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Flush toilet

Flush toilet

Overview
A flush toilet is a toilet
Toilet
A toilet is a sanitation fixture used primarily for the disposal of human excrement, often found in a small room referred to as a toilet/bathroom/lavatory...

 that disposes of human waste by using water to flush it through a drainpipe to another location. Flushing mechanisms are found more often on western toilets (used in the sitting position), but many squat toilets also are made for automated flushing. Modern toilets incorporate an 'S','U', 'J', or 'P' shaped bend that causes the water in the toilet bowl to collect and act as a seal against sewer gases.
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Encyclopedia
A flush toilet is a toilet
Toilet
A toilet is a sanitation fixture used primarily for the disposal of human excrement, often found in a small room referred to as a toilet/bathroom/lavatory...

 that disposes of human waste by using water to flush it through a drainpipe to another location. Flushing mechanisms are found more often on western toilets (used in the sitting position), but many squat toilets also are made for automated flushing. Modern toilets incorporate an 'S','U', 'J', or 'P' shaped bend that causes the water in the toilet bowl to collect and act as a seal against sewer gases. Since flush toilets are typically not designed to handle waste on site, their drain pipes must be connected to waste conveyance and waste treatment
Waste treatment
Waste treatment refers to the activities required to ensure that waste has the least practicable impact on the environment. In many countries various forms of waste treatment are required by law.-Solid waste treatment:...

 systems. A flush toilet may be euphemistically called a lavatory, a loo, a john or a water closet, abbreviated to "W.C."

History




As with many inventions, the flush toilet was the result of a long development. Therefore, instead of a single name and date, there follows a list of significant contributions to the history of the device.
  • circa 31st century BC: Britain's oldest neolithic village, Skara Brae
    Skara Brae
    Skara Brae is a large stone-built Neolithic settlement, located on the Bay of Skaill on the west coast of Mainland, Orkney, Scotland. It consists of ten clustered houses, and was occupied from roughly 3180 BCE–2500 BCE...

    , Orkney used neolithic hydraulic technology. The village's design used a river and connecting drainage system to wash waste away.
  • circa 26th century BC: Flush toilets were first used in the Indus Valley Civilization
    Indus Valley Civilization
    The Indus Valley Civilization was a Bronze Age civilization that was located in the northwestern region of the Indian subcontinent, consisting of what is now mainly modern-day Pakistan and northwest India...

    . The cities of Harappa
    Harappa
    Harappa is an archaeological site in Punjab, northeast Pakistan, about west of Sahiwal. The site takes its name from a modern village located near the former course of the Ravi River. The current village of Harappa is from the ancient site. Although modern Harappa has a train station left from...

     and Mohenjo-daro
    Mohenjo-daro
    Mohenjo-daro is an archeological site situated in what is now the province of Sindh, Pakistan. Built around 2600 BC, it was one of the largest settlements of the ancient Indus Valley Civilization, and one of the world's earliest major urban settlements, existing at the same time as the...

     had a flush toilet in almost every house, attached to a sophisticated sewage system. See also Hydraulic engineering of the Indus Valley Civilization.
  • circa 18th century BC: Flush toilet constructed at Knossos
    Knossos
    Knossos , also known as Labyrinth, or Knossos Palace, is the largest Bronze Age archaeological site on Crete and probably the ceremonial and political centre of the Minoan civilization and culture. The palace appears as a maze of workrooms, living spaces, and store rooms close to a central square...

     on Minoan
    Minoan civilization
    The Minoan civilization was a Bronze Age civilization that arose on the island of Crete and flourished from approximately the 27th century BC to the 15th century BC. It was rediscovered at the beginning of the 20th century through the work of the British archaeologist Arthur Evans...

     Crete
    Crete
    Crete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...

  • circa 15th century BC: Flush toilets used in the Minoan city of Akrotiri
    Akrotiri (Crete)
    Akrotiri is a peninsula and former municipality in the Chania peripheral unit, Crete, Greece. Since the 2011 local government reform it is part of the municipality Chania, of which it is a municipal unit. Its ancient name was Kiamon while the Byzantines called it Charaka...

    .
  • 9th century BC: Flush toilets on Bahrain
    Bahrain
    ' , officially the Kingdom of Bahrain , is a small island state near the western shores of the Persian Gulf. It is ruled by the Al Khalifa royal family. The population in 2010 stood at 1,214,705, including 235,108 non-nationals. Formerly an emirate, Bahrain was declared a kingdom in 2002.Bahrain is...

