Using PVC for the rehabilitation of sewers

Hardly any other material has been so intensively researched as PVC, in terms of environmental compatibility. As a result, the debate has become increasingly objective. In many cases, however, public opinion is not influenced by the results of comprehensive studies, but by reports highlighted by the media. Due to press articles, such as those published after the fire at Düsseldorf airport or about toys made from carcinogenic PVC, the discussion quickly returns to its emotional starting point. This leads to uncertainty and old concerns flare up again. But a fully informed and neutral view requires full knowledge of the environmental, economic and social aspects of the material, taking into account its entire lifecycle. This was first attempted in 1999. On this occasion, Prof. Dr.-Ing. Stein & Partner GmbH was commissioned by the Australian company Rib-Loc, which developed and manufactured the spiral wound pipe, to examine how PVC is viewed and used in the sewage systems in various German towns, by means of a survey initiative. In addition, attempts were made, where applicable, to determine the reasons why this material is not used.

The concerns identified at the time (see Table 2) continue to be cited by municipalities, although the basic principles for the manufacture of PVC have changed and considerably more is known about this material. Although many of the restrictive directives that applied to PVC during this period have since been lifted, municipalities continue to be guided by legislation, which aimed to restrict its use. At this time, this legislation was all very similar and can therefore be summarised as follows: "Avoid the use of construction materials that contain PVC, if a substitute can be used". The legislation differed mainly in terms of how it was implemented, depending on the financial and technical viability of the PVC substitute. In many cases, it was the planning offices that pushed for the material to be phased out, which was not without consequences for the construction and sewage sector.

This specialist report commissioned by Geiger Kanaltechnik GmbH & Co. KG addresses the current concerns and lists arguments, based on a study of the relevant literature, so that a rational, critical discussion can take place on the use of PVC in sewer systems.

1. Overview of concerns regarding the use of PVC

The most frequently cited concerns regarding the use of PVC are listed below, based on a survey conducted by Prof. Dr.-Ing. Stein & Partner in 1999, involving 29 municipalities, which were geographically distributed throughout the Federal Republic (see Table 2).

Table 1: Number and size of the participating municipaltities [1]

Size of municipalities/No. of inhabitans	Number of municipalities surveyed (questionnaires returned)
Under 100,000	5
100,000 - 500,000	14
500,000 - 1,000,000	7
Over 1,000,000	3

Table 2: Concerns regarding the use of PVC in sewer/pipe construction and rehabilitation [1]
 

Keyword	Concerns
Raw materials	The manufacture of PVC is a waste of oil resources
Manufacture	Chlorine and mercury emissions occur during the manufacture of primary monomer products.
	VC concentrations in the workplace are extremely dangerous to health.
Additives	Stabilisers pose a threat to the environment.
Processing	Damage to health may occur during the processing of end products.
In the event of fire	During the co-incineration of PVC, in the event of a fire, it burns extremely rapidly and produces toxic fumes. In addition, waste management and rehabilitation costs are very high after fires involving PVC, due to the resulting hydrochloric acid.
Waste management, landfill site	PVC construction products cause problems when disposed of at landfill sites. In 20-50 years, an avalanche of waste will come rolling down onto us.
	When PVC products are disposed of at landfill sites toxic substances are released.
Waste management, incineration	During incineration at waste incineration plants, the PVC content turns into large amounts of toxic emissions.
Waste management, recycling	PVC is a nuisance factor during Recycling.

 

1.1 Current information on PVC

The concerns regarding the use of PVC shown in Table 2 continue to be relevant. It is amazing that PVC is sometimes rejected, even though nothing is known about the problems associated with the raw materials used to manufacture it, in other words chlorine. The keywords ‘vinyl chloride’, ‘heavy metals’ and ‘dioxin’ continue to underpin the main arguments against using PVC in sewer systems. This is combined with a failure to obtain information concerning the concentration of the substances, the comprehensive safety measures already implemented within the manufacturing sector and rival products.

