The Drakenstein local municipality in Paarl, Western Cape, has begun a 20-year master plan to replace old or ageing asbestos pipes in the region with high-density polyethylene (HDPE) pipes.
The upgrade will achieve significant success in reducing water loss throughout the municipal area, according to municipality’s water services senior engineer André Kowalewski.
Water leakage and non-revenue water have become two of the biggest problems facing South African municipalities in recent years.
Water losses enabled the municipality to delay the construction of reservoirs and large pipelines for several years.
There was also a reported decrease in burst pipes. However, the reduction in residual pressures in various pressure zones had the most significant water-saving effect.
The municipality prioritised replacing 14.2 km of old asbestos pipes with new HDPE pipes, at a cost of R120-million.
Prior to embarking on the project, steel pipes and HDPE pipes were carefully compared. The municipality decided that HDPE pipes offer significantly more advantages and cost-saving benefits, especially when considering the life cycle of the HDPE pipe, which surpasses most other pipe materials.
HDPE pipes can also handle water pressure fluctuation and flow characteristics within the pipe design limits better than any other flexible system.
“If correctly designed, and with proper installation, together with the correct fittings, an HDPE system will provide the lowest maintenance compared with any other pipe material system,” Kowalewski confirms.
He adds that the most attractive advantage of HDPE is a system without pipe joints.
“We no longer have the issue of corrosion, failing joints or costly maintenance issues due to downtime, as most of the fittings used in HDPE systems are moulded out of polyethylene material.”
Tests and calculations performed on HDPE have shown the pipe material’s life span to run up to 100 years. In addition, HDPE is the most popular material to use when replacing pipes using trenchless construction methods, which means that downtime due to repairs is no longer an issue.
Read more about this topic at engineeringnews.co.za.
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