High-performance bulk water pipelines made with SA steel | Infrastructure news

Sustained bulk water delivery is the lifeblood of a functioning economy and society. IMIESA speaks to Kenny van Rooyen, managing director at Hall Longmore, about his company’s crucial role as a local content steel pipe manufacturer, its commitment to research and development (R&D), as well as partnerships with key stakeholders that deliver world-class infrastructure solutions.

A prime example of project excellence is Hall Longmore’s involvement on the Mafenya Pumping Station and Pipeline to Thlabane Reservoir project, being carried out by main contractor M&D Construction on behalf of Magalies Water in the North West province.

Design, project and construction management are being carried out by MwB Consulting Engineers, based in Rustenburg.

This infrastructure development represents Phase II of Magalies Water’s ongoing expansion and upgrade programme forming part of the Pilanesberg Bulk Water Supply Scheme.

Phase I – entailing the installation of a 42 km pipeline – was awarded to a joint venture (JV) comprising M&D and WK Construction. Completed in 2016, it stretches from Evergreen at the Vaalkop water treatment plant and culminates at Mafenya Reservoir, which was also constructed by M&D.

This structure incorporates a dual design functionality, namely a 5 Mℓ backup reservoir within a 50 Mℓ reservoir. As in Phase II, the key beneficiaries are the mining industry and surrounding communities.

Led by Martin van Aswegen, head: Pipe Division at M&D, Phase II extends the pipeline by a further 28 km from Mafenya Reservoir – situated some 5 km from Sun City – and through to the Mafenya pumping station for onward transfer to the 30 Mℓ Thlabane Reservoir in Rustenburg. On average, the pipeline is between 2.5 m to 3 m deep, housed within a 1.7 m
width trench.

Phase II pipe sections

For the project, Hall Longmore’s scope entailed the manufacture of some 5 400 tonnes of steel pipe sections (grade X42 PSL 1) to complete the 28 km bulk water line.

The bulk of the order comprises DN 900 pipe, with the exception of a 240 m section where DN 1 200 was specified. All pipe sections supplied measure 18.288 m (60 feet).

Corrosion protection

To ensure that optimum life is achieved – the benchmark being around 50 years for steel pipe – various corrosion protection measures formed part of the Hall Longmore order. The external and internal pipe sections were coated and lined for corrosion protection, and life-cycle enhancement. To ensure the overall integrity of the buried pipe, a cathodic protection system will be progressively installed by M&D.

Hall Longmore offers different corrosion protection systems depending on design and environmental requirements. Examples of typical corrosion protection coatings include the company’s three-layer polyethylene system, the Xtalene 3935 proprietary fusion bonded medium-density polyethylene (FBMDPE) product for buried pipe and above-ground applications, as well as other traditional coatings.

“Xtalene 3935 is our latest coating innovation and is made from a uniquely formulated polymer composite material. This is a proudly South African FBMDPE coating sourced from South African raw materials and blended locally,” explains Van Rooyen.

“Some four to five years in the making, product development was carried out in conjunction with the CSIR Nanomaterials Industrial Development Facility, working with Hall Longmore’s technical experts. Sasol came on board as raw material suppliers, together with Xuba from a blending and manufacturing perspective. The result is a product that sets a new benchmark for performance,” Van Rooyen continues.

Key benefits include lower water absorption properties, improved penetration resistance, enhanced bond strength yield at over 30 MPa – where the standard requires 15 MPa – and improved cathodic disbondment results. Shore hardness and elongation are also higher.

Factory setup

To meet market demand, Hall Longmore has invested in the latest advances in fluidised bed technology to apply Xtalene 3935 along with allied coating products at its factories in Wadeville, Germiston, and Duncanville in Vereeniging. These two factories are geared up to produce some 230 000 tonnes of steel pipe annually, predominantly for the Southern African bulk water market, as well as the local and international oil and gas segments.

In terms of the latter, Hall Longmore recently invested R60 million in facility upgrades at its Wadeville factory to remain current with American Petroleum Institute standards – the global benchmark in this field. This essentially requires the production of 99.9% defect-free pipe.

Quality control with precision X-ray

At Duncanville, Hall Longmore has also invested in the latest automated radiographic testing (RT) technology for non-destructive testing on its helical welded steel pipe range, central to which is a specialist fluoroscopic X-ray machine to identify any weld defects.

“This is one of the first digital RT systems to be installed by a South African steel pipe manufacturer and replaces a previous-generation analogue system in use by Hall Longmore since around 1994,” says Van Rooyen.

