REHABILITATION OF ASBESTOS CEMENT WATER MAINS FOR POTABLE WATER IN THE CZECH REPUBLIC

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1 Hydrology and Water Resources REHABILITATION OF ASBESTOS CEMENT WATER MAINS FOR POTABLE WATER IN THE CZECH REPUBLIC Ing. Marek Coufal doc. Ing. Vojtěch Václavík, Ph.D. Ing. Tomáš Dvorský, Ph.D. Institute of Environmental Engineering, Faculty of Mining and Geology, VSB-Technical University of Ostrava, Czech Republic ABSTRACT In recent history, asbestos cement pressure pipes were widely used for delivery of potable water from water sources to human settlements. Nowadays, most of the asbestos cement water mains are approaching the end of the service life. Although asbestos cement water mains are not considered to represent a significant risk to public health when in normal use, asbestos fibres released into air during rehabilitation of water mains pose a cancer and lung disease hazard. The contribution deals with problems of rehabilitation of asbestos cement water mains in the Czech Republic as well as with safety and disposal issues. The first part of the contribution briefly describes production of asbestos cement pipes and provides information on installation of asbestos cement water mains as second part deals with health effects of asbestos on humans. The final part of the contribution focuses on principal laws and regulations concerned with asbestos waste management in the Czech Republic and safety in the workplace during rehabilitation of asbestos cement water mains. Keywords: asbestos cement pipe, rehabilitation, water main, health protection, regulations INTRODUCTION Asbestos cement pipes began to be manufactured in the beginning of the 20 th century in Italy. The new kind of pipe showed a number of advantages so it rapidly began to spread to most of countries of Europe and North America. In the period between the 1950 s and the 1960 s, asbestos cement pipes were the most used material for construction of water supply networks. In the Czech Republic, production of asbestos cement pressure pipes was ceased in the middle of 1970 s. With the expected lifespan of an asbestos cement pressure pipe of approximately 50 years (varied sources differ on the expected lifespan between years; however many of asbestos cement water mains constructed in 1960 s are still in use), most of the asbestos cement water mains are approaching the end of their service life. The exact length of asbestos cement water mains, which are still operational in the Czech Republic, is not known. According to property records of Czech water companies, there were about km of water mains in the Czech Republic in 2009, of which only about 2853 km (3,9%) were made of other

2 14 th International Multidisciplinary Scientific GeoConference SGEM 2014 material than iron or plastic. It is widely expected that most of the 2853 km of water mains were constructed of asbestos cement [1], [6]. Asbestos cement pipes were manufactured of mixed thin slurry of portland cement and mixture of chrysotile asbestos fibers, mixed in the ratio from 7:1 to 8:1. Cement slurry was mixed with asbestos fibres and the mixture was brought into a rotating cylinder whose coat was formed by fine copper mesh. A layer of cement with asbestos settled on the surface of the cylinder while excess water drained out. Settled layer of cement with asbestos was collected by an endless felt belt, which was wound on a steel cylinder in order to create the shape of a pipe. The process of winding was done with simultaneous rolling under the pressure of 4-15 bar. The exact pressure of rolling depended on the diameter of the manufactured pipe. After removing from the steel cylinder, the asbestos cement pipe was put on a wooden core with the aim of preventing any deformation of the new pipe. When partially hardened, after approximately one day, the asbestos cement pipe was removed from the wooden core and put into water bath to complete the hardening. The inner surface of the asbestos cement pipes was coated with asphalt coating [2]. Asbestos cement pipes had both advantages and disadvantages. The main advantages and disadvantages are summarized in the table bellow. Tab. 1 Main advantages and disadvantages of asbestos cement pipes MAIN ADVANTAGES AND DISADVANTAGES OF ASBESTOS CEMENT PIPES ADVANTAGES Cost of manufacturing Easy installation (easy and inexpensive cutting and tapping) Lower pipe weight in comparison with iron or cast iron pipes Resistance to electrochemical corrosion and stray currents Relatively low pipe roughness which results in low friction losses DISADVANTAGES Health concerns due to asbestos fibres content Fragility of pipes (tendency to crack when under bending stress) Difficulty to repair potential failures of water mains Low resistance to vibrations from vehicular traffic Durability (relatively long service life) Low thermal conductivity There were three factories manufacturing asbestos cement pressure and sewage pipes in former Czechoslovakia. These factories were located in the towns of Hranice, Beroun and Nitra. Nowadays, after disintegration of Czechoslovakia in 1993, the towns of Hranice and Beroun are located in the Czech Republic; the town of Nitra is located in

Hydrology and Water Resources the Slovak Republic. Production of asbestos cement pipes in all three factories has been ceased. Fig.