     Island.
  • 1st to 5th centuries AD: Flush toilets were used throughout the Roman Empire
    Roman Empire
    The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

    . Some examples include those at Vindolanda
    Vindolanda
    Vindolanda was a Roman auxiliary fort just south of Hadrian's Wall in northern England. Located near the modern village of Bardon Mill, it guarded the Stanegate, the Roman road from the River Tyne to the Solway Firth...

     on Hadrian's Wall
    Hadrian's Wall
    Hadrian's Wall was a defensive fortification in Roman Britain. Begun in AD 122, during the rule of emperor Hadrian, it was the first of two fortifications built across Great Britain, the second being the Antonine Wall, lesser known of the two because its physical remains are less evident today.The...

     in Britain. With the fall of the Roman Empire, the technology was lost in the West.
  • 1206: The Arab inventor
    Inventions in the Islamic world
    A number of inventions were developed in the medieval Islamic world, a geopolitical region that has at various times extended from Spain and Africa in the west to the Indian subcontinent in the east. The inventions listed here were developed during the medieval Islamic world, which covers the...

    , Al-Jazari
    Al-Jazari
    Abū al-'Iz Ibn Ismā'īl ibn al-Razāz al-Jazarī was a Muslim polymath: a scholar, inventor, mechanical engineer, craftsman, artist, mathematician and astronomer from Al-Jazira, Mesopotamia, who lived during the Islamic Golden Age...

    , invented a hand washing device incorporating the flush mechanism now used in modern flush toilets. His device features a mechanism
    Mechanism
    Mechanism may refer to:*Mechanism , rigid bodies connected by joints in order to accomplish a desired force and/or motion transmission*Mechanism , explaining how a feature is created...

     for filling the basin with water. When the user pulls the lever, the water drains and the mechanism refills the basin.
  • 1596: Sir John Harington published A New Discourse of a Stale Subject, Called the Metamorphosis of Ajax, describing a forerunner to the modern flush toilet installed at his house at Kelston
    Kelston
    Kelston is a small village and civil parish in Somerset, north west of Bath, and east of Bristol, on the A431 road. It is situated just north of the River Avon, close to the Kelston and Saltford locks...

    . The design had a flush valve to let water out of the tank, and a wash-down design to empty the bowl. He installed one for his godmother Elizabeth I of England
    Elizabeth I of England
    Elizabeth I was queen regnant of England and Ireland from 17 November 1558 until her death. Sometimes called The Virgin Queen, Gloriana, or Good Queen Bess, Elizabeth was the fifth and last monarch of the Tudor dynasty...

     at Richmond Palace
    Richmond Palace
    Richmond Palace was a Thameside royal residence on the right bank of the river, upstream of the Palace of Westminster, to which it lay 9 miles SW of as the crow flies. It it was erected c. 1501 within the royal manor of Sheen, by Henry VII of England, formerly known by his title Earl of Richmond,...

    , although she refused to use it because it made too much noise. The Ajax was not taken up on a wide scale in England, but was adopted in France under the name Angrez.
  • 1738: A valve-type flush toilet was invented by J. F. Brondel.
  • 1775: Alexander Cummings
    Alexander Cummings
    Alexander Cummings was a Scottish watchmaker who was the first to patent a design of the flush toilet. His premises were in Bond Street, London.Born in Edinburgh in 1733, Cummings was a mathematician and mechanic as well as a watchmaker...

     invented the S-trap
    Trap (plumbing)
    In plumbing, a trap is a U-, S-, or J-shaped pipe located below or within a plumbing fixture. An S-shaped trap is also known as the S-bend invented by Alexander Cummings in 1775 but became known as the U-bend following the introduction of the U-shaped trap by Thomas Crapper in 1880. The new U-bend...

     (British patent no. 814?), still in use today, which uses standing water to seal the outlet of the bowl, preventing the escape of foul air from the sewer. His design had a sliding valve in the bowl outlet above the trap.
  • 1777: Samuel Prosser invented and patented the 'plunger closet'.
  • 1778: Joseph Bramah
    Joseph Bramah
    Joseph Bramah , born Stainborough Lane Farm, Wentworth, Yorkshire, England, was an inventor and locksmith. He is best known for having invented the hydraulic press...

     invented a hinged valve or 'crank valve' that sealed the bottom of the bowl, and a float valve system for the flush tank. His design was used mainly on boats.
  • 1851: The first popularized water closets were exhibited at The Crystal Palace
    The Crystal Palace
    The Crystal Palace was a cast-iron and glass building originally erected in Hyde Park, London, England, to house the Great Exhibition of 1851. More than 14,000 exhibitors from around the world gathered in the Palace's of exhibition space to display examples of the latest technology developed in...

     and these became the first public toilets. They had attendants dressed in white and customers were charged a penny for use. This is supposedly the origin of the phrase "To spend a penny" which did not appear in print until the 1940s.
  • 1852: George Jennings
    George Jennings
    George Jennings was an English sanitary engineer and plumber who invented the first public toilets.Josiah George Jennings was born on 10 November 1810 in Eling, at the edge of the New Forest in Hampshire. He was the eldest of seven children of Jonas Joseph Jennings and Mary Dimmock...

     invented a wash-out design with a shallow pan emptying into an S-trap.
  • 1857: The first American patent for a toilet, the 'plunger closet', was granted.
  • 1858: The first flush toilets on the European continent may have been the three "waterclosets" installed in the new town house of banker Nicolay August Andresen on 6 Kirkegaten in Christiania
    Oslo
    Oslo is a municipality, as well as the capital and most populous city in Norway. As a municipality , it was established on 1 January 1838. Founded around 1048 by King Harald III of Norway, the city was largely destroyed by fire in 1624. The city was moved under the reign of Denmark–Norway's King...