Obviously, it is not yet generally known that PVC-U pipes (U stands for unplasticised, i.e. unsoftened) have not contained the many controversial plasticisers [2], [3] for years. For this reason, PVC pipes also feature in the discussion about products containing plasticisers, although the current standards and regulations for pipes and fittings refer clearly to plasticiser-free PVC-U, as documented, for example, in the following standards:

• DIN 4262-1: Pipes and fittings for subsoil drainage of trafficked areas and underground engineering - Part 1: Pipes, fittings and joints made from PVC-U, PP and PE, 2009-10
• DIN 8061: Product diagram – Unplasticised polyvinyl chloride (PVC-U) pipes - General quality requirements and testing 2009-10
• DIN 8062: Product diagram - Unplasticised polyvinyl chloride (PVC-U) pipes, dimensions, 2009-10
• DIN 19534-3: Unplasticised polyvinyl chloride (PVC-U) pipes and fittings with ring seal sockets for non pressure underground drainage and sewerage – Part 3: Quality control and installation
• DIN EN 1401-1: Plastic piping systems for non pressure underground drainage and sewerage – Unplasticised polyvinyl chloride (PVC-U) - Part 1: Specifications for pipes, fittings und the pipe system; 2009-07

For example, PVC-U pipes and fittings stabilised with Ca/Zn are considered by eco-bau [4], the plat-form for constructors of public buildings for the Swiss Federal government, cantons (states) and cities, to fall within the highest group of environment-friendly construction materials. [5] (Fig. 1) was assessed in a similar way (without the associated concrete and stone being included in the comparison).

In the world of science, the problems associated with dioxin are now seen in a more realistic and less dramatic light. But emotions continue to run high in public debates. For a long time, a lack of knowledge of the effects of dioxins on people and the environment, years of handling these substances carelessly and concerns following the first major dioxin accident in Seveso (1976) made it impossible to discuss the topic rationally. The discussion surrounding how PVC behaves in the event of a fire was particularly emotive, due to the accident at Düsseldorf airport (1996). Although, according to [7], the reports of the public prosecution office and the independent expert commission, appointed to assess the consequences of the Düsseldorf airport fire, found that PVC had not played any particular part, either in terms of personal injury or damage to property, including the necessary reconstruction work, compared to other materials, and was certainly not responsible for causing the fire, it has not been possible to eliminate preconceptions about PVC. As the survey also confirmed, the lack of information about PVC also extends to the field of waste management.

Experience has shown that legislation aimed at restricting the use of PVC is mostly based on igno-rance of the current information. In regions where there has been intensive discussion focusing on PVC-related problems, the relevant restrictive legislation has been amended or left unenforced. Ex-amples include the federal states of Hessen, Mecklenburg-Vorpommern, Thüringen, Niedersachsen, Berlin and Bremen [8].

2. Assessment of concerns

2.1 Concern: The manufacture of PVC is a waste of oil resources

Pure polyvinyl chloride (PVC) consists of 57% chlorine and is made from vinyl chloride monomer by means of polymerisation. Vinyl chloride is manufactured either by causing hydrogen chloride to react with acetylene or by separating 1,2-dichlorethane, in order to produce vinyl chloride and hydrogen chloride. The manufacture of PVC can therefore be divided into the following stages (see Table 3):

Table 3: Stages in the manufactures of PVC

Primary monomer products:	Monomer production:	Polymerisation:
Chlorine Ethene (Ethylene) Acetylene	Intergrated oxychlorination Acetylene/ethylene process	Suspension process Emulsion process Mass process

 

The main raw materials for PVC are chlorine and ethene (ethylene). Chlorine is salt-based (generally rock or sea salt). As a raw material, an almost unlimited supply of salt is available. At the same time, chlorine is one of the most widely distributed elements in the natural world. Crude oil is the raw material, from which ethene is derived and is produced in the refinery when crude oil is distilled and during subsequent petrochemical processing. Approx. 80% of crude oil is used to generate electricity, heat and as a fuel for transport. Although crude oil is the basic raw mate-rial for almost all plastics, they account for only 4% of the crude oil obtained. The proportion of crude oil used to create PVC is well below 1%. Compared to other plastics, the advantage of PVC is that it requires only 43% of the product weight in ethylene, which has positive implications for the use of fossil resources. [9].

