General Information
PVC-UH: Unplasticized Poly (vinyl chloride) material for injection moulded components with a proved MRS-value of at least 25 Mpa
PVC-O: Bioriented Poly (vinyl chloride) with higher long term service strength
PVC-C: Chlorinated Poly (vinyl chloride) with higher long term service temperature
PVC-Hi or PVC-M: Modified Poly (vinyl chloride) with higher impact resistance, and lower brittleness at low temperature.
For flexible designed pipes: the soil supports all the stresses on the pipe (including soil weight) and the pipes deform slightly but do not break. For pipes made of traditional materials, the soil concentrates the stresses directly on to the crown of the pipe; these pipes do not deform but a failure mode results in a break in the pipe.
For most of the "good quality soils" (e.g. granular types of soil) the soil supports all the stresses and, as this type of soil can be easily compacted, the deformation of the PVC pipes is only 1 or 2% which does not affect the functional properties nor the tightness of the systems at all. In weak soils ("plastic soils") the PVC piping systems deform slightly more (in the range of 5 to 10%) but they still perform perfectly well.
For all piping materials very difficult soil conditions will need a thorough examination or calculation by qualified civil engineers and certain European or national standards ask for static calculation for the piping systems.
Health & Safety
PVC-U, PVC-O, and C-PVC pipe systems are completely safe for drinking water applications and have been used in such applications throughout Europe (and elsewhere) for many decades.
In Europe, the safety of PVC-U, PVC-O, and C-PVC pipe systems for the transportation of drinking water is currently regulated and assessed nationally, although significant effort is ongoing at the European level for the harmonisation of regulations and test methods. Regulations are presently determined by national bodies, and third-party certification is carried out by accredited laboratories and institutes who subsequently also carry out regular audits to ensure continued compliance.
As part of the harmonisation activities, European (EN) standards are under development for a number of test methods designed to assess the suitability of plastics pipe systems for drinking water. These standards include tests for organoleptic assessment (odour and flavour), the migration & leaching of substances into the water, and microbial growth.
Migration: Different methods are used to detect the migration of substances present in PVC-U, PVC-O, and C-PVC formulations. Leaching behaviour is assessed by prolonged direct contact of the potable water with the products in very severe conditions. Then the "migration water" is checked using different techniques, including searches for traces of molecules below the level of a few µg/l. Virtually nothing leaches out: the leachates are very similar to the blanks used when analysing them with techniques such as gas chromatography combined with mass spectroscopy (GC-MS).
Lead is not used anymore in stabilisers, and such stabilisers have never been a source of lead in drinking water, as the stabilisers are immobilised within the PVC pipe structure during the manufacturing process. New stabiliser systems being used as alternatives to lead are fully assessed ("positive listing") and do not affect the drinking water characteristics in any way.
Traces of vinyl chloride monomer, sometimes exceeding the regulatory limit of 0.5 µg of VCM/l of water, have been detected in some cases. It is important to keep in mind that this 0.5 µg/l limit is based on a guideline from the World Health Organisation (WHO), where the value has been set to guarantee an acceptable health risk, even in case of exposure during an entire lifetime.
These cases are related to exceptional circumstances (small diameter pipes in thinly populated regions, hence with intermittent flow). Most importantly, these cases appeared only in pipes installed before the 1970s when the health risks of VCM were identified. PVC resin produced before then, although meeting all standards applicable at that time, contained higher levels of residual monomer than presently. Under usual conditions of use, water transported in PVC pipes produced in those days also complies today with the current drinking water regulation. However, model calculations show that in exceptional circumstances (small diameter pipes, infrequent use) the VCM level reached after a period without flow can exceed the limit. No measurement result above the limit has ever been found in water flowing in pipes made from PVC produced after 1980.
It is important to stress that no vinyl chloride monomer is produced by the degradation or incineration of PVC products.
In any case, VCM concentration can easily be reduced to below the WHO guidance limit by flushing the pipe or by boiling the water. The high volatility of VCM leads to a rapid transfer from water into the atmosphere, where VCM degrades by reaction with photochemically produced substances naturally present in the atmosphere. This limits its half-life in the atmosphere to between a few hours and a few days. VCM is therefore not persistent in the environment.
Microbial growth: PVC-U, PVC-O, and C-PVC pipes are known to perform very well according to the different methods used in Europe for the assessment of microbial growth of products in contact with drinking water (Germany, United Kingdom, and The Netherlands). Many field studies confirm this good behaviour, which is linked to the absence of migration and the very good surface properties of these piping systems.
Odour & Flavour: Owing to the absence of migration and low bacterial growth in PVC-U, PVC-O, and C-PVC, the organoleptic properties of pipes made from these materials are generally very good, as confirmed by regular testing by different European institutes.
As part of the EU harmonisation process, EN standards include EN 1420 and EN 1622 for the assessment of organoleptic properties and water quality; CEN-TR 16364 for the prediction of migration using mathematical modelling; EN 16421 for assessing microbial growth; and EN 15768 for the GC-MS identification of water-leachable organic substances. Additionally, EN 14395-1 is used for the organoleptic assessment of water in storage systems.
Apart from these standardisation initiatives, a European positive list for substances used in plastics materials in contact with drinking water is also under development. This harmonised EU positive list will eventually replace several existing national drinking water positive lists. Further guidance can be found in ISO TR 10358.
References
European Commission. (2024). Commission Implementing Decision (EU) 2024/367 of 23 January 2024 laying down rules for the application of Directive (EU) 2020/2184 of the European Parliament and of the Council by establishing the European positive lists of starting substances, compositions and constituents authorised for use in the manufacture of materials or products that come into contact with water intended for human consumption. EUR-Lex. Link
Zhang, L., & Liu, S. (2014). Investigation of organic compounds migration from polymeric pipes into drinking water under long retention times. Procedia Engineering, 70, 1753–1761. Link
Van der Kooij, D., & Veenendaal, H. R. (2007). Assessment of the microbial growth potential of materials in contact with treated water intended for human consumption. Kiwa Water Research. Link
Mercea, P. V., Losher, C., Benz, H., Petrasch, M., Costa, C., Stone, V. W., & Toșa, V. (2021). Migration of substances from unplasticized polyvinylchloride into drinking water: Estimation of conservative diffusion coefficients. Polymer Testing, 107, 107385. Link
International Organization for Standardization. (1993). ISO/TR 10358: Plastics pipes and fittings – Combined chemical-resistance classification table. ISO.