2 OVP couplings for asbestos cement pipes (seals not included) Individual asbestos cement pipe sections were connected with the use of variety of special couplings

These cast iron fittings were made specially for construction of asbestos cement water mains. Fig.

3 Hydrology and Water Resources the Slovak Republic. Production of asbestos cement pipes in all three factories has been ceased. Fig. 1 Asbestos cement pipes (notice the wall thickness in comparison with the size of the mobile phone) Fig. 2 OVP couplings for asbestos cement pipes (seals not included) Individual asbestos cement pipe sections were connected with the use of variety of special couplings such as Gibault, OVP, Simplex or Reka. Only straight pipes were made of asbestos cement. All needed bends and tees were made of cast iron. These cast iron fittings were made specially for construction of asbestos cement water mains. Fig. 3 Gibault s coupling for AC pipes (on the left) and cast iron all socket tee for AC pipes (on the right) [3] Durability and reliability of asbestos cement water supply networks depended on the quality of installation. Installation of asbestos cement water mains had to be performed with caution due to fragility of pipes. The trench was excavated at least 100 mm deeper

14 th International Multidisciplinary Scientific GeoConference SGEM 2014 than normally required and a levelled bed of suitable material (preferably sand with grains no bigger than 5 mm) was created.

4 Gibault s coupling when dug out after approximately 50 years from assembling Fig.

4 14 th International Multidisciplinary Scientific GeoConference SGEM 2014 than normally required and a levelled bed of suitable material (preferably sand with grains no bigger than 5 mm) was created. The bed was spread over the full width of the trench. The embedment of the pipes was made of fine soil or sand and carefully compacted [3]. Fig. 4 Gibault s coupling when dug out after approximately 50 years from assembling Fig. 5 Gibault s coupling in cut-out section of AC pipes TYPES OF ASBESTOS The term asbestos refers to a group of six naturally occurring silicate minerals with thin microscopic fibres, which are compounds of silicon, oxygen, hydrogen and various metal cations. Asbestos minerals are divided into two main groups serpentines and amphiboles. The forms of asbestos are serpentine mineral chrysotile (also known as white asbestos; the only member of the serpentines group) and amphibole minerals amosite (often referred to as brown asbestos), crocidolite (blue asbestos), tremolite, anthophyllite and actinolite. All six asbestos mineral types are known to be carcinogenous to humans [4]. HEALTH EFFECTS OF ASBESTOS ON HUMANS Health effects of asbestos on humans have been widely published around the world. When asbestos tiny fibres are released into the air, they can be breathed in and trapped in the lungs. Exposure to asbestos can cause four main diseases [5]: Mesothelioma (more precisely termed as malignant mesothelioma), which is cancer of the lining of the lungs. Mesothelioma is always fatal and is almost exclusively caused by exposure to asbestos. Asbestos-related lung cancer, which is identical to lung cancer from other causes and is almost always fatal. Asbestosis, which causes scarring of the lungs. Asbestosis is not always fatal but can be a very debilitating disease, greatly affecting quality of life.

