Weholite Physical Properties

Weholite pipes are made from high density polyethylene – HDPE - and represent a significant contribution in the development of thermoplastic structured wall pipe systems.

In the design of water distribution systems, thermoplastic structured wall pipes represent an interesting alternative because of their excellent physical, hydraulic and mechanical properties. Manufactured from corrosion-resistant HDPE, Weholite pipes behave differently to traditional steel, ductile iron, concrete and other pipe systems.

Weholite pipe properties have many decisive benefits for piping systems, which include:

  • Light weight
  • Easy to Handle and Install
  • Impact Resistant
  • Durable
  • Superior Hydraulics Properties
  • Reliability
  • Fusion Welded Joints
  • Watertight Mechanical joints
  • Abrasion Resistant
  • Corrosion Resistant
  • Environmental Deterioration Resistant
  • Eliminating System Infiltration
  • Non-Toxic
  • Much lower carbon footprint
  • Environmental Friendly Production
  • UV-Resistant
  • 100-year design life when buried (60 years above ground in normal climatic conditions)
Light weight

Weholite is an excellent choice because of its light weight. Installation is quick and reliable, with the pipes easily transported to the jobsite, even in poor ground conditions. Light pipe materials have a distinct advantage for foundation work, because Weholite does not apply as much load to its bedding as do heavier pipe materials.

Low pipe weight reduces costs and shortens the installation time, and owing to light weight, Weholite pipes do not require heavy equipment for laying a pipeline or for unloading the pipes at the construction site.

Impact Resistant

Weholite is manufactured from HDPE which has a high resistance to impact at low temperatures, even down to -40°C. This means it will not sustain damage during handling or transportation when there are extremely adverse weather conditions.

Reliability & Durability

Weholite pipes have both outstanding reliability & durability. They offer a corrosion- free installation, have excellent chemical resistance and have superior abrasion- resistant qualities, compared to traditional pipe materials, which gives them both reliability and durability. These claims can be substantiated by the fact that PE pipes have been used extensively in the mining industry for many years. Installed correctly, PE pipework systems can provide an effective working life in excess of 100 years.

Weholite pipes are also resistant to changing atmospheric conditions and they can be installed and transported both in low (i.e., temperatures below freezing point) and high (i.e., hot tropical and desert temperature conditions) ambient temperatures. This reliability means that, Weholite pipes are used worldwide regardless of extreme climatic conditions.


Weholite pipes are suitable for gravity and low-pressure applications. The corrosive and abrasion resistant properties of HDPE provide a very durable pipe. Flow rates for Weholite can be calculated using Colebrook White formula, with a Roughness Coefficient (k s ) of 0.03 mm (Manning’s 0.009). Polyethylene does not readily bond with or adhere to other materials. Siltation and sliming do not occur in the way they do in traditional materials, and long-term flow characteristics remain constant.

Roughness Coefficient (Ks)

The Roughness Coefficient (k s ) for the Colebrook formula of 0.03mm and the Manning’s value (n) of 0.009 have been obtained by full scale field hydraulic measurements undertaken by the Independent Enterprise of Water Supply and Sewage, Civil Engineering Department of the Technical University Swietkzyska, Poland under the direction of Professor Andrezej Kuliczkowski, and separately, by The Hydro Research Centre at Cardiff University in South Wales. These test reports are available upon request.

Chemical Resistant

For all practical purposes, Weholite pipes are chemically inert within the normal range of use. They are resistant to most chemical compounds unlike pipes made of conventional pipe construction materials (e.g., metal and concrete) that easily corrode and age when carrying or exposed to corrosive substances.
The resistance, of course, of Weholite pipes to chemical compounds has like all structural material certain limits that are subject to temperature, liquid concentration and working pressure.
If there are any doubts about the chemical resistance properties of Weholite pipes, please contact us.

More information on the chemical resistance of PE is given in ISO 10358.

Abrasion Resistant

Weholite pipe material has the following abrasion resistant characteristics.
In the Darmstadt abrasion test (DIN v. 19534, part 2), samples of commonly used pipe materials are filled with a mixture of sand and water, and then subjected to a specified number of rocking cycles. The thickness of the abraded pipe material was measured at regular intervals during this test and the result indicates, in the case of polyethylene (PE) pipe materials, an exceptionally high abrasion resistance.
For example, on the graph 400,000 load cycles indicate 0.3mm of abraded material for PE pipes, whereas fibre glass reinforced pipe abraded material is 6-8 times higher. In general HDPE pipes are highly resistance to abrasion. This is because its molecular composition creates a “trampoline” response when impacted by tumbling aggregate such as grit and solids.

HDPE (High Density Polyethylene) has the highest resistance to abrasion of all of the pipe-manufacturing materials.

Micro-Organism Resistance

Weholite is resistant to all means of deterioration or destruction that exists in nature, from animals, fungi, bacteria and insects, to acidic soils, atmospheric corrosion, etc.

Physiologically Safe

Weholite pipe is physiologically safe when used for liquids or other food related products that are intended for either human or animal consumption. Weholite pipe has a smooth inner surface that neither absorbs chemicals from, nor dissipates contaminants to the contained liquids.

Temperature Range

Weholite can be used in extreme temperature ranges as stated below:

  • 80°C for short-term use
  • 45°C for long-term use
  • -40°C for long-term use

Carbon Credentials

Weholite can contribute significantly to a reduction in carbon footprint. This is due to the lightweight, which minimises transportation emissions. Furthermore, due to the ease of construction, there is a reduction in installation time and a substantial further reduction in carbon emissions.

Using Weholite Eliminates System Infiltration

Infiltration is defined as storm or groundwater that indirectly enters the system through cracks and failed joints in pipes, lateral connections and manholes. Infiltration is characterised by an increase in sewerage flow during rain events followed by a much slower return to average dry weather flow (AWDF). In areas of high groundwater, the ADWF may be constantly elevated due to this issue.

Infiltration is a major problem facing water authorities and local communities across East Africa. Costs run into millions of dollars in managing and treating unwanted water. Not only that, but when water moves, soil and sediment move with it; entering sewers and stormwater systems; which, can cause formation of voids and subsequent ground subsidence as well as surface damage to roads and pavements, not to mention flooding.


The raw material used in the manufactures of Weholite pipes and fittings contains at least 2% carbon black content, which has an outstanding resistance to ultra-violet radiation. The black colour has sacrificial UV stabilizers that absorb UV energy to protect the material from UV deterioration.

Weholite pipes can be stored or installed in the open and above ground and be exposed to continual UV radiation without aging or having any detrimental effect on its unprotected surface.

Besides UV stabilizers, Weholite pipe products have also been compounded with antioxidants and thermal stabilizers to protect them against deterioration from exposure to weathering effects.

Handling and Installation

Installing Weholite pipework is simple and easy. Important factors for installation are the lightweight of the pipe, ease of handling, transporting to the jobsite and method of installation. Longer pipe lengths speed up the installation time, reduce the number of joints and help reduce overall installation costs.

Case Studies

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