European Committee for Standardization. (2014). CEN/TR 16364: Prediction of migration from plastics using mathematical modelling. CEN.
European Committee for Standardization. (2014). EN 16421: Influence of materials on water for human consumption – Enhancement of microbial growth (EMG) test. CEN.
European Committee for Standardization. (2015). EN 15768: Water quality – Gas chromatographic-mass spectrometric determination of water leachable organic substances (GC-MS). CEN.
European Committee for Standardization. (2004). EN 14395-1: Influence of materials on water intended for human consumption – Organoleptic assessment of water in storage systems – Part 1: Test method. CEN.
European Parliament and Council of the European Union. (2020). Directive (EU) 2020/2184 of 16 December 2020 on the quality of water intended for human consumption (recast). EUR-Lex. Link
Danish Environmental Protection Agency. (2005). Field study of plastic pipes in water supplies (Environmental Project No. 1049). Link
European Commission. (2024). Commission Delegated Decision (EU) 2024/1441 of 11 March 2024 supplementing Directive (EU) 2020/2184 by laying down a methodology to measure microplastics in water intended for human consumption. EUR-Lex. Link
Across Europe, with some exceptions like the Netherlands and Denmark where groundwater is exclusively used, chlorination of drinking water is a common method for preventing the presence of pathogenic bacteria and ensuring that EU member states conform to the EU Drinking Water Directive.
Although chlorine can affect the taste and odour of water, it has long been considered the best way to provide safe water at the tap. The concentrations used in Europe are calculated so that the remaining chlorine at the tap is approximately 0.1 mg/l.
Even at levels of 1 mg/l, as used in several countries, there is virtually no interaction with the PVC piping system:
- The "chlorine demand" of the material is nil.
- The chemical interaction with PVC is so low that the piping systems can withstand hundreds of years under such conditions (even at temperatures higher than 20°C, which is the normal maximum "drinking water" temperature).
References
Fumire, J. (2008). Resistance of PVC pipes against disinfectants. In Plastics Pipes XIV Conference, Budapest. Retrieved from https://plasticpipesconference.com/site/database
PVC pipes, including PVC-U, PVC-O, and C-PVC, are approved for use in potable water systems in many countries around the world. These pipes undergo rigorous standards and testing to ensure they do not contaminate the water they transport.
Migration & Leaching: PVC is utilised below its glass transition temperature (80°C). This acts as a functional barrier preventing any low molecular weight substances from migrating into drinking water. Migration tests have shown that migration levels are far below the detection limit of modern analytical techniques. Different methods assess the migration of substances present in PVC formulations. Leaching behaviour is evaluated by prolonged direct contact of potable water with the products under severe conditions. The "migration water" is then analysed using techniques like gas chromatography combined with mass spectroscopy (GC-MS). The results show that virtually nothing leaches out, and the leachates are very similar to the blanks used in the analysis.
Safety in Europe: PVC-U, PVC-O, and C-PVC pipe systems have been used safely for drinking water applications throughout Europe for many decades. The safety of these systems is currently regulated and assessed at the national level, although there's an ongoing effort at the European level for harmonisation of regulations and test methods. Accredited laboratories and institutes carry out third-party certification and regular audits to ensure continued compliance.
Stabilisers: Lead is no longer used in stabilisers, and such stabilisers have never been a source of lead in drinking water. The stabilisers are immobilised within the PVC pipe structure during manufacturing. New stabiliser systems being used as alternatives to lead do not affect drinking water characteristics.
Vinyl Chloride Monomer (VCM): Traces of VCM, sometimes exceeding the regulatory limit of 0.5 µg of VCM/l of water, have been detected in some cases. However, these cases are related to exceptional circumstances and only in pipes installed before the 1970s. PVC pipes produced after 1980 have never shown measurements above the limit. It's important to note that no VCM is produced by the degradation or incineration of PVC products. VCM concentration can easily be reduced by flushing the pipe or boiling the water. VCM is not persistent in the environment.
Microbial Growth: PVC pipes perform exceptionally well in terms of microbial growth. This is due to the absence of migration and the excellent surface properties of these piping systems.
Odour & Flavour: Due to the absence of migration and low bacterial growth in PVC pipes, the organoleptic properties (related to taste and smell) of water transported in these pipes are generally very good.
European Standards: As part of the EU harmonisation process, several EN standards are under development or in use for assessing various properties of PVC pipes, including organoleptic properties, microbial growth, and migration.
Future Developments: A European positive list for substances used in plastics materials in contact with drinking water is under development. This list will eventually replace several existing national drinking water positive lists.
In conclusion, PVC pipes, when used and manufactured according to established standards, are safe for transporting drinking water and do not release carcinogenic substances into the water.
References
Mercea, P. V., Losher, C., Benz, H., Petrasch, M., Costa, C., Stone, V. W., & Toșa, V. (2021). Migration of substances from unplasticized polyvinylchloride into drinking water: Estimation of conservative diffusion coefficients. Polymer Testing, 107, 107385. https://doi.org/10.1016/j.polymertesting.2021.107385
Zhang, L., & Liu, S. (2014). Investigation of organic compounds migration from polymeric pipes into drinking water under long retention times. Procedia Engineering, 70, 1753–1761. https://doi.org/10.1016/j.proeng.2014.02.193
European Committee for Standardization. (2014). CEN/TR 16364: Prediction of migration from plastics using mathematical modelling. CEN.
European Committee for Standardization. (2015). EN 15768: Water quality – Gas chromatographic-mass spectrometric determination of water leachable organic substances (GC-MS). CEN.
European Commission. (2024). Commission Implementing Decision (EU) 2024/367 of 23 January 2024 laying down rules for the application of Directive (EU) 2020/2184 of the European Parliament and of the Council by establishing the European positive lists of starting substances, compositions and constituents authorised for use in the manufacture of materials or products that come into contact with water intended for human consumption. EUR-Lex. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202400367
European Parliament and Council of the European Union. (2020). Directive (EU) 2020/2184 of 16 December 2020 on the quality of water intended for human consumption (recast). EUR-Lex. https://eur-lex.europa.eu/eli/dir/2020/2184/oj
European Commission. (2024). Commission Delegated Decision (EU) 2024/1441 of 11 March 2024 supplementing Directive (EU) 2020/2184 by laying down a methodology to measure microplastics in water intended for human consumption. EUR-Lex. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32024D1441
Starting substances for materials to be used in drinking water products are regulated under the EU’s recast Drinking Water Directive. Within this framework, a positive list specifies which starting substances can be used and their allowed migration limits. VCM and the other substances needed to manufacture PVC resin, compounds and pipes are included in the list. It is important to understand that VCM is a precursor, and that all PVC resin grades manufactured by the ECVM members and the other European PVC manufacturers have less than 1 ppm VCM content, which means PVC pipes are safe for drinking water applications.
