IMIESA September 2024

www.imesa.org.za

IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa

INFRASTRUCTURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY • WASTE

INDUSTRY INSIGHT John Montgomery

General Manager, APE Pumps & Mather+Platt

OEM pump partnerships facilitate best-in-class client performance

RENEWABLE ENERGY & ELECTRIFICATION

Novel weir design for Kikagati hydropower project

PIPE SYSTEMS

The evolution of plastic pipes

ROADS & BRIDGES

Rehabilitating the flood damaged Mhlali River Bridge

GABION BASKETS

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INSIDE

VOLUME 49 NO. 08 SEPTEMBER 2024

18 www.imesa.org.za

Regulars

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IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa

INFRASTRUCTURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY • WASTE

INDUSTRY INSIGHT John Montgomery

General Manager, APE Pumps & Mather+Platt

Waste Management

Editor’s comment

3

New legislation highlights need for

President’s comment

5

solar waste management solutions

Index to advertisers

48

OEM pump partnerships facilitate best-in-class client performance

Water & Wastewater

RENEWABLE ENERGY & ELECTRIFICATION

Cover Story

Novel weir design for Kikagati hydropower project

PIPE SYSTEMS

Xylem SA achieves certification in

Gabion Baskets leads with creative

The evolution of plastic pipes

ROADS & BRIDGES

environmentally engineered solutions

Rehabilitating the flood damaged Mhlali River Bridge

GABION BASKETS

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ON THE COVER

Celebrating its 18th anniversary in 2024, Gabion Baskets has rapidly evolved over the years to provide a turnkey solution for an expanding spectrum of environmentally engineered gabion structures. IMIESA speaks to Louis Cheyne, managing director at Gabion Baskets about their journey to date. P6

ISO 14001 and ISO 45001

29

Managing your garden the Water Wise way

30

Legal

Building professional capacity key to

Two-stage tendering in SA’s construction

infrastructure delivery

10

Texas bridge installed in under 24 hours

OEM pump partnerships facilitate best-in-class client performance

sector needs collaboration

12

Environmental Stewardship 15

Developments in design, construction and rehabilitation of sewers: Part 1

waste and energy crisis

16

The transition of South Africa from bitumen exporter to importer: Consequences for the

Perfecting the weir design for the 18

road industry

38

Pipe Systems

Cement & Concrete

The evolution of plastic pipes. A journey from

Precast concrete an essential component

ancient civilisations to modern infrastructure

22

in boutique winery construction

43

Impact-resistant flooring upgrade completed

New production lines will reinforce Sizabantu’s leadership in PVC-O pipes

36

Southern African Bitumen Association

A sustainable solution to South Africa’s

Kikagati hydropower project

34

Trenchless Technology

Water conservation in spring: Essential

At the forefront of technological innovation since 1952, original equipment manufacturers (OEMs) APE Pumps and Mather+Platt (the Group) continue to refine and expand their integrated solutions and services. IMIESA speaks to John Montgomery, General Manager, about key trends and developments as the Group ramps up production to meet the operations and maintenance requirements of the water and allied industrial sectors, like energy. P12

33

Rehabilitation of the flood damaged Mhlali River Bridge

strategies for sustainable buildings

32

Roads & Bridges

Industry Insight

Renewable Energy & Electrification

PIPE SYSTEMS

6

IMESA

INDUSTRY INSIGHT

22

28

24

for Department of Basic Education

47

Common gaps and pitfalls to watch.

Vehicles & Equipment

The importance of quality control in thermoplastic pipe manufacturing

34

ROADS & BRIDGES

26

A Proudly South African Titan

43

CEMENT & CONCRETE

48

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ANNUAL SUBSCRIPTION: R805.00 (INCL VAT) ISSN 0257 1978 IMIESA, Inst.MUNIC. ENG. S. AFR. © Copyright 2024. All rights reserved. _________________________________________________ IMESA CONTACTS HEAD OFFICE: Manager: Ingrid Botton P.O. Box 2190, Westville, 3630 Tel: +27 (0)31 266 3263 Email: admin@imesa.org.za Website: www.imesa.org.za BORDER Secretary: Celeste Vosloo Tel: +27 (0)43 705 2433 Email: celestev@buffalocity.gov.za EASTERN CAPE Secretary: Susan Canestra Tel: +27 (0)41 585 4142 ext. 7 Email: imesaec@imesa.org.za KWAZULU-NATAL Secretary: Narisha Sogan Tel: +27 (0)31 266 3263 Email: imesakzn@imesa.org.za NORTHERN PROVINCES Secretary: Zurika Louw Tel: +27 (0)82 322 5208 Email: np@imesa.org.za SOUTHERN CAPE KAROO Secretary: Henrietta Oliver Tel: +27 (0)79 390 7536 Email: imesasck@imesa.org.za WESTERN CAPE Secretary: Michelle Ackerman Tel: +27 (0)21 444 7112 Email: imesawc@imesa.org.za FREE STATE & NORTHERN CAPE Secretary: Wilma Van Der Walt Tel: +27 (0)83 457 4362 Email: imesafsnc@imesa.org.za All material herein IMIESA is copyright protected and may not be reproduced without the prior written permission of the publisher. The views of the authors do not necessarily reflect those of the Institute of Municipal Engineering of Southern Africa or the publishers.

Debt has its benefits if used wisely

T

here’s good debt and bad debt.

Examples of the former include a home loan secured on a high-growth investment property, or the commercial acquisition of a market leading manufacturer.

In turn, bad debt examples include credit card expenses incurred on frivolous luxury items, and poor revenue collection within the municipal space – such as electricity billing – leading to an increase in borrowings to offset financial shortfalls.

At the top end of the scale is public debt, which can be both positive and negative, depending on how loans are utilised. For governments globally, the ultimate objective is to facilitate economic growth and sustained services – like infrastructure development – without spiralling into a growing deficit. However, even where sound decisions are made, there are a myriad of external factors to consider and hedge against, like inflation, oil price and currency fluctuations, interest rates, wars, and the global state of the economy in general.

From a debt-to-GDP ratio perspective, for any country to borrow more than it earns is going to present a challenge when it comes to its ability to pay back loans. However, as the saying goes, “You have to spend money to make money”. In South Africa’s case, we face a shrinking tax pool, so borrowing is on the increase to fund social initiatives and projects, as well as to address SOE financial challenges – particularly at Eskom.

According to a National Treasury report released in 2023, debt is expected to stabilise at around 73,6% of GDP in 2025/26, which is within globally benchmarked thresholds. In parallel, the South Africa Reserve Bank (SARB) continues to keep a tight rein on inflation, which is a crucial part of the process.

A measure of relief was welcomed following SARB’s decision to cut the repurchase rate by 25 basis points to 8% in September 2024 following improvements in South Africa’s consumer inflation data. The latter was recorded at around 4,4% in August 2024, according to Statistics South Africa. An allied factor facilitating a rate cut was an approximately 0,4% improvement in the country’s GDP for Q2 2024. However, the South African

A cash injection by the New Development Bank As part of catalysing current and future growth, South Africa recently received confirmation of a major phased funding injection by the New Development Bank (a BRICS financial institution established in 2015 of which South Africa is a member) to help revitalise our vital freight logistics and water sectors. The announcement took place at the New Development Bank’s 9th Annual Meeting of the Board of Governors, held in Cape Town during August 2024.

This entails approval for a loan of up to US$1 billion to finance water and sanitation infrastructure development under the Municipal Infrastructure Grant (MIG). A R5 billion loan agreement with Transnet was also approved to assist the SOE in modernising and improving South Africa’s freight rail sector.

In a fur ther positive development, on 10th September 2024, the New Development Bank issued 3- and 5-year notes totalling R1 billion in the South African bond market.

A return on investment As with any developing nation, it’s a work in progress, but in South Africa’s case there are distinctive poverty and inequality gaps, which have been well documented. Therefore, the primary focus must be on a policy framework that boosts confidence within the private sector to unlock and invest in an inclusive future based on macroeconomic goals rather than political ideology.

Businesses borrow to make profits; governments crowd in funding to make ever y citizen’s future a sustainable one as active participants in growing a world-class economy. So, let’s make sure, collectively, that government loans do yield the best results.

Alastair

To our avid readers, check out what we are talking about on our website, Facebook page or follow us on Twitter and have your say. www.imesa.org.za

IMESA

IMESA

imesa_za

imesa

www.imesa.org.za

The official magazine of the Institute of Municipal Engineering of Southern Africa

INFRASTRUCTURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY • WASTE

INDUSTRY INSIGHT

Cover opportunity

John Montgomery

General Manager, APE Pumps & Mather+Platt

OEM pump partnerships facilitate best-in-class client performance

In each issue, IMIESA offers advertisers the opportunity to get to the front of the line by placing a company, product or service on the front cover of the journal. Buying this position will afford the advertiser the cover story and maximum exposure. For more information on cover bookings, contact Joanne Lawrie on +27 (0)82 346 5338.

RENEWABLE ENERGY & ELECTRIFICATION

Novel weir design for Kikagati hydropower project

PIPE SYSTEMS

The evolution of plastic pipes

ROADS & BRIDGES

Rehabilitating the flood damaged Mhlali River Bridge

The ABC logo is a valued stamp of measurement and trust. IMIESA is ABC audited and certified.

economy needs a far greater boost to move it back into the 2% plus range.

GABION BASKETS

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IMIESA September 2024

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87

TH IMESA

2024

IMESA

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PRESIDENT’S COMMENT

IMESA

This will be my penultimate President’s message as my 2022-2024 term draws to a close, with the official handing over of the baton to our new incoming President for the 2024-2026 period taking place at the upcoming 87th IMESA Conference.

Perfecting excellence is an exact process

B

eing held between the 6th and 8 th November 2024 at the GrandWest in Cape Town, we’ve had an exceptional response from industry, with attendance already confirmed by more than 500 delegates (including representatives from 86 municipalities) and counting, with all 70 exhibitor stands sold out.

