process feature | Sewerage and drainage pipe
moving products from the stocking area to the trench. Trucks find it very difficult, if not impossible, to access the working area. Using heavy machinery is very complicated, and there are difficulties in moving around the working area.
At the same time, narrow streets mean narrow
trenches, resulting in limited worker and machinery manoeuvrability. On top of this, the Ancienne Médina is a residential
area, and the main tourist area in Casablanca – so the streets are constantly crowded with people. This means that restrictions are limited: some streets are a mandatory route to reach certain areas, so cannot be blocked or cut off by construction work.
Compact PVC Ferroplast PVC pipes are manufactured according to the required Moroccan standard, NF P 16352. They are supplied in diameters up to 500mm, and delivered a number of advantages to the project. The main advantage of the plastic pipes, from a
A wide range of PVC fittings helped Ferroplast to work through many project obstacles
city centre of Casablanca. The first section (priority works) was established according to the needs set by the Urban Agency to cover the whole tourist circuit of the Médina.
Technical specifications The existing potable water supply network is nearly 20km in length. Most pipes (72%) are made of grey cast iron and date from the 1930s. Other pipe materials used include fibre cement, PVC and HDPE. The existing sewerage network is around 18km long. Most pipes are made of compressed concrete, and around 86% of them are more than 50 years old. The majority of both networks is old and ageing. Ferroplast offered Lydec complete renewal of the
sewerage network using plastic materials: compact PVC pipes; structured wall PE pipes; PVC fittings; and HDPE manholes. As well as the known benefits of using plastic
materials, choice of the materials was determined by: the fact that they were technically most suited; the ability to save costs and speed up installation time; and the fact they are environmentally friendly.
Main obstacles Of all the difficulties encountered during the project, the main one has been the lack of space for pipe installa- tion due to the narrow, winding streets. This affected three main activities: transport, installation and pedestrians. Regarding transport, there is great difficulty in
10 PIPE & PROFILE EXTRUSION | May/June 2012
logistical viewpoint, was their lightness. Their light weight makes them much easier to transport – and install – than heavier materials such as cast iron or concrete. This not only applies to the actual installation, but also to the stocking. At the same time, their flexibility helps them adapt to
possible earth movements, after installation. The smooth inner walls result in higher flow rates,
and better washing away of solid particles. This allows for smaller slopes – and so lower excavation costs. The smoothness of the walls means they are not damaged by solid particles transported in water, which helps to extend service life.
Other benefits include: water tightness – in either
direction; chemical resistance; and impact resistance, even at low temperature. On top of this, PVC has a calculated residual lifetime
of 50 years, with some studies indicating over 100 years. If properly installed and operated, it will even exceed this. The polyethylene pipes, made according to European
standard EN 13476, are supplied in diameters up to 1000mm. The advantages of using these types of pipes are similar to those of PVC. Their lightness makes them easy to manipulate, so
there is less need for human or machinery resources compared to other materials. Their flexibility helps them to withstand severe deformation, making them ideal for installation in ground that is uneven, or that is subject to frequent movement. A wide range of PVC fittings also helped Ferroplast
to work through the project obstacles and difficulties. Mechanical saddles, for example, make connections
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