Traces of vinyl chloride monomer (VCM) have been detected in some instances, occasionally exceeding the regulatory limit of 0.5 µg of VCM per liter of water. It's crucial to understand that these occurrences are tied to exceptional circumstances and were primarily associated with PVC pipes installed prior to the 1970s. PVC pipes manufactured after 1980 have consistently tested below this limit.
Furthermore, PVC products do not produce VCM when they degrade or are incinerated. If there are concerns about VCM concentration, it can be effectively reduced by simply flushing the pipe or boiling the water. Additionally, VCM does not persist in the environment, ensuring it doesn't pose a long-term environmental risk.
References
European Parliament and Council of the European Union. (2020). Directive (EU) 2020/2184 of 16 December 2020 on the quality of water intended for human consumption (recast). EUR-Lex. https://eur-lex.europa.eu/eli/dir/2020/2184/oj
PVC is inherently self-extinguishing and does not require any additional flame retardants to meet most flammability requirements.
Piping systems may have to withstand "resistance to fire" given in standards or regulations. In other cases, there are no national requirements or regulations for the fire behavior of piping systems in relation to their function within the building structure. The European system of classification for the reaction to fire test of construction products is described in EN 13501-1, which includes optional requirements for smoke and burning droplets.
The Euroclass system is based on different tests depending on the level of fire protection that is required of the end product in its intended application. PVC piping systems are generally classified as Euroclass B and burning droplets are not a concern for them.
Some characteristics not covered by the EU classification system may be specified in national quality marks, for example intumescence in France.
Compared to other polymeric materials, PVC exhibits superior fire safety characteristics due to its inherent properties. It is less flammable, seldom continues to burn without a significant fire source, and has a notably lower heat release rate, which is crucial in controlling the intensity of a fire.
This results in PVC generating less heat and at a slower rate than many materials, thereby reducing the rate and intensity of fire spread. Additionally, PVC's smoke production is generally lower in full-scale fire scenarios, as it burns less readily, which is vital for maintaining visibility and minimizing health risks during a fire. The smoke toxicity of PVC is also comparable to that of most commercial materials, indicating no increased risk of toxic fume generation.
References
Hirschler, M. M. (2017). Poly(vinyl chloride) and its fire properties. Fire and Materials, 41(8), 993-1006. https://doi.org/10.1002/fam.2431
European Committee for Standardization. (2018). EN 13501-1:2018 Fire classification of construction products and building elements - Part 1: Classification using data from reaction to fire tests. CEN.
PVC pipes are rigid and therefore do not require adding plasticisers in their formulation. Plasticisers are used to soften PVC in articles such as membranes, films, flooring products, cables.
Learn more about the different plasticisers and their uses and properties.
In Europe, organotin is not used for PVC pipes, except for applications requiring high chemical resistance and some fittings manufactured in Southern Europe. Instead, manufacturers use calcium-zinc-based stabilisers, which are non-hazardous and do not affect the drinking water characteristics in any way.
However, because there are many different types of organotin, environmental advocacy groups have used this to sow confusion about the safety of organotin stabilisers used in PVC pipe manufactured in North America.
Studies have shown that one organotin, dibutyltin dichloride (DBTDC), may cause adverse health effects. Yet this substance is not present in any of the raw materials used in North American PVC pipe, nor is it formed at any point during pipe manufacture, installation, or use. In the U.S. and Canada, the raw materials used to make PVC pipe often include heat stabilisers that contain tin. These organotin stabilisers have been tested and found to be safe for use in potable water applications. Certification to NSF/ANSI Standard 61 confirms that leaching of organotin stabilisers used in PVC water pipe is not a concern.
The bottom line is that PVC pipe produced in North America does not contain dibutyltin dichloride and the tin stabilisers that are used are not a health risk.
Performance and Durability
The durability of PVC pipes is related, as it is for all other thermoplastic materials, to the chemical degradation of the polymer used in the pipes. However, unlike other thermoplastic pipes, PVC pipes do not oxidise.
Stabilisers are used in PVC pipes to prevent degradation of the polymer during the extrusion process and storage before the pipes are buried in the ground. When the pipes are buried, no chemical degradation is expected to occur, and the durability of the PVC material in buried pipes is expected to be significant, possibly exceeding 1000 years.
In standardised pipes for potable water (EN 1452), the expected lifetime of PVC pipes under pressure is extrapolated based on hoop stress testing for up to 20,000 hours. This allows an estimation of the durability by extrapolation to a life expectancy under pressure of 50 to 100 years. In real applications, buried PVC pressure pipes in Germany dug up after 70 years of active use were proven to still be fit for purpose when analysed and are likely to have a further life expectancy of 50 years.
A meta-study commissioned by TEPPFA, conducted by the Austrian Polymer Competence Centre at Montanuniversität Leoben, confirmed that plastic pipes, including PVC-U, can have safe service lifetimes well above 100 years. The study summarised significant independent research from peer-reviewed journals, standards, reports, and studies on pressure and non-pressure applications. The study found no evidence of material degradation in properly manufactured and installed pipes, suggesting that pipes made of PVC-U, polyethylene, and polypropylene can exceed a 100-year lifespan under operational conditions at a maximum of 20°C.
Notably, TEPPFA and PVC4Pipes also published a joint position paper supporting the 100-year design life of PVC-U and PVC-Hi pressure pipe systems buried in the ground for water and natural gas supply. These pipes, designed and tested to withstand long-term stress, are validated to maintain their integrity and performance well beyond 100 years when standard practices are followed during installation and operation.
In addition, to further increase the design life of PVC-U pipes, PVC4Pipes has sponsored a research project in collaboration with CEIS, led by Plastic Pipes Specialist Joaquin Lahoz Castillo. Launched in 2020, this investigation focuses on demonstrating that PVC-U pressure pipes can be serviced for over 100 years. The study correlates processing temperatures with the long-term hydrostatic strength of the pipes, using ISO 9080 standards. Preliminary results indicate that an extrusion temperature of 180ºC is sufficient to achieve MRS250 classification. Higher temperatures, up to 195ºC, marginally improve long-term performance but risk material degradation. These findings enable water networks to be designed with a 100+ year lifespan, using standard design coefficients previously applied for 50-year systems.
