SewerPlex

The co-efficient thermal linear expansion of polyethylene varies with temperature but at ambient 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 re-rate 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)

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

The PE100 polyethylene resin used in POLIplex pipes and fittings are pre-compounded, either black or coloured with pigment, complying with AS/NZS 4131. Anti-oxidants are used to inhibit oxidation of the polymer at the compounding stage and during subsequent processing.

Carbon black is used in all black POLIplex pipe at a concentration of 2.25 ± 0.25% by mass as an ultra violet radiation absorber.

In natural and coloured POLIplex materials, hindered amine light stabiliser (HALS), ultra violet absorber. is used in lieu of carbon black.

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 although aromatic and chlorinated solvents will cause some swelling. Polyethylene is affected by strongly oxidising substances such as halogens and concentrated inorganic acids. POLIplex® 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.

View the Iplex Chemical Resistant Tool

SewerPlex is manufactured to AS/NZS 4130 from resin compounds complying with AS/NZS 4131 and are StandardsMark licensed to AS/NZS 4130 by third-party certifier SAI Global.

View Iplex Product Certifications

Poliplex pipes are co-extruded with a black external skin (with grey stripes) and natural (cream) internal surface.

SewerPlex pipe and fittings are joined using the electrofusion process. Iplex offer a full range of SewerPlex fittings:

• Couplings
• Caps
• Sweep junction
• Sweep Bends
• Puddle Flanges
• Backdrops
• Maintenance Shaft Drops
• Saddles
• Sediment Traps

Sewerplex Range and Pipe Dimensions

Iplex has published verified Environmental Product Declaration (EPD) on our range of Polyethylene pipes. 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.

View Iplex's Poliplex® polyethylene pipe EPD