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Iplex Millennium® is a high stress crack resistant (HSCR) grade of PE100 pipe that provides up to ten times greater resistance to slow crack growth than conventional PE100 pipe. It has the same pressure burst strength of conventional PE100 pipe, but is specifically formulated for use in critical or high value pipeline assets where the risk of premature failure from slow crack growth is possible. Iplex Millennium® provides designers with the opportunity to increase the pipeline’s service life without increasing the wall thickness, providing a safer option and ‘peace of mind’ for the project engineer/system owner.

Millennium 1


Millennium® pipes are used to convey all types of liquids and gases for above and below ground applications including:

  • Urban water and gas supply

  • Irrigation supply

  • Vacuum, pressure and gravity sewer systems

  • Submarine pipelines and ocean outfalls

  • Trenchless pipeline installation and rehabilitation

  • Industrial process pipe work

  • Upstream coal seam gas and water pipelines

Millennium® PE100 HSCR Technical Guide


Iplex’s Millennium® performance provides greater confidence to the designer, constructor and owner of polyethylene pipelines installed with trenchless technologies.


Features Benefits
Reduced wall thickness Compared to the conventional trenchless design factor approach that is commonly applied to compensate for potential surface damage, Iplex Millennium® pipe can be confidently used in the SDR determined by pressure and temperature factors alone. With thinner walled Millennium® pipe, substantial installation and pump energy costs can be realised.
Installation cost savings The high stress crack resistance of Iplex’s Millennium® pipe allows the use of excavated soil, eliminating the need to import granular embedment in open trench applications. This can save a contractor up to 20% of the pipeline construction costs.
Increased service life expectation Iplex’s Millennium® pipe can easily achieve an anticipated service life of 100 years due to its greater tolerance of surface damage. This is a substantial benefit to pipeline owners who are required to make accounting provisions for the replacement of assets.
Safer gas pipelines In gas networks where ‘squeeze-off’ is used to manage pipeline flows for planned or emergency maintenance, Iplex’s Millennium® pipe increases resistance to the initiation of slow crack growth wherever these stress concentrators are present, leading to a longer service life and enhanced network dependability.
Material Options

Material Options

Mechanical Properties
Property Value & Unit
Density (Specific Gravity) 955kg/m2
Yield Strain 10%
Yield Stress 25MPa
Compressive Strength 32MPa
Tensile Modulus 900MPa
Hardness Shore D 63
Poisson’s Ratio 0.4
Ring bending modulus (3 mins) 950MPa
Ring bending modulus (50 yrs) 260MPa
Thermal Properties
Property Value & Unit
Coefficient of Thermal Expansion 1.8 x 10-4/°C
Thermal Conductivity 0.38W/m.K

Typical Fire Resistance Properties

Property Value & Unit
Ignitability 13
Smoke Development 3
Spread of Flame 7
Heat Evolved 6
Temperature Effect On Pressure Rating

The co-efficient thermal linear expansion of polyethylene varies with temperatures but at ambient temperatures, lies in the range 1.2 to 2.4 x 10-4 per degree C. In broad terms, this is about twenty times that of steel and therefore unrestrained pipe will expand or contract much more than the steel structure that may be supporting it.

Should the pipe be fully restrained, the strain due to thermal change will generate stress in the material. However due to the relatively low tensile deformation modulus of polyethylene and assuming a typical ambient temperature fluctuation of less than 40°C, it can be assumed that the safe allowable stress will not be exceeded. Over the longer term, stress relaxation will increase the ability of polyeth­ylene to accommodate high thermal strains.

The conductivity of polyethylene varies with temperature almost linearly and is typically 0.47 W/m.K at 0°C to 0.37W/m.K at 70°C.

The specific heat of polyethylene varies with temperature from 1800 Joules/kg.K at 0°C to 2200J/kg.K at 60°C.

All temperatures above 25°C, it is necessary to rerate polyethylene pressure pipe systems. The table below provides guidance as to the maximum operating pressure of PE100 pipes at temperature. It should be noted that at constant temperatures greater than 40°C, the 50-year design life of POLlplex® pipes may be reduced.

Thermal rerating of PE100 polyethylene POLIplex® pipe

Maximum allowable operating pressure - PE100 Water pipe (m head)

Temp°C PN4 PN6.3 PN8 PN10 PN12.5 PN16 PN20 PN25
20 40 63 80 100 125 160 200 250
25 36 58 73 91 115 145 182 227
30 36 58 73 91 115 145 182 227
35 33 53 67 83 106 133 167 208
40 33 53 67 83 106 133 167 208
45 (35 y)* 31 49 62 77 99 123 154 192
50 (22 y)* 29 46 57 71 91 114 143 179
55 (15 y)* 29 46 57 71 91 114 143 179
60 (7 y)* 27 43 53 67 85 107 133 167
80 (1 y)* 20 32 40 50 63 80 100 125

i. The values tabled are for POLlplex® pipe manufactured to AS/NZS 4130 and fittings made from compounds complying with AS/NZS 4131.

ii. The times given in years as (35y) are allowable extrapolation limits obtained by applying the factors in Table 1 of ISO 9080 to two years of test data at 80°C. Where appropriate, specific advice should be obtained from the manufacturer and data provided shall be derived from testing to ISO 9080.


