Plastic pipework: Difference between revisions

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{{short description|Tubular section or hollow cylinder made of  plastic}}

[[File:Polyethylene Pipe lengths.jpg|thumb|343x343px|Plastic Pipepipe lengths manufactured in Australia by [[Extrudingextruding]] [[High-density polyethylene|HDPE]] material.]]

'''Plastic pipe''' is a tubular section, or hollow cylinder, made of [[plastic]]. It is usually, but not necessarily, of circular cross-section, used mainly to convey substances which can flow—liquids and gases (fluids), slurries, powders and masses of small solids. It can also be used for structural applications; hollow [[Pipe (fluid conveyance)|pipes]] are far stiffer per unit weight than solid members.

'''Plastic pipework''' is used for the conveyance of [[drinking water]], [[Wastewater|waste water]], [[chemical]]s, heating fluid and [[Coolant|cooling fluids]], [[foodstuff]]s, ultra-pure liquids, [[Slurry|slurries]], [[gas]]es, [[compressed air]], [[irrigation]], [[plastic pressure pipe systems]], and [[vacuum system application]]sapplications.

== Types ==

There are three basic types of plastic pipespipe:

===Solid wall pipe===

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*[[Sewerage|Sewer]] applications: High [[chemical resistance]]

Plastic pipes are capable of fulfilling the specific requirement for each application. They do so over a long lifetime and with reliability and safety.<ref>{{Cite webnews|url=https://www.acu-tech.com.au/about-us/why-use-hdpe/|title=Why Use HDPE - What is HDPE Pipe?|website=Acu-Tech Piping Systems|language=en-AU|access-date=2019-01-04}}</ref> The key success factor is achieved by maintaining consistently high quality levels. For plastic pipe products, these levels are defined by the different standards. Two aspects are fundamentally important for the performance of plastic pipes: flexibility and long lifetime.<ref>{{Cite web|url = http://www.teppfa.eu/why-use-plastic-pipe-systems/|title = Why use Plastic Pipe Systems|last = TEPPFA, The European Plastic Pipes and Fittings Association}}</ref>

==Materials used==

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* ABS ([[acrylonitrile butadiene styrene|Acrylonitrile Butadiene Styrene]])

* CPVC ([[Chlorinatedchlorinated polyvinyl chloride|Chlorinated Polyvinyl Chloride]])

* HDPE ([[Highhigh-density polyethylene|High-Density Polyethylene)]])

* PB-1 ([[polybutylene]])

* PE ([[polyethylene]]) of various densities, also abbreviated to [[Low-density polyethylene|LDPE]], [[Medium-density polyethylene|MDPE]] and [[High-density polyethylene|HDPE]] (low, medium and high density polyethylene;<ref>{{Cite web|url=http://www.whatishdpe.com|title=What is HDPE}}</ref> the medium density version is at times referred to as "black alkathene" in the UK)

* PE-RT (polyethylene of Raisedraised Temperaturetemperature (RT))

* PEX ([[cross-linked polyethylene]])

* PP ([[polypropylene]])

* PVDF ([[polyvinylidene fluoride|Polyvinylidene Difluoridedifluoride]])

* UPVC ([[unplasticized polyvinyl chloride|Unplasticized Polyvinyl Chloride]])

{{col div col end}}

==Material characteristics==

===ABS (Acrylonitrileacrylonitrile Butadienebutadiene Styrenestyrene)===

[[Acrylonitrile butadiene styrene|Acrylonitrile]] Butadiene Styrene (ABS)]] is used for the conveyance of potable water, slurries and chemicals. Most commonly used for DWV (drain-waste-vent) applications. It has a wide temperature range, from -40&nbsp;°C to +60&nbsp;°C.

ABS is a [[thermoplastic]] material and was originally developed in the early 1950s for use in [[oil field]]s and the chemical industry. The variability of the material and its relative cost effectiveness has made it a popular engineering plastic. It can be tailored to a range of applications by modifying the ratio of the individual chemical components.

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This material is also used in non-pressure piping systems for [[soil]] and waste.<ref>{{Cite web|url = http://www.teppfa.eu/fast-guide-to-materials/|title = Fast Guide to Materials|last = TEPPFA, The European Plastic Pipes and Fittings Association}}</ref>

=== CPVC (Chlorinatedchlorinated Polyvinylpolyvinyl Chloridechloride) ===

[[Chlorinated polyvinyl chloride|Chlorinated Polyvinyl Chloride]] (CPVC)]] is resistant to many acids, bases, salts, paraffinic hydrocarbons, halogens and alcohols. It is not resistant to solvents, aromatics and some chlorinated hydrocarbons. It can carry higher temperature liquids than uPVC with a max operating temperature reaching {{convert|200|°F|°C|1}}. Due to its greater temperature threshold and chemical resistance, CPVC is one of the main recommended material choices in residential, commercial, and industrial water and liquid transport.

