Playground Equipment Critical Fall Height and Surface Area

The depth and area of the BounceBack rubberised wet pour safety surface depends on:

  • The Free Fall Height of the playground equipment along with
  • The Critical Fall Height of the surface.

The wet pour surface depths on this page are a result of specific testing, and apply only to BounceBack wet pour surfaces.

Correctly specified playground flooring is critical to the safety of children.

Surfacing Depth

Free Fall Height is a measurement of distance between a play surface and the protective surface.

Critical Fall Height relates to the impact attenuation of the surface material and is “the maximum height from which a life threatening head injury would not be expected to occur.”

Therefore, the fall height of the equipment should not exceed the critical height of the surface in the design of playgrounds and the type and depth of surfacing used under the equipment.

Free Fall Height is measured from the point at which the feet can stand and not the overall top of the playground equipment.

Many pieces of equipment have tops or coverings so the measurement is not taken from that point but where the child would be standing at the highest point during normal play. The fall height of see-saws is the maximum height attainable by the seat and the fall height of spring rockers is the height of the seat.

The diagram gives the critical fall height and the minimum required wet pour safety surface thickness.

BounceBack Wetpour Critical Fall Height
Fall HeightDepth

Critical Fall Height for Swings

The fall height for swings is measured from the centre of the stationary swing seat at 60 degrees.

To calculate this divide the chain length by 2 and add the distance from the seat to the ground (see image)

Wetpour critical fall height for swings

Surfacing Area Around Equipment

The extent of the playground flooring safety surface required around play equipment is dictated by the height of a potential fall.

Stationary Equipment

Stationary play equipment with a FFH (Free Fall Height) of 1.5m or less should have surfacing which extends at least 1.5m beyond the edges of the equipment. For equipment with a FFH of more than 1.5m, subtract 1.5 from the FFH and multiply the result by 0.667, then add back the 1.5m.

Having an adequate and appropriate playground surface, and maintaining it properly, are the most important things a playground owner/operator can do to minimize the severity of playground injuries.

The above information is designed to help you assess the depth and extent of your safety surfacing but please don’t hesitate to contact us should you require any further advice or information.

The table opposite demonstrates this principle:


Free Fall HeightSurface Distance


Safety is important to us and our customers

The information above is for guidance and to help with understanding of safety surfacing requirements. Every job is individually assessed to take account of individual circumstances. We may recommend a deeper or wider surface.

Appropriate safety factors are an important consideration with all our projects, not only good practice but it ensures reduced risk. We are reliable and responsible, please call.

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