Comparison of Conventional PE100 to Millennium®’s Performance

Iplex’s Millennium®'s performance is identical to conventional PE100 pipe with the exception of Slow Crack Growth (SCG) resistance. Having independent testing, Millennium® has demonstrated 10 times greater time to failure due to SCG than that which is required of conventional PE100 pipes.

  Conventional PE100 Pipe Performance Iplex’s Millennium®
50 Year MRS @ 20°C 10MPa 10MPa
Hoop Strength 5.4 MPa @ 80°C 165h 165h
Hoop Strength 5.0 MPa @ 80°C 1,000 h 1,000 h
Strain at Yield 10% 10%
Elongation at Break ≥ 350% ≥ 350%
Slow Crack Growth (NPT/ ISO 13479) ≥ 500 h ≥ 5,000 h
Chemical Resistance

Polyethylene is a polyolefin resin. In chemical terms: a non-polar high molecular weight paraffin of the hydrocarbon family. Hence it is very resistant to (non-oxidising) strong acids, strong bases and salts. It is mildly affected by aliphatic solvents, aromatic and chlorinated solvents will cause some swelling. Polyethylene is affected by strongly oxidising substances such as halogens and concentrated inorganic acids. POLlplex® pressure pipes should not be used to convey water disinfected with chlorine dioxide at any temperature which has been found to rapidly deplete the antioxidant additives at elevated temperature. A full Chemical Resistance Library can be viewed on lplex's website

View the Iplex Chemical Resistant Tool

Product Details

Product Details

Standards and Approvals

In Australian pressure applications, polyethylene pipe is covered by AS/NZS 4130 and material Standard AS/NZS 4131. Iplex Millennium® conforms in all respects with AS/NZS 4130. The Plastics Industry Pipe Association of Australia (PIPA) have published guideline POP016 (High Stress Crack Resistant PE100) outlining the four tests which polyethylene compounds must meet to be defined as PE100 HSCR. A copy of this guideline can be downloaded from the PIPA website

Iplex Millennium® has also been appraised by Water Services Association of Australian (WSAA) - Product Appraisal Report 1610.

View Iplex Product Certifications

Colour and Markings

Iplex Millennium® pipes are colour coded as per AS/NZS 4130 to easily distinguish between the different types of pipes applications Millennium® pipes can be manufactured all black, with stripes and external coloured jackets.

Millennium® PE100 pipe colour identification

Product Application
Millennium® PE100 Black  
Millennium® PE100 Blueline Drinking water
Millennium® PE100 Purple Stripe Recycled water
Millennium® PE100 Cream Stripe Sewerage
Millennium® PE100 Yellow Stripe Gas
Environmental Credentials

Iplex Pipelines has published verified Environmental Product Declarations (EPD) on our range of polyethylene pipes, including Iplex Millennium®.

EPD’s are third-party certified documents based on ISO 14025 and EN 15804 Standards that communicate transparent and comparable information about the life-cycle environmental impact of a product or service. Specifically, product declarations include information on the environmental impact of raw material acquisition, energy use and efficiency, composition of materials and chemical substances, emissions to air, soil and water and waste generation.

Most importantly, EPD®’s are of great assistance to our customers; the builders and developers seeking to construct environmentally responsible infrastructure, because EPD®’s present key environmental product performance data in a uniform format that facilitates comparison between alternate materials.

Access to the Iplex Polyethylene Pipe EPD® provides constructors, operators and owners with the evidence they require to claim credit points under the Green Building Council of Australia and the Infrastructure Sustainability Council of Australia’s rating systems.

View Iplex's POLIplex® polyethylene pipe EPD

Millennium® Pipe Range and Dimensions

Millennium® HSCR PE100 pipes are available from DN16 – DN1200

Iplex using POLIplex® Series 1 - Pressure Pipe Dimensions Table


Millennium® Pipeline Design – Allowance for External Damage
Millennium® Pipeline Design – Design Stress Concentration and Slow Crack Growth
Millennium® Pipeline Design – Expert Opinion
Installation & Testing

Installation & Testing

Millennium® Installation & Testing Applications Benefited by Millennium® Pipe

Enquire about Millennium®