Swimming pool engineers are being urged to keep vigilant and make sure they alert pool owners and operators to the dangers of single main drains in swimming pools. “Over the past 30 years there have been many cases of entrapment in swimming pools internationally, many of which have caused life changing injuries, and some have been fatal,” warns Chris Carr, FISPE.
Chris advises there are still many pools in the UK with only one main drain, generally built in the 1960’s and 70’s. The Swimming Pool and Allied Trades Association (SPATA) introduced updated Standards to advise that all new pools fitted with deep suction outlets should be installed in pairs. Initially it was proposed that each pair of main drains should be at least two metres apart (edge to edge) but more recently that distance can now be reduced depending on the physical design of the pool.
“By fitting two main drains, the intention is that a person should not be able to cover both main drains at the same time, and if one drain becomes blocked, then the full flow should be taken through the uncovered drain,” says Chris who emphasises the connecting pipework should be sized correctly.
“As swimming pool engineers, whenever on site, we do have a responsibly to inform the pool owner or manager regarding the entrapment risks of using a pool with only one main drain. “It is important to point out the dangers in writing, as a conversation can easily be forgotten, particularly if you are speaking to a new pool owner.”
Chris continues: “To overcome the risks for pools fitted with one main drain, there is a practical solution which is far more realistic than the cost of installing two main drains and replacing all the suction pipework to the plant room. The alternative is to install a safety vacuum release system (SVRS) in the plant room before the filtration pump.
In most cases this can be easily installed in about three hours and at a fraction of the cost of installing two main drains and replacing pipework. “Once installed the device should be set to introduce air into the water flowing through the suction pipework if a higher than acceptable vacuum is present,” advises Chris. “The introduction of air by this device will prevent the suction ‘hold down’ force created by a person blocking the drain, allowing them to pull away uninjured.”
