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Skyscraper Plumbing
Sugar Land Marriott
Designing skyscrapers is an extremely complicated art that integrates several
different logistic operations and utilities. Plumbing is one of the more
challenging problems to solve due to the loss in pressure as water travels up a
vertical pipe.
Plumbing engineers found out that as you lift water above a datum, you lose 1
pound per square inch for every 2.3 feet of elevation. This small but
incremental loss makes achieving high water pressure at the top of a water
column very difficult. Most water fixtures require at least 25 psi to operate
or flush properly, so measures to insure consistent water pressure throughout
the building must be implemented. As the building get taller, another problem
arises as the water pressure at the bottom of a vertical pipe becomes too great
for safe operation and building codes.
The Solution The early
solution to this problem was a water tank mounted on the top of a building with
fill pumps at the bottom of the building, a simple gravity down feed
arrangement.
Today, a system of pressure-reducing valves and sub-risers are used to manage
the inconsistent water pressure throughout a skyscraper. Pressure-reducing
valves reduce the pressure at the bottom of the building, while sub-risers
increase the pressure for the skyscrapers upper floors. Today's systems lack a
main tank, but rather integrate the whole system within a buildings walls and
basement.
Water pressure controlling devices are constantly evolving as new concerns
about the environment arise and the publics awareness about green building
practices increases.
Drainage Drainage is another
common issue in skyscrapers, and is often just as difficult to solve as water
pressure problems. When water falls vertically down a pipe, the water will
adhere to the pipe's walls until the pipe's cross sectional area is about
one-fourth full. Once the gravity propelled water hits a horizontal bend in the
pipe, the flow velocity drops dramatically, and fills the pipe considerably more
due to the lost speed. It is common practice to use relief or yoke vents to
slow the water before it encounters a horizontal flow change. The piping at the
base of a vertical drainage column must be secured, as to reduce the risk of
breaking joints.
- Venting
For water to travel down a vertical pipe, air is necessary. Air
ventilation must be controlled so that low pressure zones can be created,
and the flow of water can continue. The low pressure zones should not be
placed near a fixture, or else poor drainage could occur (often recognized
by a gulping sound and poor flow performance). It is however okay to place
air vents in the fixtures themselves to increase water flow.
Material
Most high-rise plumbing systems use Type-L copper. On some very
tall buildings, stainless steel must be used because of the extra pressure.
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