LEGIONELLA - World Health Organization

Box . Types of pools
Sw mm ng pools
Swimming pools may be supplied with fresh (surface or ground), marine or thermal water
(i.e. from natural hot springs). Pools may be domestic (private), semi-public (e.g. hotel,
school, health club, housing complex or cruise ship) or public (e.g. municipal) and they
may be supervised or unsupervised. Swimming pools may be located indoors, outdoors
(i.e. open air) or both; also, they may be heated or unheated.
In terms of structure, the conventional pool is often referred to as the main, public or municipal
pool. It is by tradition rectangular, with no extra water features (other than possible provision
for diving), and it is used by people of all ages and abilities. Temporary or portable structures
are often used in the domestic setting. In addition, there are many specialist pools for a
particular user type — for example, paddling pools, learner or teaching pools, diving pools
and pools with special features such as “flumes” or water slides. Although termed “swimming”
pools, they are often used for a variety of recreational activities, such as aqua aerobics,
scuba diving and so on.
Plunge pools
Plunge pools are generally used in association with saunas, steam rooms or hot tubs,
and are designed to cool users by immersion in unheated water. They are usually only
large enough for a single person, but can be larger. For the purposes of this document,
they are considered to be the same as swimming pools.
Hot tubs
For the purposes of this document, the term “hot tubs” is used to denote various facilities
that are designed for sitting in (rather than swimming), contain water usually above 32 ºC,
are generally aerated, contain treated water, and are not drained, cleaned or refilled for each
user. They may be domestic, semi-public or public, and may be located indoors or outdoors.
They are known by a wide range of names, including spa pools, whirlpools, whirlpool
spas, heated spas, bubble baths or Jacuzzi (a trade name that is also used generically).
Both domestic hot tubs and those in commercial premises have dramatically increased
in popularity in recent years; they are now found in sports centres, hotels, leisure and
health spa complexes, on cruise ships and, increasingly, in the home environment.
In some countries, especially when in health spa resorts, hot tubs may also be known as
hydrotherapy spas or pools, though these terms are more usually applied to pools used
within health-care premises (e.g. physiotherapy departments) for treatment that may
include swimming (see below).
Wh rlpool baths
Whirlpool baths are a type of hot tub often found in bathrooms of hotel suites or private
residences. They are fitted with high-velocity water jets and/or air injection but, unlike the
hot tubs described above, the water is emptied after each use. They are mainly intended
for a single individual, but double versions are available.
0 LEGIONELLA AND THE PREVENTION OF LEGIONELLOSIS