References
Pinter, G., Travnicek, L., & Arbeiter, F. (2024). 100 years lifetime of plastic pipes: Meta-study. European Plastic Pipes and Fittings Association. https://www.teppfa.eu/wp-content/uploads/2024-04-25-Meta-study-100-years-of-lifetime-of-plastic-pipes.pdf
TEPPFA & PVC4Pipes. (2019). TEPPFA PVC4Pipes position paper for a 100-year service lifetime. https://pvc4pipes.com/wp-content/uploads/2019/04/TEPPFA_PVC4Pipes-Position-Paper-for-a-100-years-service-lifetime-final.pdf
Lahoz Castillo, J. (2024). Securing a 100+ year design lifetime for PVC-U pressure pipes. CEIS.
PVC pipes maintain reliable performance at sub-zero temperatures as long as the conveyed fluid is flowing freely. While several national guidelines recommend installing PVC pipes when temperatures are above 0°C, modern PVC pipe systems often exceed these minimum requirements.
The impact resistance of PVC pipes is defined by various product standards, such as EN 1401 and EN 1452. For instance, a 110 mm diameter sewage pipe must be able to withstand the impact of a 1 kg mass dropped from 1.60 m at 0°C. In practice, many PVC pipes surpass these minimum impact resistance requirements, ensuring dependable performance even in low-temperature conditions.
Special impact-resistant types, including PVC-Hi and molecularly oriented PVC (PVC-O), demonstrate superior resistance to impacts at sub-zero temperatures. PVC-U pipes certified with the Nordic Poly Mark undergo testing for impact resistance at -10°C and are specifically designed for installation and operation in cold climates. These pipes, marked with the “Ice Crystal” symbol, highlight their resilience and suitability for use in extreme cold common to Nordic countries. It is important to note that product standards do not establish a specific lower limit for installation temperatures.
Once installed, PVC pipes can operate effectively at much lower temperatures, well below 0°C, without any significant mechanical issues, as long as they are not subjected to substantial mechanical shocks during operation.
References
INSTA-CERT. (2024). Specific rules for Nordic certification in accordance with EN 1452: Plastics piping systems for non-pressure applications. INSTA-CERT SBC EN ISO 1452_March 2024_UK.pdf.
INSTA-CERT. (2021). Specific rules for Nordic certification in accordance with EN 1401-1: Plastics piping systems for non-pressure underground drainage and sewerage. INSTA-CERT SBC EN 1401-1.
INSTA-CERT. (2018). Specific rules for Nordic certification in accordance with EN 1329-1: Plastics piping systems for soil and waste discharge within the building structure. INSTA-CERT SBC EN 1329-1.
Plastics Pipes Group. (n.d.). PVC pipe systems [UK national guideline].
STR-PVC. (n.d.). Livret Syndotec [French national guideline].
AseTUB. (n.d.). Manual técnico conducciones de PVC [Spanish technical manual].
Uni-Bell PVC Pipe Association. (2013, March 13). Cold weather: No practical effect on PVC pipe installation and use. Retrieved from https://www.uni-bell.org/Portals/0/ResourceFile/cold-weather-no-practical-effect-on-pvc-pipe-installation-and-use.pdf
Molecor. (n.d.). PVC-O pipes at low temperatures: No practical effect on pipe installation and use. Retrieved from https://molecor.com/en/molecor-pvc-o-pipes-low-temperatures-no-practical-effect-pipe-installation-and-use
All plastic materials subjected to a constant load undergo progressive deformation over time. This phenomenon, caused by the displacement of molecular chains among themselves, is commonly referred to as creep. Creep primarily depends on the type of plastic, its molecular structure, operating temperature, and time (for example, it may take several hundred years for PVC pressure pipes to fail due to creep).
For non-pressure pipes, standards describe the relationship between short-term and long-term creep, known as the Creep Ratio (ISO EN 9967). This ratio is also utilized in the design of plastic pipes.
Among plastic pipes, PVC pipes have the lowest creep ratio. For instance, in the European project for structured wall pipe standards (prEN 13476), the ratios required for different materials are:
PVC-U < 2.5 and PP, PE < 4.
A lower creep ratio indicates that, over the long term, the material retains properties similar to those it initially exhibited.
References
ISO. (2016.). ISO EN 9967: Thermoplastics piping and ducting systems – Determination of creep ratio.
European Committee for Standardization. (n.d.). prEN 13476: Structured-wall piping systems of thermoplastics – Specifications for pipes and fittings.
Plastics Pipes Group. (n.d.). PVC pipe systems [Technical guideline].
STR-PVC. (n.d.). Livret Syndotec [French technical guideline].
AseTUB. (n.d.). Manual técnico conducciones de PVC [Spanish technical manual].
Associazione Idrotecnica Italiana. (n.d.). Le condotte in PVC [Italian guideline].
Prolonged exposure of PVC pipes to direct sunlight may cause a thin film of degradation on the exposed surface of the pipe over time. This microscopic layer, with a thickness of about 0.05 mm, will gradually become visible as discolouration (so-called bleaching) and stops once the surface exposure ceases.
Experience has shown that this microscopic layer protects the underlying material from ultraviolet light, ensuring that the rest of the pipe wall remains unaffected by sunlight. If you make a gentle scratch on the outer pipe surface, you will see that the normal colour is visible just under this very thin layer.
Extensive tests carried out on pipes exposed to sunlight for up to 4 years demonstrate a slight increase in tensile strength and modulus of elasticity and a minor decrease in impact strength. In practical terms, the overall pipe properties remain virtually unchanged, and pipes affected by this phenomenon may be used for normal installation.
References
BPF Plastics Pipes Group. (2002). PVC pipe systems for water supply (Version 01/02, Revised).
Uni-Bell PVC Pipe Association. (n.d.). UV exposure has no practical effects on PVC pipe performance. Retrieved from https://www.uni-bell.org/wp-content/uploads/2018/10/uv-exposure-has-no-practical-effects-on-pvc-pipe-performance.pdf
Permeability is the ability of chemical substances to enter the pipe system through the pipe walls or joints.
The occurrence of this kind of event has been reviewed by various water distribution companies, and no major problems have been reported with PVC piping systems.