We also have 84 golfers booked for the Annual IMESA Golf Day preceding the conference on 5th September at Bellville Golf Club.

For those who have not yet registered, there’s still time to book a slot at what will be one of the most informative and engaging conferences we’ve hosted to date to showcase and find innovative responses to our evolving infrastructure landscape.

As IMESA, our overriding mandate is the promotion of excellence and ethical practice in municipal engineering, and we’ve made strong gains in this regard through our engagements with key associations, government stakeholders at all levels, and practitioners in the construction sector.

Audit outcomes However, as we can see from the recent 2022/2023 Auditor-General’s consolidated general repor t on local government audit outcomes there’s still a great deal of work required to ensure a universal performance standard across all 257 municipalities. This is underscored by the fact that only 34 municipalities obtained clean audits with no findings. To achieve total compliance will require more intensified and proactive collaboration between political leaders, municipal finance and administration, as well as municipal engineering heads.

Impediments highlighted in the AuditorGeneral’s findings include inadequate budgets for repairs and maintenance, gaps in skills and capacities, revenue losses and ensuing debt burdens, as well as Sibusiso Mjwara, PrTechEng, MIMESA, FSAICE, MWISA, MIPET

grants allocated that are not being spent for vital infrastructure projects.

Alignment with common goals Coordination and proactive communication are key. An example is the typical interface between municipal water service authorities and their water boards – the latter responsible for the treatment, sale and supply of potable bulk water via their distribution networks. This is interdependent on an effective and efficient municipal water reticulation network. Both need to be continuously maintained and upgraded in terms of asset management programmes to meet growing demand in line with scheduled construction programmes, linked to approved tender and procurement processes.

Where a disconnect exists, there are downstream consequences. There have been instances, for example, where municipal pipelines have been installed and buried, but not connected to bulk water utility lines for several years. As a result, they inevitably fail because its contrary to their design parameters, which contributes to wasteful expenditure, plus potential community conflict.

Other typical bottlenecks include land legal issues – like approvals for pipe servitudes – which can unexpectedly derail project implementation when all the preparation work is not completed upfront. The sample principle applies for aspects like Environmental Impact Assessments, and water use licenses.

Another burning issue is construction and development work that takes place in known flood plains – with or without municipal planning, plus bylaw approval. Earlier this year, IMESA rolled out a series of workshops to introduce the industry to a new essential tool kit for local authorities, namely A Best Practice Guideline for Design Flood Estimation in Municipal Areas in South Africa.

Its development is thanks to a multi-stakeholder initiative led jointly

by IMESA and the Water Research Commission.

We now plan to run a further series of workshops in 2025, with a focus on metros, as well as district and local municipalities.

Ongoing professional development Training and more training are a core part of the solution to ensure that municipalities have the necessary engineering personnel in place – equipped with the right skills – to effectively execute projects. In this respect, it’s important to emphasise that municipal leaders should prioritise the release of engineering personnel for training – especially mentorship programmes for ECSA registration.

It’s also vital that their voices are heard and acknowledged within senior municipal management structures in finalising approved projects, based on qualified, experienced engineering input for proposed design/build solutions. That includes equipping personnel for current and future BIM developments that are now integral for multidisciplinary project management.

These and other initiatives will make a major difference in deciding on the best possible interventions, which often have a direct bearing on financial matters. A case in point is the pressing need to combat real and apparent non-revenue water losses. Appointing competent contractors is also obviously crucial.

IFME Excellence Awards From an IMESA best practice viewpoint, we’re holding thumbs that our two entries for the International Federation of Municipal Engineering (IFME) 2024 Excellence Awards will bear fruit.

The Awards coincide with the Future Green City World Congress, being held from 23rd to 26th September 2024 in Utrecht, the Netherlands.

I’ll be attending the conference and will report back in the October 2024 edition of IMIESA, showcasing how local and international projects are meaningfully contributing to best-in-class infrastructure. As is the case locally and globally, it all comes together with enabling private and public sector facilitation, in partnership with communities.

IMIESA September 2024

5

GABION BASKETS LEADS WITH CREATIVE ENVIRONMENTALLY ENGINEERED SOLUTIONS Celebrating its 18th anniversary in 2024, Gabion Baskets has rapidly evolved over the years to provide a turnkey solution for an expanding spectrum of environmentally engineered gabion structures. IMIESA speaks to Louis Cheyne, managing director at Gabion Baskets about their journey to date.

O

ur objective from the onset was to be an industry leader in South Africa, and to grow our cross-border penetration as a preferred gabion manufacturer, and we’ve achieved remarkable success on both fronts,” says Cheyne.

“Another key success factor has been a progressive diversification of our total solutions of fering, backed by design recommendation, training and installation services, which has resulted in us providing solutions for projects of increasing complexity for private and public sector clients across all industries. These range from mass gravity retaining walls to marine and river erosion works, and multi-faceted architectural and landscaping applications.”

One of the evolving trends has been the provision of gabion systems for mass gravity retaining walls of increasing height, an area where Gabion Baskets has established a solid foundation over the years through its

6 IMIESA September 2024

experience in the mining sector – one of the most rigorous industries in terms of health and safety compliance.

Projects completed in South Africa and Africa, in countries that include the DRC, Ghana and Mozambique, have typically entailed the fabrication and supply of gabion systems for primary crusher tip walls up to 9 m in height. Some of these designs incorporate Gabion Baskets’ Gab-Tail system to create reinforced soil walls. The latter is a standard rock-filled gabion basket with a mesh tail extended horizontally back into the backfilled embankment.

“The employment of mass gravity gabion retaining walls within the mining industry underscores their ability to withstand major loads. It also reinforces one of the core advantages of gabion construction, namely that the rock fill can often be sourced on site, lowering installation costs compared to alternative in-situ concrete structures, which also take longer to build.

“The same holds true for most other construction applications that benefit from the unique characteristics of environmentally engineered gabion solutions, like the roads and bridges market. The latter is a core market for us for a series of interventions that include embankment stabilisation, as well as abutments for modular steel bridge structures, where we’ve supplied products for the South African government’s rural bridge programmes,” says Cheyne.

Integrated solutions Over the years, Gabion Baskets has expanded its turnkey offering to include integrated solutions for its gabion systems. These include

ASSAGAY ROAD, KWAZULU-NATAL Perspectives of the 9 m high retaining wall built for a private client in Assagay Road, Hillcrest

COVER STORY

Phase II at the Silver Star Casino entailed the addition of a new 6 m high and 32 m long section

SILVER STAR CASINO, KRUGERSDROP Gabion Baskets’ scope in Phase I for the Silver Star Casino project entailed supply, design recommendations and project management services for the construction of a 9 m high and 40 m long stepped backed retaining wall, which tied into the flanks of bordering gabion sections originally installed

geotextiles, sandbags, biodegradable blankets and barrier protection systems.

“Depending on the application, woven or non-woven geotextiles (for either sandy or clayey soils) are an essential component in any gabion design. In turn biodegradable blankets are invaluable for promoting soil cover and vegetation to counter embankment erosion, either on their own or on top of gabion mattress systems. The use of plants like vetiver grass, whose strong roots grow down to around 5 m, have also been used as part of an integrated soil stabilisation system, underscoring the benefits of combining hard engineering with nature-based responses,” Cheyne continues.

Silver Star Casino As part of its diversification strategy, Gabion Baskets has transferred its knowledge and experience from the mainstream mining and civils segments into the residential and

commercial markets with resounding success.

Pride of place is the Silver Star Casino project in Krugersdorp, completed over three phases from Q4 2023 to Q1 2024.

Replacing an existing and extensive concrete retaining block mass gravity wall that had failed in places, Gabion Baskets’ scope in Phase I entailed supply, design recommendations and project management ser vices for its replacement with a 9 m high and 40 m long stepped backed retaining wall, which tied into the flanks of bordering gabion sections originally installed. This was followed in Phase II by an additional new 6 m high and 32 m long section of similar design. Then in Phase III a 10 m long retaining catchment wall was constructed above the wall built in Phase I to ensure effective stormwater management.

“Due to their approximately 33% void fill factor, the composition of rock filled gabion baskets promotes controlled permeability with

the incorporation of geotextile liners below and behind the structure. At times, though, additional drainage interventions, like the installation of stormwater pipes within the wall are important in high rainfall areas, as well as those prone to frequent floods,” Cheyne explains.

Assagay Road The latter point is well illustrated by the severity of the storms that hit the eThekwini region during April 2022, as well as ensuing events through to 2024, which have caused widespread landslides, plus severe damage to infrastructure and buildings. Across the board, massive soil erosion has presented the ideal scenario for gabion reinstatement and in this respect Gabion Baskets’ Pinetown office in KwaZulu-Natal has been constantly busy supply gabions and providing project management support for repair works.

Its largest to date is an intricate mass gravity wall for a residential client in Assagay Road, Hillcrest, where a major embankment slope collapse swept away a section of private road linking a residential dwelling. The 9 m high mass gravity retaining wall constructed, designed by the client’s engineer, includes PVC pipes for

IMIESA September 2024

7

COVER STORY

KYLOE VILLAGE DAM In February 2023, a momentous meteorological event unfolded in the vicinity of the renowned God's Window, situated between Graskop and Bushbuckridge, which experienced an astounding 754 mm of precipitation. This climatic occurrence wreaked havoc on various critical infrastructure elements, including Sappi’s Kyloe Village Dam. The spillway of the dam bore the brunt of the damage, succumbing to complete erosion. Additionally, this meteorological episode led to the formation of a donga, measuring approximately 100 m in length, 20 m in width at its widest point, and with a depth reaching around 5 m.

The remediation works were completed by Civil, Structural, and EcoEngineering, based in Nelspruit, which is also Gabion Basket’s agent for Limpopo and Mpumalanga.

stormwater drainage, as well as to minimise the risk of hydraulic pressure build-up behind the wall. A core portion of the works features Gabion Baskets' Gab-tail system.

River works in Africa When flooding occurs, one of the hardest hit areas are rivers: their banks become increasingly undermined by erosion, and any neighbouring structures are at risk. The larger the river, the worst the downstream scenario, as has been the case for properties bordering Zambia’s mighty Zambezi.

