HDPE Benefits
HDPE pipes are made from HD-PE100 (acc. to DIN16961, EN13476, ASTM F894, ISO9969 etc.) and are produced with an integrated electro - fusion joint socket and spigot. The pipe is helically extruded with profiles or solid wall, tailor made for any kind of application within the standards. The pipes have no welding seams or any weak points and are solid when made from new, high-density PE100. There is no recycled or mixed material used when manufacturing the pipe. Proper manufacturing assures a service cycle of 100 years.
The electro - fusion jointing system according to the DVS Rules assures a homogenous, leak-free and flexible pipe system, without any weak points on the joints. The electro fusion welding process is an optimized process to be used directly in trenches with very quick welding time. The effect is that the pipe system in the soil is flexible even under heavy loads or seismic movements and will not develop cracks, breaks or displacement. The pipe system will continue to provide service and will not break!
The pipes are also lightweight and can be adjusted for any kind of internal and/or outer pressure. This is a cost savings in avoiding the use of over designed pipes.
The pipe system will provide service for more than 100 years without any leakage, break, cracks or displacement. The material is UV resistant and also very environmentally friendly.
HDPE will not leak: It prevents pollution of the environment.
HDPE material does not interact chemically with the soil, so it’s absolutely environmentally friendly and can be 100% recycled.
Bacteria and other organisms cannot get a foothold on the pipe due to its smooth inner surface.
The bright color of the inner surface makes the pipe system inspection-friendly.
No heavy - lifting equipment is needed to install the pipes, lifting with simple excavators is possible. In a bigger city, it is no longer necessary to close all lanes of the road for the pipe installation work.
Quick installation, as you have seen at job sites will reduce the costs of construction significantly.
Under normal use an HDPE pipe system should be leak free for 100 years!
BENEFITS (Wikipedia)
Due to the fusion welded system, the need for anchors or thrust restraint blocks are eliminated, as the joints become fully end load resistant, reducing costs for material and installation time. This also allows for safer excavation close to the pipeline in future, which is particularly important for high pressure gas pipelines. Coils of PE Pipe make trench-less installation safer and less intrusive on the surrounding environment.
HDPE Pipe Systems are available for many applications, providing for standard trenching of water mains, fire ring mains, sewer mains, and gas mains pipelines, as well as horizontal drilling for electrical and telecommunications conduits. According to a company that manufactures HDPE, HDPE systems are cost-effective to install and have long-term maintenance cost savings, and also allow for cheaper installation methods, such as HDD (horizontal directional drilling), sliplining, pipe bursting, floating and submerged pipe.
HDPE pipe is very durable and flexible and can be bent on site to a radius twenty-five times the nominal pipe diameter - for SDR11 and SDR17 pipe, at or below 20°C ambient temperature. This provides major cost savings, when compared to different pipe systems, some of which require glued fittings, restraints or thrust blocks for even minor changes in direction. Because of the high impact resistance and flexibility of HDPE pipe, it is well suited to installation in dynamic soils including in earthquake-prone areas. HDPE pipe has very high flow capacity, because of its smooth bore and end-to-end jointing methods. HDPE pipe does not corrode in the environment, and will maintain its flow capabilities over time, unlike ferrous piping systems, which will rust and build up internal resistance to fluid flowing through it.
Because food-grade polyethylene virgin material is used to fabricate HDPE pipes, they are safe for the transfer of potable water, provided that any initial debris has been flushed out. HDPE pipe is resistant to many chemicals, facilitating its use in process plants or around corrosive or acidic environments, without needing to use protective coatings or galvanising, as is required on steel pipes. As HDPE has a very low thermal conductivity, it can maintain more uniform temperatures compared to metal pipes, when carrying fluids, which will greatly reduce any need for insulation to control condensation around the pipeline.
Manufacture
To make pipe lengths, HDPE resin is heated and extruded through a die, which determines the diameter of the pipeline. The wall thickness of the pipe is determined by a combination of the size of the die, speed of the screw and the speed of the haul-off tractor. Polyethylene pipe is usually black in color due to the addition of 3-5% of carbon black being added to the clear polyethylene material. The addition of carbon black creates a product which is UV resistant. Other colours are available but are less common. Coloured or striped HDPE pipe is usually 90-95% black material, with just a coloured skin or stripe on the outside 5%.
The following shows the process for HDPE Pipe Extrusion:
Polyethylene raw material is pulled from a silo, into the hopper dryer, which removes any moisture from the pellets. Then it is pulled by a vacuum pump into the blender, where it is heated by a barrel heater. The PE material becomes molten at around 180 °C (356 °F), allowing it to be fed through a mould/die, which shapes the molten material into a circular shape. After coming through the die, the newly formed pipe quickly enters the cooling tanks, which submerge or spray water at the pipe exterior, each one reducing the temperature of the pipe by 10-20 degrees. Because polyethylene has a high specific heat capacity, the pipe must be cooled in stages, to avoid deforming the shape, and by the time it reaches the "haul-off tractor," it is hard enough to be gently pulled by the 2-3 belts. A digital or powder printer, the size, type, date and manufacturers name is printed on the side of the pipe. It is then cut by a saw cutter, either into lengths of 3 or 6 or 12 or 24 meters (9.8 or 19.7 or 39.4 or 78.7 ft), or it is coiled to 50 or 100 or 200 m (164 or 328 or 656 ft) lengths on a coiler.
A different die is used for striped HDPE pipe, which has small channels that the coloured material runs through, just before it is pushed through the die. This means the stripes are formed as an integral part of the pipe and are not likely to separate from the main pipe body. Co-extruded, or co-ex HDPE pipe, has a second extrusion screw which adds an extra skin of colour around the black HDPE pipe, this allows the pipe to be coloured on the outside, for identification or thermal cooling requirements.
Although HDPE pipe is often estimated to last 50 years, they are in fact more likely to have life expectancies of 100 years. PIPA (Plastics Industry Pipe Association) and the Plastic Pipe Institute (PPI) have written technical white papers on HDPE design life. The PIPA paper is called "Life Expectancy for Plastics Pipes" which mentions that because of the fifty-year stress regression data, people falsely assume that plastic pipe systems' life expectancy is only fifty years. In fact, these pipe systems can be reasonably expected to last up to or more than 100 years. In Australia, PE pipes and PE fittings were introduced during the mid-1900s, mainly for irrigation or water supply, but also for gas, fuel, and other industrial applications. The use of this 50-year time interval, leads to a misunderstanding that it represents a 50-year pipe life. For pipe systems that have been correctly manufactured and installed, the actual life cannot be predicted, but can be expected to be over 100 years until major rehabilitation is needed..