Young Brunette Girl Posing At The Swimming Pool

Hot tubs and spa pools
Hot tubs and spa pools are common heated pools used for relaxation and sometimes for therapy. Commercial spas are common in the swimming pool area or sauna area of a health club or fitness centre, in men's clubs, women's clubs, motels and exclusive five star hotel suites. Spa clubs may have very large pools, some segmented into increasing temperatures. In Japan, men's clubs with many spas of different size and temperature are common. Commercial spas are generally made of concrete, with a mosaic tiled interior. More recently with the innovation of the Pre-Form Composite method where Mosaic tiles are bonded to the shell this enables Commercial SPA's to be completely factory manufactured to specification and delivered in one piece. Hot tubs are typically made somewhat like a wine barrel with straight sides, from wood such as Californian redwood held in place by metal hoops. Immersion of the head is not recommended in spas or hot tubs due to a potential risk of underwater entrapment from the pump suction forces. However, commercial installations in many countries must comply with various safety standards which reduce this risk considerably.
Home spas are a worldwide retail item in western countries since the 1980s, and are sold in dedicated spa stores, pool shops, department stores, the Internet, and catalog sales books. They are almost always made from heat-extruded acrylic sheet Perspex, often colored in marble look-alike patterns. They rarely exceed 8 sq ft (0.74 m2) and are typically 3 ft 6 in (1.07 m) deep, restricted by the availability of the raw sheet sizes (typically manufactured in Japan). There is often a mid-depth seating or lounging system, and contoured lounger style reclining seats are common. Upmarket spas include various jet nozzles (massage, pulsating etc.), a drinks tray, lights, LCD flat-screen TV sets and other features that make the pool a recreation center. Due to their family-oriented nature, home spas are normally operated from 36 to 39 °C (97 to 102 °F). Many pools are incorporated in a redwood or simulated wood surround, and are termed "portable" as they may be placed on a patio rather than sunken into a permanent location. Some portable spas are shallow and narrow enough to fit sideways through a standard door and be used inside a room. Low power electric immersion heaters are common with home spas.