To date, Gabion Baskets has provided integrated solutions for various private tourism entities that include the Musango River Lodge, and Lolebezi Safari Lodge.

For the Musango River Lodge, works commenced in September 2021, with one of Gabion Baskets’ training instructors on site to equip the local contactor and community labour with the installation skills required.

There were existing gabion walls in place, but the design execution was flawed, combined with poor installation technique.

A gabion mattress foundation had also not been included.

The remediated solution entailed a river embankment retaining wall extending over a length of approximately 300 m with varying heights of 1 m to 4 m, this time correctly founded on a gabion mattress extending out into the river. The latter is key to preventing any scouring of the toe of the wall to ensure longterm structural integrity.

“An innovative design recommendation adopted was the installation of flat steel plates extending into the river, placed on a soil berm, to facilitate the installation of the mattress aprons,” Cheyne explains, adding that a further 30 m extension was added on a subsequent project.

Similar works were executed for Lolebezi Safari Lodge in 2022, but this time the scope was greater, entailing the installation of a gabion structure over a length of approximately 450 m long and average heights of 1 to 2 m, which were completed by the same contracting team responsible for the Musango River Lodge project.

The natural aesthetics of gabion structures is now widely adopted for creative applications, which include this fire pit built using galvanised welded mesh

8 IMIESA September 2024

Current potential projects include a design proposal for another lodge bordering the Zambezi River in Livingstone, where the current riverfront protection measures are ineffective.

“In recent years, we’ve supplied various solutions for hotels and lodges in Livingstone, in addition to other parts of Zambia, where there’s huge demand for erosion control systems,” Cheyne continues.

Residential work is also high in demand, with Gabion Baskets recently providing the design recommendation, training services and material (gabions and geotextiles) for a new mass gravity wall extending over a distance of some 100 m for a private development in Livingstone.

Incorporating a stairway structure, the wall is founded to a depth of 500 mm and retains a platform for the building of a new home.

Retaining wall systems installed at the Contantia Nek Estate development in Hout Bay, Cape Town during 2024

Innovative use of welded mesh gabions to form steps and a garden platform

COVER STORY

PRIVATE RESIDENCE, LIVINGSTONE, ZAMBIA Pedestrian rollers were used to compact the gravel backfill for the platform within 1 m of the wall, with larger compactors employed for the balance of the works, which were completed in September 2024.

Establishing the foundation “In the beginning, when we established our factory and head office in Lombardy East, Johannesburg, we used to supply around 5 tonnes a day; now that’s increased to some 10 tonnes, equating to 200 tonnes a month produced on a day shift basis, so we can double that production when required. We’ve also recently extended our factory building footprint on site to meet current and future increases in production,” Cheyne continues.

Historically, Gabion Basket’s factory and head office was established in June 2006 in partnership with the Barnes Group of Companies (Barnes), translating into key supply chain benefits through the latter’s entity, Barnes Fencing Industries, based in Kempton Park, Gauteng. The latter is a principal manufacturer of steel products, including the hexagonal double twisted woven mesh wire and square welded mesh required for Gabion Baskets’ production.

“For the South African factor y start-up phase, we transferred key machinery from Barnes’s Botswana plant where we were initially operating. Since then, we’ve constantly

A 100 m long mass gravity retaining wall, incorporating a staircase, which creates the platform for the construction of a private residence

ramped up our machinery investments to support ongoing expansion and to ensure ontime delivery.”

As par t of this process, an industrial engineering consultant was retained to optimise and modernise manufacturing throughput so that multiple production lines could be created for woven mesh, welded mesh, and allied products like gabion barrier systems. An allied process is now ongoing at Gabion Baskets’ Pinetown and Cape Town facilities to introduce progressive implementation at these centres.

The ultimate goal is to be as close as possible to local markets.

Development and training “As we always emphasise, gabions are engineered systems and should never be installed by contactors unless they have proven credentials. The same approach applies to professional design engineers, who must be qualified for all load-bearing mass gravity wall structures above 1,5 m,” says Cheyne.

“In broader terms, we also recognise that gabion engineering – a practice dating back thousands of years – may not be fully understood and appreciated by modern day practitioners

who may not have been exposed to this field in their tertiary studies,” he adds.

“Therefore, we are placing renewed emphasis on rolling out theoretical training presentations for engineers, technologists and technicians on how to design gabion structures. Understanding where gabions can and should be employed is vital.

“When installed correctly by a trained contractor, gabions on land will last at least 50 years, with a similar performance in rivers if all the techniques and SANS standards are observed, in the process achieving one of the most sustainable and aesthetically engineered outcomes within our built environment,” Cheyne concludes.

www.gabionbaskets.co.za

This example of a failed river wall reinforces the need for expert design and training

A symmetrical river wall completed for a lodge owner in Zambia. Gabion Baskets provided the design recommendation, training services, as well as gabion and geotextile materials

An example of a gabion mass gravity wall built around 30 years ago

IMIESA September 2024

9

IMESA

Building professional capacity key to infrastructure delivery There was a strong turnout for the 2024 IMESA Northern Provinces (NP) Branch Seminar and Annual General Meeting (AGM) on 30th August 2024, as public and private sector practitioners gathered to vote in the 2024-2026 Management Committee and draw insights from the speakers at this annual event.

R

epresenting the Gauteng, Limpopo, Mpumalanga and North West provinces, the NP Branch is the largest body spearheading the Institute of Municipal Engineering of Southern Africa’s (IMESA’s) mandate to promote excellence across South Africa’s 257 municipalities, interacting with national and provincial stakeholders and the multi-faceted built environment sector.

“Foremost among these endeavours is IMESA’s drive to ensure that engineers, technologists and technicians transition to professional registration with the Engineering Council of South Africa (ECSA),” said Moeketsi Mohlabi, outgoing NP Branch Chairman, who led the seminar and AGM event.

“To achieve this requires ongoing engagement with ECSA to ensure that IMESA and prospective candidates have a clear understanding of the requirements. From there, our pool of registered professionals in industry and within the municipal space are better positioned to provide the required mentorship inter ventions to suppor t candidates on their route to professional registration,” he continues.

“This is a crucial process to ensure that South Africa delivers on its pressing infrastructure priorities with the right levels of professional proficiency, quality and accountability. Employers have a responsibility to implement the necessary training plans.”

Identification of Engineering Work and Codes of Practice To update delegates on the latest developments, Mbulelo Hlalukana, ECSA Assistant Manager, delivered a presentation entitled “Identification of Engineering Work and Codes of Practice,” across their defined engineering registration categories, as well as the procedure for recognition and verification of local and international qualifications.

Essentially, the “Identification of Engineering Work” process defines the type of work and

10 IMIESA September 2024

IMESA Northern Provinces (NP) Branch Management Committee for the 2024 to 2026 term From left to right: Khomotso Mdluli: NP Secretariat; Kuben Govender: NP Deputy Branch Chairman; Kwena Maphoto: NP Branch Chairman; Annaline Cronje: NP Treasurer; and Moeketsi Mohlabi: Outgoing NP Branch Chairman

scope that each category can perform, as well as the defined qualifications routes for advancement to higher registration levels, e.g. from an engineering technologist to a professional engineer, based on their years of experience.

To date, ECSA has conducted a series of consultations with stakeholders to refine the system and, more recently, has sent out a sur vey to registered persons to gather input on the gazetted guidelines for professional fees.

“The key driver in terms of the ‘Identification of Engineering Work’ is the protection of the public, as well as the environment by clearly defining competencies, levels of complexity and outcomes in terms of best practices for each registration level,” said Hlalukana.

“The end goal is to make registration compulsory going forward, and to add new categories where applicable. ECSA has also developed a mentorship programme to assist prospective candidates in identifying mentors to complete their registration process, which is currently a challenge for many aspiring applicants.”

City of Polokwane roads upgrades Underscoring the value of professionalism in overcoming challenges in project execution, the next speaker, Rirhandzu Mabunda, Director: Roads and Stormwater at Polokwane Municipality, showcased a series of road rehabilitation programmes being undertaken within the city footprint on routes that in many cases have already exceeded their designed lifespan. Design and construction supervision is carried out in-house, with around R77 million budgeted for the 2024/2025 financial year.

“The city developed a priority list of 102 streets as part of the asset renewal programme, which were identified according to their importance and level of distress.

This was subsequently reduced to 52 streets due to funding constraints, with phased implementation ongoing,” she explained, adding that a current portion of the funding is being sourced through the Capital Replacement Revenue, Integrated Urban Development Grant, Public Transport Network Grant, and Municipal Disaster Recovery Grant.

IMESA

“The key takeaway is that, as with many municipalities, we need to work with the capital on hand, and to optimise the benefits where it will make the most positive socioeconomic impact. However, to truly get on top of our programmes – including pothole eradication – there’s an urgent need for far greater funding support in Polokwane and nationally to maintain and upgrade urban and secondar y roads. Where practical, predictive maintenance is the key to lowering downstream maintenance costs.”

Road signs that can and cannot be seen Costs aside, there should never be a compromise on road safety – especially signage, which is the vital early warning mechanism for all drivers, as well as an essential indicator for pedestrian and nonmotorised forms of transportation.

This was the essential thrust of Garry Savill’s presentation, Past Chairman of the South African Road Traffic Safety Management Association (SARTSMA), who presented on the topic “Introduction to reflective sheeting for road traffic signs.” SARTSMA represents manufacturers and suppliers of safety products installed on roads, all of which are compliant in terms of South African standards.

“Despite the existence of stringent specifications, however, there are widespread examples of non-compliant signage, which can increase the risk for road users, especially at night, when safe visibility can reduce considerably. This emphasises the vital importance of material reflectivity compliance, with major advances in this respect made in reflective fluorescent sheeting technology,” Savill explained.

During his presentation, he illustrated the degree of night-time visibility available when it comes to compliant and non-compliant signage. In very dark conditions, the latter become almost invisible. And as he pointed out, this scenario is exacerbated by the age of the driver: the older you are, the less you can scientifically see at night.

