To summarise the wide range of safety surfacing options, we have briefly defined the most common types with regard to their structure:

Sand (gravel)

Sand is the classic on playgrounds in Germany. This is mainly due to its low purchase price, although this is currently changing. The advantage that sand offers is that it is relatively easy to install and, at the same time, is a play feature in itself, as children can do things like dig, play in it or mould it into shapes. However, sand also has disadvantages, as it needs to be cleaned in regular intervals. Animal excrement and fungi often nestle there. If the sand is damp for a long time, these problems even increase. A grain size of 0.25–8 mm is permissible according to Table 4 of standard DIN EN 1176, and with a layer thickness of 30 cm, it can even be used for a fall height of up to 3 m.

Wood chips

Wood chips are the ecological alternative to sand. These are less sensitive to contamination, are less quickly played away and have a longer lifespan. They consist of shredded wood and are also suitable for a fall height of up to 3 m with a particle size of 5-30 mm and a layer thickness of 30 mm according to Table 4 of standard DIN EN 1176.

Bark mulch

Bark mulch consists of crushed bark and is mostly used as ground cover. Among other things, it ensures, that the soil does not dry out and that vegetation grows. According to table 4 of standard DIN EN 1176 bark mulch is also allowed to be used as safety surfacing material on playgrounds. With a particle size of 20-80 mm and a layer thickness of 30 cm, it provides reliable safety surfacing for falls from a height of up to 3 metres.

Topsoil / turf / concrete

Actually, natural grass is only permissible up to a maximum fall height of one metre, but there is an exception in Germany allowing it to be used up to 1.50 m. However, other materials such as concrete or topsoil can only be used without problems up to a fall height of 60 cm. This is clearly understandable in the case of concrete or cobblestones, as they do not offer any real ‘protection’. 60 cm is the fall height from which no risk of serious injury is assumed. The assessment of natural grass, on the other hand, is problematic because it is difficult to standardise the properties of grass. How high has it grown? How dense is it? And what happens when it has been “played away”? All these are factors that cannot be determined and do not actually allow for a uniform, ‘standardised’ assessment.

Safety tiles

Safety tiles are made of synthetic material and are manufactured industrially. This has the advantage that they can be custom-made in line with the relevant playground design. After the appropriate tests in the laboratory, as offered by ISP GmbH, it can be determined exactly which thickness of a tile is permissible for which fall height. Therefore, the providers usually offer their products in several thicknesses. They can also be customised during production for drainage purposes – the material itself is water-permeable. Furthermore, they are easy to install and replace. Solutions are available for a maximum fall height of 3 m.

In-situ soils

In-situ soils are a visually appealing and very stable solution for safety surfacing. They are also usually made of synthetic materials, but there are also solutions on the market where natural materials, such as cork, are added. This type of safety surfacing material is freshly installed at the relevant playground. It often consists of a base layer and a top layer, as in athletic running tracks. This provides an optimisation, for example with regard to strength and drainage. Depending on the material and thickness, a maximum fall height of up to 3 m is also permissible here.

Synthetic turf is also increasingly used as safety surfacing in playgrounds. The somewhat more natural appearance is often the main reason to do so.

However, in most cases, it is either an unbound synthetic turf or a synthetic turf with a pure sand infill with a correspondingly thick elastic base layer (in-situ or prefabricated). The thickness depends on the maximum fall height tested.

The elastic layer is crucial for the impact-attenuating properties of this playground surface.