    , insured in January 1859. The toilets were probably imported from England, as they were referred to by the English term "waterclosets" in the insurance ledger.
  • 1860: Another early watercloset on the European continent was also imported from England. It was installed in the rooms of Queen Victoria
    Victoria of the United Kingdom
    Victoria was the monarch of the United Kingdom of Great Britain and Ireland from 20 June 1837 until her death. From 1 May 1876, she used the additional title of Empress of India....

     in Ehrenburg Palace
    Ehrenburg Palace
    Ehrenburg Palace is a palace in Coburg, Germany.The palace was built by John Ernest, Duke of Saxe-Coburg in 1543.The new city palace was built around a dissolved Franciscan monastery....

     (Coburg, Germany); she was the only one who was allowed to use it.
  • 1880s: Thomas Crapper
    Thomas Crapper
    Thomas Crapper was a plumber who founded Thomas Crapper & Co. in London. Contrary to widespread misconceptions, Crapper did not invent the flush toilet. He did, however, do much to increase the popularity of the toilet, and developed some important related inventions, such as the ballcock...

    's plumbing company built flush toilets of Giblin's design. Although not the original inventor, Crapper popularized the siphon system for emptying the tank, replacing the earlier floating valve system which was prone to leaks. Some of Crapper's designs were made by Thomas Twyford
    Thomas Twyford
    Thomas William Twyford was a Pottery manufacturer in England.He invented the single piece, ceramic toilet. He also made infamous Thomas Crapper's toilet....

    . The similarity between Crapper's name and the much older word crap is a coincidence.
  • 1885: The first modern pedestal 'flush-down' toilet was demonstrated by Frederick Humpherson of the Beaufort Works, Chelsea
    Chelsea, London
    Chelsea is an area of West London, England, bounded to the south by the River Thames, where its frontage runs from Chelsea Bridge along the Chelsea Embankment, Cheyne Walk, Lots Road and Chelsea Harbour. Its eastern boundary was once defined by the River Westbourne, which is now in a pipe above...

    , England
    England
    England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

    .
  • 1885: Thomas Twyford
    Thomas Twyford
    Thomas William Twyford was a Pottery manufacturer in England.He invented the single piece, ceramic toilet. He also made infamous Thomas Crapper's toilet....

     built the first one-piece ceramic toilet using the flush-out siphon design by J. G. Jennings.
  • 1898: Albert Giblin received British patent 4990 for the "Silent Valveless Water Waste Preventer", a siphon discharge system.
  • 1906: William Elvis Sloan
    William Elvis Sloan
    William Elvis Sloan I invented the Flushometer flushing mechanism, which is currently installed in millions of commercial, institutional and industrial restrooms worldwide.-Biography:...

     invented the Flushometer
    Flushometer
    the Royal Flushometer is a product of the Sloan Valve Company that uses an inline handle to flush urinals. It was invented by William Elvis Sloan.-Function:...

    , which used pressurized water directly from the supply line for faster recycle time between flushes. The Flushometer is still in use today in public restrooms worldwide.
  • 1907: Thomas MacAvity Stewart of Saint John, New Brunswick
    Saint John, New Brunswick
    City of Saint John , or commonly Saint John, is the largest city in the province of New Brunswick, and the first incorporated city in Canada. The city is situated along the north shore of the Bay of Fundy at the mouth of the Saint John River. In 2006 the city proper had a population of 74,043...

     patented the vortex-flushing toilet bowl, which creates a self cleansing effect.
  • 1980: Bruce Thompson, working for Caroma in Australia
    Australia
    Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

    , developed the Duoset cistern with two buttons and two flush volumes
    Dual flush toilet
    A dual-flush toilet is a variation of the flush toilet that uses two buttons or handles to flush different levels of water. It was invented by Australian inventor Bruce Thompson in 1980 while working for Caroma, and although the first generation dual-flush toilet caught on, a redesign in 1993 cut...

     as a water-saving measure. Modern versions of the Duoset are now available worldwide, and save the average household 67% of their normal water usage.

Flushing mechanism


The flushing mechanism provides a large flow of water into the bowl (which is described later in this article). The mechanism usually incorporates one or more parts of the following designs:

Tank fill valve



Tank fill valves are found in all tank-style toilets. The valves are of two main designs: the side-float design and the concentric-float design. The side-float design has existed for over a hundred years. The concentric-design has only existed since 1957, but is gradually becoming more popular than the side-float design, and Fluidmaster, founded in the United States by inventor Adolf Schoepe
Adolf Schoepe
Adolf Schoepe was a German-American inventor and businessman.Schoepe, a master metalworker with no formal education, immigrated to the United States in 1927. At the time he did not speak English, and had only about $25...