“That’s why reflectively is so impor tant, and that’s dependent on colour material selection and advancements locally and internationally in orange, yellow-green, and yellow fluorescent upgrades for day and night-time driving, where they all make a positive difference,” he expanded.

The headlight obser vation angle also differs at night depending on the height of the driver’s seating position; in other words, car and truck drivers will see the sign at night sooner and more clearly in the former as opposed to the latter case.

As the obser vation angle increases the sign will appear less bright. This has major implications for transportation engineers in positioning signs correctly.

PRESENTERS 1 Mbulelo Hlalukana, ECSA Assistant Manager 2 Rirhandzu Mabunda, Director: Roads and Stormwater at Polokwane Municipality 3 Garry Savill, Past Chairman of the South African Road Traffic Safety Management Association 4 Lusanda Agbasi, Deputy Director: Sanitation Operational and Capacity Support at the Department of Water and Sanitation

Implementation of the national faecal sludge management strategy The final presentation was a key one in terms of addressing sanitation ser vice deliver y gaps. Here, Lusanda Agbasi, Deputy Director: Sanitation Operational and Capacity Support at the Department of Water and Sanitation (DWS), outlined the realities in her presentation entitled the “Implementation of the national faecal sludge management strategy.”

While most provinces have significantly reduced the gap between those who do and don’t have waterborne sanitation, there are still a percentage of South African citizens that don’t enjoy this privilege. So, in this scenario, Agbasi presented the business case for a ramp up in the interim of on-site sanitation – a common practice globally within developing nations.

“It’s a challenge that cannot be ignored. It’s also one that requires the highest standard of municipal engineering commitment and dedication in ensuring the dignity and right of this currently under serviced portion of our population,” said Agbasi.

“We also need to ensure that these onsite systems are hygienic and are effectively serviced to prevent potential groundwater contamination through illegal dumping

Delegates attending the 2024 IMESA Northern Provinces Branch Seminar and Annual General Meeting on 30th August 2024

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instead of going to a formal wastewater treatment works. The preferred alternative approach is dedicated on-site treatment facilities to handle the unique waste characteristics and to promote circular economy initiatives such as the treatment of sludge as an agricultural fertiliser.”

In response, the DWS is currently working with numerous municipal water ser vice authorities to improve on-site sanitation services. A funding support mechanism is also in the works.

Closing remarks “Our thanks go to the speakers for their well-prepared presentations, and also to our members for joining us for this year’s seminar,” Mohlabi summed up.

“The points and issues raised simply serve to reinforce the value and importance of IMESA as South Africa’s dedicated entity for the advancement of the municipal engineering profession. We are the tip of the sword when it comes to delivery and positive change within our evolving infrastructure environment,” he concluded.

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INDUSTRY INSIGHT At the forefront of technological innovation since 1952, original equipment manufacturers (OEMs) APE Pumps and Mather+Platt (the Group) continue to refine and expand their integrated solutions and ser vices. IMIESA speaks to John Montgomer y, General Manager, about key trends and developments as the Group ramps up production to meet the operations and maintenance requirements of the water and allied industrial sectors, like energy.

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round ten years ago, the Group had already doubled the size of its manufacturing facility in Germiston, Gauteng, which is now undergoing a further major expansion to meet burgeoning current and future capacity for both new pumps solutions and refurbishments.

This entails an extension to the Group’s building footprint, which includes the addition of a new 30 tonne overhead crane to accommodate largerscale pumps, and a test bay for its smaller range of split-case and end-suction pumps.

“This test bay features the latest instrumentation technologies and incorporates a live communications feed so that customers can log on remotely to our digital platform to view tests in progress,” says Montgomery.

OEM pump partnerships facilitate best-in-class client performance Recommissioning stages following the overhaul and refurbishment of a 650 Mℓ Mather+Platt pump for Gauteng’s Water Board

Pattern-making and 3D technology “We’ve also extended our pattern-making shop and now have six qualified patternmakers in-house following the recent recruitment of additional specialists in this field. This development is significant because it now positions us as one of, if not the largest, pattern-making shops in South Africa and Africa,” he expands.

“Greater patternmaking capacity – crucial for the custom or standard design of foundry pump castings – now

John Montgomery, General Manager for APE Pumps and Mather+Platt

INDUSTRY INSIGHT further shortens our production lead times. It also ensures we have the expertise in place to meet out strict quality control criteria.”

In parallel, the Group has extended its 3D printing capabilities using carbon fibre to produce key elements like impeller vanes for specific pump categories. These vanes can typically be fabricated within five hours.

This technology dovetails with the Group’s investment in 3D laser scanners, which are employed to draw-up and create dimensional specifications to ensure a per fect pump fit. Supported by an information technology hub, this enables the seamless exchange of technical information between the engineering design team and the pattern-making shop.

“Alongside our manufacturing capabilities, investments in technology and skilled personnel reinforce our commitment to providing a turnkey solution for industry, which is a growing priority as clients increasingly shift to outsourced operations and maintenance (O&M) contracts by partnering with leading OEMs that have an expert knowledge of their own systems,” Montgomery continues.

“This is an evident trend among South Africa’s Water Boards as they focus on cost and performance efficiencies, but far less so at this stage among municipal water service authorities, where there’s a growing crisis in terms of widespread shortfalls in service delivery.

“This is underscored by the Department of Water and Sanitation’s 2023 Blue Drop report. Going forward, the prediction is that leading Water Boards will be required to play an increasing oversight role in assisting municipalities to become compliant.”

Third parties versus OEMs As Montgomery points out, the bulk of South Africa’s municipalities still work through third parties, who are often not qualified to complete the work, exacerbating pump failures, especially where non-OEM or pirate parts are used. A third-party arrangement also tends to be more expensive, and impacts on

APE Pumps and Mather+Platt make extensive use of 3D laser scanning technology, which is employed to draw-up and verify dimensional specifications to ensure a perfect pump fit

turnaround times, placing further pressure on cash-strapped municipalities.

Plus, those municipalities that opt for perceived “cheaper” pump imports not suited for local conditions are realising the impact in terms of lower-than-expected performance in coping with the typically high sedimentation and therefore abrasive conditions commonly associated with South Africa’s rivers during raw water abstraction. Plus, after-sales support is often not locally based, with long lead times for parts.

“The proven approach is a direct local OEM interface because it caps costs at agreed thresholds. The latter is gaining traction within South Africa’s Water Boards and the energy sector, where there is a major drive towards concluding Service Level Agreements (SLAs) with OEMs. The two-way benefit is that these clients are authorised to audit our performance,” says Montgomery.

The conclusion of SLAs with an expert OEM provides the client with total quality assurance.

In turn, with an SLA in place, the OEM can then plan more effectively in terms of stock inventory to fast-track delivery dates for planned maintenance, as well as make contingency provision for unscheduled interventions.

QCPs In the Group’s case, their service incorporates continuous near real-time monitoring of all its SLA installations, combined with detailed condition assessment ser vices prior to executing a pump repair. In terms of the latter, as a starting point, pumps are stripped at the Group’s facility and checked against the original OEM drawings to ensure a full dimensional inspection. Thereafter, a detailed strip report is provided to the client. From there, a Quality Control Plan (QCP) agreement is concluded by the Group and the client’s engineers.

“Prior to concluding the QPC, our standard practice is for the client’s quality team to physically inspect the stripped pump at our facility and either suppor t out report findings or make alternative recommendations on the repair. Where this The use of 3D laser scanning enables the creation of digital twins that allow APE Pumps and Mather+Platt’s engineering team to verify designs against the physical installation requirements

IMIESA September 2024

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INDUSTRY INSIGHT

APE Pumps and Mather+Platt’s fabrication facility in Germiston is undergoing a major expansion to meet rising production demands, which includes investments in class-leading machinery

is the case, a concession clause is added to the QCP,” says Montgomery.

“Once the repair is approved and completed, say with the addition of a new impeller or shaft, the client’s team will then inspect the pump again before we close out the job.

Overall, it’s a transparent and highly effective process,” Montgomery continues, adding that the Group also provides parallel training for its and the client’s technical and operations personnel, to maximise teamwork and downstream proficiency.

Record pump overhaul for Gauteng’s water utility A key differentiator among Water Boards is that they have the in-house technical expertise and resources to monitor their pump system performance in terms of planned predictive and preventative maintenance.

A case in point is a recent pump refurbishment for Gauteng’s Water Board. This contract was secured as a turnkey project in terms of APE Pumps and Mather+Platt’s grading as an 8ME contractor according to the Construction Industry Development Board rating system.

The pump refurbished is a Mather+Platt unit purpose designed and commissioned in

the 1980s and has a performance capacity of up to 650 Mℓ per day, making it one of the largest ever installed in South Africa.

It operates alongside three identical Mather+Platt pumps that were installed at the same time at the utility’s Lethabo raw water abstraction pump station, situated partially underneath the Vaal River. These pumps play a combined role in supplying around 50% of Gauteng’s water requirements.

Weighing around 44 tonnes, each pump has a suction capability of 1 200 mm, a discharge outlet of 1 000 mm, while the 4 000 kW electric motor powering the unit weights 27,8 tonnes, with a rotor mass of 7,8 tonnes.

“This is the first time since their installation that one of these pumps has been sent back to our factory for a complete refurbishment.

Thanks to detailed planning between the client and Group’s team, we were able to achieve a rapid repair on this critical unit, with flawless execution,” says Montgomery.

Removed from its housing at the end of July 2024, the pump was refurbished and reinstalled within two months, two weeks ahead of schedule.

“We had a designated eight hour window during a controlled shutdown to remove the

pump, employing a rigging sub-contractor for this purpose. They were also responsible for transferring the unit to the awaiting trucks for transfer to our factory. Due to the size of the pump, it had to be disassembled into three pieces, namely the top casing, then the rotating elements, followed by the bottom casing. The same rigging team were then also responsible for the pump’s reinstallation in reverse sequence,” Montgomery continues.