For example, the intrinsic permeability of PVC is approximately 10 times lower than that of polyolefins.
Several studies have investigated the permeability of plastic pipes and pipes made of other materials. Research has shown that PVC water mains can be safely used in any level of gasoline contamination, even with free product, provided there is a minimal average water flow in the mains. While benzene, toluene, ethylbenzene, and xylenes (BTEX) may permeate gaskets, U.S. EPA maximum contaminant levels (MCLs) will not be exceeded. PVC pipes can also be used during periods of stagnation (e.g., service connections) for any level of groundwater contamination by gasoline. Additionally, studies have concluded that rigid PVC acts as an effective barrier against the permeation of environmental pollutants, such as BTEX and trichloroethylene (TCE), at commonly encountered contamination levels in groundwater.
In PVC pipe systems, the joint zone may be a weak point, but the exposed area of the elastomeric seal compared to the total area of the pipe surface is minimal. Several of the studies also examined the effects of hydrocarbons on sealing rings; two of them found that NBR seals are more resistant than SBR seals.
References
Vonk, R. (1985). Permeation of organic compounds through pipe materials (Publication No. 85). KIWA, Neuwegein, Netherlands.
Cassaday, D., Cole, N., Bishop, M., & Pfau, R. (1983). Evaluation of the permeation of organic solvents through gasketed jointed and unjointed poly (vinyl chloride), asbestos cement, and ductile iron water pipes – Phase 1 report. Battelle Columbus Laboratories for the Vinyl Institute, Division of the Society of the Plastics Industry, Inc.
Berens, A. R. (1985). Prediction of organic chemical permeation through PVC pipe. Journal of the American Water Works Association, 77(11), 57–64.
Ong, S. K., Gaunt, J., Mao, F., Cheng, H., Esteve-Agelet, L., & Hurburgh, C. (2007). Impact of hydrocarbons on PE/PVC pipes and pipe gaskets (Project No. 2946). Awwra Research Foundation.
PVC pipes have excellent resistance to chemical attack, making them particularly suitable for a wide range of applications.
In normal civil engineering applications, PVC push-fit pipes are not subject to chemical attack. In contaminated ground or specific foul water and industrial systems, they are highly resistant to strong acids, alkalis, and surfactants. They can be used in the presence of sulphuric acid, which often exists under abnormal conditions related to sewerage systems.
PVC piping systems are used in industrial applications due to their excellent chemical resistance. However, sealing rings are not recommended for these applications, and solvent-cemented joints are preferred.
PVC is resistant to most oils, fats, alcohols, and petrol; however, some petrol-based fuels containing benzene can cause swelling.
PVC is suitable for use in contact with aliphatic hydrocarbons, but aromatic hydrocarbons can cause unacceptable swelling, even through absorption from the vapour phase.
PVC is resistant to all but the most severe oxidising conditions. Hydrogen peroxide at all concentrations has no effect, and even concentrated solutions of oxidising salts, such as potassium permanganate, cause only superficial attack.
PVC is generally unsuitable for use in contact with aromatic and chlorinated hydrocarbons, ketones, nitro compounds, esters, and cyclic ethers, which penetrate the PVC causing marked swelling and softening. These penetrating solvents may be harmful to PVC even when diluted, but when they are diluted, their effects diminish significantly, and at very low concentrations, such as those present in many effluents, they can be handled safely.
Further guidance can be found in ISO TR 10358.
References
Journal of the Institute of Gas Engineers. (1962, March). Chemical resistance of PVC, 2(3), 185–194.
International Organization for Standardization. (1993). ISO/TR 10358: Plastics pipes and fittings – Combined chemical-resistance classification table. ISO.
The pipe system designer must calculate all the conditions that affect a water network, including static and transient effects, to obtain the basic parameters, as for example, the allowable operating pressure (PFA) and the allowable maximum operating pressure (PMA). After calculations, the designer will choose between the several classes that are possible in rigid PVC pipes.
The pressure classes for conventional rigid PVC pipes are defined in the standard EN 1452: "Plastic piping systems for water supply. PVC-U" and the pressure classes for molecular oriented (PVC-O) pipes are defined in ISO 16422: "Pipes and joints made of oriented unplasticised Polyvinyl chloride for the conveyance of water."
The following classes are available for PVC piping and; the most used in Europe are for PVC-U 10 and 16 and for PVC-O 16 and 25:
This coefficient is illustrated by the following graph:.
Design Coefficient - PVC Pipes for Water Distribution
According to ISO 12162 the minimum value for design coefficients (C min ) are as follows:
- PVC-U 1.6
- PVC-A 1.4
- PVC-O 1.4
PVC pipes and fittings are generally regarded as superior to other materials like vitrified clay (VC) and concrete (including both standard concrete and fiber-reinforced concrete, FRC) in terms of resistance to root intrusion. This superiority is attributed to the lower surface roughness and porosity of PVC, which significantly reduces the likelihood of roots penetrating through sealing joints. Studies have confirmed that PVC's smoother surfaces and tighter-fitting joints offer better protection against root intrusion compared to the rougher surfaces and more porous nature of VC and concrete pipes.
In comparison to concrete pipes, both standard and FRC, PVC pipes also demonstrate superior performance in preventing root intrusion. Concrete pipes, due to their rigid structure and tendency to crack over time, are more susceptible to root infiltration, especially at joints. Research has shown that concrete pipes experience more frequent root intrusions per joint compared to PVC pipes. Specifically, the mean number of root intrusions per joint for PVC pipes was significantly lower than that for concrete pipes. This makes PVC a preferable choice for minimizing the risk of root-related issues in sewer systems.
Despite PVC's advantages, it is important to recognize that these pipes are not completely immune to root intrusion. The performance of PVC pipes heavily depends on the quality of installation and maintenance. Proper bedding and installation are crucial to prevent vertical deformations and joint failures, which can increase the risk of root intrusion. For instance, improper installation can lead to vertical deformations and changes in pipe diameter, compromising the integrity of the joints and making them more susceptible to root intrusion.
The interfacial pressure at the joints of PVC pipes plays a critical role in preventing root intrusion. Research indicates that lower interfacial pressures (0.04–0.20 MPa) are associated with a higher likelihood of root intrusion. Therefore, it is recommended to maintain higher interfacial pressures, as specified by standards, to minimize the risk of roots penetrating the joints. Properly installed and maintained joints with adequate interfacial pressure help ensure the long-term effectiveness of PVC pipes in resisting root intrusion.
