The Ultimate Guide To CFH (Critical Fall Height)

Critical Fall Height (CFH) only applies to playgrounds with play equipment and sometimes, a trim trail.

CFH is the height from which it is assessed that a surface will absorb the impact of a child’s fall, to reduce the risk if serious head injury. This will determine the depth and area size of safety surfacing your playground requires, meeting British and European Standards.

How do I work out the Depth of Surfacing for my play equipment?

This varies between each surfacing company as their products are tested individually. Billy Bounce surfacing has been independently tested by the Centre for Sports Technology under BSEN 1177:1998, BSEN 7188:1998 and BS 5696: Part 3: 1979.

For stationary equipment, the CFH is calculated from the highest point on the equipment which is intended for play – usually the platform height. For equipment from which a child hangs, the height of the hand support is used.

Here’s a diagram demonstrating the guidelines for our rubber safety surfacing underneath stationery play equipment. Don’t worry about understanding it fully, our team are here to calculate the depth after coming out to the site, to assess the area.

BB CFH slide

How do I work out the Critical Fall Height for Swings?

Rarely do we see swings in schools and nurseries. However, for any Maths teachers – the critical fall height of swings is calculated differently from stationary equipment. We calculate the CFH from the centre of the stationary seat surface at 60 degrees. To work this out, we divide the length of the chain of the swing by two, then add the distance from the seat to the ground. Here’s a diagram demonstrating the formula used.

BB CFH swing

How do I work out the Area of Surfacing for my play equipment?

Not only is the depth of safety surfacing crucial for your play equipment, but you also need to take into account the area size of surfacing. This is in case of any tumbles that may occur from children falling from the play equipment.

For stationary equipment, if the critical fall height is 1.5m or less, then the surfacing should extend to at least 1.5m beyond the edge of equipment. See the table below for play equipment over this critical fall.

How do I work out the Area of Surfacing for Swings?

Again, swings live by a separate formula when it comes to determining the area size of safety surfacing. Multiply the length of the chain holding the seat by .867 then add 1.15m. The width of surfacing required for seats no greater than 500mm is 1.75m, that’s 0.875mm of surfacing each way from the seat centre.

For swings with seats wider than 500mm the difference between the seat width and 500mm must be added to the 1.75m (50% to each side of the swing centre).

For more information on working out the Critical Fall Height, call one of our Technical Representatives  – 01282 414131.