Swimming pool

Swimming pool:

A swimming pool, swimming bath, or wading pool is an artificially enclosed body of 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 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, other sports, and training of lifeguards and astronauts.

History:

The "great bath" at the site of Mohenjo-Daro was most likely dug during the 3rd millennium BC. This pool is 12 by 7 meters, is lined with bricks and was covered with a tar-based sealant.
Ancient Greeks and Romans built artificial pools for athletic training in the palaestras, for nautical games and for military exercises. Roman emperors had private swimming pools in which fish were also kept, hence the Latin word for pool, piscina. The first heated swimming pool was built by Gaius Maecenas of Rome in the first century BC. Gaius Maecenas was a rich Roman lord and considered one of the first patrons of arts.
Ancient Sinhalese built pairs of pools called "Kuttam Pokuna" in the kingdom of Anuradhapura, Sri Lanka in 4th century BC. Those were decorated with flights of steps, punkalas or pots of abundance and scroll design.
Swimming pools became popular in Britain in mid 19th century. By 1837, six indoor pools with diving boards were built in London, England. After the modern Olympic Games began in 1896 and included swimming races, the popularity of swimming pools began to spread (reference: Encyclopedia Britannica). In 1939, Oxford had its first major public indoor pool at Temple Cowley, and swimming began to take off. The Amateur Swimming Association was founded in 1869 in England, and the Oxford Swimming Club in 1909 with its home at Temple Cowley Pool. The presence of indoor baths in the cobbled area of Merton Street, London may have persuaded the less hardy of the aquatic brigade to join. So, bathers gradually became swimmers, and bathing pools swimming pools.

In the USA, the Racquet Club of Philadelphia clubhouse (1907) boasts one of the world's first modern above-ground swimming pools. The first swimming pool to go to sea on an ocean liner was installed on the White Star Line's Adriatic in 1907.
After World War I and the departure of "Long John" style swimming costumes, interest in competitive swimming grew. Standards improved and training became essential.
Home swimming pools became popular in the USA after World War II and the publicity given to swimming sports by Hollywood films like Esther Williams Million Dollar Mermaid made a home pool a desirable status symbol. In 1956, the US National Swimming Pool Institute was founded. It has since been renamed the Association of Pool & Spa Professionals, and now develops pool construction standards and provides training to pool builders and service technicians. More than 50 years later, the home or residential swimming pool is ubiquitous and even the smallest world nations enjoy a thriving swimming pool industry (e.g. New Zealand pop. 4,116,900 [Source NZ Census 7 March 2006] - with 65,000 home swimming pools and 125,000 spa pools).

World's largest:

The largest swimming pool ever built was reputedly in Moscow after the Palace of Soviets remained uncompleted. The foundations were converted into an open air swimming pool after the process of de-Stalinisation.[citation needed] After the fall of communism, Christ the Saviour Cathedral was re-built (it had originally been on the site) between 1995 and 2000.
In the 21st century, there seem to be many contenders for "the largest swimming pool on earth", reputedly at Cox's Bazar, Bangladesh; at Club Med Camarina, Sicily; Sunlite Pool, Coney Island, Cincinnati; and Garden City, Kansas with their 220 foot by 330 foot pool (67m x 100m) that holds 26,000,000 gallons (100 million litres) of water. A recent construction in Tokyo, Japan may top them all.
The largest indoor wave pool in North America is at the West Edmonton Mall [1] and the largest indoor pool is at the Neutral Buoyancy Lab in the Sonny Carter Training Center at NASA JSC in Houston[2]. The longest swimming pool is the Orthlieb Pool in Casablanca, Morocco. It is 480 meters (1,574 feet) long and 75 meters (246 feet) wide. It is filled with sea water and covers 8.9 acres (3.60 Ha). [Source: Internet] The recreational diving center Nemo 33 near Brussels, Belgium is home to the world's deepest swimming pool. The pool has two large flat-bottomed areas at depth levels of 5m (16 ft) and 10m (32 ft), and a large circular pit descending to a depth of 33m (108 ft).[3]
The Fleishhacker Pool was the largest swimming pool in the United States. Opened on 23 April 1925, it measured 300 m by 45 m (1,000 ft by 150 ft) and was so large that the lifeguards required kayaks for patrol. It was closed in 1971 due to low patronage.[4]
According to the Guinness World Records the largest swimming pool in the world certified by the is San Alfonso del Mar Seawater pool in Algarrobo, Chile. It is 1,013 m (3,324 ft) long and has a area of 8 ha (19.77 acre), it was completed in December 2006 [5]

Dimensions:

Length:

