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80 ENTRAPMENT:SPN Master pages 14/09/2009 13:28 Page 2
spnfeature
Are you aware of
the silent danger?
In the aftermath of the death earlier this summer of a
British teenager on holiday – (see World News)
international safety expert Robbie Phillips urges the
UK specialist spool and spa trade to be more aware
of the threat of more entrapment accidents
e all now urgently have to bottom or side of the pool/spa tank. Flow and hair are drawn through the drain.
W
assess the risk of suction meter testing to enable you to Never allow a child to play in a way that
entrapment and hair comprehensively risk assess this danger in could permit the child’s hair to come near
entanglement in your pools your pool can be accomplished using the drain cover. If a drain cover is missing
and spas. specific equipment. Sensitive Water or broken, shut down the facility until the
Commercial swimming pools, Solutions Ltd. has used this equipment cover is replaced and securely fitted.
hydrotherapy pools, wading/paddling successfully for years. Everyone involved in the design and
pools, whirl pools and spas all have one In the USA since the 1980s there were at construction should work to produce a safe
thing in common – a circulation system. least 147 incidents documented of suction facility. It is essential that knowledgeable
This means that water must leave the entrapment in swimming pools, including pool contractors and consultants are
pool and then re-enter at another point 36 deaths. Suction entrapment occurs employed. The operator should be aware
following filtering and disinfection. This when a swimmer, usually a small child, is of the potential dangers and risk assesses
can have serious repercussions if not trapped by the suction forces created by the operation of critical valves. Isolating
properly risk assessed. Bottom drains in the water rushing out of the drain at the the surface removal system can radically
pools and water outlets in spas can be a bottom of the pool. change the system hydraulics which can
serious danger to users. cause serious dangerous hazards in relation
We need to be aware of two dangers: Hair Entanglement: to suction. spn
In spa pools the danger of hair
Suction Entrapment: entanglement is very real. When bathers
Bottom drains in swimming pools should swim too close to bottom drains or
be at least two metres apart and also suction outlets of incorrect design or
EXAMPLES OF POTENTIAL
have all openings 8mm in width or place their heads underwater in a spa too
SOURCES OF SUCTION
diameter (larger = easier entrapment of close to water outlets their hair may
fingers, smaller = increased suction!). become entangled in the grilles/outlets.
ENTRAPMENT
There should be two so if one becomes In a spa this danger is increased by the Incorrect operation or fitting
blocked then the other can still divert a narrow suction pipe work often increasing Creation of one line suction to main
proportion of flow to prevent a vacuum velocity and also the design of the or ancillary circulation pumps
being formed. Ideally these bottom drains outlets which often moves in a circular (booster, flume etc.)
should have raised centres to prevent a motion (vortex) aiding entanglement. If a Number of drains
bather sealing the entire drain with their bather becomes trapped often the only Design of drain outlets and covers
body, coupled with this the pumps should way to free them is to cut the hair All one line suctions removed
have a pressure sensor enabling it to shut although it’s surprising to note that Anti vortex covers used
off before a vacuum is formed. The scissors do not work efficiently Broken grids are a potentially lethal
bottom drain suction problem can be underwater and often a knife is the only problem
increased if water levels drop below implement that will suffice, this can
skimmer/scum trough overflow system. If induce severe trauma at minimum! It was Robbie Phillips is a pool and spa
this occurs, and the surface draw off line recently noted that in the USA reports of consultant based in Great
is isolated to prevent air getting into the 49 incidents (including 13 deaths) in Britain. He has conducted
system, then all suction water from the which people’s hair was sucked into the numerous safety audits
pool will be through the bottom drain, suction fitting of a spa, hot tub, or internationally. He can be
increasing its suction and velocity. No whirlpool, causing the victim’s head to be contact by email at the following
pool should ever be run on bottom drains held under water. Hair entanglement address:
alone due to the danger of suction occurs when a bather’s hair becomes robbie@sensitivewatersolutions.co.uk
entrapment/hair entanglement on the entangled in a drain cover as the water
80 Swimming Pool News October 09 Digital edition available at www.swimmingpoolnews.co.uk
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