PVC PIPES AND FITTINGS

The pipe market is the biggest user of PVC resin in South Africa. There are currently four major producers of PVC in the market, who between them are responsible for 60 % of the pipes being sold in the country. 78 000 tons of PVC pipe has entered the South African market. Of this, the vast majority (72%) is for pressure applications, and only 28% for non-pressure.

The benefits of using PVC pipes are numerous and include:

• Long-lasting, practical and affordable: PVC pipes have a proven performance record of over 50 years (with some studies showing the life expectancy of PVC pipes to be over 100 years). PVC pipes have a proven track record of excellent long-term performance and offer extended, trouble free service life.

• Lower cost and quicker Installation time: PVC pipes offer significant cost savings for projects, even more so when installation, low breakage rates and life cycle costs are taken into consideration. The longevity of PVC pipes also means the pipes function more efficiently, reducing maintenance and ongoing work to the pipe making it more affordable over time. Compared to steel and concrete, plastic pipes are well-suited to labour intensive construction techniques because they are lighter and easier to handle. There are no concerns about costly cathodic protection requirements when using plastic pipes.

• Installing PVC pipes is on average: 30% faster than when installing the same size concrete pipe.

• Sustainability: Sustainability and promoting a circular economy are two of the key benefits of PVC pipes. Multi-layered PVC pipe systems allow manufacturers to reuse post-consumer and own-inhouse recycled material in specific applications. In addition to their lower environmental impact, multi-layer sewer PVC pipes also have the required properties to design life.

• Resistant to corrosion: Corrosion is one of the biggest issues with sewers that can render them structurally unsound and no longer watertight. Traditionally, high-pressure pipelines were made from steel with coatings bonded to the steel pipe in order to protect them. On the other hand, sewers that were gravity pipelines of 300mm and larger in diameter were traditionally made from concrete. Under certain combinations of hydraulic performance and the effluent being conveyed, these traditional sewers systems are subject to biogenic corrosion due to the formation of hydrogen sulphide within the effluent and its subsequent release into the sewer atmosphere, where it is biologically converted into sulphuric acid. The latter then attacks the alkalinity of the pipe, causing it to deteriorate. Rehabilitating these pipelines with PVC plastic linings designed to resist the groundwater pressure that developed between the host pipe and liner present a long-lasting solution with a design life of 100 years or more.

• Resistant to chemicals: PVC pipes exhibit excellent resistance to a wide range of chemical reagents and disinfectant chemicals. With low risk of materials eating through the pipe, PVC pipes are highly suitable for most water infrastructure projects as they can convey most strong acids, alkalis and aqueous solutions (except those which are strongly oxidising), aliphatic hydrocarbons, fluorides, photographic and plating solutions, brine, mineral oils, fats and alcohols.

• Reduced failures and blockages in wastewater pipelines: A major concern within any pipeline system is pipe blockages, a costly and complicated problem that can cause untold damage and hours of repairs. Slow flowing water through a pipeline creates more opportunity for potential blockages and failures in a system with many connections. The extremely smooth lining of PVC pipe – when compared to a copper, clay or concrete pipe – reduces water flow resistance and ensures that water reaches its intended destination with proper pressure. PVC piping allows water to flow freely and maximises water pressure. The increase flow of PVC pipes also prevents build up in sewage and wastewater systems.

• High flow rates for water transfer: The ultra-smooth surface of PVC pipes reduces pumping costs in water supply pipelines and outperforms alternative materials in performance and cost effectiveness. The smooth bore allows high flow rates and reduces the potential for blockage and failures.

• Leak free joints: Water loss is eliminated thanks to PVC pipes having leak-free joints. Older technology and other pipe materials could result in up to 40 % water loss as a result of leaks.

• Flexible: PVC pipes are extremely flexible and can flex without breaking when loaded externally from soil weight and heavy-duty traffic. Rigid pipes, such as those made of concrete, clay or ceramic are unable to flex when loaded and will experience wall crushing and collapse when their load limit is reached.