Liquid Water for baths, sinks and basins can be provided by separate hot and cold high-pressure taps, derived from Edward Chrimes's of
Rotherham, 1845 invention; this arrangement is common in older installations, particularly in public washrooms/lavatories and utility rooms/laundries. In kitchens and bathrooms,
mixer taps are commonly used. In this case, hot and cold water from the two valves is mixed before reaching the outlet, allowing the water to emerge at any temperature between that of the hot and cold water supplies. Mixer taps were invented by Thomas Campbell of
Saint John, New Brunswick, and patented in 1880. uses a center handle to control temperature (increased by anti-clockwise rotation). Below it is a lever controlling flow rate and routing, stopping flow when centred and sending water to the tub when positioned to the left, the
shower to the right. For baths and showers, mixer taps frequently incorporate some sort of
pressure balancing feature so that the hot/cold mixture ratio will not be affected by transient changes in the pressure of one or other of the supplies. This helps avoid
scalding or uncomfortable chilling as other water loads occur (such as the flushing of a toilet). Rather than two separate valves, mixer taps frequently use a single, more complex, valve controlled by a single handle (
single handle mixer). The handle moves up and down to control the amount of water flow and from side to side to control the temperature of the water. Especially for baths and showers, the latest designs are
thermostatic mixing valves that do this using a built-in
thermostat, and can be mechanical or electronic. There are also taps with color LEDs to show the temperature of the water. When two pipes are installed, the hot tap generally has a red indicator while the cold tap generally has a blue or green indicator. In the United States, the taps are frequently also labeled with an "H" or "C". In countries with
Romance languages, the letters "C" for hot and "F" for cold are used (from French "chaud"/Italian "caldo"/Spanish "caliente" (hot) and French "froid"/Italian "freddo"/Spanish "frio" (cold)). Portuguese would use Q (for "quente", hot) and F. This can create confusion for English-speaking visitors. Mixer taps may have a red-blue stripe or arrows indicating which side will give hot and which cold. In most countries, there is a standard arrangement of hot/cold taps. For example, in the United States and many other countries, the hot tap is on the left by
building code requirements. Many installations exist where this standard has been ignored (called "crossed connections" by plumbers). Mis-assembly of some single-valve mixer taps will exchange hot and cold even if the fixture has been plumbed correctly. In the United States, the
Americans with Disabilities Act provide requirements for faucets, such as requiring less than five pounds of force to operate, and requiring that the user does not have to twist their wrist. .|alt= Most handles in homes are fastened to the valve shafts with screws, but on many commercial and industrial applications they are fitted with a removable key called a "loose key", "water key", or "
sillcock key", which has a square peg and a square-ended key to turn off and on the water; the "loose key" can be removed to prevent vandals from turning on the water. Before the "loose key" was invented it was common for some landlords or caretakers to take off the handle of a tap, which had teeth that would meet up with the
gears on the valve shaft. This tooth and cog system is still used on most modern taps. "Loose keys" may also be found outside homes to prevent passers-by from using them. Taps are normally connected to the water supply by means of a "swivel tap connector", which is attached to the end of the water pipe using a soldered or compression fitting, and has a large nut to screw onto the threaded "tail" of the tap, which hangs down underneath the bath, basin or sink. A fibre washer (which expands when wet, aiding the seal) is used between the connector and the tap tail. Tap tails are normally " or 12 mm in diameter for sinks and " or 19 mm for baths, although continental Europe sometimes uses a " (still imperial) size. The same connection method is used for a
ballcock. The term
tap is widely used to describe the valve used to dispense
draft beer from a
keg, whether gravity feed or pressurized.
Gas A
gas tap is a specific form of
ball valve used in residential, commercial, and laboratory applications for coarse control of the release of
fuel gases (such as
natural gas,
coal gas, and
syngas). Like all ball valves its handle will parallel the gas line when open and be perpendicular when closed, making for easy visual identification of its status. ==Physics==