A swimming pool, swimming
bath, wading pool, or simply a pool, is a usually artificially constructed
container filled with water intended for swimming or water-based recreation.
There are many standard sizes; the largest and deepest is the Olympic size. A
pool can be built either above or in the ground, and from materials such as
metal, plastic, fiberglass or concrete.
Pools that may be used by many people or by the general public are called
public, while pools used exclusively by a few people or in a home are called
private. Many health clubs, fitness centers and private clubs have public pools
used mostly for exercise. Many hotels and massage parlors have public pools for
relaxation. Hot tubs and spas are pools with hot water, used for relaxation or
therapy, and are common in homes, hotels, clubs and massage parlors. Swimming
pools are also used for diving and other water sports, as well as for the
training of lifeguards and astronauts.
Chemical disinfectants such as chlorine, bromine or mineral sanitizers, and
additional filters are often used in swimming pools to prevent growth and spread
of bacteria, viruses, algae and insect larvae. Alternatively, pools can be made
without chemical disinfectants by using a biofilter with additional filters. In
both cases, pools need to be fitted with an adequate flow rate.
A sauna (pronounced /ˈsɑunɑ/), is
a small room or house designed as a place to experience dry or wet heat
sessions, or an establishment with one or more of these and auxiliary
facilities. These facilities derive from the Finnish sauna. The word "sauna" is
also used figuratively to describe an unusually hot or humid environment.
A sauna session can be a social affair in which the participants disrobe and sit
or recline in temperatures of over 80 °C (176 °F). This induces relaxation and
Saunas can be divided into two basic styles: Conventional saunas that warm the
air or infrared saunas that warm objects. Infrared saunas may use various
materials in their heating area such as charcoal, active carbon fibers, and
A hot tub is a large
home-made or manufactured tub or small pool full of heated water and used for
soaking, relaxation, massage, or hydrotherapy. In most cases, they have jets for
massage purposes. Hot tubs are usually located outdoors, and are often sheltered
for protection from the elements, as well as for privacy. Other variants in
naming include "SPA", and the trade name "Jacuzzi". These variants can be used
to mean an indoor fixture, but a "Hot Tub" is almost always outdoors.
There are essentially two different styles of hot tubs:
* Simple wooden-staved soaking tubs
* One piece plastic tubs (usually referred to as spas)
Hot tubs are usually heated using an electric or natural gas heater, though
there are also submersible wood-fired heaters, as well as solar hot water
systems. Hot tubs are also found at natural hot springs; in this case, the water
may be dangerously hot and must be combined with cool water for a safe soaking
Water sanitization is very important in hot tubs, as many organisms thrive in a
warm, wet environment. Maintaining the hot tub water chemistry is also necessary
for proper sanitization and to prevent damage to the hot tub.
Traditional Steam Rooms
Historically, steam rooms have been constructed with various forms of tile using
ceramic or some form of stone. These tile materials, including the grout and
mortar components, are highly porous. It only take a few days for organic
material – matter such as mold, mildew, bacteria to flourish within the pores of
this material in a steam room environment. Because the source of heat in a steam
room is in the moisture, temperatures within steam rooms are typically between
105 to 110 degrees. The result is a warm, wet and porous environment ideal for
the harvesting of all types of harmful organic matter.
New Steam Room Trend
There has been a shift from tile steam rooms to more of a hybrid system that is
both more efficient and more sanitary. The hybrid steam room is made of a
composite fiberglass and acrylic and does not require the waterproofing commonly
associated with tile steam rooms. Traditional tile steam rooms typically require
deep cleanings on a daily basis, and within just a couple of years, grout
deteriorates requiring replacement, thus leading to the need for retiling every
four to six years. These hybrid steam systems, on the other hand, sterilize
automatically every night and only need to be wiped down with basic eco-friendly
An electrically operated water pump is the prime motivator in recirculating the
water from the pool. Water is forced through a filter and then returned to the
pool. A typical pool pump uses 500 watts to 2,000 watts. Commercial and public
pool pumps usually run 24 hours a day for the entire operating season of the
pool. Residential pool pumps are typical run for 4 hours per day in winter (when
the pool is not in use) and up to 24 hours in summer. To save electricity costs
most people run for between 6 hours and 12 hours in summer with the pump being
controlled by an electronic timer. Commercial pools require a minimum 4 hour
circulation of the total water volume.
Some pool pumps have two motor speeds to reduce power consumption at times when
full power is not needed. Other pump manufacturers (typically Italian or other
European) have redesigned their units to use a smaller electric motor with
heavier windings, therefore consuming less energy, to power a larger pump
impeller. Variable-speed pumps reduce power consumption even more. These pumps
run slowly 24 hours a day. The slow speed typically cleans better because
smaller particles can be filtered. At the slow speed, minimal resistance in the
pipes reduces the energy needed to move the water.
Pool pumps typically are "self priming": they may be positioned above the mean
water level of the pool yet still start up and function after a timed rest
period. Pumps that do not "self prime" are termed "flooded suction" and must be
gravity fed by the pool by being located below the mean level of the pool water.
