polyester (GRP) hot tubs are made of a plastic matrix reinforced by fine fibers of glass. Inflatable PVC hot tubs. An inflatable hot tub is an air-filled spa structure. Air is pumped into a vinyl skin that expands and creates a solid form. Most commonly round in shape. Safety Sitting in water above normal body temperatures can cause drowsiness which may lead to unconsciousness and subsequently result in drowning. The U.S. Consumer Product Safety Commission (CPSC) recommends that water temperatures never exceed . A temperature of is considered safe for a healthy adult. Soaking in water above can cause fetal damage during the first three months of pregnancy. It is also recommended to install residual-current devices for protection against electrocution. The greater danger associated with electrical shock in the water is that the person may be rendered immobile and unable to rescue themselves or to call for help and then drown. Hot tubs and spas are equipped with drains that can create powerful suction and between 1980 and 1996, the CPSC had reports of more than 700 deaths in spas and hot tubs, about one-third of which were drownings to children under age five. In the same period 18 incidents were reported to the CPSC involving body part entrapment. To reduce the risk of entrapment, US safety standards require that each spa have two drains for each pump, reducing the amount of suction. From 1999 to 2007 there were 26 reports to the CPSC concerning circulation entrapments hot tubs and spas, including three deaths. In 2001 and in 2012 the CPSC issued recalls for spa heaters which overheated and caused fires. The Uniform Swimming Pool, Spa and Hot Tub Code is a model code developed by the International Association of Plumbing and Mechanical Officials (IAPMO) to govern the installation and inspection of plumbing systems associated with swimming pools, spas and hot tubs as a means of promoting the public's health, safety and welfare. Disease risk Poorly sanitized hot tubs have been linked to a number of diseases, principally caused by facultative anaerobic bacteria. Such incidents include hot tub folliculitis and legionellosis. Gallery See also Finnish sauna Hot tub filters History of water filters Ofuro Sauna Steam shower Turkish bath Uniform Swimming Pool, Spa and Hot Tub Code Whirlpool tub References External links Swimming pools Bathing Garden features Plumbing Hydrotherapy Bathrooms