Slip resistance design considerations

Slips occur when a pedestrian loses traction due to a variety of sometimes uncontrollable conditions such as wet, soiled or dusty surfaces, inadequate maintenance or cleaning regimes, inappropriate footwear for a given activity or even the loss of slip resistance over time due to wear and tear. Slips and injuries can also occur due to how a pedestrian might be moving across a surface such as running or not paying adequate attention. These varying factors have an impact on the likelihood of a slip and a possible injury occurring.

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Design considerations

Prior to selecting and specifying a floor finish, consideration should be given to the likely uses and environmental conditions a floor finish will be subject to, which might be different to the regular usage of the floor. Consider the following when specifying a floor finish:

Typology and programme

This has an impact on the selection of an appropriate slip rating. A food court would anticipate frequent food and drink spills which might demand a higher slip resistance level. Consideration needs to be given to programming of the space as well as reasonably foreseeable alternative uses. A gym floor would anticipate the use of rubberised running sports shoes, however a gym is likely to be used to hold other community events with occupants who have different footwear. Where loads are being pushed or pulled by individuals, greater surface traction will be required.

Location/environmental condition

This has an impact on changing conditions, for example at a building entrance where external wet surfaces from rain can be tracked indoors. Using mats to absorb moisture can be effective, but the flooring underneath should have high wet slip resistance. Similar issues are relevant around other areas such as pools and their adjacent spaces. Building entrance mats can also enable the capture of dirt and other contaminants that adhere to footwear; this helps to protect the floor and reduces the amount of required maintenance.

Footwear

This has an impact on a pedestrian’s traction with the floor surface. Industrial work environments might require the use of specific types of footwear whereas community facilities are likely to be used by people with varying types of footwear. Event spaces would be used by individuals where high-heels might be common. Different footwear might respond differently to different surface treatments. Chequerplate surfaces provide good slip resistance when people are wearing safety shoes with profiled soles, but the same surfaces can be quite slippery when people are wearing shoes with hard flat soles.

Nature of movement

An individual’s gait and movement will have an impact on their traction. While running might occur with specific footwear in a gym, a hospital might also experience areas where quick movement might occur unexpectedly.

Mobility and capability of users

This needs to be considered particularly in places such as hospitals or aged care facilities where users may have mobility challenges resulting in an unsteady gait or concentration. The use of walking aides such as crutches or frames may impact the likelihood of slips and falls. In addition, differing cognitive abilities or sight abilities might require consideration of contrasting colours to guide pedestrians and indicate changed surface conditions.

Transition between surfaces

This can impact a person’s traction such as if moving from a very rough slip-resistant surface to a very smooth polished surface. A person’s gait and speed might be appropriate on one surface and not the other. Consideration of implementing transitionary surfaces between the two may enhance the slip resistance and indicate a change in surface. HB 197 advises that adjacent floor surfaces should progressively increase or decrease in slip resistance classifications.

Lighting conditions

This can impact a person’s perception of the space. Dark areas may obscure surface hazards whereas well-lit spaces improve visibility and decrease the likelihood of slips. A cinema will operate in both well lit and very dark conditions. Refer Acumen note Lighting guide for inclusive design.

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Maintaining slip resistance

Longevity and consistent performance of slip-resistant flooring rely on appropriate maintenance. Cleaning agents should not leave behind residues that could compromise slip resistance. Scheduled re-testing, as advised in AS 4663-2013 for existing surfaces, is also recommended. Floor maintenance procedures are likely to be prescribed by the manufacturer, so relevant end users such as cleaners must be made aware of the cleaning requirements of different floor materials. Manufacturers of some flooring products specify that they must be kept dry and clean in order to be slip-resistant.

Surface finishes may wear over time resulting in a change to the slip-resistance characteristics of the installed products. Accelerated wear testing might help to provide some guidance when comparing like products. There are no current standards on the application of accelerated wear testing. It is worth noting that most floor finishes experience the greatest drop in their wear after initial usage. Accelerated wear tests after 500 or 1000 wear cycles may be sufficient to understand the loss of slip resistances of a given material.

Slip rating classifications are based on bands of slip resistance values. A P3 classification is given to a material under a wet pendulum test that receives a value of 35-44 and a P2 classification is given for a value of 25-34. If a given material scores 36 and is classified at a P3, after wear from usage it may fall to a P2 much more quickly than a material which scores 43 in the wet pendulum test. It would therefore be appropriate to review the test results and compare the slip resistance values to AS 4586 to ensure that a specified material sits at the higher end of the classification banding.

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Existing surface slip resistance remediation

When existing surfaces are found to be inadequate, the slip resistance rating can be increased via a number of alternative options which fall into three general categories of applied coatings, retrofitted products and surface alteration. AS/NZS 3661.2:1994 Slip resistance of pedestrian surfaces provides guidance on maintaining slip resistance and recommendations to enhance the slip resistance of a variety of materials.

• Applied coatings: can be achieved through epoxy or specialised paints which may have textured grit included which bonds to the existing surface. Penetrative sealers can be applied to porous surfaces to alter the slip resistance, particularly of natural materials.
• Retrofitted products: include adhesive strips and tapes, mats or newly applied materials which have an increased slip rating.
• Surface alterations: can occur through a number of means either chemical etching, surface scabbling, sanding, sand blasting or saw cuts which introduce grooves or texture.

In-situ testing should be undertaken after the application of the new or revised surface treatment is completed to ensure the required slip resistance rating has been achieved. Where remedial treatments have been used, periodic slip resistance testing is strongly advised.

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Specialist advice

Architects should consider obtaining specialist advice when specifying floor finishes, for example:

• Access consultants can provide guidance related to occupant requirements for various facilities and people of varying mobilities.
• Building and facility management personnel can provide recommendations on cleaning and maintenance methodologies and the likelihood of maintenance regimes being appropriately undertaken.
• Manufacturers, suppliers and installers can provide specific technical advice on the ability of a surface to maintain its slip resistance and its appropriate selection for specific application.
• Work Health Safety (WHS) consultants can provide guidance on appropriate slip resistance requirements for workplaces and other higher risk uses.
• Slip resistance professionals, who are involved in the provision of testing and consultancy services, can provide guidance for complex requirements.

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