, makes them.

The side-float design incorporates a float, usually ball-shaped, which is located to one side of the main valve tower at the end of a rod or arm. As the side-float rises, so does the side-float-arm. The arm is connected to a linkage which blocks the water flow into the toilet tank, and thus maintains a constant level in the tank.
The newer concentric-float fill valve consists of a tower which is encircled by a plastic float assembly. Operation is otherwise the same as a side-float fill valve, even though the float position is somewhat different. By virtue of its more compact layout, interference between the float and other obstacles (tank insulation, flush valve, and so on) is greatly reduced, thus increasing reliability. The concentric-float fill valve is also designed to signal to users automatically when there is a leak in the tank, by making much more noise when a leak is present than the older style side-float fill valve, which tends to be nearly silent when a slow leak is present.

Tank style with flapper-flush-valve



In a tank-based system, the storage tank (or cistern) collects between 6 and 17 liters of water over a period of time. This system is suitable for locations plumbed with 1/2" (15 mm) or 3/8" (10 mm) water pipes.
The storage tank is kept full by a tank fill-valve. The storage tank is usually mounted directly upon the bowl, although some tanks are mounted on the wall a few feet above the bowl in an attempt to increase the flush water pressure as it enters the bowl. Tanks near the ceiling are flushed by means of a dangling pull chain, often with a large ornate handle, connected to a flush lever on the cistern itself. "Pulling the chain" remains a British euphemism for flushing the toilet, although this type of tank or cistern is becoming rare. A similar German
German language
German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....

 expression is Wasser ziehen ("to pull water").

In tanks using a flapper-flush-valve, the outlet at the bottom of the tank is covered by a buoyant plastic cover or flapper, which is held in place against a fitting (the flush valve seat) by water pressure. To flush the toilet, the user pushes a lever, which lifts the flush valve from the valve seat. The valve then floats clear of the seat, allowing the tank to empty quickly into the bowl. As the water level drops, the floating flush valve descends back to the bottom of the tank and covers the outlet pipe again. This system is common in homes in the USA
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and in continental Europe. Recently this flush system has also become available in the UK due to a change in regulations.

Tank style with siphon-flush-valve


This system, invented by Albert Giblin and common in the UK
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, uses a storage tank similar to that used in the flapper-flush-valve system above. This flush valve system is sometimes referred to as a valveless system, since no traditional type of valve is required. Some would argue, however, that any system of regulating the flow of a fluid is still technically a valve. In the siphon-flush-valve system, the user pushes a lever or button, forcing the water up into the tank siphon passageway which then empties the water in the tank into the bowl. The advantage of a siphon over the flush valve is that it has no sealing washer
Washer (mechanical)
A washer is a thin plate with a hole that is normally used to distribute the load of a threaded fastener, such as a screw or nut. Other uses are as a spacer, spring , wear pad, preload indicating device, locking device, and to reduce vibration...

s that can wear out and cause leaks, so it is favoured in places where there is a need to conserve water. Until recently, the use of siphon-type cisterns was mandatory in the UK to avoid the potential waste of water by millions of leaking toilets with flapper valves but due to EU harmonisation the regulations have changed. These valves can sometimes be more difficult to operate than a "flapper"-based flush valve because the lever requires more torque than a flapper-flush-valve system. This additional torque required at the tank lever is due to the fact that a user must forcefully lift a certain amount of water up into the siphon passageway in order to initiate the siphon action in the tank.

Older installations, known as "high suite combinations", used a high-level cistern (tank), fitted above head height, that was operated by pulling a chain hanging down from a lever attached to the cistern. When more modern close-coupled cistern and bowl combinations were first introduced, these were first referred to as "low suite combinations". Modern versions have a neater-looking low-level cistern with a lever that the user can reach directly, or a close-coupled cistern that is even lower down and integrated with the bowl. In recent decades the close coupled tank/bowl combination has become the most popular residential system, as it has been found by ceramic engineers that improved waterway design is a more effective way to enhance the bowl's flushing action than high tank mounting.

It can now be found in dual flush versions.