Transportation to and from the Group’s Germiston facility was covered by a specialist insurance policy for the pump’s replacement value.

To perfect their methodology statement, APE Pumps and Mather+Platt’s technical team executed a full 3D scan of the entire pump station layout to ensure that the removed pump could be reinstalled precisely. The works also included electrical and instrumentation components, as well as the blank coverings for the suction inlet and discharge outlet during the pump’s decommissioning, plus the design and fabrication of new pipe stands.

“Thanks to 3D technology, our engineers and technicians could generate a virtual twin of the physical layout, which is now a common approach that we adopt on all projects. This ensured that all elements and connections, including the pipe stands, could be interrogated and verified,” Montgomery explains.

The power of commitment “It all comes down to our best-in-class personnel – they all contribute individually and collectively to our relentless pursuit of excellence. We well understand the time critical natural of the fluid transfer industry, particularly in the water and energy space,” adds Montgomery.

“Our company philosophy is therefore to empower all employees at every level through mentorship and training, so they have the autonomy and authority to make informed, qualified decisions. The same principle holds true for our holding company, WPIL Limited – one of the largest global OEM pump brand leaders – who give us free rein to deliver Proudly South African manufactured solutions.

As a result, customers have the best possible interface when working with APE Pumps and Mather+Platt to meet their fluid transfer objectives, founded on our 72-year track record to date,” Montgomery concludes.

www.apepumps.co.za www.matherandplatt.com

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ENVIRONMENTAL STEWARDSHIP

WATER CONSERVATION IN SPRING: ESSENTIAL STRATEGIES FOR SUSTAINABLE BUILDINGS The arrival of spring brings with it a sense of renewal and warmth, making it the ideal season to review and implement water-saving techniques on our construction/building projects.

Conducting a leak detection audit

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ater scarcity has emerged as a concerning issue globally, with climate change at the centre of attention, driving the need for urgent and effective water conservation measures.

Water-saving techniques can be effectively incorporated into building design and maintenance to help developers, architects, and facility managers to meet sustainability targets, save on operating expenses, and increase the long-term value of real estate.

1 Implement smart irrigation systems

In recent years, smart irrigation systems have been developed to tackle unnecessary water wastage. Imagine returning home on a rainy day, only to discover your sprinkler system running!

These systems are equipped with weather

Smart irrigation systems utilise realtime weather data and soil moisture levels, to customise your watering schedule

Educating water users about sustainable conservation practices is central to Rand Water’s WaterWise programme

sensors and automated controls, ensuring that your landscape receives just the right amount of water when needed. After switching to these smarter systems, many homeowners report savings of up to 50% on water usage.

Smart irrigation systems utilise real-time weather data and soil moisture levels, to customise your watering schedule. Additionally, they provide insights into your water consumption and can even detect leaks within your system.

method can drastically reduce the pressure on the use of municipal water supply.

2 Upgrade to water efficient features

5 Educate building occupants

Spring is a perfect time to re-evaluate and upgrade your water features in your building or home. The incorporation of low flow showerheads, dual-flush toilets, and low-flow faucets can all drastically cut water by up to 50%-70% in your building/ households without sacrificing functionality.

Installing these fixtures in older buildings is an affordable approach to reduce water usage and encourage sustainability.

3 Harvest Rainwater

Rainwater harvesting is a useful way to save water, particularly in summer. Rainwater can be collected and stored in rain barrels, JoJo tanks or underground cisterns for non-potable needs such as flushing the toilet (which uses 6-9 litres of water per flush) or irrigating the garden. This

Sources: • https://plantscreative.com/blog/2020/07/20/how-to-save-water-and-money-with-smart-irrigation • https://www.greenbuildingafrica.co.za/green-your-home/ways-to-save/low-flow-tapsand-showers/#:~:text=Installing%20low%20flow%20showerheads%20and,without%20 compromising%20on%20water%20pressure • www.dffe.gov.za

4 Conduct a Water Audit

A comprehensive water audit of the building/home can help pinpoint the source of water wastage and suggest ways to reduce it. Spring season is the ideal time to conduct a water audit because of increased water use, which can reveal more inefficiencies that could otherwise go unnoticed.

At the Sandton Convention Centre during the 2002 World Summit on Sustainable Development (WSSD), it was reported that the water usage in the kitchen was reduced by 70% in just two weeks by educating staff on water efficiency and installing a water meter to monitor consumption.

A substantial amount of water is wasted due to a lack of awareness. Thus, awareness remains the key to successful water conservation.

How to achieve this: educate tenants, employees, and visitors about the importance of water-saving practices and how they can contribute. Simple actions like turning off taps, repor ting leaks, and using waterefficient appliances can collectively make a significant impact.

www.randwater.co.za 0860 10 10 60

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RENEWABLE ENERGY & ELECTRIFICATION

BEH’s organic biogas plant in Bronkhorstspruit, Gauteng

A SUSTAINABLE SOLUTION TO SOUTH AFRICA’S WASTE AND ENERGY CRISIS Generating energy from waste is a concept that is gaining traction in South Africa. A case in point is SRK Consulting’s appointment by Bio2Watt Energy Holdings (BEH) as the independent environmental consultants to undertake the requisite environmental permitting processes for a new biogas plant on a 5 ha site at Sunderland Ridge, west of Centurion.

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ccording to Darr yll Kilian, par tner and principal environmental consultant at SRK Consulting, this innovative project brings benefits in terms of producing much-needed energy while reducing landfill requirements and greenhouse gas emissions.

The plant will process organic waste from the agriculture and food sectors to produce biogas, which will be conver ted into electricity for the national grid; the biogas will also be compressed and sold to an offtake customer. The other product of the

16 IMIESA September 2024

process is digestate – a quality fer tiliser containing all nutrients and micronutrients necessary for modern farming.

Landfill alternative A recent audit of landfill sites in Gauteng showed that the province faces a serious and urgent challenge with its traditional waste disposal methods. The audit found that there is very limited space remaining on existing landfill sites, and virtually no suitable locations or opportunities for new sites.

Natasha Moodley, principal environmental consultant at SRK, notes that the project is

a trailblazer in a game-changing global trend away from the traditional dumping of waste.

“By diverting waste from a range of local sources, the plant will reduce the need for new landfills,” says Moodley, who is par t of the SRK environmental team on this project. “This will make a valuable contribution to government’s mandate to reduce landfill development by 50% in the near future.”

“At the same time, the conversion of methane to energy means a significant reduction in the volume of methane entering the atmosphere. Methane is up to 80 times more destructive than carbon dioxide in its impact on climate change, so the plant pushes for ward circular green economy effor ts in Gauteng on an industrial scale.”

Problem solving with experience According to Tamar yn Hale, also an SRK Consulting principal environmental consultant involved in the project, the consultancy was contracted by BEH to conduct the environmental authorisation

RENEWABLE ENERGY & ELECTRIFICATION

Darryll Kilian, partner and principal environmental consultant at SRK Consulting

Natasha Moodley, principal environmental consultant at SRK Consulting

Tamaryn Hale, principal environmental consultant at SRK Consulting

process, atmospheric emission license and water use licence application.

Celebrating its 50th anniversary this year, SRK has considerable experience in these fields, and there were cer tain factors which added to the learnings gained on this project.

“One of the findings of the environmental impact assessment (EIA) was the presence of an extensive dolomitic belt underlying the proposed area of construction,” says Hale. “This required various adjustments to be made to the design and planning – with solutions being developed through collaboration with several specialists, including a dolomite specialist engineer, process engineers and civil engineers.

The process was also facilitated by close working relationships between SRK, our client and regulators.”

The project’s oppor tunity to sell compressed gas also introduced the need for pipeline infrastructure, in turn triggering certain additional environmental licencing requirements.

project’s ongoing relationship with local stakeholders, Hale points out.

major hazardous installations (MHI), human rights and gender impacts.

Global standards

More to come

“In addition to complying with South Africa’s robust regulations, the EIA was aligned with the International Financial Corporation (IFC) per formance standard requirements,” Hale explains. As par t of BEH’s community upliftment programme, a stakeholder engagement plan and genderbased analysis were under taken for the lifespan of the project.

Moodley highlights that these international standards also strengthened the environmental management plan (EMP), which stipulated the additional mitigation measures for the identified impacts.

SRK’s multidisciplinar y team was well utilised on the project, providing in-house exper tise on various technical studies in the EIA – including social impact, sur face water, climate change, air emissions and noise pollution. Kilian notes that the company also has an extensive network of professional associates whose fields were relevant to this project, such as heritage,

The Sunderland Ridge project is the third such initiative from BEH, whose first plant has been operating in Bronkhorstspruit, Gauteng, for almost a decade. It has already contributed around 100 GWh to the national grid. Construction on a second plant – this one at Malmesbury in the Western Cape – is planned to start later this year and is approved to produce 9,8 MW. “Biogas projects like these, with their energy and other benefits, hold great promise for a greener future in South Africa,” adds Kilian.

“Technology to transform organic waste to biogas has been developing over the past couple of decades, allowing our economy to leapfrog to the latest technology. Our EIA has also shown that the impacts of these projects can be ef fectively managed, through quality studies, considered impact assessment and effective stakeholder par ticipation,” Kilian concludes.

Example of a primary digester

Example of a secondary digester

Heightened interest “It was heartening to see the interest and active response for this project from the various stakeholders,” say Moodley. “We received plenty of feedback and comments during the permitting phases – from the competent authorities, regulators and community members, as well as the Council for Geoscience – which greatly strengthened the EIA process.”

In the public engagement process, for instance, local residents were enthusiastic to find out more about the project and its technology and were generally ver y suppor tive of the project.

Such engagements are a critical aspect of planning these developments, and of the

IMIESA September 2024

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The project at an advanced stage of construction, showing the completed mass concrete weir containing the small permanent headpond

PERFECTING THE WEIR DESIGN FOR THE KIKAGATI HYDROPOWER PROJECT

Constructed at a cost of around US$87 million, the 16 MW Kikagati Hydropower Project (KHPP) was successfully commissioned in December 2022 and now generates 115 GWh of renewable, reliable electricity each year for the neighbouring people of Uganda and Tanzania. A key success factor in meeting the programme deadlines was an alternative design proposal for the diversion weir.