=== HDPE (Highhigh-Densitydensity Polyethylenepolyethylene) ===

[[High-density polyethylene|High-Density Polyethylene]] (HDPE)]] - HDPE pipe is strong, flexible and light weight. It has a zero leak rate when fused together.<ref>{{cite webnews|url=https://isco-pipe.com/pipe/|title=HDPE Pipe|newspaper=Isco Industries |access-date=16 March 2021}}</ref>

===PB-1 (polybutylene) ===

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===PE (polyethylene)===

[[File:Acu-Therm Coex white skinned HDPE Pipe lengths..jpg|thumb|Polyethylene Piping in Australia, made from HDPE material.]]

[[Polyethylene]] has been successfully used for the safe conveyance of potable and waste water, hazardous waste, and compressed gases for many years. Two variants are [[HDPE pipe|HDPE Pipe]] ([[high-density polyethylene]])<ref>{{cite web|title=HDPE|url=http://plasticpipe.org/pdf/high_density_polyethylene_pipe_systems.pdf|publisher=Plastics Pipe Institute|access-date=2011-12-29}}</ref> and the more heat resistant [[PEX]] (cross-linked polyethylene, also XLPE).

PE has been used for pipes since the early 1950s. PE pipes are made by [[extrusion]] in a variety of sizes dimensions. PE is lightweight, flexible and easy to weld. Its smooth interior finish ensures good flow characteristics. Continuous development of the material has enhanced its performance, leading to rapidly increasing usage by major water and gas utility companies throughout the world.

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PP is a thermoplastic polymer made from polypropylene. It was first invented in the 1950s and has been used for pipes since the 1970s. Due to the high impact resistance combined with good stiffness and high chemical resistance makes this material suitable for sewer applications. A good performance at operating temperature range from up to {{convert|60|°C|°F}} (continuous) makes this material suitable for in-house discharge systems for soil & waste. A special PP grade with high temperature behaviour up to {{convert|90|°C|°F}} (short-term) makes that material a good choice for in-house warm water supply.<ref>{{Cite web|url = http://www.teppfa.eu/fast-guide-to-materials/|title = Fast guide to materials|last = TEPPFA, The European Plastic Pipes and Fittings Association}}</ref>

===PVDF (Polyvinylidenepolyvinylidene Difluoridedifluoride)===

[[Polyvinylidene fluoride| Polyvinylidene Difluoridedifluoride]] (PVDF)]] is a fairly non-reactive, [[thermoplastic]] [[fluoropolymer]] with excellent chemical and thermal resistance for plastic pipework uses. PVDF resin is produced through polymerization of the [[vinylidene fluoride]] monomer. The PVDF resin is then used to make PVDF pipe as well as many other products.

Industries and applications select PVDF pipe due to its inert, durable qualities. PVDF piping is used most in the chemical process industry due to its ability to plumb aggressive, corrosive solutions. PVDF pipe also sees common use in high purity applications, semi-conductor fabrication, electronics / electricity, pharmaceutical developments, and nuclear waste processing.

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PVDF piping specifications and performance characteristics approve PVDF pipe up to {{convert|248|°F|°C}} under pressurized system conditions. The pipe does not support fungus growth according to military test standard method 508, 81-0B. Dissimilar from other common thermoplastic pipes, (uPVC, CPVC, PE, PP), PVDF does not exhibit sensitivity to UV light or ozone oxidative damage, approving it for long term outdoor uses.<ref>{{Cite web|url=https://pvcpipesupplies.com/media/documents/kynar_specs.pdf|title=PVDF Performance Characteristics & Data|website=Arkema}}</ref>

===uPVC (unplasticized Polyvinylpolyvinyl Chloridechloride)===

[[File:Dura-Blue PVC Pipe for Underground Water Mains.JPG|thumb|right|[[Unplasticized polyvinyl chloride]] pipe for underground [[water mains]]]]

uPVC or PVC-U, is a thermoplastic material derived from common salt and fossil fuels. The pipe material has the longest track record of all plastic materials. The first uPVC pipes were made in the 1930s. Beginning in the 1950s, uPVC pipes were used to replace corroded metal pipes and thus bring fresh drinking water to a growing rural and later urban population. uPVC pipes are certified safe for drinking water per NSF Standard 61 and used extensively for water distribution and transmission pipelines throughout North America and around the world. uPVC is allowed for waste lines in homes and is the most often used pipe for sanitary sewers.