Most pools in the world are measured in metres, but in the United States pools are almost always measured in feet and yards. In the United Kingdom most pools are in metres, but older pools measured in yards still exist. In the US pools tend to either be 25 yards (short course yards), 25 metres (short course metres) or 50 metres (long course). US high schools and the NCAA conduct short course (25 yards) competition. There also exist many pools 33⅓ m long, so that 3 lengths = 100 m. This is sometimes jokingly referred to as "inter-course".
USA Swimming (USA-S) swims in both metric and non-metric pools. However, the international standard is metres, and world records are only recognized when swum in 50 m pools (or 25m for short course).
In general, the shorter the pool, the faster the time for the same distance, since the swimmer gains speed from pushing off the wall after each turn at the end of the pool.

Depth:

The depth of a swimming pool depends on the purpose of the pool, and whether it is open to the public or strictly for private use. If it is a private casual, relaxing pool, it may go from 1.0m to 1.8m (3 to 6 feet) deep. If it is a public pool designed for diving, it may slope from 3 to 4.8 m (10 to 14 feet) in the deep end. A children's play pool may be from 30 cm to 1.2 m (1 to 4 feet) deep. Most public pools have differing depths to accommodate different swimmer requirements. In many states, it is a requirement to show the water depth with clearly marked depths affixed to the pool walls.
After an incident in Washington state in 1993, most US and other pool builders are reluctant to equip a residential swimming pool with a diving springboard, so home diving pools are much less common these days. In the incident 14-year-old Shawn Meneely made a "suicide dive" in a private swimming pool and was seriously injured (tetraplegic). Family lawyer Fred Zeder successfully sued the diving board manufacturer, the pool builder, and the National Spa & Pool Institute over the inappropriate depth of the pool.[6] The NSPI had specified a minimum depth of 8 ft 6 in (2.55m) which proved to be insufficient in the above case. The multi-million dollar lawsuit was eventually settled in 2001 for $US6,600,000 ($US8,000,000 after interest was added) in favor of the plaintiff. The NSPI was held to be liable, and was financially strained by the case. It filed twice for Chapter 11 bankruptcy protection and was successfully reorganized into a new swimming pool industry association. [6]

Private pools:

Private pools are usually smaller than public pools, on average 16' x 32' (4.8m x 9.6m) to 20' x 40' (6m x 12m) whereas public pools usually start at 80 0" (25.0m). Home pools can be permanently built-in, or be assembled above ground and disassembled after summer. Privately owned outdoor pools in backyards or gardens started to proliferate in the 1950s in regions with warm summer climates, particularly in the United States. In some US locations, home pools are so common that it is rare to find a new house being built without a pool being considered in the design.[citation needed]
Private pools are increasingly a feature of homes in greater latitudes. For example, in London many larger homes are now refurbished with indoor pools, usually in the basement or in a conservatory. In some European cities, including Munich, it is relatively common for people living in older properties to convert existing internal motorcar garages into indoor pool areas.[citation needed]Construction methods for private pools vary greatly. Construction standards for private residential pools have been developed by the US Association of Pool & Spa Professionals (APSP) and approved by the American National Standards Institute. The main types of in-ground pools are concrete, vinyl liner, and fiberglass. Above-ground pools (also called "on-ground pools") are usually cheaper to build. They are especially popular in places where ground freezing makes excavation difficult and threatens damage to the pool structure.
Inexpensive temporary PVC pools can be bought in supermarkets and taken down after summer. They are used mostly outdoors in yards, are typically shallow, and often their sides that are inflated with air to stay rigid. When finished, the water and air can be let out and this type of pool can be folded up for convenient storage. They are regarded in the swimming pool industry as "splasher" pools intended for cooling off and amusing toddlers and children, not for swimming.
Some people use hot tubs and spas at home to soak their bodies in water for recreation. See #Hot tubs and spa pools.
Many toys are available for children and other people to play with in pool water. They are often blown up with air so they are soft but still reasonably rugged, and can float in water.
Many countries now have strict pool fencing laws for private swimming pools, which require pool areas to be isolated so that unauthorized children younger than six years cannot enter. Many countries require a similar level of protection for the children residing in or visiting the house, although many pool owners prefer the visual aspect of the pool in close proximity to their living areas, and will not provide this level of protection. There is no general consensus between states or countries on the requirements to fence private swimming pools, and in many places they are not required at all, particularly in rural settings.

Pools must be sanitized to prevent growth and spread of bacteria, viruses, algae and insect larvae that can cause disease. This is done using filters and chemical disinfectants. A pool cover can keep debris out of a pool that is not in use. In cold climates, pools must be closed in winter to prevent them and their pipes from cracking due to ice.