TPi October 2011

plast ic pipes

Restraining flood damage with internal pipe joint

joints play a vital role in waterlogged applications and areas with cohesive soils. Also, the resin-coated internal metal components lead to corrosion- free systems. What’s more, no thrust blocks are required, which ultimately leads to additional savings in time and materials.” Durolok features an easy installation process that requires no additional tools to fit and tighten the restraint device. The internal restraint system eliminates the need for trained operators to fit the restraint device, and also removes the risk of human errors such as over- tightening the clamps and tie bars in traditional systems. The Durolok restraint joint system is manufactured and distributed exclusively in South Africa by DPI Plastics. The joints are available in sizes 110, 160 and 200mm, fitted to PVCU and PVCM pipes conforming to the SANS 966 part 1 and part 2 and SANS 791 specifications.

of pipelines, however, Durolok piping can be used in both temporary and permanent repairs, as the system does not rely on support from backfill or thrust blocks for the containment of end-thrust. The final result is considerable time savings in terms of the reinstatement of pipeline services, and the prevention of premature failure in future flooding events.” Mr De Villiers pointed out that traditional piping systems employ push fit joints fitted with rubber ring seals, making the water-tight integrity of the pipe reliant on good compaction of the surrounding backfill material. This is to prevent lateral and vertical movement at the joints and bends, as well as excessive stresses in the pipe walls, which may lead to failure of both the joints and the pipe. “The effect of excessive water in the soil may lead to a loss of compaction of the backfill material, which in turn may lead to pipe failure. This is why restraint

DPI Plastics is a manufacturer of PVC and HDPE water reticulation and drainage pipe and fitting systems, with two ISO 9001 certified South African factories based in Johannesburg and Cape Town. The company claims that municipalities can save time and money on repairing water-damaged infrastructure by making use of its Durolok internal restraint joint for PVCU and PVCM pipes. The internal restraint joint allows piping systems damaged by heavy and destructive rainfall across South Africa to be repaired in flooded areas a lot sooner. DPI Plastics product manager Mike De Villiers commented, “A major challenge facing municipalities at the moment is that permanent repairs to infrastructure damage can only take place after the water levels have subsided and the moisture content of the soil has returned to an acceptable level. In the case

DPI Plastics – South Africa headoffice@dpiplastics.co.za www.dpiplastics.co.za

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Tube Products International October 2011

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