Metal Reinforced Polyethylene Pipes in China

Session 6B
2:40 pm

Wei Ruoqi, Beijing Research Institute of Chemical Industry Sinospec

China is the largest and the fastest growing country in sewage discharges. According to the statistic from the National Ministry of Construction, the total volume of Chinese sewage is more than 40 billion tons every year. At present, The total length of urban sewage pipes network is about 180 thousands km, and more than 60% of them were laid 1980s ago, they were mainly concrete pipe, cast iron pipes, ceramic pipes, and underdrains, etc. There are a large number of problems in these piping systems, such as overmuch pipe wall and joints leak, pipe damage and blockage, all of them have resulted in groundwater pollution. China’s capacity of dealing with sewage is still relatively low, the state-based pipe network facilities are not perfect. Therefore, the construction of urban network is an important task in China.

As bearing external pressure, structural wall pipes are largely used in large-diameter buried plastic drain sewage pipe in China. Because the domestic users want to save resin and get as higher ring stiffness as possible, so based on the application of the structure wall pipe, the metal-reinforced polyethylene pipes came into being. There are four main varieties of metal-reinforced polyethylene pipes: Steel-reinforced polyethylene spiral corrugated pipe, Polyethylene plastic-steel spirally enwound drained pipes, Buried pairs of flat-walled steel-plastic composite enwound drained pipes, Metal reinforced plastic drained pipes. Their main characteristics are as following: 1) High ring stiffness, 2) Saving material cost, 3) Good corrosion resistance. Their main joint styles are as following: 1) Heat-melt extrusion welding, 2) Electric heat-melt zone connection, 3) Stainless steel clamp-type flexible connection, 4) Heat shrinkable sleeve (zone) connection. Specifications of product are mainly between 200 ~ 3000mm, ring stiffness is between 4 ~ 16 k N/m2.

In recent years, metal-reinforced polyethylene pipes have been widely used and achieved success in major project in China. Application shows that pipes organically integrate steel pipe’s properties with plastic’s properties. As a combination of steel and plastic, besides retaining a lot of advantages of plastic pipes, for example reliable seal, long service life, excellent flexibility, good abrasion resistance, light weight and easy to install and so on, metal-reinforced polyethylene pipes have high stiffness and high strength.

Wei Ruoqi
National Test Center Director

Li Yu-e
Engineer (lab for testing plastic pipes and fittings)