5 Hydrology and Water Resources Diffuse pleural thickening (thickening of the membrane surrounding the lungs), which can restrict lung expansion leading to breathlessness. Like other building materials containing asbestos, AC pipes are neither manufactured nor used for construction of new water mains in the Czech Republic due to asbestos carcinogenicity. Nevertheless, there are still some operational water mains made from asbestos cement pipes. Asbestos carcinogenicity has been widely published in Czech mass media since 1990 s, often with unqualified statements made by officials on use of asbestos cement pressure pipes in water industry. Due to this campaign, members of public started to ask frequent questions about safety of potable water delivered through the pipe networks containing asbestos cement pipes. In 2002, the National Institute of Public Health of the Czech Republic issued a statement on use of asbestos cement pipes for delivery of potable water [6] to inform members of public about a risk associated with the use of asbestos cement pipes for potable water delivery. The statement was reissued in 2014 [7], with added information on available studies and also cited, inter alia, information on asbestos fibres in drinking water published in WHO Guidelines for Drinking Water Quality [8]. The statement informed that neither available experimental nor epidemiological studies support the hypothesis that an increased cancer risk is associated with the ingestion of asbestos fibres in drinking water. Therefore potable water delivered through asbestos cement water mains is not considered to represent a significant risk to public health. At the same time the statement warned, that asbestos fibres released into air during rehabilitation of asbestos cement water mains pose a cancer and lung disease hazard when inhaled so appropriate safety precautions must be taken to protect the involved workers against asbestos exposure. PRINCIPAL LAWS AND REGULATIONS IN THE CZECH REPUBLIC In the Czech Republic, several laws regulate the conditions for asbestos waste management. These laws, understandably, also apply to rehabilitation of asbestos cement pipe networks. The principal Czech laws concerned with asbestos waste management during rehabilitation of asbestos cement water mains in the Czech Republic are as follows: Act No. 183/2006 Coll. on town and country planning and building regulations (commonly known as the Building Act). According to the Building Act, the owner of the construction site is obliged to notify the building authority of any intention to demolish a construction that contains asbestos. Act No. 185/2001 Coll. on Waste. The act regulates obligations pertaining to asbestos waste management. According to the act, the producer of waste containing asbestos and the licensed person managing the waste containing asbestos shall be obliged to ensure that asbestos fibres or dust are not released into the air when managing such waste and that liquids containing asbestos fibers are not spilled. Waste containing asbestos fibres or asbestos dust may only be deposited in landfills designed for this purpose. Waste must be treated, packed or immediately covered after being deposited in the landfill. The operator of the landfill shall be obliged to ensure that asbestos particles are not released into the air.

6 14 th International Multidisciplinary Scientific GeoConference SGEM 2014 Act No. 258/2000 Coll. on Protection of Public Health. The act establishes the obligation to inform Public Health Authority about asbestos waste management. Employers doing work with the risk of exposure to asbestos are required to announce such work to competent Public Health Authority 30 days prior to asbestos waste management. The announcement to the Public Health Authority is not required in case of sporadic short-term exposure to asbestos. Sporadic short-term exposure to asbestos is regulated by Decree No. 394/2006 Coll. Decree No. 394/2006 Coll. defining work with sporadic and short term exposure to asbestos and the procedure for determination of sporadic and short term exposure within these activities. Act No. 309/2006 Coll. which regulates further requirements concerning occupational health and safety in labour law relations as well as the provision for the protection of health and safety at work or the provision of services outside labour law relations. Government Regulation No. 361/2007 Coll. establishing the conditions of occupational health protection. The government regulation incorporates relevant directives of the European Parliament and of the Council and has as its aim the protection of workers against risks to their health, including prevention of such risks, arising or likely to arise from exposure to asbestos at work. Act No. 309/2006 Coll., which regulates further requirements for health and safety at work in labour relations and concerning occupational health and safety protection in activities or services provided outside labour relations (Act on Further Requirements on Occupational Health and Safety). Decree no. 432/2003 Coll., by which conditions for the categorization of work are determined, limit values of indices from biological exposure tests, conditions for the sampling of biological materials for biological exposure and the particulars of the reports on work with asbestos and biological agents. Decree No. 381/2001 Coll., in which the Waste Catalogue is stated. The decree specifies waste catalogue and list of hazardous waste. Decree No 383/2001 Coll., on details of waste management. All mentioned acts, regulations and decrees are continuously amended and updated through their life to reflect latest scientific knowledge and technological progress. REMOVAL OF ASBESTOS CEMENT PIPES AND WORKPLACE SAFETY Safe removal of asbestos cement pipes is a complicated process. Removal of asbestos cement pipes must be performed in accordance with safety and health standards to protect workers from exposure to asbestos. Unlike in other countries, there is no special directive on the procedure for removal of asbestos cement pipes in the Czech Republic. Considering the above-mentioned laws and regulations, the following general principles should be applied during work as necessary precautions to prevent (where practicable) or maximally reduce exposure to asbestos fibres:

