Health and safety is an integral aspect of landscape design. Whatever the aesthetic considerations of a project, they must not put its end users at risk. For public or communal spaces, good safety practice is upheld by legal constraints. For example, the Equality Act of 2010 requires public spaces to be accessible and safe for use by disabled users. This includes those in wheelchairs, but there is a duty of care as well for projects commissioned by private clients.
Precautions around planting, such as avoiding poisonous species in areas with young children are essential. The safety aspects of landscaping revolve chiefly around the ‘hard’ features and the risk of falling on or from them. The chances of falls on steps, decks and walkways can never reach zero. But, their design will make the difference between a safe environment and a hazardous one.
Poorly designed steps are a recipe for falls. Identifying where a staircase starts and ends, ensuring all rises are highlighted. Providing protective barriers and handrails will all help to mitigate the risk. In public spaces, changes in level must be visible to partially sighted users. The principle is advisable in domestic scenarios, where even clients with 20/20 vision will want help spotting the edges of steps after dark.
Visibility can improve through lighting or by creating a colour contrast between the noses of steps and the other parts of the staircase. The common way to determine contrasts in colour is by comparing their LRVs (Light Reflectance Values). This is derived by measuring the proportion of visible light reflected by a surface. LRVs range from 0 (black) to 100 (white), and the noses of steps should have an LRV at least 30 points different from the LRV of the rest of the staircase. Tactile strips on steps will also help blind and partially-sighted people locate and navigate them. Drops from the side of steps should have protective barriers. Drops from decks raised above the natural ground level should also feature this.
In addition to the conformation of hard landscaping features, the materials in use will have a significant bearing on how safe they are. The major risk is of slips, especially when surfaces are wet or icy.
Pendulum Test Ratings are the most common form of slip resistance measuring, and the one favoured by the Health & Safety Executive. It replicates the effect of someone’s heel coming into contact with a surface. A pendulum machine is set above a surface such that when the pendulum arm swings. It then touches the surface and an indicator pushes forward, providing a Pendulum Test Value (PTV). The more resistance it meets, the higher the PTV and the less slippery the surface. PTVs with values up to 24 are considered as high risk, those between 25 and 35 as moderate risk, and 36 and above low risk.
As you would expect, when surfaces are wet, their PTVs drop. For example, a typical hardwood will have a very respectable PTV of 65 when dry, but only 22 when wet – i.e. it switches from low to high risk. This is one of the reasons why man-made composite materials are growing in popularity. An example of this would be Millboard’s Weathered Oak decking has a PTV of 66 in the dry, and 54 in the wet – both well into the ‘low risk’ range.
Fortunately, the range of materials available today means safety is obtainable without sacrificing visual appeal. Thoughtful consideration of potential risks, knowing how they can be mitigated, and an understanding of how different materials perform will deliver results that people of all ages will both admire – and be safe in.