 

Indication of slip potential in water-contaminated conditions can be obtained by using a micro-roughness meter to measure the peak-to-valley roughness of the floor surface.  Results are expressed as a floor’s “RZ” value, which does not directly state slip-resistance but does provide an indication of slip potential. The micro-roughness hand-held meter (Figure 5) is easy to use and is often employed to double check Pendulum Tester data. A limitation of the unit, however, is it cannot be used for exceedingly rough floors.

 

MANAGING THE RISK OF SLIP RESISTANCE

When selecting the texture of the floor surface for required slip-resistance, the four most important issues to consider are degree of contamination, applied cleaning regime, slopes, and the shoes or boots that personnel are wearing.

Contamination

Floors can be contaminated by a wide variety of things, such as water, fats, oils, food debris, and a combination of them. The greater the contaminant viscosity, the greater the texture required to achieve the desired slip-resistance. Table 2 indicates the typical minimum values of peak-to-valley roughness levels, as measured by the micro-roughness meter, required to give satisfactory slip-resistance for different contaminants.

 

This is a good supplementary way of determining slip-resistance in combination with the Pendulum Tester or other dynamic method.

Minimum roughness, µm Contaminant
20 Clean water, coffee, soft drinks
45  Milk, soap solution 
60  Cooking stock 
70  Olive oil 
>70  Margarine 

Cleaning and maintenance 

Cleaning methods must always be adjusted to the environment and operations.  Higher surface roughness, for instance, requires more scrubbing and mechanical work, and a rough floor needs to be flushed with higher amounts of water than a smooth one.  On the other hand, constant application of intense and frequent mechanical cleaning may wear down the floor surface and result in lower slip resistance over time than what was originally specified.

 

For this reason, some owners have introduced the “Sustainable Slip-Resistance” approach for their production facilities. In this case, long-term slip-resistance is checked by a test in which the coefficient of friction is measured at the outset for a new floor surface and then again after numerous cleaning cycles. 

 

The most effective cleaning method normally requires the use of mechanical floor cleaning machines in conjunction with appropriate cleaning chemicals. An important part of managing slip resistance is to ensure the cleaning regime complies with the flooring manufacturer`s recommendations.

 

Slopes and surface regularity

Slopes are needed to move liquid across the floor to a drain by gravity.  Meanwhile, slip-resistance requires surface roughness, which can impede the flow of liquid toward a drain.  Steeper falls increase the gravitation effect but may create problems underfoot. There are no standards for falls, but food industry norms suggest ratios between 1:100 and 1:80, and as much as 1:50 in free draining floors.  Notwithstanding, a textured surface may require a higher fall to allow fluids to drain naturally.

 

The degree of fall and the surface regularity—i.e., flatness of screeds--largely determine the tendency for water and other contaminants to “pond” on the floor.  Ponding can result in higher contaminant film thickness, which can reduce slip-resistance.  For synthetic resin flooring, the BS8024-1 standard specifies the degree of regularity required to minimize ponding.

 

Flaws in surface regularity can cause trip hazards, increased wear, problems with vehicle wheels, and difficulties installing equipment.  Surface regularity is generally measured by a 2m straightedge laid flat against the screed and measuring any deviation between the two with a slip gauge or other device.  According to British Standards specifications, surface regularity for screeds are classified as following:

Class Maximum Permissible Departure from a 2 m Straight Edge - mm Application
SR1 3 mm High Standard: Special floors
SR2 5 mm Normal Standard: Normal use in commercial and industrial buildings
SR3 10 mm Utility Standard: Other floors where surface regularity is critical

Footwear

In industrial flooring situations where floors are wet and contamination is unavoidable, workers should use footwear specially designed for those conditions.  Not all “safety” shoes are necessarily safe in all situations. The material that a sole is made from and its texture will determine its slip-resistance against a given floor surface.  After matching up variables, shoes and boots should be regularly inspected for wear, as should floors for any significant surface changes.

 

Safety is everyone’s responsibility, from the very top of a company to people working at all levels.  Safety should be a fundamental part of every company’s corporate culture.  Workers who feel the company cares about them care about the company.

 

At Sika, we have the products and services to help make your workplace safer and more productive.  We can help you choose the right flooring with the right functionality, the right ease of cleaning, and the right level of surface roughness for all parts of your facility. When you think floors, think Sika.

REFERENCES

HSE information sheet: Food Sheet No 6. 9/1998

HSE: Assessing Slip Resistance. 5/2012

FerFa: Measuring and Managing the Level of Slip
Resistance Provided by Resin Flooring. 4/2012

Christopher G.J Baker: Handbook of Food Factory
Design. 2013