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How to Calculate the Total Volume of LIAS Required
  1. Measure the maximum free fall height.
    This is the greatest vertical distance between any accessible part of the equipment intended for play and the surface beneath. Where barriers and guard rails are provided, for example around platforms, stairs or ramps, the free fall height should be taken as the height of the platform, stair or ramp. For further information, refer to the API guide to the provision of rubber and loose fill impact absorbing surfaces.
    Play equipment inevitably has different fall heights at different points. The type of LIAS used should take this into account.

  2. The free fall height, together with the results of laboratory testing, will determine which products can be used and at what depth they should be installed.
    To comply with BS EN 1177, item 4.1.3 states that if loose particulate material is used it shall be installed to a layer thickness of 200 mm more than that found by laboratory testing to be necessary to achieve the required critical fall test.

  3. Measure the surface area to be covered, in square metres rounded up to the nearest half metre.

  4. The table below gives a guide to the area in square metres, covered by one cubic metre, when evenly laid at the given depths. The 'Playsand' LIAS is sold by weight.

    LIAS depth required 500 mm 400 mm 300 mm 200 mm 100 mm
    Square metres covered by 1m³ of LIAS 2.0 2.5 3.3 5.0 10.0
    Square metres covered by 1 tonne of LIAS 2.4 3.0 4.0 6.0 12.0


  5. Divide the total area to be covered by the figure in the appropriate depth column, to get the pre-settlement quantity of material required in cubic metres.

  6. Refer to the 'Melcourt Product Specification and Performance Guide' (item 7) to determine the product settlement factor.

  7. To calculate the total quantity of material required, add the basic quantity as in 5 above, to the settlement quantity calculated as in 6 above.



    Example

    To calculate the total quantity of Melcourt Playbark® 10/50 required where :-

    Therefore :-

    1. Refer to the Melcourt LIAS Critical Height Test Results in Accordance with British Standard 7188:1998.
    2. Laboratory testing showed that Melcourt Playbark® 10/50 achieved a critical fall height of 2.45 metres, at 100 mm LIAS depth.

      The maximum critical fall height in the example is 2.40 metres, therefore to comply with BS EN 1177, item 4.1.3. the depth of Melcourt Playbark® 10/50 will need to be 100 mm + 200 mm i.e. 300 mm settled depth.

    To complete the calculation :-

    Surface area of 365 square metres x 300 mm depth = 109.50 cubic metres
    Add 'settlement factor' from technical information sheet i.e. 10% = 10.95 cubic metres
    Total = 120.45 cubic metres


    Quantity of Melcourt Playbark® 10/50 required, rounded up to the nearest whole cubic metre = 121 cubic metres.