8521 Swimming pools and spas (39) Proprietary swimming pools, spas and saunas, complete with all items provided as part of the proprietary package. Non-proprietary pools, spas and saunas of specific design. General building construction and materials may be defined under other CBI headings (concrete, concrete masonry, tiling etc.). 8522 Swimming pool water systems (0) Swimming pools, spas and saunas, associated water treatment, circulation and heating equipment, prepared for connection to building services not provided as part of the system. 8523 Outdoor showers (1) Outdoor showers with shower head(s) and taps/mixer, may include, waste, tray, enclosure, shower tower, etc, prepared for connection to building services not provided as part of the system. Includes, general showers with cold or hot and cold water, therapeutic showers 8524 Decontamination showers (0) Shower enclosures, with temperature control and multiple jets to provide decontamination by dilution Associated tanks for containing the waste water for subsequent treatment, including drainage lines