2.2 Concern: Chlorine and mercury emissions occur during the manufacture of primary  monomer products

The raw products for the production of chlorine are hydrochloric acid (HCI), potassium chloride (KCI) and, above all, sodium chloride (NaCl), which are broken down, using electrolysis, into chlorine and co-products (sodium hydroxide and hydrogen). Approx. 97% of chlorine is obtained by subjecting aqueous sodium chloride solutions to electrolysis (chlor-alkali electrolysis) [10]. The leading role of this process is explained, not least by the almost unlimited supply of sodium chloride in solid form (rock salt) in salt deposits and as a salt dissolved in the seas. Three processes can be used for the electrolysis of sodium chloride,

• Amalgam process (also known as the mercury process)
• Diaphragm process
• Membrane process

The above three processes only differ in terms of the nature and working method used in the partition, which separates the chlorine, as an anode product, from the cathode product sodium hydroxide and hydrogen: the amalgam or mercury process, using an impermeable, liquid diaphragm, the diaphragm process with a permeable diaphragm and the membrane process with a water impermeable, selective ion-conducting membrane. In particular, this last process differs from the amalgam process as it takes significantly less energy and has far less impact on the environment [9].

For a long time, the amalgam process was the standard method, which created reasons to attack the entire electrolysis process, because of the use of mercury and resulting emissions. In the meantime, this process is continuously being replaced by the more environment-friendly and energy-saving membrane process. Throughout the world, the amalgam process is being used less, including in Ger-many, as confirmed by PVC production figures for Germany for 2003 [11]. Of the approx. 4.4 million tonnes of chlorine produced:

• 1.2 million tonnes (27%) were produced using the amalgam process
• 1.0 million tonnes (23%) were produced using the diaphragm process
• 2.2 million tonnes chlorine (50%) were produced using the membrane process [9].

Overall, according to information from the Federal Environment Agency [12], improved production processes and changeover to the membrane process made it possible to reduce total mercury emis-sions from 1984 - 2004 in Western Europe by approx. 90% and by almost 99% in Germany from 1972 - 2003.

2.3 Concern: VC concentrations in the workplace are extremely dangerous to health

The raw material for polyvinyl chloride is vinyl chloride monomer – a gas that only takes on solid form during polymerisation and consists of long molecule chains. The structural formula of vinyl chloride monomer (VCM) is (C₂H₃Cl). For decades, the vinyl chloride produced during the manufacture of PVC was considered a harmless substance and even used an anaesthetic in medicine [13]. It was only recognised in the early 1970s that high concentrations in the air that we breathe are carcinogenic if we are exposed to them over an extended period. The industry reacted by introducing:

• Increased use of protective breathing apparatus,
• Improved ventilation and air extraction,
• Suction and sealing devices,
• Use of automatic cleaning equipment,
• Extensive modification of existing plants,
• Replacement of fittings and seal components [13].

In 1999, the EU Council of Ministers decided to include vinyl chloride monomers (VC) in the industrial safety directive (90/394/EEL) and set the maximum permitted level in the workplace at 3 ppm. Highly stringent safety measures have since been introduced in the chemical industry all over the world. Comprehensive industrial safety and technical measures have ensured, together with statutory regula-tions according to [9], [14], that VC has not posed any special health risk for many years.

For a long time, VC has only been used in closed manufacturing systems, so that it poses no risk to employees. Since 1977, no new cases occurred of the angiosarcoma of the liver that was observed in the early 1970s [9], [14].

2.4 Concern: Stabilisers pose a threat to the enviroment

PVC is never processed in its pure form. During the polymerisation process certain characteristics can be obtained, but it is only possible, by means of a wide range of additives, to adjust the characteristics of the PVC to the applicable use.

PVC additives serve to improve physical characteristics, such as temperature, light and weather resistance, resilience, elasticity and transparency, as well as workability. These additives include heat stabilisers, UV stabilisers, anti-oxidants, colourings (pigments), flame retardants, lubricants and fillers. Hard PVC consists of approx. 10-25% additives. Before processing, any additives are homogenously distributed and incorporated in the raw PVC by mixing, agglomerating, granulating or pasting (compounding) [10].

The use of stabilisers is specific to PVC-U, while the other additives are also used in other plastics. Heat, UV light, atmospheric oxygen and moisture damage the polymers, so that a chain degradation takes place, which causes the mechanical characteristics to deteriorate. For these reasons and in order to process PVC at temperatures of around 180°C, it is necessary to add stabilisers to the raw PVC, which prevent or delay the hydrogen chloride separation [15]. Essentially, compounds are used, which are based on lead, calcium/zinc, tin and, to a far lesser extent, cadmium [9], [10], [16].

When pipes are manufactured, however, no stabilisers containing cadmium have been used for many years. The use of stabilisers containing lead is also being reduced steadily, by using suitable formula-tions and substitutes. Lead is present in the pipes as a slightly soluble lead compound, so that the permissible threshold values are far from being exceeded in drinking water pipes made from PVC-U. The substitution of calcium/zinc or tin stabilisers for lead has already begun and will increase in the future. In the EU, it is planned that no lead at all will be used by 2015 [17]. As an alternative, calci-um/zinc-based or mixed-metal systems are possible for many uses [9].