External factors such as soil type and environmental conditions also influence the performance of PVC pipes. For example, stiffer soils can help reduce deformations around the pipes, thereby maintaining the integrity of the joints more effectively. Conversely, in areas with softer soils, the pipes may experience more movement and deformation, leading to potential joint failures and increased susceptibility to root intrusion. Therefore, understanding and mitigating these external factors is essential for optimizing the performance of PVC pipes.
Long-term studies and CCTV inspections have shown that while PVC pipes generally perform well, issues such as root intrusion can still occur over time. Regular inspections and maintenance are necessary to identify and address potential problems early on. This proactive approach ensures the longevity and reliability of PVC sewer systems, helping to maintain their superior resistance to root intrusion.
Further studies, such as the research conducted on sewer pipes in Melbourne, have shown that soil disturbance during installation can create pathways for roots to grow from the surface towards the pipes. This is particularly true for well-drained sandy soils, which are conducive to deeper root growth. The Melbourne study highlighted that the majority of blockages occurred in sandy topsoils, emphasizing the need for proper installation and maintenance to prevent root intrusion.
Innovations in PVC pipe technology have further enhanced their resistance to root intrusion. A new pipe joining technology involves the creation of a lip-ring inside the socket during the manufacturing process. When the male pipe is inserted during installation, the lip-ring is pushed, closing the space between the male and female sewer pipes. This mechanical barrier effectively prevents the infiltration of roots. The new socket design has been certified for tightness by ISO 13259-compliant lab tests and meets EN 1401 standards, further ensuring the reliability and durability of PVC pipes in preventing root intrusion.
In conclusion, PVC pipes offer significant advantages in terms of resistance to root intrusion compared to other materials like VC, standard concrete, and FRC. However, maintaining high interfacial pressures at the joints, ensuring proper installation, and conducting regular inspections are crucial to maximize their performance and durability. By addressing these factors, the long-term effectiveness of PVC pipes in preventing root intrusion can be significantly enhanced.
References
Makris, K. F., Langeveld, J., & Clemens, F. H. L. R. (2019). A review on the durability of PVC sewer pipes: research vs. practice. Structure and Infrastructure Engineering, 16(6), 880-897. https://doi.org/10.1080/15732479.2019.1701235
Östberg, J., Martinsson, M., Ståhl, O., & Fransson, A. M. (2012). Risk of root intrusion by tree and shrub species into sewer pipes in Swedish urban areas. Urban Forestry & Urban Greening, 11, 65-71. https://doi.org/10.1016/j.ufug.2011.11.004
Obradović, D. (2017). The impact of tree root systems on wastewater pipes. Zajednički Temelji '17: zbornik radova, 65-71. https://doi.org/10.24919/2519-2922.2017.217287
Randrup, T. (2000). Occurrence of tree roots in Danish municipal sewer systems. Arboricultural Journal, 24, 283-306. https://doi.org/10.1080/03071375.2000.9747257
Makris, K. F., Langeveld, J., & Clemens, F. H. L. R. (2019). A review on the durability of PVC sewer pipes: research vs. practice. Structure and Infrastructure Engineering, 16(6), 880-897. https://doi.org/10.1080/15732479.2019.1701235
Pohls, O., Bailey, N. G., & May, P. B. (2004). Study of Root Invasion of Sewer Pipes and Potential Ameliorative Techniques. Acta Horticulturae, 643, 113-121. https://doi.org/10.17660/ActaHortic.2004.643.17
IPM Srl. (2021, 7 October). Roots intrusion resistance: PVC pipes with patented system to prevent roots’ intrusion. https://www.ipm-italy.it/news-en/new-innovation/roots-intrusion-resistance
Installation and Network Characteristics
- PVC pipes, fittings and ancillary parts are manufactured with tight tolerances on dimensions, which means that the elastomeric seal in the joint provides leak-free transportation of potable water as well as sewerage.
- The push fit joint system makes PVC pipe systems easy to assemble.
- The joints are superior to most other pipe connection systems due to quick and easy handling in the trench with no need for special tooling.
- The pipes are easily cut and placed in the trench, making them a winner on installation cost.
- Push-fit PVC pipes allow thermal expansion and contraction of the PVC pipelines.
- In practise installation can be carried out with the minimum open length of trench enabling very limited transportation of excavation equipment.
- Push-fit joints allow small changes of direction in a pipeline and for larger changes of direction there exists a huge range of PVC fittings which can provide the necessary solution.
Stiffness depends mainly on two factors: E modulus, which is a physical property of every material, and the geometry of the profile of the pipe. The behaviour of the pipe, and the deformation it reaches over time, is not only dependant on stiffness, but on soil and installation conditions. A higher stiffness gives a better performance, but the following graph shows the behaviour and influence of both stiffness and installation conditions. Under a qualified installation, stiffness is not so relevant and all stiffness classes are suitable to be used.
Some organisations for plastic pipes have proposed or developed methods to rapidly evaluate the behaviour of buried pipes.
Figure 1: Design graph for determining the pipe deflections immediately after installation and after settlement of the soil
The diagram proposed by TEPPFA (The European Plastic Pipes and Fittings Association) clearly shows that SN4 or SN8 piping systems present very good behaviour when the level of workmanship is good or at least standard.
On the vertical axis, the pipe deflection is shown and on the horizontal the pipe stiffness classes. For each installation group an area is given in which the deflection after installation is expected. The upper edge of the area represents the maximum deflection to be expected. The lower edge of the area shows the average deflection to be expected.
The graph shows the deflections immediately after installation. It does not include the effect of traffic load, depth of cover or groundwater. The soil will further compact in the course of time. This further compaction is caused by the weight of the soil, the percolation of rain and ground water through the soil and by traffic load.
In order to obtain the final deflection including the effect of traffic, one shall add a consolidation value to the initial deflection. These consolidation values are listed in the table in the graph. Hence the final deflection becomes:
Final deflection = Initial deflection + C f
PVC4Pipes recommends SN 8 as a standard pipe that covers a depth of burial ranging from 0.6 to 6 metres in most soil conditions. Other depths of burial can be employed for PVC pipes (up to 15m) but, for these depths, specific conditions have to be studied on a case by case basis.
Many other calculation methods are listed in different European countries, but all of them agree on the wide versatility of PVC systems.