Tank style with high-pressure or pressure-assist valve


This system utilizes mains water pressure to pre-pressurize a plastic tank located inside of what otherwise appears to be the more typical ceramic flush tank. A flush cycle begins each time a user flushes the bowl. After a user flushes and the water in the pre-pressurized tank has finished emptying into the bowl, the outlet valve in the plastic tank shuts. Then the high pressure water from the city main refills the plastic tank. Inside the tank is an air-filled balloon-like rubber diaphragm. As the higher-pressure mains water enters the tank, the rubber diaphragm is also pressurized and shrinks accordingly. During flushing, the compressed air inside the diaphragm pushes the water into the bowl at a flow rate which is significantly higher than a tank style gravity-flow toilet. This system requires slightly less water than a gravity-flow toilet. Pressure-assist toilets are sometimes found in both private (single, multiple and lodging) bathrooms as well as light commercial installations (such as offices). They seldom clog, but the pressurized tanks require replacement about once every 10 years. They also tend to be noisier - a concern for residential settings. The inner bowl stays cleaner (in appearance) than gravity counterparts because of the larger water surface area and the toilet's forceful flush. Newer toilets from several companies such as Kohler that are pressure-assisted use 1.4 gal to 1.1 gal per flush.

Tankless style with high-pressure (flushometer) valve


In 1906, William Sloan
William Elvis Sloan
William Elvis Sloan I invented the Flushometer flushing mechanism, which is currently installed in millions of commercial, institutional and industrial restrooms worldwide.-Biography:...

 first made his "flushometer" style toilet flush valve, incorporating his patented design, available to the public. The design proved to be very popular and efficient, and remains so to this day. Flushometer toilet flush valves are still often installed in commercial restrooms, and are frequently used for both toilets and urinals. Since they have no tank, they have zero recharge time, and can be used immediately by the next user of the toilet. They can be easily identified by their distinctive chrome pipe-work, and by the absence of a toilet tank or cistern, wherever they are employed.

Some flushometer models require the user to either depress a lever or press a button, which in turn opens a flush valve
Valve
A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...

 allowing mains-pressure water to flow directly into the toilet bowl or urinal. Other flushometer models are electronically triggered, using an infrared sensor to initiate the flushing process. Typically, on electronically triggered models, an override button is provided in case the user wishes to manually trigger flushing earlier. Some electronically triggered models also incorporate a true mechanical manual override which can be used in the event of the failure of the electronic system. In retrofit installations, a self-contained battery-powered or hard-wired unit can be added to an existing manual flushometer to flush automatically when a user departs.

Once a flushometer valve has been flushed, and after a preset interval, the flushometer mechanism closes the valve and stops the flow. The flushometer system requires no storage tank, but requires a high volume of water in a very short time. Thus a 3/4 inch (19 mm) pipe at minimum, or preferably a 1 inch (25 mm) pipe, must be used, but as the high volume is used only for a short duration, very little water is used for the amount of flushing efficacy delivered. Water main pressures must be above 30 pound per square inches (2.1 bar). While the higher water pressure employed by a flushometer valve does scour the bowl more efficiently than a gravity-driven system, and while fewer blockages typically occur as a result of this higher water pressure, flushometer systems still require approximately the same amount of water as a gravity system to operate (1.6 gpf).

Tipping bucket type "valve"


A simple rotating bucket is located within the tank, that is lever activated manually.

Bowl design


The bowl, loo or pan, of a toilet is the receptacle that receives bodily waste. A toilet bowl is most often made of a ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...

, but can sometimes be made of stainless steel or composite plastics. Toilet bowls are mounted in any one of three basic manners: above-floor mounted (pedestal
Pedestal
Pedestal is a term generally applied to the support of a statue or a vase....

), wall mounted (cantilever
Cantilever
A cantilever is a beam anchored at only one end. The beam carries the load to the support where it is resisted by moment and shear stress. Cantilever construction allows for overhanging structures without external bracing. Cantilevers can also be constructed with trusses or slabs.This is in...

), or in-floor mounted (natural position
Squat toilet
A squat toilet is a toilet used by squatting, rather than sitting. There are several types of squat toilets, but they all consist essentially of a hole in the ground...

).

Within the bowl, there are three main water-way design systems: the siphoning trapped system (found primarily in North American residential installations, and in North American light commercial installations), the non-siphoning trapped system (found in most other installations both inside and outside of North America), and the valve-closet system (found in many specialty applications, such as in trains, planes, buses, and other such installations around the world). Older style toilets called "washout" toilets are now only found in a few locations.

Siphoning-toilet


The siphoning-toilet is perhaps the most popular design in North America for residential and light commercial toilet installations. Some other terms for these types of toilets are "siphon jet", "siphon wash", and in North America, "wash down". All siphoning-toilets incorporate an 'S' shaped water-way. The water-ways in these toilets are designed with slightly smaller diameters than a non-siphoning toilet, so that the water-way will naturally fill up with water, each time it is flushed, thus creating the siphon action. To flush the toilet the user activates a flushing mechanism (see above), which pours a large quantity of water quickly into the bowl. This creates a flow large enough to purge the bowl's water-way of all air, thus causing the bowl to empty rapidly due to the siphon action that has been created. This flow stops as soon as the water level in the bowl drops below the first bend of the siphon, allowing air to enter the S-pipe to break the column of liquid and to halt the siphonic action.