Internationally, the accepted norm for pipes that fail the RT weld defect test should be less than 3%. Using the latest digital RT, Hall Longmore was well within that range for the Magalies Water project. Another major advance is that digital RT is around 10 times faster in terms of inspection speeds. That translates into faster just-in-time pipe fabrication
and delivery.

“From M&D’s perspective, that level of quality control (QC) is essential in ensuring that we deliver the best result for the client,” says Van Aswegen, adding that M&D’s QC team conducted two weekly inspections of work in progress at the Duncanville factory where the helical welded steel pipe sections ordered are produced.

Strategic partnerships

“M&D’s engagement with Hall Longmore dates back to around 2008 and we’ve always respected them for their manufacturing capabilities, flexibility and expertise. That was crucial in providing Magalies Water with a value-engineered solution,” Van Aswegen continues.

During the tender bidding process, a number of different material proposals – like GRP, plastic and steel – needed to be evaluated by the client’s consulting engineers, along with various coating and lining solutions. In addition to a local content provision, the tender also specified the need for community participation and enterprise development.

“Thanks to our track record for construction excellence, and Hall Longmore’s reputation as a renowned steel pipe specialist, M&D secured Phase II and is advancing well with the programme,” says Van Aswegen. “At M&D, we define our purpose in terms of our ‘4 Gs’, namely Growing a Great company with Great people and Great partnerships.”

From an enterprise development perspective, Hall Longmore formed a JV with a local supplier to progressively deliver the 28 km of pipe ordered. M&D in turn has deployed local SMME subcontractors within the four different wards that the pipeline passes through for final project elements. As part of the contract, M&D is providing related training and mentorship.

The helical welded steel pipes supplied have a straightforward bevelled end that requires a standard internal and external welding technique to secure the individual sections. Having said that, the welding itself is a professional skill and an area of expertise within M&D.

All the special pipe fittings required – such as bends, tees, valve chambers, etc. – are manufactured at M&D’s fabrication facility in Kya Sands, Gauteng. The Kya Sands Shop is ISO 3834 Part 2 accredited and mainly supports M&D’s in-house requirement. Externally, these sections are wrapped with a viscoelastic (VeP) material for corrosion protection, with the internal coating adhering to the same specification as the solvent-free epoxy specified for the Hall Longmore pipe sections. The pipe section field joints are protected with the same VeP material.

Pipe delivery rate and storage

To optimise project and programme management, M&D has established pipe yards along the route. With Hall Longmore’s enterprise partner progressively stocking them with the ordered specification for each section, this has enabled M&D to proceed with confidence with its planned daily pipelaying targets.

“The pipe delivery rate was seamless, at 1.5 km to 1.8 km per week. That kept pace with our installation rate, which is around
900 m to 1.2 km per week,” says Van Aswegen.

M&D submitted its tender for Phase II in March 2022, and was awarded the contract in July 2022.

The pipe order was placed immediately in July 2022 and the initial batches started to leave the Duncanville factory in February 2023. Hall Longmore and its enterprise JV partner will deliver the final consignment at the end of July 2023. In the meantime, M&D is forging ahead for scheduled completion of Phase II by the end of April 2024.

“This is one of the best projects Hall Longmore has been involved on in terms of the efficiency of the tender, award, construction and supply chain process,” notes Van Rooyen. 

Market outlook

From a pipe manufacturer’s perspective, Hall Longmore is very encouraged going forward by the renewed focus from the Department of Water and Sanitation on priority projects, as well as the approximately R40.3 billion allocated for the 2023/24 financial year, and some R43.9 billion and R48.4 billion for 2024/25 and 2025/26, respectively.

The approximately R10.1 billion allocated to municipalities for 2023/24 through the Regional Bulk Infrastructure Grant (RBIG), plus a further R4.6 billion through the Water Services Infrastructure Grant (WSIG), will also enable much needed upgrades in essential services within South Africa’s towns and cities.

“The ongoing consolidation of South Africa’s water boards will also help to achieve economies of scale, pool expertise and focus regional project execution more effectively, spurring an increased level of tender activity for design and construct projects. We are definitely seeing the green shoots of a project pipeline following a hiatus of five to ten years,” Van Rooyen continues.

“From a Hall Longmore standpoint, we’ve made a huge investment in the future of our country in support of essential infrastructure and the products and technologies leading contractors like M&D need to effect implementation. As a pipe manufacturer, we’ve been part of this landscape for
close to 100 years, and remain firmly committed to South African construction,” Van Rooyen concludes.

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