Over the preceding years, several developers had expressed interest in revitalising and upgrading the existing infrastructure. Then in 2015, studies resulted in a decision to proceed with a new 16 MW hydropower station and in 2018, Berkeley Energy Uganda purchased the concession area and positioned itself as the developer of the present-day scheme through Kikagati Power Company Ltd. Construction was under taken under an EPC contract between 2018 and 2022, with PAC SpA as the civil works contractor and Voith Hydro responsible for the electrical and mechanical equipment installations. The latter

PROJECT TEAM Client: Berkeley Energy Uganda through Kikagati Power Company Ltd Consulting Engineers: Knight Piésold Civil Works: PAC SpA Electrical and Mechanical Installations: Voith Hydro include three 5,5 MW Kaplan turbines and generator sets.

The energy is expor ted via a 33 kV transmission line and sold directly to the Uganda Electricity Transmission Company

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he site for the hydropower plant, situated on the Kagera River, is located near the Kikagati village in Uganda, approximately 65 km south of the city of Mbarara and on the UgandaTanzania border.

It was originally identified and developed during the 1940s, with a 4 MW turbine installed directly in the river and operated as an offgrid energy resource. This mini hydropower station ceased operations in 1979 when it was largely destroyed during the war that removed President Idi Amin from power in Uganda.

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Knight Piésold won the Renewable Energy Systems Design Excellence Award in the Engineering Technology and Innovation category for the Kikagati Hydropower Plant for Kikagati Power at the 2024 CESA Aon Engineering Excellence Awards

RENEWABLE ENERGY & ELECTRIFICATION

Limited (UETCL). UETCL sells off half of the energy to Tanzania Electric Supply Company (TANESCO).

Configuration The KHPP configuration comprises a powerhouse block and a radial gated river regulation structure on the left bank (Ugandan side). The headpond is formed by a small gravity weir constructed across the wide river channel to the right bank on the Tanzanian side. The weir terminates against a fish ladder that also forms a shoulder wall to a small embankment that extends to the left flank at the non-overflow crest level. The purpose of the diversion weir is to form a small permanent headpond, direct water to the powerhouse headrace channel, and to pass extreme flood events in a controlled manner directly over the wall.

The head and tailrace channels lead into a reinforced concrete substructure which houses the turbines and generator sets. Inflow to the turbines is controlled by regulating the headpond level through the radial gated river regulation facility constructed adjacent to the powerhouse block.

The river regulation facility comprises a reinforced concrete sluicing structure with twin 10 m wide by 8.5 m high radial gates. The gated regulation structure forms the left abutment for the diversion weir, and when fully opened the radial gates can discharge up to the 1/500 Annual Exceedance Probability Flood (AEP) peak.

Switch from RMD to mass concrete weir During construction, the designs prepared for the various components by the EPC contractor were mainly retained, apart from the diversion weir itself, which had initially been proposed as a slender retaining wall structure at tender stage.

Subsequently, the Developer and Owners Engineer investigated various alternatives for the weir during the early implementation stage. This

A section of the spillway’s stepped downstream face and apron slab and an overview of the powerhouse

led to a decision to change the slender retaining wall to a rubble masonry concrete dam (RMD).

To verify this, the first phase coffer dam was extended to allow exposure of the foundations for the first 30 m of dam wall, and a detailed geotechnical assessment of the foundation rock mass was made. The presence of competent granite rock mass over the extent of the foundation was confirmed.

Knight Piésold Consulting were then appointed to carry out a review of the RMD design details and to provide supervision during the rubble masonry concrete (RMC) trial section, leading

A downstream overview of the weir and gated river regulation facility under operation

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RENEWABLE ENERGY & ELECTRIFICATION

A fishway and a stepped basin fish ladder were constructed on the right bank

up to the main construction phase, which had been programmed over roughly six months. When the RMC trial section was undertaken, however, several inefficiencies in implementation became apparent.

The effor t required to source, handle, transport and place the stone plums to be included in the rubble masonr y dam had been significantly underestimated. This issue was further compounded by ongoing labour restrictions due to the Covid-19 pandemic.

With under 12 months remaining to Commercial Operation Date, the Phase 2 river diversion had not yet started, no work had been done on the right bank and approximately 6 000 m3 RMC still had to be placed. Therefore, an RMC construction approach was no longer viable in the time remaining. In its place, a mass concrete dam type was proposed by Knight Piésold Consulting, which was accepted.

From the onset, the fact that the Kagera River’s base flows often exceed 200 m³/s necessitated a well-planned river management and diversion strategy by the EPC contractor.

A phased approach with a ring-type cofferdam A night-time perspective of the Kikagati Hydropower station

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on the left bank allowed initial construction of the powerhouse, radial gated structure, and 30 m of the weir. The cofferdam was extended towards the right bank, eventually diverting flow through the radial gates. This allowed final cofferdam completion and access to the dam foundations.

Excavation techniques involved precision drilling and blasting, followed by dental filling with high slump concrete and consolidation grouting to improve rock mass conditions.

Concrete weir design By positioning the weir immediately upstream of a natural waterfall, the project utilised an additional head drop for hydropower generation without the need for a large dam wall, achieving over a 12 m head drop with an average weir height of 6 m.

The weir therefore features a reduced footprint and is designed as a spillway over most of its length, preser ving river width and limiting the upstream inundation area to approximately 100 hectares at full supply level.

This design minimises land use The 180 m long uncontrolled spillway is designed to handle inflows exceeding the

1/10,000 AEP event, ensuring safety even if the radial gates were inoperable. (The latter are automatically programmed to open during severe floods.) In turn, the spillway’s stepped downstream face and apron slab effectively manage over flow, preventing scour and maintaining structural integrity. The installation of a cementitious grout curtain along the weir’s upstream face also reduced permeability and enhanced foundation stability.

Weir construction Extensive concrete trials ensured that the mix design for the weir met strength and durability requirements without dedicated cooling facilities. Removing unnecessary reinforced concrete elements from the weir design also reduced material and labour costs. Additionally, standardising lift heights and joint spacing promoted the reuse of formwork, passing on further savings.

Strict temperature controls during concrete placement, including limits on placement temperature, lift heights, and joint spacing, were crucial to prevent thermal cracking.

The EPC contractor managed two aggregate sources, including a dedicated quarry where mechanical breaking was employed due to restrictions on bulk blasting.

As the works progressed, the dam was constructed in 900 mm lifts with wet curing and green cuts, and the average placement temperature was maintained at 27.9°C.

Environmental stewardship To enable passage, a fishway and a stepped basin fish ladder were constructed on the right bank, based on advice from international specialists. Additionally, a low-flow broadcrested section of the weir was built adjacent to the fish pass to allow environmental releases and encourage fish migration away from the turbine intakes on the left bank.

An aquatic monitoring programme has confirmed compliance with IFC standards for fish migration.

Another key element is a log boom and automatic raking system to manage floating debris – including floating hyacinth islands – thereby improving downstream water quality and the preservation of the local ecosystem.

In turn, the socioeconomic environment gains with the provision of sustained renewable runof-river energy.

5 REASONS WHY A SAPPMA

MEMBERSHIP MAKES SENSE

SAPPMA is an Association of leading companies in the plastics piping business, with the purpose of facilitating high standards of ethics, product quality and technical information. It is an open association, well regulated by strong Articles of Association and Code of Conduct and is registered as a Section 21 Company incorporated not for gain.

01

Members have a collective voice at engineering associations, consulting engineering firms, municipalities, water authorities and contractors.

Access to expert technical information: advice, consultations, technical manual, conferences, webinars, technical publications and ongoing training.

03

Access to the market survey results/reports, product standards, quality systems, test procedures.

Free access to the latest SANS standards, with representation at certification authorities and test facilities in terms of standards, testing, monitoring and quality control.

05

02 04

Members are set apart from other players in the market by passing the SAPPMA factory audits and adherence to the SAPPMA Code of Conduct.

As a member of SAPPMA, you will be participating in the only representative plastic pipe forum in the country. Members are afforded valuable networking opportunities, social interaction and enjoy a sense of community.

NEED MORE REASONS TO JOIN? CONSIDER THIS...

• SAPPMA represents more than 80 % of the plastic pipe market in Southern Africa. Members are supported by an established brand that is solely aimed at protecting the customer and the infrastructure of the country.

• Our members represent manufacturers, polymer manufacturers, suppliers, individual members and certification bodies.

• The SAPPMA mark on a product has become a sought-after quality guarantee and give customers and end-users the peace of mind that their product meets local and international quality standards.

06

THE FOLLOWING BUSINESSES AND INDUSTRIES CAN QUALIFY FOR A SAPPMA MEMBERSHIP:

• Pipe & fittings manufacturers • Raw material suppliers • Consultants • Construction companies • Municipalities • Water Boards • Contractors • Installers • Individuals

JOIN SAPPMA TODAY! www.sappma.co.za

PIPE SYSTEMS

THE EVOLUTION OF PLASTIC PIPES

A journey from ancient civilisations to modern infrastructure The history of plumbing is deeply rooted in the ancient civilisations of the world. From the grand cities of the Greeks, Romans, Persians, Indians, and Chinese, the need for efficient water supply and waste management systems was recognised early on.

T

hese ancient societies were among the first to develop public baths, necessitating the creation of plumbing systems to provide potable water and manage waste disposal for their growing populations.

By 2700 BC, the Indus Valley Civilisation had already standardised the use of earthen pipes with broad flanges, sealed with asphalt to prevent leakages – an impressive feat in early urban engineering. The Romans further advanced plumbing with the introduction of lead pipes, which were inscribed to prevent water theft – a testament to the value they placed on this vital resource.

Despite these early innovations, progress in plumbing systems was remarkably slow.

It wasn't until the 1800s, with the rise of densely populated cities, that public health authorities began advocating for better waste disposal systems.

