Hot and cold water pipes, sometimes referred to as domestic pipes, are most commonly used in building and construction. Good hot and cold water pipes are impermeable, preventing any contamination of water carried by the pipes from the surrounding soil. The choice of resin is a key factor in ensuring such high environmental performance. Concern over the safety of drinking water and decline in water quality has led to phasing out of old pipes systems. Hygiene, cost effectiveness and zero-corrosion of plastic pipes provide a clear advantage in water delivery systems. Commonly used plastic pipes for hot and cold water systems are: Cross linked PE pipes Also known as PEX pipe. It is manufactured from HDPE and is cross linked with organic peroxides, silane or electron beam radiation. Almost all PEX is made from high density polyethylene. PEX contains cross-linked bonds in the polymer structure, changing the thermoplastic to a thermoset. Cross-linking is accomplished during or after the extrusion of the tubing. The required degree of cross-linking, according to ASTM Standard F 876-93, is 65-89%. The high-temperature as well as low temperature properties of the polymer are improved. Adequate strength to 120-150°C is maintained by reducing the tendency to flow. Chemical resistance is enhanced by resisting dissolution. Impact and tensile strength, scratch resistance, and resistance to brittle fracture are enhanced. Random Polypropylene pipes It is more rigid compared to PEX pipes, requiring it to be cut into 4 meters. This increases installation cost compared to PEX pipe system. PP-R pipes have been developed for full range plumbing and heating systems and successfully approved in many countries world-wide. Features of PP-R pipe include: • Non-toxic, no rust, never scaling, non-breeding bacteria, fast flow rate. • Use of homogeneous hot melt connection, pipe and pipe fittings completely fused into one • Energy-saving insulation: thermal conductivity is only one-eighth of metal pipe for hot water pipe insulation leading to excellent energy saving effect. • Light weight, high strength ratio, anti-stress test intensity is over 5MPA, toughness, good impact resistance. • Able to withstand hot water and high pressure, cold temperatures, and is acceptable to a great expansion. Recently a new polypropylene material class has been introduced on the market -polypropylene random-copolymer with modified crystallinity and enhanced temperature resistance (PP-RCT). The characteristics of this material lead to a beneficial pipe design for safe and economical installation. Benefits of PE-X, PP-R and PP-RCT piping systems include: • Long life of at least 50 years • No limitations to pH value of water • No contact corrosion when exposed to iron particles • Taste and odour neutral • Bacteriologically neutral • Ease of manufacture • Fast and easy installation • Entire plastics systems available • Good chemical resistance • Low tendency to incrustations Chlorinated polyvinyl chloride (CPVC) pipes Is a thermoplastic produced by chlorination of polyvinyl chloride (PVC) resin, produced by post polymerization of PVC polymer. It has a higher heat deflection temperature compared to PVC. It also has better chemical resistance compared to PEX pipe. The installation involves labour, making it more expensive in the developed regions. CPVC is PVC that has been chlorinated via a free radical chlorination reaction. This reaction is typically initiated by application of thermal or UV energy utilizing various approaches. In the process, chlorine gas is decomposed into free radical chlorine which is then reacted with PVC in a post-production step, essentially replacing a portion of the hydrogen in the PVC with chlorine. The chlorine content may vary from as low as PVC 56.7% to as high as 74% by mass. Various additives are also introduced into the resin to make the material processable. These additives may consist of stabilizers, impact modifiers, pigments and lubricants. CPVC shares most of the features and properties of PVC. It is also readily workable, including machining, welding and forming, and has excellent corrosion resistance at elevated temperatures. The ability to bend, shape and weld CPVC enables its use in a wide variety of processes and applications. It exhibits fire-retardant properties and is a popular engineering material due to its relatively low cost, high glass transition temperature, high heat distortion temperature, chemical inertness and flame and smoke properties. Polybutene 1 pipes Is developed by polymerization of butene 1. The main use of PB-1 is in flexible pressure piping systems for hot and cold drinking water distribution, pre-insulated district heating networks and surface heating and cooling systems. The most striking features are weldability, temperature resistance, flexibility and high hydrostatic pressure resistance. The material can be classified PB 125 with a minimum required strength (MRS) of 12.5 MPa. Other features include low noise transmission, low linear thermal expansion, no corrosion and calcification. Although it has good heat resistance, it is expensive. Because the products are supplied on coils they are easy to handle on site. The availability of long pipe lengths means that the requirement for joints in the system is reduced. PE-X and PP for aluminum composite pipes Multi layer plastic pipe made from plastic sandwiched with a layer of metal such as aluminum in between two layers off plastic. Aluminum composite pipes (also called multilayer pipes) typically