Rigid PVC pipes are easy to handle manually as the weight of each section is relatively low. The assembly of rigid PVC pipe sections and their connections to other pipe fittings can be undertaken by using a sealing ring or, for some industrial applications, by the use of an adhesive; this depends for which application the pipes will be used, or on the different traditions country by country.
Short section lengths of rigid PVC pipes make it easy to install and to adjust the length at junctions etc. Rigid PVC pipes can also be repaired quickly and easily with only a short length of pipe needing to be removed.
In different countries when talking about the measurement of lengths of pipe there are two different measurements used and they are: "without socket" known as the working length, or "with socket" known as the overall length.
- Lightweight: PVC pipes are light and easy to handle (up to 6 m length), significantly reducing the need for mechanical support for placing and fixing the pipes together, leading to a cost efficient installation.
- Joints: PVC piping systems can be installed with different types of joints: solvent cement joints and push-fit joints. Across Europe , push-fit joints are usually preferred for municipal installations. The use of push-fit joints is a very important characteristic as it not only assures a watertight, safe and durable union, but permits a fast and simple mounting, an important cost saving during installation, as it avoids using complex welding operations and costly investments in sophisticated equipment and specialised skills.
- Fittings and special operations: PVC pipe systems are normally completed with the widest range of fittings and ancillary products, allowing a modular installation and high quality of the full network. When finishing work has to be done by hand (For example making holes, installing saddles and cuts in the pipes), rigid PVC is easy to work with, and does not need complex tools or special expertise.
Sustainability and Environmental Footprint
PVC is made by combining ethylene and hydrogen chloride or chlorine, to produce ethylene dichloride (EDC). EDC is then converted into vinyl chloride monomer (VCM). VCM is polymerised into PVC at high temperature and pressure. Both EDC and VCM are hazardous substances that require proper handling. The process of converting EDC and VCM into PVC takes place in a closed system, with no exposure to humans and the environment. In Europe, strict regulations exist to protect workers and the environment. Additionally, the safe handling of EDC and VCM is part of the voluntary charter that European PVC raw material producers, members of ECVM (the European Council of Vinyl Manufacturers), have signed up to, and plants undergo regular third-party audits to verify compliance with legislative requirements.
Emissions limit values are set based on Best Available Techniques of the Industrial Emissions Directive. For these reasons, ECHA (the European Chemicals Agency) has concluded in its Investigation Report on PVC and PVC additives that “the operational conditions and risk management measures implemented in the VCM/PVC industry are adequate and effective to control the risk for workers from EDC and VCM,” and that “the levels of residual ECD/VCM in PVC articles seem to be appropriately controlled in Europe.”
Beyond EDC and VCM, the PVC industry also controls the emission of other chemicals: there are no relevant emissions of chloroform, hexachlorobutadiene, or PCBs from European VCM plants. VCM plants do not use or emit any CCl4. The emissions of dioxins and furans are regulated by the Industrial Emissions Directive, and dioxin/furans emission data are collected yearly by ECVM, showing a constant downward trend.
References
European Council of Vinyl Manufacturers. (2019, updated 2023). ECVM Industry Charter for the Production of Vinyl Chloride Monomer & PVC. https://pvc.org/sustainability/industry-responsible-care/ecvm-charter/
European Chemicals Agency. (2023). Investigation report on PVC and PVC additives. https://echa.europa.eu/documents/10162/17233/rest_pvc_investigation_report_en.pdf
PVC pipes have been shown to offer significant environmental advantages over non-plastic materials like ductile iron and concrete, primarily in terms of carbon footprint and energy efficiency. Recent peer-reviewed research has demonstrated that, for sewer pipes, PVC outperforms reinforced concrete and ductile iron by reducing the carbon footprint by approximately 45% and 35%, respectively. This reduction is largely due to PVC’s lighter weight, which minimizes the energy required for production, transportation, and installation.
Moreover, PVC pipes consume less energy across their life cycle compared to other piping materials. Research from Australia confirms that, in all scenarios, PVC pipes require less energy than alternatives such as ductile iron or concrete. The life cycle of PVC pipes encompasses the energy consumed in the extraction of natural resources, manufacturing, transportation, and product delivery, consistently outperforming traditional materials.
Independent comparative Life Cycle Assessments (LCAs) conducted by the Flemish Institute for Technological Research (VITO) and reviewed by Denkstatt further confirm the low environmental impact of PVC pipes. These LCAs follow strict ISO standards (ISO 14040, ISO 14044) and the European EN 15804 standard, ensuring that the environmental performance of PVC pipes is accurately measured. The assessments demonstrate that PVC pipes have the lowest environmental footprint compared to non-plastic materials in various piping applications.
The Environmental Product Declarations (EPDs) for PVC resin, based on data from Plastics Europe’s Eco-profile programme, highlight the efficiency of PVC production. The production of PVC requires less feedstock energy compared to other polymers, thanks to its 57% chlorine content derived from common salt. This results in a significantly lower environmental impact during production and use.
Recent advancements in PVC production processes have contributed to a steady reduction in environmental impacts. European chlorine production, a key component in PVC, has reduced its Global Warming Potential impact by 22.3% between 2011 and 2020, thanks to innovations such as the switch to membrane electrolysis. These improvements directly benefit the overall environmental performance of PVC pipes.
In addition to its energy efficiency and reduced carbon footprint, PVC pipes are recyclable, further contributing to their eco-efficiency. Ongoing investments in innovation have led to the development of bio-attributed and bio-circular PVC resin and non-fossil additives, which are already being used in PVC pipe production. This aligns with the European PVC industry’s commitment to continual environmental improvement.
Overall, PVC pipes offer a more environmentally sustainable option compared to non-plastic materials like ductile iron and concrete. Their lower carbon footprint, energy efficiency, and recyclability make them a favorable choice for a wide range of piping applications.
References
Flemish Institute for Technological Research (VITO). (n.d.). Comparative Life Cycle Assessments for Plastic Pipes. European Plastic Pipe and Fittings Association (TEPPFA). https://www.teppfa.eu/sustainability
Plastics Europe (n.d.). Eco-profiles set. https://plasticseurope.org/ sustainability/circularity/life-cycle-thinking/eco-profiles-set/
McKinsey. (2022). Climate impact of plastics. https://www.mckinsey.com/industries/chemicals/our-insights/climate-impact-of-plastics
Meng, F., Brandão, M., & Cullen, J. M. (2024). Replacing plastics with alternatives is worse for greenhouse gas emissions in most cases. Environmental Science & Technology, 58(6), 1234-1245. https://doi.org/10.1021/acs.est.3c05191
Yes. PVC pipes contribute directly and indirectly to many of the Sustainable Development Goals (SDGs).