Most pool pumps available today incorporate a small filter basket termed a "hair
and lint strainer" or "lint pot" as the last effort to avoid leaf or hair
contamination reaching the close-tolerance impeller section of the pump.
A pressure-fed filter is typically placed in line immediately after the water
pump. The filter typically contains a media such as graded sand (called '14/24
Filter Media' in the UK system of grading the size of sand by sifting through a
fine brass-wire mesh of 14 to the inch to 24 to the inch). A pressure fed sand
filter is termed a 'High Rate' sand filter, and will generally filter turbid
water down to 10 micrometers in size. The rapid sand filter type are
periodically 'back washed' as contaminants reduce water flow and increase back
pressure. Indicated by a pressure gauge on the pressure side of the filter
reaching into the 'red line' area, the pool owner is alerted to the need to
'backwash' the unit. The sand in the filter will typically last five to seven
years before all the "rough edges" are worn off and the more tightly packed sand
no longer works as intended. Recommended filtration for public/commercial pools
are 1 ton sand per 100,000 liters water.
Introduced in the early 1900s was another type of sand filter; the 'Rapid Sand'
filter, whereby water was pumped into the top of a large volume tank (3' 0" or
more cube) containing filter grade sand, and returning to the pool through a
pipe at the bottom of the tank. As there is no pressure inside this tank, they
were also known as 'gravity filters'. These type of filters are not greatly
effective, and are no longer common in home swimming pools, being replaced by
the pressure-fed type filter.
Other filter media
Other filters use diatomaceous earth to help filter out contaminants. Commonly
referred to as 'D.E.' filters, they exhibit superior filtration capabilities.
Often a D.E. filter will trap water-borne contaminants as small as 1 micrometer
in size. D.E. filters are banned in some states, as they must be emptied out
periodically and the contaminated media flushed down the sewer, causing a
problem in some districts' sewage systems.
Other filter media that have been introduced to the residential swimming pool
market since 1970 include sand particles and paper type cartridge filters of 50
to 150 square feet (14 m2) filter area arranged in a tightly packed 12" diameter
x 24" long (300 mm x 600 mm) accordion-like circular cartridge. These units can
be 'daisy-chained' together to collectively filter almost any size home pool.
The cartridges are typically cleaned by removal from the filter body and
hosing-off down a sewer connection. They are popular where backwashed water from
a sand filter is not allowed to be discharged or goes into the aquifer.
Water is typically drawn from the pool via a rectangular aperture in the wall
connected through to a device fitted into one (or more) wall/s of the pool. The
internals of the skimmer are accessed from the pool deck through a circular or
rectangle lid, about one foot in diameter. On lifting the lid (if the pool is
operational) you will see water being drawn from the pool, over a floating weir
(operating from a vertical position to 90 degrees angle away from the pool, in
order to stop leaves and debris being back-flooded into the pool by wave
action), and down into a removable "skimmer basket", the purpose of which is to
entrap leaves and other floating debris. The aperture visible from the pool side
is typically 1' 0" wide by 6" high, which intersects the water midway though the
center of the aperture. Skimmers with apertures wider than this are termed "wide
angle" skimmers and may be as much as 2' 0" wide (600 mm). Floating skimmers
have the advantage of not being affected by the level of the water as these are
adjusted to work with the rate of pump suction and will retain optimum skimming
regardless of water level leading to a markedly reduced amount of bio-material
in the water. Skimmers should always have a leaf basket or filter between it and
the pump to avoid blockages in the pipes leading to the pump and filter.
Overflow channel pools
An overflow channel is a gutter that surrounds the pool, covered by a removable
grille. Surface water flows over the edge of the pool and runs by gravity to the
filtration plant, usually via a catchment and top-up tank. Often the exterior
pool wall is higher than the overflow channel, eliminating the possibility of
pool water overflowing onto the adjacent pool surround. Other designs may not
have this feature, relying instead on a wider drainage system to trap any
Overflow channels allow faster turnover of the surface water than is possible
with simple weir skimmers, which is why they are commonly found in public pools.
They can also be attractive designs, particularly when transformed into a total
"vanishing edge" pool. This design has been used to great effect in prize
winning contemporary home design, notably in Southern California and the
surrounding desert states.
Pool water returns
The final link in the pool recirculation system: skimmer-pump-filter-returns are
the water returns. Typically these are referred to as "eyeballs" as they
incorporate a swiveling nozzle that can be locked down to point in the desired
direction and are reminiscent of a swiveling human eyeball. The directional
adjustment is usually a 360 degree radius circle of 45 degrees away from the
pool wall. Most home pools would incorporate at least two such "eyeballs". One
recent development in skimmers was the 1970s "Aquagenie(TM)" which differers
considerably operationally from conventional skimmers—most of which are quite
similar in operation, if not appearance—by both drawing the pool water and
returning it to the same location through a submerged slot which diverts the
water downwards and in a wide fan shape. The concept incorporates a reservoir
system to contain saturated trichor tablets which the resulting high strength
chlorinated water dribbles back into the recirculation system, so it doubles up
as a chlorine feeder as well as a normal skimmer. Arguably an "improvement" in
skimmer design, patents on the device expired in 2003 and the system is now
available from several US manufacturers.