Manufacturer secures large high pressure valve order

A pile of pipes behind a fence covered in a Denso Ultraflex 1250 tape, a specially formulated anti-corrosion system.

IN THE GROOVE The grooved joint pipe and coupling system supplied by Stewarts & Lloyds spanned 24 km

30th June 2023


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Steel, tube and engineering product supplier Stewarts & Lloyds’ Pipes & Fittings branch has secured a multimillion-rand order for high pressure valves with the Chris Hani district municipality, in the Eastern Cape, to complete the newly laid bulk water supply network to the local community of Mnyolo.

The contract entails the supply of 60 bar pressure rated air valves, scour valves and isolation valves as part of the larger bulk water supply system, and follows the initial, successful supply of a 24-km-long grooved joint pipe and coupling system that flows close to the nearest town Ngcobo, in the Eastern Cape.

The first system included the pipes and couplings supplied by Stewarts & Lloyds Pipes & Fittings, as well as reservoirs and tanks that were supplied by additional contractors.

“The pipes are South African National Standards 62 welded and galvanised steel pipes of various pressure ratings, which were needed to accommodate fluctuations in flow pressure,” says Stewarts & Lloyds Pipes & Fittings business development manager Chris Swart.

The pipes were supplied in three pressure ratings of 20 bar to 35 bar, 40 bar to 50 bar, and 51 bar to 55 bar, to meet different pressure requirements, based on the terrain and the elevation of the pipeline.

The pipeline traverses a multitude of topographies above and below the surface at various points in the system.

Stewarts & Lloyds Pipes & Fittings was also responsible for the supply of the mechanical pipe joining Victaulic QuickVic flexible couplings, which is noteworthy, given the pressure ratings of the pipeline.

Stewarts & Lloyds Pipes & Fittings is an approved water solutions distributor of Victaulic products in South Africa.

Combating Corrosion

“The ground in the area was found to be very corrosive, which meant that the pipes had to be adequately protected to prevent any erosion or degradation over their life span,” says Swart.

Therefore, the pipes, once supplied from the Stewarts & Lloyds Pipes & Fittings facility in Alrode, Gauteng, were galvanised and then wrapped with Denso Ultraflex 1250 tape – a specially formulated anti-corrosion system.

The multipurpose, surface-tolerant Ultraflex tape with a polyvinyl chloride backing and polymer-modified adhesive compound for steel pipes, fittings and structural steel is used as an alternative to spray-on corrosion systems.

Denso Ultraflex 1250 spans the length of the pipe, from coupling groove to coupling groove, and once the coupling has been positioned and tightened, Densyl Mastic Blanket is used to wrap the coupling and joint to prevent any corrosion at the joints.

“We had the opportunity to train the local workforce working on the pipeline on how to install and align the pipes, correctly secure and tighten the Victaulic couplings, and how to use the Densyl Mastic Blanket,” he notes.

Owing to the isolated area in which the project is situated, the advantage of upskilling the workers is beneficial to the local community.

The workers were awarded a competency certificate, which should enable them to be “more relevant” in the workforce, with employment “rather lacking” in the rural areas.

Swart says one of the challenges faced was materials handling, where the trucks and cranes used to carry and offload the pipes battled to gain access to the site.

“Moving that many trucks across undeveloped roads or pathways, often during wet weather, meant that some became stuck. However, after careful planning and liaising with the transport provider, the issue was easily mitigated,” he says.

Additionally, the supply of materials and subsequent value-add services was not always easily accessible, owing to a countrywide strike and a consequent slowdown in steel manufacture.

“We managed to circumvent this challenge by rallying with our suppliers and clients to make the project a resounding success,” Swart concludes.

Edited by Nadine James
Features Deputy Editor


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