In developing countries, greater efficiency in the handling of water can massively reduce the drudgery of women who might spend 6-7 hours a day fetching water of dubious quality, often gathered at great personal risk. If women are freed from the burden of daily water collection, this liberates them to do other work and contribute to productive enterprises, such as engagement in community governance, traditional medicine and education (SDGs 1, 4, 5).
A stable and safe water supply not only provides clean water and sanitation, but also improves food productivity and good health, lifting the pressure on terrestrial and aquatic ecosystems (SDGs 2, 3, 6, 14, 15).
With the VinylPlus® sustainability programme the European PVC industry has taken responsibility for product life cycles, thus contributing to save energy and resources and minimise emissions, while contributing to economic growth with suitable products for infrastructures and smarter cities (SDGs 7, 8, 9, 11, 12, 13, 17).
Yes, PVC pipes are easily recyclable. Due to the material's unique properties PVC pipes and other rigid PVC products can be recycled mechanically several times without losing their technical properties. This has been confirmed by several studies:
Since 2000 850,000 tonnes of PVC pipes and fittings have been recycled in Europe through the VinylPlus® programme. In total, more than 8.1 million tonnes of PVC have been recycled since 2000. The recyclate is used to manufacture new pipes and a range of other PVC products. Traceability and certification schemes for recyclates ensure a high degree of safety and quality for the recycled PVC.
Yes. The PVC pipe industry is an integral part of the VinylPlus® programme and is working to increase the recycling of PVC pipes across the EU. Collection schemes have been introduced and recycling undertaken through The European Plastic Pipes and Fittings Association (TEPPFA) with the support of Recovinyl.
Since 2000, 850,000 tonnes of PVC pipes and fittings have been recycled.
In addition, 75,000 tonnes of recycled PVC are safely used in new pipes.
According to the latest Recovinyl Traceability Study, PVC pipes take up 10% of all PVC recyclate in Europe
More figures and information can be found in VinylPlus' Progress Report.
References
VinylPlus. (2024). VinylPlus Progress Report 2024. https://www.vinylplus.eu/wp-content/uploads/2024/09/VinylPlus-Progress-Report-17-09_web.pdfDioxins are a group of highly toxic chemicals that can be released as unintentional byproducts during various industrial processes. Dioxin emissions primarily occur as unintentional byproducts during certain industrial activities, such as waste incineration, metal smelting, and some chemical manufacturing processes, including the manufacturing of PVC.
While dioxins are a serious matter, the European case shows it is possible to solve this issue. Europe has significantly reduced dioxin emissions over the past few decades due to stricter regulations, improved technologies, and changes in industrial practices. This also applies to PVC, which today accounts for about 0.01% of the dioxins emitted from human activities in Europe.
The formation of very small quantities of dioxins can only occur during ethylene oxychlorination, which is one of the process steps leading to the production of vinyl chloride. These dioxin molecules are absorbed by the catalyst, which intervenes in a different phase from the reactants. This facilitates the removal of the catalyst and the absorbed dioxins by filtration and controlled treatment. Waste catalyst is handled as hazardous waste and disposed of accordingly.
The latest version of the ECVM Charter limits the emissions into the air of dioxin-like components from the vinyl chloride plants to 0.08 ng Toxic Equivalent (TEQ) per cubic meter of air. Emissions in water are limited to 0.3 µg per ton of ethylene dichloride produced. Ethylene dichloride is the intermediate leading to vinyl chloride. The emission limits of dioxins during manufacturing are aligned with the strict requirements in place in Europe and must be considered extremely low. To put this into context, 0.08 ng TEQ is equivalent to 0.00000008 grams of dioxin per cubic meter of air, and 0.3 µg is equivalent to 0.0000003 grams of dioxin per ton of ethylene dichloride produced in water.
Today, thermal processes in metal mining, metalworking, and other small sources have become the main contributors to dioxin emissions, according to the German Environment Agency.
References
ECVM. (2023). ECVM Industry Charter for the Production of Vinyl Chloride Monomer & PVC. Brussels, Belgium: The European Council of Vinyl Manufacturers. https://pvc.org/wp-content/uploads/2023/04/ECVM-charter-pages.pdf
European Commission, Joint Research Centre. (2017). Best Available Techniques (BAT) Reference Document for Large Volume Organic Chemicals (LVOC) Production. https://eippcb.jrc.ec.europa.eu/sites/default/files/2019-11/JRC109279_LVOC_Bref.pdf
Umweltbundesamt [German Environment Agency]. (n.d.). Dioxins. https://www.umweltbundesamt.de/en/topics/chemicals/dioxins#what-are-dioxins-and-dioxine-like-pcbs
The incineration of chlorinated waste used to be the largest source of dioxin and furan pollution, but the introduction of better incineration and flue gas cleaning requirements under the Industrial Emissions Directive has led to a 94% reduction in emissions since the early 1990s. In the same period, the amount of waste incinerated has doubled. While PVC incineration was previously considered a source of dioxins and furans, according to the European Chemicals Agency (ECHA), it is highly questionable whether PVC waste has any role to play today.
According to ECHA, the formation of dioxins, furans, and other unwanted emissions depends on the type of furnace, operating conditions, and flue cleaning systems. There is also no proportional relationship between the amount of chlorine in the waste and the amount of dioxins and furans formed. The same conclusion has been reached in previous studies, including by the Swedish Environmental Protection Agency. In other words, the small amounts of chlorine found in salty food waste, for example, are sufficient for dioxins and furans to be formed through inappropriate incineration. Adding the amounts of PVC found in waste has little or no effect. Nor can a reduction in dioxins and furans be achieved by removing PVC from waste.
References
European Chemicals Agency. (2023). Investigation report on PVC and PVC additives. https://echa.europa.eu/documents/10162/17233/rest_pvc_investigation_report_en.pdf
Swedish Environmental Protection Agency. (1999). Life cycles assessments and solid waste - Guidelines for solid waste treatment and disposal in LCA (AFR-REPORT 279). https://p2infohouse.org/ref/37/36473.pdf
Themelis, N. J. (2010). Chlorine sources, sinks, and impacts in WTE power plants. Proceedings of the 18th Annual North American Waste-to-Energy Conference.