This period marked the beginning of underground water and sewage systems that replaced open sewage ditches and cesspools, fundamentally transforming urban sanitation.

The emergence of plastic piping systems For much of modern history, materials like clay, lead, bamboo, wood, and stone were the primary materials used for piping.

Early US cities utilised hollowed wooden logs

22 IMIESA September 2024

for water distribution, a practice that persisted into the 1800s. The advent of copper piping in the 1960s, replacing galvanised iron and lead, was a significant step forward due to copper's non-toxic properties.

The real gamechanger came with the introduction of plastic piping. Plastics, now ubiquitous in everyday life, started to gain prominence in the mid-20th century. The first synthetic plastic, Bakelite, was invented in 1909, and by the 1950s plastic production had expanded to include materials like polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP). These materials quickly became the standard for piping due to their durability, resistance to corrosion, and ease of installation.

Plastic pipes: The modern standard Today's plumbing systems are dominated by plastic pipes, which offer numerous advantages over traditional materials. PVC and HDPE are particularly popular for their strength, flexibility, and resistance to chemicals and temperature changes. These materials are commonly used for water supply, sewage, and drainage systems, as well as in applications like irrigation and gas distribution.

The manufacturing process of plastic pipes and pipe fittings involves various methods such as extrusion, injection moulding, and blow moulding.

These techniques allow for the production of pipes in a wide range of sizes and specifications, making them suitable for diverse applications.

However, the production and application of these pipes also require stringent quality control to ensure they meet international standards, especially since they form an integral par t of infrastructure.

In 1955, at the Plastics Fair in Düsseldorf, now known as the K-Fair, the first pipes made from a groundbreaking plastic material were introduced.

This material, high-density polyethylene (HDPE), was invented that same year and quickly became the solution to the significant infrastructural challenges Europe faced in the aftermath of World War II. HDPE has since built a strong reputation for its strength, reliability, and low leakage rates, with its application as a pipe material evolving rapidly. The initial material, known as Type 50 or PE50, was soon replaced by PE63 in 1959. By 1977, PE80 materials, featuring higher stiffness and improved crack resistance, were introduced.

In the 1990s, HDPE pipe material underwent a significant transformation with the development of bi-modal resin manufacturing technologies, enhancing its strength by 25% and leading to the adoption of PE100 materials, which offered greatly improved resistance to in-service cracking. Fur ther advancements were made with the introduction of high stress crack resistance materials, also known as RC materials.

Despite the relatively low crack resistance of the early materials, many polyethylene

PIPE SYSTEMS

pipelines installed in Europe during the 1960s and 1970s remain in service today and are expected to last for several more decades.

HDPE pipe materials have been manufactured in South Africa since 1972.

The current PE100 material produced by local company Safripol, known as iMPACT100®, is certified as compliant with ISO and SANS standards for water and gas piping.

The role of standards and industry associations In South Africa, the Southern African Plastic Pipe Manufacturers Association (SAPPMA) plays a crucial role in maintaining the quality and integrity of plastic pipes. SAPPMA is a voluntary, self-regulating, non-profit association that represents major stakeholders in the plastic pipe industry. It is the association's mission to create absolute customer confidence in the industry, thereby ensuring that plastic pipes are not only fit for purpose, but also offer longterm sustainability.

SAPPMA's commitment to quality is evident in its rigorous standards and quality assurance programmes. The association monitors its members to ensure adherence to national and international standards, providing an additional safeguard against sub-standard products. This is particularly important in the context of South Africa, where plastic piping networks are vital for the countr y's water supply and sewage disposal needs.

SAPPMA's commitment to quality is evident in its rigorous standards and quality assurance programmes.

The association monitors its members to ensure adherence to national and international standards, providing an additional safeguard against sub-standard products.

Earlier this year, SAPPMA launched Project Superior Quality 2024, an initiative aimed at addressing issues related to suspect quality in plastic pipes, par ticularly those made from HDPE. The project introduces stricter standards, enhanced monitoring, and a public awareness campaign to promote superior quality in the industr y. These measures underscore SAPPMA's unwavering commitment to excellence and its role as a guardian of the plastic pipe industry's reputation.

The concept of quality encompasses quite a few aspects, with two of the most important being product standards and certification. It is important to ensure that members operating in the local plastic pipe industry meet the standards of application criteria, such as supplying pipe for freshwater reticulation, when undertaking critical projects.

For this reason, SAPPMA’s factory audits remain a key factor in the success of the Association. Announced and unannounced audits take place throughout the year at all pipe manufacturers and installation companies to ensure increased quality awareness and compliance. Recently SAPPMA has also adjusted the focus of audits, with less emphasis on systems and more on materials.

Verified plastic pipe producers and affiliated suppliers are awarded the SAPPMA mark of accreditation as part of its continuous efforts to improve and maintain standards in the very important plastic pipes industry.

Although formal certification in accordance with national standards must be handled

by SANAS accredited authorities, there remains a strong need in the market for the work and influence of SAPPMA, as an experienced and knowledgeable body without profit motive. In this

regard, SAPPMA strives to maintain good contact with the certification authorities.

Recyclability of plastic pipes In addition to maintaining world-class manufacturing standards, the plastic pipes industr y holds great consideration for environmental preservation and decarbonisation.

The recycling of plastic pipes that have reached the end of their natural lifespan take place at a grand scale in the industry. This ensures that little to no plastic pipe waste is discarded into the environment, thereby adding green credentials to the plastic pipe processing and manufacturing procedure.

Although recycled plastic pipe materials are not approved for use in the manufacture of verified plastic pipes, these materials can be used for the manufacturing of alternative plastic pipe products.

Conclusion The evolution of plastic pipes represents a remarkable journey from the rudimentar y plumbing systems of ancient civilisations to the sophisticated, high-quality piping networks of today. As plastics continue to dominate the global piping market, the role of organisations like SAPPMA in maintaining standards and ensuring the longevity of infrastructure becomes increasingly vital. With initiatives like Project Superior Quality 2024, the future of plastic piping in South Africa looks set to continue on a path of innovation, quality, and sustainability.

www.sappma.co.za IMIESA September 2024

23

Sizabantu Piping System’s factory in the RBIDZ

1000 mm OD TOM®500 PVC-O pipe

New production lines will reinforce Sizabantu’s leadership in PVC-O pipes Sizabantu Piping Systems (SPS) are in the process of installing a TOM®500, their brand name for PVC-O classification 500 pipe, production line at their state-of-the-art “green” factory built in the Richards Bay Industrial Development Zone (RBIDZ) eight years ago.

T

he production line is capable of producing the largest diameter and highest-pressure class PVC-O pipe, as specified in the applicable new standard ISO 16422-2: 2024 Table 2, that will be adopted by the SABS. This is a substantial investment and is indicative of both SPS’s commitment to South Africa and the success of PVC-O in the pressure pipeline market.

SPS’s manufacturing facility in the RBIDZ currently has three lines installed

that produce from DN110 to DN630 mm OD (outside diameter) pipes in pressure classes from PN12.5 to PN25 pressure ratings (PN) as specified in the current applicable SANS 16422 standard. The current expansion project will provide an additional two lines to bring the total number of lines to five.

The new line number four will enable SPS to increase its range from DN110 to DN1200 mm OD in all pressure classes from PN12.5 up to PN25 pressure rating Large diameter TOM®500 PVC-O pipe

contained in the new ISO 16422 standard.

When the expansion project is completed, SPS’s manufacturing facility will be the second largest production facility for PVC-O in the world.

The Richards Bay factor y is currently being upgrading to accommodate the two new lines. The large bore M-OR-P 5012 line is being installed and commissioned for testing at Molecor, SPS’s technological partners in Spain, now. Testing is scheduled to be completed by December 2024, whereafter the line will be packed for shipment to South Africa and is planned to arrive in Richards Bay in mid-Februar y 2025. Installation and commissioning will be completed in South Africa by the end of March 2025 and the large bore machine will be in production from 1 April 2025.

The success of TOM®500 PVC-O pipe is indicated by the successful completion of many hundreds of projects, both inside and outside South Africa, examples of which are contained in Table 1. Numerous municipalities, water authorities, metro water authorities and regional water authorities have used TOM ®500 for projects, many of which have given official approval and included it in their list of approved products.

PVC-O standard revisions The five classifications of PVC-O pipe are specified in the current SANS (South African National Standard) for PVC-O SANS 16422 Pipes and joints made of oriented unplasticised poly(vinyl chloride) (PVC-O) for the conveyance of water under pressure - Specifications. It is a twenty-four page one par t document that specifies all the requirements, attributes and testing of PVC-O. It is an exact copy of the previous ISO 16422 of the same name.

24 IMIESA September 2024

PIPE SYSTEMS

Sample list of projects supplied

Location

Project

Length

Pipe OD

km

Pipe PN

mm

bar

Nandoni

Bulk water

51.8

500/630/800

16

Driefontein

Bulk water

36

630

16/20

Loskop

Bulk water

25

630

12/25

Tshwane

Various

250

110/630

12/16/20

Madagascar

Bulk water

23

315

16

Zambia

Upgrade

14

315

12.5/25

Zimbabwe

Bulk water

15

160/450/630

16/25

Madagascar

Bulk water

7

110/450

16

Angola

Irrigation

40

160/500

12/16/20

This ISO (International Standards Organisation) standard has been revised and replaced with a new fivepart document, the same format as the standard for PE (Polyethylene) ISO/SANS 4427. Everything contained in the old one-part document has been included in the new five-part document with some important additions.

In ISO 16422-1 Part 1: General, it more clearly differentiates the classifications of PVC-O with an Orientation Factor λ,

amongst other attributes, a vitally impor tant attribute to be specified and understood with various other manufacturers producing various PVC-O classifications.

In ISO 16422-2 Part 2: Pipes, Table 2 has been extended to 1200 mm OD pipe and PN25 (25 bar). This increase in size and class has been largely motivated

by SPS’s technology partners Molecor, Spain, who, through their innovative technology, have engineered these

increases. The five annexes specify Classification, Depth of engagement, Temperature derating, Negative pressure capacity, and Orientation (λ), both circumferential and axial.

