Plastic pressure pipe systems
From Wikipedia, the free encyclopedia
Plastic pressure pipe systems are used for the conveyance of drinking water, waste water, chemicals, heating and cooling fluids, foodstuffs, ultra-pure liquids, slurries, gases, compressed air and vacuum system applications, both for above and below ground applications. Plastic pressure pipe systems have been in use in the United States for drinking water systems since the 1950s.[1]
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[edit] Types of pipe systems
The most common pipe systems are named after the materials they are made from. The type of pipe in use is dependent on the material passed through the pipe, the operating pressure, and the operating temperature. To ensure pipes from different vendors work together, the ISO sets standards[2] for manufacturers to follow.
[edit] Materials
In addition to the fittings, valves, and accessories that comprise a pipe system, the pipes themselves vary in size and composition, depending on the application.
[edit] Acrylonitrile butadiene styrene (ABS)
ABS is suitable for the conveyance of potable water, slurries and chemicals, and is used for chilled water applications, due to its low temperature properties and compressed airline systems.
In residential settings, it is often used for drain pipes.[3]
[edit] Unplasticized polyvinyl chloride (uPVC)
uPVC, commonly known as rigid PVC is used where resistance to chemicals and abuse is required.[4]
[edit] Chlorinated polyvinyl chloride (cPVC)
cPVC has many of the same properties as uPVC, and is also resistant to many acids, bases, salts, paraffinic hydrocarbons, halogens and alcohols. It is not resistant to solvents, aromatics and some chlorinated hydrocarbons.[5]
In some places, it has been approved in residential water supply systems.[6]
[edit] Polypropylene (PP)
Polypropylene is approved for use with foodstuffs, potable and ultra pure waters, hydronic heating and cooling, reclaimed and rainwater systems, compressed air lines, and geothermal applications, as well as within the pharmaceutical and chemical industries. [7] Polypropylene is noted for its resistance to physical and chemical damage. Polypropylene is adversely affected by UV radiation and should have a protective coating if installed outside.[1]
[edit] Polyethylene (PE)
When compared to other plastics, polyethylene shows excellent diffusion resistance, and because of this property, polyethylene has been used for gas conveyance for many years.[citation needed]
Oxidative-induction time is a routine test when assessing the quality of polyethylene pipes.
[edit] Polyvinylidene fluoride (PVDF)
PVDF is widely used in the chemical industry as a piping system for aggressive liquids.[citation needed] PVDF is a homopolymer without additives such as stabilizers and processing agents. It also displays excellent flame retardant properties.[citation needed]
[edit] Polybutylene (PB)
Polybutylene pipes (also known as polybutene-1 or PB-1) share similar properties to polyethylene pipes except the material can be made thinner due to increased creep resistance.[8] PB pipes were used as water supply pipes in the United States and Canada from the 1970s to the 1990s. Due to premature aging of the pipe, leaks occurred frequently and eventually a class action lawsuit against the manufacturers was settled.[9]