Playgrounds have different areas for different uses. Hard paved areas are required for ball games and wheels, large open running areas are usually grassed, and soft surfaces are obligatory under any equipment from which a child could fall.
WHEN DO I NEED AN IMPACT ABSORBING SURFACE?
There should be a soft surface under all equipment. Any equipment available to the public, schools or care centres, with a fall height over 500mm must have a tested impact-absorbing surface under and around it to help prevent serious head injuries. The surface must comply with Australian/New Zealand Standard 4422:1996 Playground surfacing - Specifications, requirements and test materials".
The supplier of the surfacing material must provide you with confirmation that the surface they have supplied will absorb an impact from the fall height you determine for your equipment.
WHAT IS ACCEPTABLE IMPACT ABSORBING MATERIAL?
Asphalt and concrete are unacceptable surfaces for use under play equipment because they do not have any cushioning properties. Similarly, grass cannot be relied upon to provide protection for equipment over 500mm, as its ability to cushion a fall depends on wear and environmental conditions.
There is no one ideal impact absorbing surface, and your choice will depend on a variety of considerations. The two main types of materials are loose fill (such as bark, woodchip or sand) and unitary, or solid, materials (rubber or synthetic compounds).
LOOSE FILL MATERIALS
Loose fill material should be installed to whichever is the greater depth: 300mm or the depth that your soft fall supplier specifies for the height of your equipment. An extra 20% is required for heavy traffic areas (eg under fireman's poles) or compaction. The kinds of materials available are pine bark, composted bark/chip products (which resemble a fine sawdust), sand, and wood chip (Sand has great variation so is only suitable to be used if it has been property tested and approved for the height of the equipment. Wood chip if small may result in a choking hazard for under 2's, therefore it is suggested that this not be used in the babies' areas in supervised early childhood settings). These surfaces need to be raked and replenished regularly to maintain an even depth.
Loose fill material is generally cheaper, however if the cost of regular maintenance is high, then a more durable unitary (see below) material could compare favourably over time.
A unitary material is a material which is laid as a solid or whole piece. Products include synthetic grass, rubber compounds formed into sheets, tiles, or mats, and 'wet pour' rubber substances that are mixed and trowelled into place on site. The cushioning effect of these materials varies according to the thickness of the layer and the composition of the material. You must use a tested and approved material and have the manufacturer specify the required depth (from CFH test report) to match your equipment. Unitary materials are recommended in heavy traffic areas such as under swings and track rides.
AUSTRALIAN STANDARDS FOR PLAYGROUND EQUIPMENT & SURFACES
Impact absorbing surfaces must comply with Australian/New Zealand Standard 4422: 1996 Playground Surfacing specifications, requirements and test materials and the supplier should provide you with laboratory test results for Critical Fall Height (CFH). Suppliers of any surfacing materials should only install an approved product to the depth specified in their CFH Test report to suit the height of your equipment.