A "true siphoning-toilet" can be easily identified by the noise it makes. If it can be heard to suck air down the drain at the end of a flush, then it is a true siphoning toilet. If not, then it is a non-siphoning toilet.

Non-siphoning toilet



Valve closet


The valve closet has a valve or flap at the exit of the bowl with a water-tight seal to retain a pool of water in the pan. When the toilet is flushed, the valve is opened and the water in the pan flows rapidly out of the bowl into the drains, carrying the waste with it.

The earliest type of toilet, the valve closet is now scarce as a water-flush toilet. More complicated in design than other water closets, reliability is lower and maintenance more difficult. The most common use for valve closets is now in portable closets for caravans, camping, trains, and aircraft where the flushing fluid is recycled. This design is also used in train carriages in areas where the waste is allowed to be simply dumped between the tracks (the flushing of such toilets is generally prohibited when the train is in a station).

Washout toilet



Washout toilets have a shallow pool of water into which waste is deposited, with a trapped drain just behind this pool. Waste is cleared out from this pool of water by being swept over into the trap
Trap (plumbing)
In plumbing, a trap is a U-, S-, or J-shaped pipe located below or within a plumbing fixture. An S-shaped trap is also known as the S-bend invented by Alexander Cummings in 1775 but became known as the U-bend following the introduction of the U-shaped trap by Thomas Crapper in 1880. The new U-bend...

 (usually either a P-trap or an S-trap) and then beyond into a sewer by water from the flush. Washout pans were amongst the first types of ceramic toilets invented and since the early 1970s are now only found in a few localities such as in some parts of Germany.

Reverse bowl design


In Germany, Netherlands, and some regions of Poland, the bowl is designed to hold the fecal matter out of the water prior to flushing by means of a receiver shelf, whereas most U.S. or U.K. designs immediately allow it to plunge into standing water. This reverse design prevents the occurrence of any splash-up which commonly happens when fecal matter plunges into the standing water in the standard designs (although substantial deposits may cause splash-up problems of their own). The disadvantage is that it also increases the associated odor and may require the use of a brush to remove bits of feces that may have "skid-marked" on the shelf. Similar designs are found in some early toilets in the U.S., one particular brand being labeled the "Grand Niagara", as the flushing of the shelf creates a waterfall effect into the drain chamber.

Cultural variations



In India, the "Anglo-Indian" design allows the same toilet to be used in the sitting or the squatting position
Squatting position
Squatting is a posture where the weight of the body is on the feet but the knees are bent either fully or partially . In contrast, sitting, involves taking the weight of the body, at least in part, on the buttocks against the ground or a horizontal object such as a chair seat...

. This type of toilet is also used on most Russian older style trains, made in Eastern Germany (Ammendorf factory, design dated probably to the 50s), employing a pan-like shutter valve discharging waste directly on the railway. The toilet usage is permitted only on the go, and outside of major cities. These toilets are currently vanishing, together with the old trains, being replaced with modern vacuum systems.

For a review of Japanese toilet usage and history, see Toilets in Japan
Toilets in Japan
There are two styles of toilets commonly found in Japan. The oldest type is a simple squat toilet, which is still somewhat common in public conveniences. After World War II, modern Western-type flush toilets and urinals became common. The current state of the art for Western-style toilets is the...

.

Low-flow and high-efficiency toilets


Nowadays, there is a significant move towards using less water for flushing flush toilets. This has resulted in the emergence of new toilet designs and national standards on water consumption for flushing. In addition, some people are also modifying their existing flush toilets to use less water. This can be done by adding a floating weight (ie brick, water bottle) into the toilet's water tank. This allows the use of less water per flush since the water pressure is hence increased. Other modifications are often done on the water system itself; ie by using greywater, or a system that pollutes the water more gradually, more efficient use of the water is accomplished.

US Standards for new toilets


Pre-1994 residential and pre-1997 commercial flush toilets use 3.4 gallons (13 l) of water per flush (gpf or lpf). In 1992, the United States Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

 passed the Energy Policy Act of 1992
Energy Policy Act of 1992
The Energy Policy Act is a United States government act.It was passed by Congress and addressed energy efficiency, energy conservation and energy management , natural gas imports and exports , alternative fuels and requiring certain fleets to acquire alternative fuel vehicles, which are capable of...

, which mandated that beginning in 1994 common flush toilets use only 1.6 gallons (6.1 l). In response to the Act, manufacturers produced low-flow toilets, which many consumers did not like because they often required more than one flush to remove solids. Manufacturers responded to consumers' complaints by improving the toilets. The improved products are generally identified as high efficiency toilets or HETs. HETs possess an effective flush volume of 1.3 gallons (4.9 l) or less. HETs may be single-flush or dual-flush. A dual-flush toilet permits its user to choose between two amounts of water. Some HETs are pressure-assisted  (or power-assisted or pump-assisted or vacuum-assisted).