2.5 Concern: Plasticisers give off fumes and are carcinogenic.

Plasticisers are actually classified as teratogenic and harmful to human fertility. In addition, it is suspected that some phthalates can damage the liver, kidneys and are carcinogenic. As they are ‘exter-nal’ plasticisers, they do not form a chemical bond with the plastic and can be relatively easily extracted or gradually migrate out of the plastic [18].

For the rehabilitation of sewers, PVC is used, as part of the spiral wound pipe process, but PVC has also been replaced by PVC-U in this case, i.e. the PVC does not contain plasticisers, thus eliminating any potential risks caused by plasticisers.

2.6 Concern: Damage to health may occur during the processing of end products.

The UBA DE [19] takes the view that any vinyl chloride emissions produced by PVC end products are insignificant. Because they are firmly bonded to the plastic matrix, the stabilisers pose no risk, i.e. they are not released. It is only plasticisers that are suspected of releasing health damaging emissions. PVC-U pipes do not contain any plasticisers.

2.7 Concern: During the co-incineration of PVC, in the event of a fire, it burns extremely rapidly and produces toxic fumes. In addition, waste management and rehabilitation costs are very high after fires involving PVC, due to the resulting hydrochloric acid

One of the first studies to be published on the subject of how pipes behave in the event of fire is based on the analyses conducted by the American Concrete Pipe Association (ACPA), USA in 1982 [21].

This organisation conducted laboratory-based fire tests under standardised test conditions defined in the ANSI/ASTM Standard E 84 [22] under continuous flame treatment, in order to determine the flame spread value and smoke density factor of approx. 1.22 m (4 ft) long pipe half-shells made from eight different pipe materials [23].

In order to classify the flame spread value and smoke density factor during the fire tests, the reference values of an asbestos cement plate (reference value 0) and a red oak floorboard (reference value 100) were used [23].

The fire potential of each individual pipe material was also classified and defined, in compliance with the "National Fire Protection Association" (NFPA), according to its fire behaviour during fires in buildings, in compliance with NFPA No. 101 [24] (Table 4) [23].

Table 4: Fire classes according to flame spread value and smoke density factor, in compliance with NFPA No. 101 [24]

Fire class	Flame spread Value	Smoke density factor
A	0 - 25	0 - 450
B	26 - 75	0 - 450
C	76 - 200	0 - 450

 

Among other outcomes, it was also determined that only a slight blackening of the pipe surface (without it catching fire or any flame spread) and slight damage (e.g. bursting caused by the effect of heat) could be observed in the reinforced concrete. They were therefore assigned to Fire Class A, in compliance with NFPA No. 101 [23] [24].

The two PVC samples that were tested ignited and collapsed fully after a short period, although the flame spread value and smoke density factor remained within the permitted range, so that this material was also assigned to Fire Class A [23].

The PE sample combusted completely and caused such a high smoke density factor that the values permitted by the NFPA ("National Fire Protection Association") were exceeded [23].

In the Federal Republic of Germany, the fire behaviour of construction materials and components is governed by DIN 4102 [25]. In this case, the construction materials were assigned to the non-flammable Construction Material Class A and flammable Construction Material Class B. Class B distinguishes between 3 sub-classes:

• Flame retardant construction materials (B1) are essentially flammable, but should not continue to burn independently after the fire has been extinguished,
• Normally flammable construction materials (B2) can be ignited by sources of ignition and continue to burn independently – regardless of the environmental conditions
• Slightly flammable construction materials  (B3) burn rapidly. They can be ignited by small sources of ignition and continue to burn increasingly quickly without any additional heat. They pose a high fire risk [25].

Pipes and fittings made from PVC-U, in compliance with 19531 [26], fall within Construction Material Class B1. PVC-U in compliance with 8061 [2] falls within Construction Material Class B2 [9].

The fire behaviour of PVC is explained briefly below, although this subject is only relevant for under-ground drainage pipes and sewers in rare cases. An example of this type of fire is described in [20].

