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Home : Products : HDPE Introduction
 General properties of Polypropylene:
For nearly 50 years, polyethylene (PE) has been used to transport fluids. Its ability to withstand harsh chemicals without corrosion and leak as well as the tight installation, polyethylene (PE) has been regarded as the ideal material for the gas industry. Additionally, PE joints offer leak-free connections which outperform other competing materials in terms of reliability and longevity, not to mention the remarkable savings on the installation costs and life of the materials. Improvements in the strength and performance of PE materials has resulted in water, chemical & several other industry needing solutions for liquid and gas transfer to adopt PE for its pressure transmission networks.
Polyethylene (PE) belongs is a thermoplastic from the polyolefin group. Polyethylene is the best known volume plastic a relatively high molecular form, with medium to high density, has established itself in the piping systems industry.

The most wide spread use of Polyethylene is for buried gas and water pipe lines. The polyethylene we manufacture has been effectively stabilized with carbon against UV radiation effects. The stabilization also serves to counteract heat fatigue, thus increasing life
It shows superior impact strength as compared with PVC. PP is normally available in grey color and its high rigidity makes visually pleasing pipe layouts possible and the lower coefficient expansion makes installation easier.

Polyethylene consists of long molecular chains (macromolecules).  These molecules may be branched and the degree of such branching and the length of side chains have important effect on the properties of polyethylene.  Polyethylene crystallizes as the melt cools.  Parts of the long molecular chains arrange themselves by folding into very small crystallites which are joined together by amorphous regions to form macrostructures knows as spherulites.  The shorter the chains and lesser the branching, the better the process of crystallization. The crystalline region has a higher density than the amorphous region and therefore different density values are obtained depending on the degree of crystallinity.

The three basic popular available type of PE are HDPE, MDPE and LDPE.   LDPE grades have a very minimal role in pipe production and HDPE remains the dominant player in pipe manufacture.  The Properties of polyethylene are primarily determined by density, molecular weight distribution.  With increasing density (higher crystallinity), the following properties also increase:  Yield Stress (tensile Strength), Modulus of Elasticity (Rigidity), Hardness, Solvent Resistance, Impermeability to gases and vapors.    On the other hand, impact strength, transparency and stress cracking resistance decrease with increasing density.
  Density o of Crystanllinity
HDPE 0.940 to 0.965 g/cm3 60-80%
MDPE 0.930 to 0.940 g/cm3 50-60%
LDPE 0.915 to 0.930 g/cm3 35-50%
 Features and Advantages of use vs. other materials:

Elastic Suitable



Elastic Suitable for underground pipes through adjustment to local ground movement   Impact-resistant and tough Unbreakable

Thermal resistant


Smooth internal wall

Thermal resistant
Application possible between -40°C and 100°C
  Smooth internal wall
Low blockage risk due to low deposit/residue effects

Weather-resistant/UV resistant


Wear resistant

Weather-resistant/UV resistant
Application in open air unrestricted through colouring with carbon black
  Wear resistant
Lower cost due to relative long life



Chemical resistant

Non conductive
  Chemical resistant
Suitable for transport of polluted waste water

Poor heat conductivity



Poor heat conductivity
No condensation possible during short periods of cooling
Environmental friendly

Highly suitable for welding


Homogeneous welded

Highly suitable for welding
Easy installation using butt-welding and electro fusion techniques
  Homogeneous welded joints
Pull tight and leak proof