7 Hydrology and Water Resources All workers involved must be properly trained in the correct working practices (use of personal protective equipment, work methods, decontamination procedures, waste disposal etc.) and must have adequate information on the health hazards associated with working with asbestos waste. All workers involved in the cutting, removal and bagging of asbestos cement pipes must wear protective clothing and equipment. The workplace must be protected against access by persons who are not directly associated with asbestos removal work. Rehabilitated asbestos cement main must be carefully uncovered without breaking individual pipes. This should be preferably done by either manual excavation or combination of mechanical and manual excavation. Whole sections of asbestos cement pipes should be removed without cutting or breaking. Where practicable, individual asbestos cement pipes should be disconnected from water main in the couplings. If cutting of asbestos cement pipes is necessary, the pipes must be cut with low speed hand tool to minimize dust generation. The use of powered high-speed tools, which generate fine dust during cutting, is not allowed. Asbestos waste, including all off cuts, residue and contaminated soil, must be removed from the trench and wrapped in plastic bags or stored in closed containers. All bags and containers containing asbestos waste must be properly labelled. All the work area must be cleaned of all types of asbestos waste as soon as possible. Waste and debris contaminated with asbestos must be removed from the work area as soon as possible to prevent it from being crushed by moving machinery. The work area should be thoroughly clean on completion of the work. CONCLUSION There are estimated almost 3000 km of operational asbestos cement water mains in the Czech Republic. Although asbestos is a known carcinogen by the inhalation route, neither available experimental nor epidemiological studies support the hypothesis that an increased cancer risk is associated with the ingestion of asbestos fibers in drinking water. Thus, there is no necessity to supersede asbestos cement water mains by modern pipe materials before the end of their service life. However, considerable care is required during rehabilitation of asbestos cement water mains to prevent risk of inhalation of asbestos fibres. For that reason, asbestos cement pipes are treated as special waste and strict rules must be followed during handling.

8 14 th International Multidisciplinary Scientific GeoConference SGEM 2014 REFERENCES [1] FRANK, Karel. Vodovodní řady a kanalizační stoky v ČR analýza dat. SOVAK č. 3/2011, pp [2] ROTH, Jaroslav a KROUPA, Pavel. Vodárenství I. Praha: Státní nakladatelství technické literatury, pp [3] ŠTÍCHA, Václav. Vodárenství: Zásobování obyvatelstva, průmyslu a zemědělství pitnou a užitkovou vodou. Praha: Státní nakladatelství technické literatury, 1960, pp [4] INTERNATIONAL AGENCY FOR RESEARCH ON CANCER. IARC Monographs, Supplement 7: Asbestos, Lyon, pp [5] HEALTH AND SAFETY EXECUTIVE. What are the health risks from asbestos? [online]. [cit ]. Available in: [6] The National Institute of Public Health of the Czech Republic: Report of National Reference Center no. CHŽP-216/2002 on Use of Asbestos Cement Pipes for Potable Water Delivery [7] The National Institute of Public Health of the Czech Republic: Report of National Reference Center no. SZU-440/2014 on Use of Asbestos Cement Pipes for Potable Water Delivery [8] WORLD HEALTH ORGANIZATION. Guidelines for Drinking Water Quality. fourth edition. Geneva, ISBN

Directives. in construction and friction materials. Commercial. groups: serpentine (chrysotile) and amphibole (tremolite, actinolyte and others).

Directives. in construction and friction materials. Commercial. groups: serpentine (chrysotile) and amphibole (tremolite, actinolyte and others). European Union (EU) asbestos Directives Asbestos is the generic name for a variety of fibrous minerals found naturally in rock formations around the world. Because asbestos fibres are strong, durable and