In order to objectively assess the fire behaviour of a material, a variety of parameters need to be taken into account. In contrast to other plastics, PVC is slow burning, as flame retardants need to be added to these other plastics, in order to obtain this characteristic. The 57% chlorine content of PVC means that it is inherently flame retardant, so that PVC has a higher ignition temperature at 330° - 400°C than most other plastics. In general, according to [9], the use of PVC does not pose a higher fire risk compared to other plastics.

On the negative side, in this context, in the event of fire, PVC products can produce highly irritant and corrosive hydrogen chloride emissions. Burns can cause people to suffer serious harm to their respiratory organs and mucous membranes. If it is possible to speak of an advantage compared to other plastics, the advantage is that, even in non-dangerous concentrations, people know that HCL causes irritation to the mucous membranes and the irritant effect of chlorine immediately triggers panic reactions in people. This "cognitive" effect contrasts with other fumes produced by cookers, which are odourless and can be fatal. In addition, when organic compounds containing chlorine are burned, PCDD/PCDF (polychlorinated dibenzodioxin and dibenzofuran) may be produced [28]. According to Funke [29], over 200 samples were tested by the Gesellschaft für Arbeitsplatz- und Umweltanalytik (GfA) from fires, in which chloro-organic plastics, particularly PVC, had played a part. In over 90% of all samples, it was proven that PCDD and PCDF were present [28].

In the event of fires involving PVC, it is critical if hydrogen chloride comes into contact with the extinguishing water, as this leads to the formation of hydrochloric acid and causes corrosive damage to buildings. However, the significance of this effect, in terms of the extreme destruction caused by high temperatures during fires, must be considered by means of an individual risk assessment. The scene of any fire must be carefully rehabilitated, regardless of the presence or absence of PVC, according to the latest technological standards. When a fire takes place, temperatures well in excess of 1000°C occur. These extreme temperatures are the main cause of irreparable damage to buildings.

After the scene of the fire has been allowed to cool down, the main health risks are soot, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCB) and dioxins. The resulting persistent substances are, however, firmly bound to the soot and therefore only present low mobility. Even if it has to be assumed that there is a risk of dioxin uptake through inhalation during and after a fire, no increased dioxin values in the blood have so far been detected in fire service workers, who form the group that is most exposed during fires [9], [30], [31].

2.8 Concern: When PVC products are dispoised of at landfill sites toxic substances are relaesed

As PVC material is easily recyclable, PVC pipe material should not be disposed of at landfill sites but used as a recyclable material. The landfilling of recyclable materials, which include PVC, has been forbidden by law in the Federal Republic of Germany since 2005. Since 1994, a system has been developed for the collection and recycling of PVC pipes. The Arbeitsgemeinschaft PVC und Umwelt e.V. has prepared a list of all reprocessing plants in the Federal Republic. For plastic pipe systems, the collection system developed by the Kunststoffrohrverband e.V. (KRV), in partnership with accredited specialist companies, takes care of and documents the collection, preparation and recycling of all plastic pipe waste [32], [33]. Used pipes are sorted, cleaned and crushed. The crushed plastic parts are reused in the plastic industry, so that most of PVC burned in waste incineration plants does not come from the sewage sector.

However, making full use of the existing recycling potential requires people to be fully informed and willing to pay recycling costs when purchasing products. Due to the long lifecycle of PVC products in the construction industry, the amount of waste generated is currently very small in relation to manufacturing figures.

In principle, landfilled PVC products are non-biodegradable and largely neutral towards the air, soil and water. The macromolecules in PVC cannot be degraded by micro-organisms. Plasticisers behave differently but are not present in PVC-U pipes. Depolymerisation, which means the release of macro-molecular polyvinyl chloride in a toxic monomer vinyl chloride, does not take place. The high levels of chloride cannot leak out of the PVC, as they are firmly bound to the structure. It is difficult to assess whether the stabiliser, which is only physically embedded, is released due to the effect of substances contained in the landfill leachate, as the substances contained in this leachate are difficult to measure. Tests have shown that any erosion that may occur affects the particles found on the surface. Compared to other types of waste brought to landfill sites, the risk caused by harmful substances contained in PVC is extremely small.

2.9 Concern: During incineration at waste incineration plants, the PVC content turns into large amounts of toxic emissions.

According to the collection systems introduced for plastic pipe systems (see Section 2.8), most of the PVC burned at incineration plants does not come from the sewage sector.

