Movable pool structures

Good movable floor and boom design will by necessity address a number of key elements, including:

• the various loadings to be applied; there are key loadings set out in BS EN 13451-Part 11 for movable floors and booms; additional loadings may be required where floors and booms are used for other than normal submersed conditions
• the aesthetics will need to consider the materials and colours used in the pool tank; ideally the floor and boom panels will match the tile/pool tank finishes, including the racing lanes; and crucially the racing lane lines need to align
• movable boom movement can take a similar approach to movable floors; a further option is to use inflatable chambers to ‘float’ the boom to the surface
• materials are typically polypropylene, polyethylene for the visible surface panels and stainless-steel support framework
• signage for the variable pool water depths
• interfaces with the pool tank structure are critical, to enable the floor/boom to move within the pool tank, but without creating gaps between the tank/floor or boom and also accommodate applied structural loads.

Movable floors are essentially large platforms, structurally rigid, that can be moved up and down inside a pool tank.  The floor will normally have some level of buoyancy, as a minimum to counter the weight of the floor and as a maximum to support all the loads to be applied to the floor.

There are several options for movable floor movement; one approach is to use hydraulic rams with stainless steel cables and pulley blocks to move and locate a fully buoyant floor; the hydraulic rams can be located on the pool tank wall – a direct drive approach – or at pool deck level – the indirect drive approach; strict sizing criteria needs to be addressed for ratios between cable diameters/pulley block diameters to ensure that cable life is not unduly shortened; other options include screw jacks.

Movable booms are either submersible or traversable.

Submersible boom

This is housed in a recess in the floor of the pool tank and operated via a poolside electrical panel. This type of boom can only be used in one fixed location within the pool tank; it will require no physical manual input except operating the control panel itself.

Traversable boom

This is always on the surface and requires manual input each time the boom is moved along the pool; it can be located in almost any position in the pool tank.  This type of boom is often used in 50m competition pools to assist in setting the racing lane lengths to the very strict tolerances as required by FINA.

Pool access lifts are very similar in design to movable floors in that they will have a rigid platform that will be raised/lowered either by hydraulic or electro-mechanical means.

One of the first things to consider are the published  Regulations, Standards and Guidelines that should govern how systems are designed; key publications include:

• Swimming Pool Water Treatment and Quality Standards for Pools and Spas, Pool Water Treatment Advisory Group (PWTAG)
• HSG 197, Managing Health and Safety in Swimming Pools
• BS EN 13451 Swimming Pool Equipment – Part 1: General safety requirements and test methods
• BS EN 13451 Swimming Pool Equipment – Part 3: Additional specific safety requirements and test methods for inlets and outlets and water/air based water leisure features
• BS EN 13451 Swimming Pool Equipment – Part 11: Additional specific safety requirements and test methods for movable pool floors and movable bulkheads
• BS 6440, Powered lifting platforms for use by disabled persons – Code of practice, where applicable.
• Health and Safety at Work Act 1974.
• BS EN 15288-1, Swimming pools – Safety requirements for design
• BS EN 15288-2, Swimming pools – Safety requirements for operation.