The performance of a flush-toilet may be rated by a Maximum Performance (MaP) score. The low end of MaP scores is 250 (250 grams of simulated fecal matter). The high end of MaP scores is 1000. A toilet with a MaP score of 1000 should provide trouble-free service. It should remove all waste with a single flush; it should not plug; it should not harbor any odor; it should be easy to keep clean. The United States Environmental Protection Agency uses a MaP score of 350 as the minimum performance threshold for HETs. 1.6 gpf toilets are also sometimes referred as ULF (Ultra Low Flow) toilets.

Water-closet (WC), the name


The term "water-closet" was an early term for a room with a toilet. Originally, the term "wash-down closet" was used. The "water-closet" was invented in England around 1870. It did not reach the United States until the 1880s. Around this time, only luxury hotels and wealthy people had indoor private bathrooms. By 1890, the fear of the theory of disease was beginning to arise about carelessly disposed human waste being contaminated and infectious. This is stated in the book "A People and A Nation" the eighth edition. Originally, the term "bath-room" referred only to the room where the bathtub was located, which was usually a separate room, but this connotation has changed in common North American usage. In the UK, the terms "bathroom" and "toilet" are used to indicate discrete functions, even though bathrooms in modern homes have been designed according to the American norm since around the mid-sixties. The term "water closet" was probably adapted because in the late 19th century, with the advent of indoor plumbing, a toilet displaced an early clothes closet, closets being shaped to easily accommodate the spatial needs of a commode.. Early indoor toilets had in fact been known as garderobe
Garderobe
The term garderobe describes a place where clothes and other items are stored, and also a medieval toilet. In European public places, a garderobe denotes the cloakroom, wardrobe, alcove or an armoire. In Danish, Dutch, German and Spanish garderobe can mean a cloakroom. In Latvian it means checkroom...

s because they actually were used to store clothes, as the smell of ammonia was found to deter fleas and moths. The term "water closet" is still used today in some places, but it often refers to a room that has both a toilet and other plumbing fixtures such as a sink or a bathtub. Plumbing manufacturers often use the term "water-closet" to differentiate toilets from urinals. American plumbing codes still refer to a toilet as a "Water Closet" or a "WC". Many South American countries refer to a toilet as a "water" or "WC". The Royal Spanish Academy Dictionary
Diccionario de la lengua española de la Real Academia Española
The Diccionario de la lengua española de la Real Academia Española or DRAE is the most authoritative dictionary of the Spanish language. It is produced, edited, and published by the Real Academia Española ; the first edition was published in 1780...

 accepts "váter" as a name for a toilet or bathroom, which is derived from the British term "water-closet". In French the expression "aller aux waters" ("to go to the waters") has now become obsolete, but it also derives from "water closet". "WC" is still used in the French language, although not as common as the term "toilet", and pronounced as "VC", a shortened version of "double V C". In Germany the expression "Klo" (first syllable of "closet") is still used, though the term is colloquial and not welcome in polite conversation.

In Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

, Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 and the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

 (due to the bowl design (above)) the toilet is often kept in a separate room known as the "WC" even in newly built residences. In the Dutch
Dutch language
Dutch is a West Germanic language and the native language of the majority of the population of the Netherlands, Belgium, and Suriname, the three member states of the Dutch Language Union. Most speakers live in the European Union, where it is a first language for about 23 million and a second...

-speaking part (Flanders
Flanders
Flanders is the community of the Flemings but also one of the institutions in Belgium, and a geographical region located in parts of present-day Belgium, France and the Netherlands. "Flanders" can also refer to the northern part of Belgium that contains Brussels, Bruges, Ghent and Antwerp...

) as well as the French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...

-speaking part of Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 (Wallonia), "WC" is a frequently used synonym for "toilet".

Swirl direction


It is a commonly held misconception that when flushed, the water in a toilet bowl swirls one way if the toilet is north of the equator and the other way if south of the equator, due to the Coriolis effect
Coriolis effect
In physics, the Coriolis effect is a deflection of moving objects when they are viewed in a rotating reference frame. In a reference frame with clockwise rotation, the deflection is to the left of the motion of the object; in one with counter-clockwise rotation, the deflection is to the right...

 – usually, counter clockwise in the northern hemisphere, and clockwise in the southern hemisphere. In reality, the direction that the water takes is much more determined by the direction that the bowl's rim jets are pointed, and it can be made to flush in either direction in either hemisphere by simply redirecting the rim jets during manufacture. On the scale of bathtubs and toilets, the Coriolis effect is too weak to be observed except under laboratory conditions.