Waste incineration plants, at which PVC waste can also be converted into heat energy, are equipped with advanced waste gas treatment facilities, so that the resulting harmful substances can be separated. The heavy metal input caused by PVC is currently minimal, as cadmium is now hardly ever used as a stabiliser. Any heavy metals contained in the waste, most of which are not derived from PVC, are partly mobilised during incineration and reach the waste gas stream, where 99% of them are contained, together with other dust particles in the dust extraction systems. The waste incineration plants used in the EU, according to Vehlow [34], represent a dioxin sink. Based on the same findings, hydrochloric acid and heavy metals do not cause any problems during incineration. Measurements undertaken at the Forschungszentrum Karlsruhe [35] indicated a separation efficiency of 99% for both substances [9].

Due to its chlorine content, minimal carbon content and low calorific value, less energy can be ob-tained from PVC, while hydrogen chloride is produced during incineration, which reacts in the washers to produce hydrochloric acid, the stabilisers are released and dioxins are formed. As, independent of PVC, a halogen input cannot be ruled out (chloride or fluoride), it is currently a requirement that every waste incineration plant must be equipped with multi-level washers and dioxin filters. The resulting cost of operating waste gas purification systems is not significantly influenced by PVC. The hydrochloric acid created by the hydrogen chloride in the washer enters the washing medium and does not represent an additional burden. The cost of burning plastics at waste incineration plants are, according to Kirrman [36], between 260 - 400 Euros per tonne. PVC-U costs, according to Kirrman [36], 340 Euros per tonne and falls within the medium category for the materials tested. The above-average costs, which are frequently cited, for the incineration of PVC waste, were not confirmed. For this reason, there would be no changes to the cost of handling residual waste, if PVC were removed from the latter [9].

2.10 Concern: PVC is a nuisance factor during recycling.

The term "recycling"must be considered in different ways. PVC waste materials are produced at the manufacturing plant, as well after its useful life. Recycling at the manufacturing plant is now greatly improved. At all stages of PVC manufacturing, modern processes help keep waste to a minimum. Processing waste is fed straight back into the manufacturing process and never enters the waste stream. The recycling of materials has been con-tinuously improved under the leadership of the Gütegemeinschaft Kunststoffrohre. In 1994, the KRV introduced a collection and recycling system (see Section 2.8). It accepts all offcuts, as well as all dismantled plastic pipes. Collection boxes are provided to dealers free of charge. The recycled mate-rial is used, among other things, to manufacture cable protection or non-pressure pipes. For heavily soiled PVC waste or material mixtures, a raw material recycling system has been devel-oped, in which the macromolecules in the plastic waste are broken down into smaller units, including individual monomers, and regained, by means of chemical and/or thermal processes. These compo-nents can then (as secondary raw materials) be fed back into the chemical industry. As a rule, during the recycling of raw materials from PVC waste, the chlorine is regained through dechlorination and sold as hydrochloric acid/sodium chloride or used in the vinyl chloride production cycle. Depending on the process, the organic component can be extracted as a monomer or converted into synthetic gas [18]. In addition, chemical processes exist, in which the PVC waste is divided into soluble and non-soluble components. The solvent used is regained during this process and reused (recycled). However, this process is not relevant for pipes and fittings made from PVC-U, as it is intended for compounds and mixed PVC waste [18].

3. Summary

PVC is an indispensable part of the range of materials used in the construction industry. When used in sewer systems, it is used in the form of PVC-U (without plasticisers) for pipe fittings and ready-made/wound pipes. Particularly when used for the rehabilitation of sewers and drainage pipes, the material characteristics of PVC-U offer many advantages, as galling (important for impermeability) and bonding (important for shaft connection and connecting inflows) are possible. In addition, PVC-U is highly temperature resistant and hardly expands when subjected to heat. Both the material itself and end products are standardised in European and German norms and regulations (DIN EN and DWA) and can therefore be used for the applicable purposes.

Doubts continue to exist concerning the use of PVC in sewer systems, which were addressed in this study of the relevant literature, in light of the most frequently cited counter-arguments, which was commissioned by Geiger Kanaltechnik GmbH & Co. KG.

As a result, it can be seen that the concerns regarding PVC-U can essentially be considered to have been resolved, in view of the current manufacturing and recycling technology. In several federal states, this finding has led to previous restrictions and bans on the use of PVC being lifted or left unenforced. In Berlin, the regulations state that the purchase of PVC is permitted if:

• There is evidence that the new material has beed stabilisied without usig lead and cadmium
• The building components have been labelled, as evidence that they have been tested for the required product characteristics
• The applicable sector is formally required to recover the material [37].

