HDPE pipe is a flexible plastic pipe made of thermoplastic high-density polyethylene widely used for low-temperature fluid and gas transfer. In recent times, HDPE pipes got their extensive uses for carrying potable water, hazardous wastes, various gases, slurry, firewater, stormwater, etc. The strong molecular bond of HDPE pipe materials helps it to use for high-pressure pipelines. Polyethylene pipes have a long and distinguished service history for the gas, oil, mining, water, and other industries. Due to its low weight and high corrosion resistance, the HDPE pipe industry is growing tremendously. In the year 1953, Karl Ziegler and Erhard Holzkamp discovered high-density polyethene (HDPE). HDPE pipes can work satisfactorily in a wide temperature range of -2200 F to +1800 F. However, the use of HDPE Pipes is not suggested when the fluid temperature exceeds 1220 F (500 C).
HDPE pipes are made by the polymerization of ethylene, a by-product of oil. Various additives (stabilizers, fillers, plasticizers, softeners, lubricants, colorants, flame retardants, blowing agents, crosslinking agents, ultraviolet degradable additives, etc.) are added to produce the final HDPE pipe and components. HDPE pipe lengths are made by heating the HDPE resin. It is then extruded through a die, which determines the diameter of the pipeline. The Pipe wall thickness is determined by a combination of the die size, speed of the screw, and the speed of the haul-off tractor. Usually, 3-5% carbon black is added to HDPE to make it UV resistant, which turns HDPE pipes into the black in color. Other color variants are available but usually not used frequently. Coloured or striped HDPE pipe is usually 90-95% black material, where a colored stripe is provided on 5% of the outside surface.
Properties of HDPE Pipes
The physical and mechanical properties of a typical HDPE Pipe is listed below:
Governing Codes: ISO 1183, ISO 4427, AS/ NZS 4130, BS EN 12201, EN 12056, AWWA C901, AWWA C906, etc
Available size range: DN 16 to 1600 (However, other customized sizes can be manufactured)
The density of HDPE Pipe: 930-970 kg/m3
Typical Mechanical Properties of HDPE Pipe are given in Table-1 below. However, these values vary from one manufacturer to another. So, must be consulted with the manufacturer.
The HDPE pipe fittings can be performed in several ways as described below. It should be noted that based on the type of the fittings included in the specifications of the design one should do pipe fittings in different parts of the plan. HDPE pipes are usually produced with two simple ends. Therefore, in order to establish a connection between the two branches, it is necessary to connect one simple end of a branch to the other simple end with a connection to each other. The various methods used to connect HDPE pipes, accessories and valves, are as follows:
1- Thermal Butt (HDPE Butt Fusion Fittings)
2- Thermal bushing
3- Electro Fusion(HDPE Electrofusion Fittings)
7- Rubber gasket latching
It should be explained that all of the above methods are currently not applicable due to the lack of production of the necessary supplies in the country, but the explanations needed to use them, if produced, are given. The consultant engineer will determine the pipe connection method according to the facilities available at the time of work in the specifications of the design. At the moment, the butt thermal connection is used for the main projects of HDPE piping and the flange connection is used for special fittings. The contractor is required to provide arrangements, and qualified personnel for any method specified in the layout specifications, and, accordingly, proceed with the connection.
What is UPVC?
UPVC Pipe Fittings stand for Unplasticized polyvinyl chloride. Due to its strong resistance to chemicals, and elements of nature, UPVC makes an ideal choice for residential and commercial plumbing constructions. It also includes UPVC Gasketed Fittings and UPVC Solvent Weld Fittings.