Whilst carrying out a free-of-charge site visit at a leisure centre in the Midlands this month, our team detected a small whirlpool or ‘vortex’ on the surface of the water – a sure sign that the suction rate through the sump main drain on the pool floor was too high. A sight that immediately sets our alarm bells ringing. Whilst appearing as an inoffensive eddy on the surface, the strength and power that is being exerted beneath can be lethal to swimmers.
Swimmers, especially youngsters, are often drawn by curiosity to the currents formed by the excessive suction at the sump on the pool floor with possible disasterous results. Hair can be sucked through the grille and twisted round and round until it is impossible for the swimmer to disentangle themselves. Any partial obstruction of the sump – for example someone sitting on it – magnifies its force and unless failsafe mechanisms are in place can end in fatality.
This problem is generally found in pools with a single outlet, and guidelines for new pools state that there should be a minimum of two suction outlets per pump, at least two meters apart. In addition there must be cut off mechanisms within the pump system to ensure entrapment does not occur. However, in existing pools installing new pipes and plumbing is extremely costly and is often not feasible. Commercial & Specialised Diving have a cost-effective and easy to install solution for you.
We can install anti-vortex grilles as a low cost and effective alternative, with little or no disruption to the day to day running of your pool. These are raised grilles that allow water to pass both through the face of the grille as well as the perimeter between the grille and pool floor. This design means that it is less likely for all openings to be covered simultaneously, greatly reducing the risk of entrapment. Our divers installed one at the Midland’s leisure centre making it safe with no pool down time needed at all.
CSD also carry out flow-rate and hair entrapment testing, so you can be sure your pool is a safe environment for your swimmers – Call us today to find out more, and look out for further information on vortexes, entrapement and anti-vortex grilles in next month’s Update.