consist of 5 layers: a middle layer of aluminum bonded on each side by an adhesive layer to an inner and outer layer of PE-X, PP-R or PP-RCT. These pipes have gained such widespread acceptance because they combine the benefits of plastics and metals. The plastic inner pipe provides corrosion resistance that metal pipes alone cannot offer. Composite pipes possess a lower thermal expansion which, in conjunction with the higher stiffness, reduces the number of required pipe supports and compensation elements. Overall cost savings in the installation are achieved. Additionally, the aluminum layer acts as a barrier to oxygen diffusion, which is beneficial in heating applications. However, the production of composite pipes requires high investment and production skills. Investment costs for composite pipe production lines are significantly higher than for standard pipe extrusion. The design, production and quality supervision of composite pipes also require high skill levels. Various welding technologies are utilised for the manufacture of Al-composite PE-X pipes, comprising laser butt-welding of the aluminum or welding of the overlapping aluminum foil. In each case a secure aluminum layer is obtained. On the inside the PE-X layer ensures a long service life and high durability; whereas on the outside PE-X provides the best mechanical protection of the aluminum layer and for secure jointing with compression fitting. The most beneficial feature of composite PE-X pipes is their ability to retain their shape once they are bent, thereby facilitating the installation and minimising the number of joints. PEX pipe is quite popular in Europe and North America. CPVC system is popular in the Middle Eastern region (Saudi Arabia) and North America (USA). PB-1 piping systems are no longer being sold in North America. The overall market share in Europe and Asia is rather small but PB-1 piping systems have shown a steady growth in recent years. In certain domestic markets, e.g. UK, Korea and Spain, PB-1 piping systems have a strong position. Manufacturers of pipe systems have enjoyed strong growth over the past couple of years driven by the recovery in the German building industry and strong growth in Central and Eastern European markets, but face challenging times ahead as residential building activity drops steeply and commercial and infrastructure project investment slows down. The position and status of Europe’s leading suppliers of plastics pipes is reviewed in a new report from Applied Market Information. Plastic pipe production in Europe is dominated by a few major groups. Wavin is the clear market leader and has further consolidated its position in recent years with acquisitions which have included Hepworth Building Products in the UK and Pilsa Plastic in Turkey, which will give it an important foothold to target the rapidly developing markets in the Balkans, the CIS and the Middle East. The current challenging business climate though has resulted in some downsizing and restructuring in the Irish and UK markets. Pipelife, Europe’s second largest producer has also made a number of acquisitions over the past five years, as well as expanding into Russia. A notable change since the last edition has been the restructuring at Uponor. Following a series of disappointing results in the early 2000s the company changed strategy and decided to divest some of its commodity businesses in soil and waste and concentrate on higher value systems for residential markets. These changes have resulted in the closure and disposal of several operations over the past five years. While in volume terms it is now outside the top 10, it remains one of the market leaders in value terms. The industry is estimated to use over 3 mln tons of polymer, accounting for around 8% of total European demand for thermoplastics. The gravity pipe sector is by far the largest in terms of both volume and value accounting for more than 70% of the total demand for plastics pipes in Europe. PVC is the main material used in gravity pipes although it is expected that its share of the market will decline slowly as PE and PP systems penetrate the market. The building cycle is also expected to take a strong downward turn in the face of the global “credit crunch” and a slowing of European economic growth which will further impact on demand for PVC gravity pipes. Polyethylene gravity pipe is expected to benefit from investment in storm water and road drainage with twin wall pipes making progress against concrete in the larger diameter sector. The cable protection sector is extremely volatile because of fluctuations in telecom and cable network investments but remains an important segment of the market. For pressure pipes the main plastic material used is polyethylene (PE 80 and PE 100). Growth has largely been driven by the replacement of metal pipes (ductile iron for water pressure, copper and steel for hot and cold plumbing) and PVC. There has been particularly strong growth in PE 100 systems. In water pressure pipes, it has made gains at the expense of ductile iron but has also replaced some PE 80 systems. The market for gas pressure pipes tends to fluctuate significantly from year to year depending on the investment plans of the gas providers. In hot and cold water plumbing and heating applications the main polymer material used is cross-linked polyethylene (PEX) although recent years has seen considerable growth in the use of multilayer composite pipes of PEX/aluminum or raised temperature polyethylene (PE-RT)/aluminum.