The above notes show that these requierments can be met by PVC-U rehabilitation products

However, PVC is not a universal material and its use is associated with advantages and limitations. The latter relate particular to its fire behaviour, so that pipes and fittings made from PVC-U, as well as other plastics, should not be used unreservedly areas at high risk of fire. A suitable pipe material for the rehabilitation of drainage pipes and sewers should be selected at least by using the following criteria as a basis for comparison:

• Laying / installation costs
• Installation conditions
• Running conditions
• Pipe performance
• Environmental issues

The worldwide implementation of the current standards, as listed in this article, for the manufacture and composition of PVC-U, are crucial for the use of PVC-U, if we are to avoid reintroducing the problems described here when PVC is imported. Checking the country of origin and applicable standard should therefore form an essential part of the decision, when selecting a particular PVC-U material.

References

[1] Prof. Dr.-Ing. Stein & Partner GmbH: Untersuchung der Akzeptanz von PVC in der Abwassertechnik unter besonderer Berücksichtigung der Verwendung von PVC beim Wickelrohr-Sanierungsverfahren (Rib-Loc mit und ohne Ringraumverfüllung, 1999 (unveröffentlicht)

[2] Weichmacher DEHP: Tägliche Aufnahme höher als angenommen? Stellungnahme des Bundes Instituts für Risikobewertung (BfR) vom 23. Juli 2003

[3] Phthalate – Die nützlichen Weichmacher mit den unerwünschten Eigenschaften, Umwelt Bundesamt, Februar 2007

[4] Plattform öffentlicher Bauherrschaften von Bund, Kantonen und Städten der Schweiz mit Empfehlungen zum nachhaltigen Planen, Bauen und Bewirtschaften von Gebäuden und Anlagen; www.eco-bau.ch/index.cfm?Nav=11

[5]S. Busser und R. Frischknecht: Ökobilanzen von Rohren - Vergleich verschiedener Rohrmaterialien für Haustechnik, Versorgung und Industrie, ESU-service Ltd., im Auftrag von Georg Fischer Piping Systems, 2008

[6] Impulse, Das Magazin des Kunststoffrohrverbandes 01.2013

[7] 10 Jahre danach - Düsseldorfer Flughafenbrand, Arbeitsgemeinschaft PVC und Umwelt e.V. (http://www.pvcrecyclingfinder.com/pvc-recycling-news/einzelansicht/artikel/10-jahre-dan.html)

[8] PVC – nachhaltiger Kunststoff mit neuen Perspektiven, Arbeitsgemeinschaft PVC und Umwelt e.V., 08.2007

[9] PVC-Heute, Die aktuelle Situation des Werkstoffs Hart-PVC in den relevanten Themenbereichen, Institut für industrielle Ökologie, 09.2007

[10] Kollmann, H.; et. al.: Stoffströme und Emissionen durch Produktion, Verwendung und Entsorgung von PVC, Band l, Kurzfassung, Forschungszentrum Julien GmbH, JÜL-Spez. 543, Juli 1990

[11] Rothert, A.: Positionen zur Chemie mit Chlor - VCI Internetartikel; 11.2005

[12] Umweltbundesamt Berlin: National Focal Point – IP; Integrierte Vermeidung und Verminderung der Umweltverschmutzung (IVU), Referenzdokument über die besten Verfügbaren Techniken in der Chloralkaliindustrie; 12.2001

[13] Daunderer: vinyl chloride ffl-2.3,  Klinische Toxikologie-61. Erg.-Lfg. 12/90

[14] Arbeitsgemeinschaft PVC und Umwelt: Wissenswertes über PVC, 08.2005

[15] Brahms, E.; et. aL: Papier - Kunststoff - Verpackung. Eine Mengen- und Schadstoffbetrachtung, Berichte 1/1989. Hrsg.: Umweltbundesamt, Erich Schmidt Verlag, Berlin 1989

[16] UBA-DE, Fraunhofer Institut, Ökopol; Leitfaden zur Anwendung umweltverträglicher Stoffe; Februar 2003

[17] Fraunhofer Institut ICT; Technologiestudie zur Verarbeitung von Polyvinylchlorid (PVC); Pfinztal, Mai 2005

[18] BBU GMBH: Gutachten zur Bewertung der Entsorgung von verunreinigten PVC-Abfällen im Auftrag des Ministerium für Landwirtschaft, Umwelt und ländliche Räume des Landes Schleswig-Holstein, 06.2007

