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Buildings Plumbing Systems
Plumbing
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Plumbing, system of pipes and fixtures installed in a
building for the distribution and use of potable (drinkable) water and the
removal of waterborne wastes.
It is usually distinguished from water and sewage systems that serve a
group of buildings or a city.
One of the problems of every civilization in which the
population has been centralized in cities and towns has been the development of
adequate plumbing systems.
In certain parts of Europe the complex aqueducts built by
the Romans to supply their cities with potable water can still be seen.
However, the early systems built for the disposal of
human wastes were less elaborate.
Human wastes were often transported from the cities in carts
or buckets or else discharged into an open, water-filled system of ditches that
led from the city to a lake or stream.
Improvement in plumbing systems was very slow. Virtually no
progress was made from the time of the Romans until the 19th century.
The relatively primitive sanitation facilities were
inadequate for the large, crowded population centres that sprang up during the
Industrial Revolution, and outbreaks of typhoid fever and dysentery were
often spread by the consumption of water contaminated with human wastes.
Eventually these epidemics were curbed by the development
of separate, underground water and sewage systems, which eliminated open sewage
ditches.
In addition, plumbing fixtures were designed to handle
potable water and water-borne wastes within buildings.
The term plumbing fixture embraces not only showers,
bathtubs, lavatory basins, and toilets but also such devices as washing
machines, garbage-disposal units, hot-water heaters, dishwashers, and drinking
fountains.
The water-carrying pipes and other materials used in a
plumbing system must be strong, noncorrosive, and durable enough to equal or
exceed the expected life of the building in which they are installed.
Toilets, urinals, and lavatories usually are made of stable
porcelain or vitreous china, although they sometimes are made of glazed cast
iron, steel, or stainless steel.
Ordinary water pipes usually are made of steel, copper,
brass, plastic, or other nontoxic material; and the most common materials for
sewage pipes are cast iron, steel, copper, and asbestos cement.
Methods of water distribution vary. For towns and cities,
municipally or privately owned water companies treat and purify water collected
from wells, lakes, rivers, and ponds and distribute it to individual buildings.
In rural areas water is commonly obtained directly from
individual wells.
In most cities, water is forced through the distribution
system by pumps, although, in rare instances, when the source of water is
located in mountains or hills above a city, the pressure generated by
gravity is sufficient to distribute water throughout the system.
In other cases, water is pumped from the collection and
purification facilities into elevated storage tanks and then allowed to flow
throughout the system by gravity.
But in most municipalities water is pumped directly through
the system; elevated storage tanks may also be provided to serve as
pressure-stabilization devices and as an auxiliary source in the event of
pump failure or of a catastrophe, such as fire, that might require more
water than the pumps or the water source are able to supply.
The pressure developed in the water-supply system and
the friction generated by the water moving through the pipes are the two
factors that limit both the height to which water can be distributed and the
maximum flow rate available at any point in the system.
A building’s system for waste disposal has two parts:
the drainage system and the venting system.
The drainage portion comprises pipes leading from
various fixture drains to the central main, which is connected to the municipal
or private sewage system.
The venting system consists of pipes leading from an air
inlet (usually on the building’s roof) to various points within the drainage
system; it protects the sanitary traps from siphoning or blowing by
equalizing the pressure inside and outside the drainage system.
Sanitary fixture traps provide a water seal between the
sewer pipes and the rooms in which plumbing fixtures are installed.
The most commonly used sanitary trap is a U bend, or dip,
installed in the drainpipe adjacent to the outlet of each fixture.
A portion of the waste water discharged by the fixture is
retained in the U, forming a seal that separates the fixture from the open
drainpipes.
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