The first PVC pipes were introduced in the 1930’s for use in sanitary drainage systems. Polyethylene was developed in 1933 and one of its first applications was cable protection for radar insulation during WW2.
The 1950’s saw the first pressurised plastic drinking water pipes installed in the Netherlands and production of the first plastic valve. Polyethylene was used to create ducting pipes for insulation followed by the first use of the extrusion method in manufacture of HDPE to create drainage pipes in the UK.
During the 1960’s rain water pipes, guttering and down pipes using plastic materials were introduced into the housing development market. PVC soil systems were launched and the introduction of ring seals increased the use of plastic sewerage pipes. After the first British Standard was launched for soil systems, local authorities started to specify PVC systems.
By 1970 plastics in above ground drainage accounted for 50% market share, while plastic rainwater systems accounted for over 60% of new installations. The 1970’s also saw the introduction of plastic pipes being used in highway drainage, the introduction of plastic cable ducts and the introduction of the first yellow HDPE pressure pipe for gas supply introduced in conjunction with British Gas. This required development of a yellow pigmented product. There was rapid growth of Polyethylene used by the water and gas industries and the use of CPVC in hot and cold plumbing systems was launched.
The 1980’s saw the introduction of HDPE pressure pipes for water and the use of blue pigmented MDPE material for potable water for the UK water industry. A change in the manufacturing techniques of drainage pipes occurred and twinwall and multi-wall pipes were launched. The late 1980's saw the introduction of spirally wound pipes signifying a major advance in technology allowing bespoke pipes to be created and customised to individual requirements. Plastics began to increase their penetration of new markets including commercial buildings and multi-occupancy buildings up to 20 storeys. Polybutylene was chosen for the manufacture of push fit systems in hot and cold water plumbing. Polybutylene pipe was introduced in 1982 where its flexibility, speed of installation and resistance to bursting was ideal for the use in caravans.
In the 1990’s plastic plumbing pipework was first used in underfloor heating systems. The flexibility of plastic pipe systems manufactured from PB and PEX provides easy handling and installation for Underfloor Heating circuits. Growth in these systems benefited the use of flexible systems in main H&C water applications as well as Underfloor Heating. Throughout the 1990’s plastics manufacturers worked with housing developers to convert build practice from traditional copper to plastic. As products became more widely available through builders and plumbing merchants the uptake of the new plastic systems grew. The benefits of plastic plumbing systems are ideally suited to the new build market. Many utilities companies introduced and favoured the use of chemically modified PVC. The use of HDPE rainwater systems offered very high performance of products for high rise and commercial applications utilising fusion weld jointing.
During the early 2000’s engineered joists or I-beams were introduced into the New House Build market for intermediate floor constructions. I-beam joists cannot be notched at the top, which is the traditional route through floors for copper pipe. Therefore threading flexible plastic systems through these joists is a much easier installation practice on site. This change in practice stimulated rapid growth in use of plastics in the new housing market. In 2001, 7% of new domestic properties were built using plastic pipework for the hot and cold plumbing systems and by 2007, this had increased to 90%. The plastic pipe industry heavily invested in making plastic pipework products sustainable and reducing their carbon footprint. Soil systems with high acoustic performance properties were developed which increased their usage in multi-occupancy buildings where noise from sanitary installations needs to be kept to a minimum. Polyethylene became a major material of choice for many gas and water utilities worldwide for new lines and renovation.
In more recent years the cost benefits of using a plastic system have come to the fore as traditional metal raw material costs have escalated. The benefit of lower and more stable pricing, combined with reduced number of joints on site and reduced time to joint can deliver an overall reduction in installed cost of over 30% for the installation of a radiator central heating system. Plastic systems also have no scrap value so do not carry the same risk of theft as traditional copper systems. Flexible plastic plumbing systems are ideal for RMI applications as the pipe can be easily cabled around existing fixtures, floorboards do not need removing and furniture do not have to be moved. Plastic systems are therefore being adopted more and more for day to day H&C plumbing use.