Suction Entrapment - The Silent Killer in Swimming Pools

Whether it be a swim in the 66-million-gallon, San Alfonso Del Mar Resort pool, which is longer than nine football pitches, or a relaxing dip in the 24 carat gold plated St. Regis Lhasa Resort pool, every hotel strives to offer its guests the ultimate, safe bathing experience. Sadly, in the case of some hotels, not all guests come away with pleasant memories, and some don’t even get to leave with their lives.

The sad truth is that despite the headline-making stories of children being seriously injured, or drowned from pool entrapment, many overseas hotels with older pools have yet to make one relatively simple change that could prevent such tragedies.  

Pool entrapment most commonly occurs when a bather comes into close contact with a single main drain in a pool or spa and is pulled onto it by the suction of the circulation pump. It is often children who are the victims, as they do not have the strength of an adult and are unable to break free from powerful suction forces. A recent experiment conducted revealed that it can take around 225Kg of force to free an object trapped on a single drain. Incidents of pool entrapment are far more common than one might imagine, and multiple hotels around the world have experienced the horror of dealing with such tragedies. 

In the UK, new pools are built to comply with BS EN 15288 and SPATA standards, and have two interconnected drains, each capable of taking 100% of the suction design flow rate, which are arranged so that there is no risk of bathers becoming trapped. If a bather were to block one drain, the second drain continues to draw water from the pool, avoiding a vacuum forming in the first drain. However, for those holidaymakers who head abroad for their vacation, chances are that the country they are heading to may not adhere to such safety guidelines, and children may well end up in one of the millions of pools that only have a single drain.

The fact that these types of tragedies still occur is even sadder when you realise that there is a simple solution that has been in common use in some of the leading hotel chains, as well as numerous commercial and domestic pools, for years. And this solution involves far less work than fitting a second drain. A Suction Vacuum Release System (e.g. Vac-Alert) is a non-electrical self-monitoring, low-maintenance safety system, that responds in milliseconds to an increase in pump suction created by an obstruction on the main drain, freeing a trapped swimmer from a life-threatening situation. Once triggered, the Vac-Alert’s spring-loaded piston reacts quickly, opening to atmosphere and allowing air to be drawn into the suction pipework, releasing any vacuum in the suction pipework.  Even with this type of device fitted, operators still need to ensure their sump covers are of a modern (and locally compliant) design to reduce entanglement risk too.  

In the UK, all commercial pool operators should check that their pool suction outlets and covers are safe and have been properly risk assessed for entrapment and entanglement by competent persons according to BS EN 13451-3. These tests should be repeated if there are any changes or upgrades of the pool's filtration, pipework or pump systems.  

Further Advice

UK & EU  BS EN 13451-3:2022 Swimming pool equipment - Part 3: Additional specific safety requirements and test methods for inlets and outlets and water/air based water leisure features installed in pools for public use.

For UK advice for spa pools, refer to PWTAG Technical Note 66 https://www.pwtag.org/download/suction-entrapment-in-spa-pools-tn66/

The Pool Operators Club® video course "Entrapment & Entanglement Hazards" provides detailed advice, guidance and solutions : https://www.pooloperatorsclub.com/view/courses/entrapment-entanglement-hazards/3218268-default-section/10468405-entrapment-entanglement-hazards-mp4

 In the USA: American National Standards Institute / Association of Pool and Spa Professionals / International Code Council (ANSI/APSP/ICC). American National Standard for Suction Entrapment Avoidance in Swimming Pools, Wading Pools, Spas, Hot Tubs and Catch Basins ANSI/APSP/ICC-7 2013, United States, 2013. 

Canada:  Lifesaving Society Canada’s National Safety Standards (Lifesaving Society Canada’s National Safety Standards do not replace or supersede local, provincial/territorial or federal legislation or regulations, but they are considered the standard to which aquatic facility operators should work towards). Guidance also available from Pool & Hot Tub Council of Canada: www.poolcouncil.ca/wp-content/uploads/2023/05/Suction-Entrapment-Avoidance-Provisions-G-0109.pdf

 Australia: AS 1926.3-2010 Swimming pool safety, Part 3: Water recirculation systems https://store.standards.org.au/product/as-1926-3-2010

AS 2610.1-2007 Spa pools, Part 1: Public spas

 New Zealand: Swimming Pool Design standard NZS 4441:2008 https://www.standards.govt.nz/shop/nzs-44412008

/