Light in weight

Fast and cost-saving installation
  Light in weight
Cost saving in transport and handling
 Advantages Of Use :
arrow bullet Long track record of excellent performance, approaching 50 years worldwide
arrow bullet High impact and breakage resistance
arrow bullet High resistance to chemicals, corrosion, decaying and abrasion.
arrow bullet Higher durability & advantage of easy installation and transport without material loss.
arrow bullet High resistance to direct sunlight (UV resistance for long time from UV resistance agent included in the manufacturing process).
arrow bullet High Stress Crack Resistance prevents inching growth of cracks.
arrow bullet Lesser fittings for connection due to higher elasticity: PE pipes are bendable with a radius of approx. 20-25 times of its outer diameter.  Excellent elasticity resulting in installation ease. Coils can be made upto 110 mm Dia in several hundred metres long - resulting in lesser joints.
arrow bullet Lesser vulnerability from earth movements like landslide, earthquakes , etc.
arrow bullet Availability of different pressure resistance option: PE pipes can be produced resistant to 12 different pressure class from 2.5 bar up to 32 bar.
arrow bullet Perfect leak proof joints possible - no cracks - no breaks and no deformation.
arrow bullet Advantage of safe application in irregular surfaces like sea, river passages, low temp terrain.
arrow bullet Availability of several connection methods (butt welding. electro fusion, push fit etc.)
arrow bullet Smooth internal surface brings considerable savings in the service and overall line costs.
arrow bullet Very long service life under severe conditions.
arrow bullet Light in weight enabling high speed movement & installation.
arrow bullet Non Toxic, Food Grade can also be used in food and pharma industry.
Corrosion resistance: PE is basically chemically inert. This pipe system does not rust and corrode. This system resists chemical attack from aggressive soils. There is no need for protective layer or finishing process.
Leak tight: Butt fused joints create a homogenous system. The fusion weld for this system is very strong. Therefore, unlike ring type joints or the other mechanical jointing systems, there is no risk of leakage resulting from joint distortion.
Optimum flow rate: Smooth inside pipe surface allows for a high Hazen-Williams “c” factor. “c” remains constant throughout the lifetime of the system due to an innate high resistance to scale and biological build up. Polyethylene (PE) is also biologically inert.
Excellent water hammer characteristics to withstand surges: The inherent properties of polyethylene allow the system to significantly lower the effect of surges compared to PVC and ductile iron systems.
Flexibility: PE pipes can be coiled and supplied in length of up to 300m for small diameter pipes. This feature is one of the many contributions to cost savings during the installation process.
Resistance to geological conditions: PE piping systems have inherent resistance to ground temperature fluctuations and earth instability.
High strain allowed virtually eliminated failure due to freezing pipes.
Reduced installation costs.
Advantages Of  PE pipe vs Other pipes:
Properties PVC PE 100 D.IRON <GRP
Brittleness Properties Frail Very Resistanct Resistanct Partly Resistance
Maximum Produced Length (m) 6 500 6 6/12
Corrosion Resistance - Abrasion Resistance Partly Resistance Very Resistance Very Frail Frail
Hygienic Superiority Worrisome Excellent Worrisome Problematic
Wall Elasticity coeff. 33 377 1 < 33
Water Hammer Damping Ability * Problematic Excellent Problematic Problematic

Need for Trench Widening (%Pipe Diameter) More than 110% More than 5-10% More than 110% More than 200%
Bedding Necessity Around Pipe (Max:100, Min:0) 100 10 60 100
Adaptation to Ground Movement No Adapts No No
Branching Possibility Very Difficult Very Easy Difficult Difficult
  PE100,ND 140,Din=123.4mm PVC,ND140in=126.6mm Steel&Cast-lron ,Din=123.4
  a/g Pmax Pop Pmin a/g Pmax Pop Pmin a/g Pmax Pop Pmin
M/S Sec. bar Bar bar Sec bar bar bar Sec. Bar bar bar
  13,4              38,7       128,4      
1      11,34 10,0 8,66    13,88 10,0 6,12    22,85 10,0 -2,85
2    12,68 10,0 7,32    7,75 10,0 2,25     35,69 10,0 -15,7
3    14,03 10,0 5,97    21,63 10,0 -1,62     48,54 10,0 -28,5

(A) Velocity of pressure wave in pipe depends on EP&EW.
(g) Acceleration due to gravity.

for Example:
At 10 bar and 3m/s water velocity,due to water impacts,there is a 40% pressure increase on PE100 pipes,while on PVC 116%,steel&cast iron pipe there is a 385%
Pressure increase.Taking into account water impact:
pipes with low wall elasticity coefficient either will be designed with higher pressure than the operating pressure ,or if it is till a certain degree pressure-resistant,it should be operated at quite low operating pressure.