For the smoking device, see Hookah and Bong
A water pipe is a pipe or tube, frequently made of plastic or metal,
that carries pressurized and treated fresh water to a building, as well as
inside the building. History
For many centuries, lead was the favoured material for water pipes,
because its malleability made it practical to work into shape. This was a
source of lead-related health problems in the years before the health hazards
of ingesting lead were fully understood; among these were stillbirths and high
rates of infant mortality. Lead water pipes were still in common use in the
early 20th century and remain in many households. Lead-tin alloy solder was
commonly used to join copper pipes, but modern practice uses tin-antimony alloy
solder to join copper in order to eliminate lead hazards.
Despite the Romans' common use of lead pipes, their aqueducts rarely poisoned
people. Unlike other parts of the world where lead pipes cause poisoning, the
Roman water had so much calcium in it, that a layer of plaque prevented the
water contacting the lead itself. What often causes confusion is the large
amount of evidence of widespread lead poisoning, particularly amongst those
who would have had easy access to piped water. This was an unfortunate result of
lead being used in cookware and as an additive to processed food and drink,
such as a preservative in wine. Roman lead pipe inscriptions provided
information on the owner to prevent water theft.
Wooden pipes were used in London and elsewhere during the 16th and 17th
centuries. The pipes were hollowed-out logs, which were tapered at the end with
a small hole in which the water would pass through. The multiple pipes were
then sealed together with hot animal fat. They were often used in Montreal
and Boston in the 1800s, and built-up wooden tubes were widely used in the USA
during the 20th century. These pipes, used in place of corrugated iron or
reinforced concrete pipes, were made of sections cut from short lengths of wood.
Locking of adjacent rings with hardwood dowel pins produced a flexible
structure. About 100,000 feet of these wooden pipes were installed during WW2
in drainage culverts, storm sewers and conduits, under highways and at army
camps, naval stations, airfields and ordnance plants.
Cast iron and ductile iron pipe was long a lower-cost alternative to copper,
before the advent of durable plastic materials but special non-conductive
fittings must be used where transitions are to be made to other metallic pipes,
except for terminal fittings, in order to avoid corrosion owing to
electrochemical reactions between dissimilar metals.
Bronze fittings and short pipe segments are commonly used in combination with
various materials. Difference between pipes and tubes
The difference between pipes and tubes is simply in the way it is sized. PVC
pipe for plumbing applications and galvanized steel pipe for instance, are
measured in IPS. Copper tube, CPVC, PeX and other tubing is measured nominally,
which is basically an average diameter. These sizing schemes allow for universal
adaptation of transitional fittings. For instance, 1/2" PeX tubing is the same
size as 1/2" copper tubing. 1/2" PVC on the other hand is not the same size as
1/2" tubing, and therefore requires either a threaded male or female adapter
to connect them. When used in agricultural irrigation, the singular
form "pipe" is often used as a plural. Pipe is available in rigid "joints",
which come in various lengths depending on the material. Tubing, in particular
copper, comes in rigid hard tempered "joints" or soft tempered rolls. PeX and
CPVC tubing also comes in rigid "joints" or flexible rolls. The temper of the
copper, that is whether it is a rigid "joint" or flexible roll, does not
affect the sizing. The thicknesses of the water pipe and
tube walls can vary. Pipe wall thickness is denoted by various schedules or for
large bore polyethylene pipe in the UK by the Standard Dimension Ratio, defined
as the ratio of the pipe diameter to its wall thickness. Pipe wall thickness
increases with schedule, and is available in schedules 20, 40, 80, and
higher in special cases. The schedule is largely determined by the operating
pressure of the system, with higher pressures commanding greater thickness.
Copper tubing is available in four wall thicknesses: type DWV, type 'M', type
'L', and type 'K'. Because piping and tubing are commodities, having a greater
wall thickness implies higher initial cost. Thicker walled pipe generally
implies greater durability and higher pressure tolerances.
Wall thickness does not affect pipe or tubing size. 1/2" L copper has the same
outer diameter as 1/2" K or M copper. The same applies to pipe schedules. As a
result, a slight increase in pressure losses is realized due to a decrease in
flowpath as wall thickness is increased. In other words, 1 foot of 1/2" L copper
has slightly less volume than 1 foot of 1/2 M copper.
Demand for copper products has fallen due to the dramatic increase in the
price of copper, resulting in increased demand for alternative products
including PEX and stainless steel. Gallery
See also Notes
References External links
Lead Water Pipes and Infant Mortality in Turn-of-the-Century Massachusetts
Case Studies in Environmental Medicine - Lead Toxicity
ToxFAQs: Lead