Toilet clogging


Clogging is a common problem of flush toilets. It usually occurs as a result of an attempt to flush unsuitable items, or too much toilet paper, although it can occur spontaneously due to limescale
Limescale
Limescale is the hard, off-white, chalky deposit found in kettles, hot-water boilers and the inside of inadequately maintained hot-water central heating systems...

 fouling of the drain pipe. Flushing hair should also be avoided. Clogging is particularly insidious, as it is usually not discovered immediately, but only later by an unsuspecting user trying to flush a loaded toilet. Overflowing of the water mixed with excrements may then occur, depending on the bowl volume, tank capacity and severity of clogging. For this reason, rooms with flush toilets should be designed as wet rooms, with a second drain on the floor, and a shower head capable of reaching whole floor area. Common means to remedy clogging include use of toilet plunger
Plunger
A plunger is a common device that is used to release stoppages in plumbing. The tool consists of a rubber cup with an attached stick "shaft", usually made of wood or bronze. Before use, any objects such as hair in the plug grate should be removed and, if possible the overflow hole should be...

, drain cleaner
Drain cleaner
A drain cleaner is a consumer product or device that unblocks sewer pipes or helps to prevent the occurrence of clogged drains; the term may also refer to the individual who performs the activity...

 or a plumber's snake
Plumber's snake
A plumber's snake, sometimes known as a "toilet jack" or "electric eel", is a flexible auger used to remove clogs in plumbing that cannot be loosened with a plunger....

.

Fire safety in multi-story buildings




Toilets in multi-story building
Building
In architecture, construction, engineering, real estate development and technology the word building may refer to one of the following:...

s, located on fire-resistance rated
Fire-resistance rating
A fire-resistance rating typically means the duration for which a passive fire protection system can withstand a standard fire resistance test. This can be quantified simply as a measure of time, or it may entail a host of other criteria, involving other evidence of functionality or fitness for...

 floors typically require at least two through-penetrations
Penetration (firestop)
A penetration, in firestopping, is an opening, such as one created by the use of a cast-in-place sleeve, in a wall or floor assembly required to have a fire-resistance rating, for the purpose of accommodating the passage of a mechanical, electrical or structural penetrant. The penetration may or...

, which can compromise the rating of the floor if left untreated. One opening is for the fresh water supply to flush and/or fill the water tank. The other through-penetration is for the drain pipe. The fresh water supply line requires routine firestopping. The drain pipe, however, is exempt from firestopping in many building code
Building code
A building code, or building control, is a set of rules that specify the minimum acceptable level of safety for constructed objects such as buildings and nonbuilding structures. The main purpose of building codes are to protect public health, safety and general welfare as they relate to the...

s, particularly when noncombustible piping
Piping
Within industry, piping is a system of pipes used to convey fluids from one location to another. The engineering discipline of piping design studies the efficient transport of fluid....

 is used, because the penetration terminates on the unexposed side in a ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...

 bowl filled with water, which can withstand significant fires. Intumescent
Intumescent
An intumescent is a substance which swells as a result of heat exposure, thus increasing in volume, and decreasing in density. Intumescents are typically used in passive fire protection and, in America, require listing and approval use and compliance in their installed configurations in order to...

 firestops are often used, in the event plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

 pipes are used for toilet drains, so that the melting plastic pipe is choked off in the event of an accidental fire. It is, however, customary to fill the metallic drain pipe annulus
Annulus (firestop)
The Annulus, or annular space, is the space between a penetrant and whatever surrounds it, such as the sides of an opening or a sleeve, as the case may be.Sometimes an annulus can be "offset", meaning that the penetrant is not centred...

 with rockwool
Mineral wool
Mineral wool, mineral fibers or man-made mineral fibers are fibers made from natural or synthetic minerals or metal oxides. The latter term is generally used to refer solely to synthetic materials including fiberglass, ceramic fibers and stone wool...

 packing
Packing (firestopping)
Packing is the process and/or the materials used in filling both service penetrations and building joints with backer materials as approved components within a firestop.-Purpose:...

. Even with the best of intentions, it would be difficult for the firestopper to install a sealant
Sealant
A sealant may be viscous material that has little or no flow characteristics and stay where they are applied or thin and runny so as to allow it to penetrate the substrate by means of capillary reaction...

, because he is not allowed or inclined to remove the flange, which is what is partially used to support the drain pipe below during the installation process.

See also

  • Ecological sanitation
    Ecological sanitation
    Ecological sanitation, also known as ecosan or eco-san, are terms coined to describe a form of sanitation that usually involves urine diversion and the recycling of water and nutrients contained within human wastes back into the local environment....

  • Toilet rim block
    Toilet rim block
    A Toilet rim block is a disinfectant block used in flush toilets which slowly dissolves in water. They often come sold in a small holder that is attached over the rim of a toilet and hangs down into the bowl, so as the toilet gets flushed, the water passes through the holder coming into contact...

  • Toilets in Japan
    Toilets in Japan
    There are two styles of toilets commonly found in Japan. The oldest type is a simple squat toilet, which is still somewhat common in public conveniences. After World War II, modern Western-type flush toilets and urinals became common. The current state of the art for Western-style toilets is the...

  • Urinal

External links