Further pressure and non-pressure applications in the field of sewers, soil and waste, gas (low pressure) and cable protection soon followed. The material's contribution to public health, hygiene and well-being has therefore been significant.

[[Polyvinyl chloride]] or uPVC (unplasticized polyvinyl chloride) pipes are not well suited for hot water lines and have been restricted from inside water supply line use in the USAUS for homes since 2006. Code IRC P2904.5 uPVC Not listed.

uPVC has high chemical resistance across its [[operating temperature]] range, with a broad band of operating pressures. Max operating temperature is reported at {{convert|140|°F|°C}}, and max working pressure: {{convert|450|psi|kPa|abbr=on}}. Due to its long-term strength characteristics, high stiffness and cost effectiveness, uPVC systems account for a large proportion of plastic piping installations and some estimations put it that greater than {{convert|2,000,000|mi|km}} of uPVC pipe are currently in service across applications.

=== uPVC Variantsvariants ===

Based on the standard polyvinyl chloride material, three other variants are in use.

One variant called OPVC, or PVCO, represents an important landmark in the history of plastic pipe technology. This molecular-oriented bi-axial high performance version combines higher strength with extra impact resistance.

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===Pipe system failure===

Some reasons why plastic piping systems may fail are poor product bonding/gluing during installation and naturally- occurring physical damage, such as from tree root infiltration.

Plastic pipes were also found to fail more often during dry, hot summers.<ref>{{Cite journal|url=https://www.nature.com/articles/s41598-023-33548-7|title=Assessment of the impacts of climate change on water supply system pipe failures|date=2023 |doi=10.1038/s41598-023-33548-7 |last1=Fan |first1=Xudong |last2=Zhang |first2=Xijin |last3=Yu |first3=Allen |last4=Speitel |first4=Matthew |last5=Yu |first5=Xiong |journal=Scientific Reports |volume=13 |page=7349 |bibcode=2023NatSR..13.7349F |pmc=10163270 }}</ref>

=== Flexibility ===

Plastic Pipes are classified by their [[stiffness|ring stiffness]]. The preferred stiffness classes as described in several product standards are: SN2, SN4, SN8 and SN16, where SN is Nominal Stiffness (kN/m2). Stiffness of pipes is important if they are to withstand external loadings during installation. The higher the figure, the stiffer the pipe.{{cn|date=October 2024}}

After correct installation, pipe deflection remains limited but it will continue to some extent for a while. In relation to the soil in which it is embedded, the plastic pipe behaves in a 'flexible' way. This means that further deflection in time depends on the settlement of the soil around the pipe.{{cn|date=October 2024}}

Basically, the pipe follows the soil movement or settlement of the backfill, as technicians call it. This means that good installation of pipes will result in good soil settlement. Further deflection will remain limited.{{cn|date=October 2024}}

For flexible pipes, the soil loading is distributed and supported by the surrounding soil. Stresses and strains caused by the deflection of the pipe will occur within the pipe wall. However, the induced stresses will never exceed the allowed limit values.{{cn|date=October 2024}}

The thermoplastic behavior of the pipe material is such that the induced stresses are relaxing to a low level. It has to be noted that inducedInduced strains are far below the allowable levels.{{cn|date=October 2024}}

This flexible behaviour means that the pipe will not fail. It will exhibit only more deflection while keeping its function without breaking.{{cn|date=October 2024}}

However, rigid pipes by their very nature are not flexible and will not follow ground movements. They will bear all the ground loadings, whatever the soil settlement. This means that when a rigid pipe is subject to excessive loading, it will reach the limit for stress values more quickly and break.{{cn|date=October 2024}}

It can therefore be concluded that the flexibility of plastic pipes offers an extra dimension of safety. Buried Pipes need flexibility.<ref>{{Cite web|url = http://www.teppfa.eu/why-use-plastic-pipe-systems/|title = Why use Plastic pipe systems|last = TEPPFA, The European Plastic Pipes and Fittings Association}}</ref>

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==External links==

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*{{cite book

|author=NCCER

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*[http://www.ppfahome.org/ Plastics Pipes and Fittings Association (PPFA)]

*[http://www.teppfa.com/index.asp The European Plastic Pipes and Fittings Association (TEPPFA)]

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