[19] UBA DE; Substitution von PBT*- Stoffen in Produkten und Prozessen, Leitfaden zur Anwendung umweltverträglicher Stoffe für die Hersteller und gewerblichen Anwender gewässerrelevanter Chemischer Produkte; Teil5; Berlin, 02.2003

[20] Kanalrohr-Brand offenbar die Ursache für giftige Rauchwolke in Lüdenscheid, WAZ, 08.04.2013, 10:21 Uhr, http://www.derwesten.de/staedte/nachrichten-aus-luedenscheid-halver-und-schalksmuehle/kanalrohr-brand-offenbar-die-ursache-fuer-giftige-rauchwolke-in-luedenscheid-id7811657.html#plx321109217

[21] American Concrete Pipe Association (Hrsg.): Buried Facts – Fire in Sewers and Culverts. No. 02-201, Vienna (Virginia), May 1982.

[22] ANSI/ASTM Standard E 84: Test Method for Surface Burning Characteristics of Building Materials" (Volume 04.07, 2001).

[23] Teilexpertise "Thermisches Verhalten". Leitfaden zur Auswahl von Rohrwerkstoffen für kommunale Entwässerungssysteme, Prof. Dr.-Ing. Stein & Partner GmbH, 12.2004

[24] NFPA No. 101: Life Safety Code. National Fire Protection Association (NFPA) (Hrsg.), Ausgabe 2003.

[25] DIN 4102: Brandverhalten von Baustoffen und Bauteilen, Teil 1: Baustoffe; Begriffe, Anforderungen und Prüfungen, Beuth-Verlag GmbH, 05.1998

[26] DIN 19531-10: Rohr und Formstücke aus weichmacherfreiem Polyvinylchlorid (PVC-U) für Abwasserleitungen innerhalb von Gebäuden - Teil 10: Brandverhalten, Überwachung und Verlegehinweise, Beuth-Verlag GmbH, 12.1999

[27] DIN 8061: Rohre aus weichmacherfreiem Polyvinylchlorid (PVC-U) - Allgemeine Güteanforderungen, Prüfung, Beuth-Verlag GmbH,  10.2009

[28] D. Hohmann: Umweltrelevante und werkstoffbestimmende Entscheidungskriterien für den Einsatz von PVC oder alternativen Kunststoffe in der Kanalisation, INSTITUT FÜR KONSTRUKTIVEN INGENIEURBAU ARBEITSGRUPPE LEITUNGSBAU UND LEITUNGSINSTANDHALTUNG, PROF.DR.-ING. D. STEIN, Bochum, 1992

[29] Funke, W. et. al.: Polychlorierte Dibenzofurane (PCDF) und Polychlorierte Dibenzo (p)dioxine (PCDD) in Rückständen und Emissionen eines Brandes in Anwesenheit von PVC-haltigen Materialien. Staub-Reinhaltung der Luft 48(1988)

[30] Ruhr-Universität Bochum und Heinrich-Heine-Universität Düsseldorf im Auftrag des Ministeriums für Arbeit, Gesundheit und Soziales des Landes Nordrhein-Westfalen; Umweltmedizinische Untersuchungen an Feuerwehrleuten; 1993

[31] Ministerium für Umwelt, Raumordnung und Landwirtschaft des Landes Nordrhein-Westfalen; Dokumentation Grossbrand Lengerich; 1994

[32] www.aktion-pvc-recycling.de à Recyclingsystem des KRV e.V.

[33] Ullmann, K.,: Ein bewährter und zukunftsfähiger Werkstoff

[34] Vehlow J.; Waste combustion and the dioxin issue; Korean Institute of Science and Technology (KIST); Europe Environmental Technology Workshop; Saarbrücken 1997

[35] Dr. H.-R. Paur; Forschungszentrum Karlsruhe, Institut für Technische Chemie, Multifunctional Scrubber for Incineration Plants; Simultaneous Removal of Mercury, Submicron Particles, and Dioxins

[36] Kirrman; Incineration of PVC and other products in MSW; 11.2000

[37] Verwaltungsvorschrift für die Anwendung von Umweltschutzforderungen bei der Beschaffung von Liefer-, Bau- und Dienstleistungen (Verwaltungsvorschrift Beschaffung und Umwelt – VwVBU), SenStadtUM IX B 22, Berlin, 23. Oktober 2012

 

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