In ISO 16422-3 Par t 3: Fittings, the physical characteristics including tensile strength are specified. The three annexes specify Hydrostatic strength (MRP) according to ISO 9080, Circumferential orientation factor, and dimensions up to 630 mm OD pipe.

In ISO 16422-5 Par t 5: Fitness for purpose of the system, Table 1 specifies the shor t term positive and negative pressure capability of the joint, and the long-term positive pressure capability.

Figure 1 proves the capability for surge conditions is 2 x PN. Figure 2 proves the negative pressure capability is -0.8 bar, and the long-term positive pressure capability is specified.

It is anticipated the revised five-par t ISO 16422 will be adopted by the SABS, as has been done historically, and will become SANS 16422 in 2025.

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www.rainbowtanks.co.za sales@rainbowres.com | +27 (0)11 965 6016

PIPE SYSTEMS

COMMON GAPS AND PITFALLS TO WATCH

THE IMPORTANCE OF QUALITY CONTROL IN THERMOPLASTIC PIPE MANUFACTURING Key personnel roles

Infrastructure development remains in focus and demand; the quality of materials used in construction projects plays a crucial role in determining the longevity and reliability of our built environment. Among these materials, plastic pipes have become increasingly popular due to their durability, costeffectiveness, and versatility. By Ian Venter

H

owever, the benefits of plastic pipes can only be fully realised when stringent quality control measures are in place throughout the manufacturing process. This article explores the critical aspects of quality control in plastic pipe manufacturing, highlighting common gaps and pitfalls that industry professionals should know.

Definition of an effective QC process An effective Quality Control (QC) process in plastic pipe manufacturing is a comprehensive system designed to ensure that products consistently meet or exceed specified quality standards.

Several international standards govern this process, most notably the ISO 9001:2015 for quality management systems (QMS), ISO 9004 for sustained success through QMS, and the SANS ISO standards for PVC Polyvinylchloride and Polyethylene (PE) piping systems.

ISO 9001:2015 provides a framework for implementing a quality management system focusing on customer satisfaction, process approach, and continuous improvement. It requires organisations to establish, document, implement,

26 IMIESA September 2024

and maintain a QMS, ensuring that all processes are identified, their sequence and interaction determined, and necessary resources provided.

SANS ISO, specific to PVC and PE piping systems, sets out requirements for the pipes, fittings, valves, and ancillary equipment made from PVC and PE materials. These standards cover material properties, dimensions, mechanical characteristics, and performance requirements.

An effective QC process in pipe manufacturing should encompass the following: • Raw Material Control: Ensuring that incoming materials meet specified requirements.

• Process Control: Monitoring and controlling manufacturing processes to maintain consistency.

• Product Testing: Conducting rigorous tests on finished products to verify compliance with standards.

• Documentation and Traceability: Maintaining comprehensive records for each batch of products.

• Continuous Improvement: Regularly reviewing and updating processes based on performance data and feedback.

The success of a quality control process heavily relies on the personnel involved. Key roles within the QC process include: • Q uality Control Manager: Oversees the entire quality management system, ensuring compliance with relevant standards and coordinating quality improvement initiatives.

• Procurement Officer: Responsible for sourcing and purchasing raw materials that meet quality specifications. They play a crucial role in supplier management and ensuring the quality of inputs.

• Production Manager: Oversees the manufacturing process, ensuring production lines operate efficiently while maintaining quality standards.

• Q uality Assurance Inspector: Conducts inspections and tests at various stages of production, from raw material reception to final product testing.

• Documentation Specialist: Manages the control of documents and records across all processes, ensuring traceability and compliance with documentation requirements.

• Training Coordinator: Develops and implements training programmes to keep staff updated on quality practices and safety protocols.

Each role contributes significantly to maintaining high-quality standards throughout the manufacturing process.

Criteria for selection: What specifiers should expect When selecting a plastic pipe manufacturer, specifiers should look for several key indicators of quality and reliability. Foremost, the manufacturer should demonstrate full compliance with relevant ISO standards and industry-specific regulations. Also look for evidence of a welldocumented and implemented QMS covering all production aspects.

Furthermore, the manufacturer should have inhouse testing capabilities to perform routine quality checks and more advanced tests as required. It’s essential that there are robust systems in place to trace products back to their raw materials and production batches.

Additionally, manufacturers should demonstrate a commitment to research and development, seeking to improve their processes and products based on customer feedback and industry advancements. In turn, a dedicated focus on sustainable practices and environmental stewardship is equally important.

PIPE SYSTEMS

Also choose manufacturers who of fer comprehensive technical suppor t and documentation to assist in proper product selection and installation.

Importance of audits Internal and external audits play a crucial role in maintaining and improving quality control in plastic pipe manufacturing. They serve both as a systematic and independent examination of the quality management system, providing valuable insights into their effectiveness, plus indicating areas for improvement.

Internal audits should be conducted by trained staff within the organisation. A key benefit is that they help identify non-conformities and potential improvements before they become significant issues. They also fostering a culture of continuous improvement and quality awareness among employees while preparing the organisation for external audits.

In turn, external audits should be conducted by independent third-party organisations, thereby providing an unbiased assessment of the quality management system. They are often required for certification to ISO standards; overall they enhance credibility with customers and stakeholders.

Regular audits help manufacturers ensure compliance with standards and regulations, identify and address weaknesses in the quality control process, validate the effectiveness of existing quality control measures, and drive continuous improvement in product quality and manufacturing processes.

Acceptable Quality Level Thresholds Establishing appropriate Acceptable Quality Level (AQL) thresholds is crucial for maintaining product quality while balancing manufacturing efficiency.

AQL is the maximum percentage of defective items considered acceptable in a batch.

For plastic pipe manufacturing, AQL thresholds should be set for various quality parameters, including: • Dimensional accuracy • Surface finish • Mechanical properties (e.g., tensile strength, impact resistance, etc.)

• Joint integrity • Visual defects Setting appropriate AQL thresholds involves considering industry standards and customer requirements; analysing historical quality data; balancing quality expectations with production costs; and regularly reviewing and adjusting thresholds based on performance data.

For example, PipePer fect Ltd might set an AQL of 1%, meaning they’ll accept a batch if no more than one out of 100 pipes are defective.

This threshold should be accompanied by clearly defining what constitutes a defect and how inspections will be conducted.

When non-conformities are identified, a robust corrective action process should be in place, including: • Immediate containment of non-conforming products.

• Root cause analysis.

• Implementation of corrective measures.

• Verification of the effectiveness of corrective actions.

• Preventive measures to avoid recurrence.

Certificate of Conformance: Mandatory or Optional?

A Certificate of Conformance (CoC) certifies that supplied goods or services meet required specifications. In the context of plastic pipe manufacturing, the question arises: Should CoCs be mandatory?

Arguments for mandatory CoCs include a customer assurance that products meet specified requirements. CoCs also enhance traceability and accountability; facilitate compliance with regulatory requirements; and can expedite the inspection process for customers.

In turn, the arguments against mandatory CoCs include concerns that this may increase the administrative burden and costs for manufacturers. CoCs could also lead to over-reliance on documentation rather than actual product quality, plus there’s a potential for misuse or falsification if not adequately controlled.

A balanced approach might involve making CoCs mandatory for critical applications or high-risk products; offering CoCs as an optional service for standard products; implementing robust systems to ensure the integrity and accuracy of CoCs; and educating customers on the proper use and limitations of CoCs. Ultimately, deciding whether to make CoCs mandatory should consider industry norms, customer expectations, and the risks associated with the product’s application.

Closing remarks Quality control in manufacturing is not just a regulatory requirement; it’s a critical factor in ensuring our infrastructure’s safety, reliability, and longevity. By implementing comprehensive quality control processes, manufacturers can: • Enhance product reliability and performance.

• Reduce waste and production costs.

• Improve customer satisfaction and brand reputation.

• Ensure compliance with industry standards and regulations.

ABOUT THE AUTHOR A former technical manager at the Southern African Plastic Pipe Manufacturers Association (SAPPMA), Ian Venter launched Polymers and Piping Systems in June 2024. The company specialises in producing high-quality thermoplastic products and providing comprehensive solutions for piping systems. Ian holds a National Higher Diploma in Polymer Technology and has significantly contributed to advancing industry standards in his field.

• Drive continuous improvement in manufacturing processes.

However, achieving effective quality control requires vigilance against common pitfalls, including: • I nadequate staff training on quality procedures.

• Over-reliance on end-product testing rather than process control.

•P oor documentation and traceability systems.

•N eglecting supplier quality management.

• Failure to adapt quality processes to new technologies or materials.

By addressing these challenges and maintaining a solid commitment to quality throughout the organisation, plastic pipe manufacturers can position themselves as leaders in the industry, contributing to the development of sustainable and reliable infrastructure worldwide.

In conclusion, as the demand for high quality plastic pipes grows, manufacturers prioritising robust quality control processes will be best positioned to meet market needs and regulatory requirements.

Specifiers and end-users should remain vigilant in their selection of manufacturers, looking for those who demonstrate a comprehensive approach to quality management backed by reliable and relevant certifications, transparent processes, and a track record of excellence.

Should the need arise for further discussion, please contact Ian Venter at IanVenter@ppfssa. com or via phone at +27 82 770 8244 for detailed training material. PPfSSA - BLOG

IMIESA September 2024

27

WASTE MANAGEMENT

The Electricity Regulation Amendment Act signed into law in August 2024 is predicted to lead to a rapid growth of renewable energy sources provided by independent power producers, and an ensuing increase in solar waste.

This has the potential to damage the environment if not correctly disposed of.

T

he International Renewable Energy Agency, in their Endof-life management: Solar photovoltaic panels repor t, predicted that recycling solar PV panels at the end of their roughly 30-year lifetime could unlock an estimated 78 million tonnes of raw materials and other valuable components globally by 2050. Solar panels contain aluminium, cadmium, copper and glass among other recyclable materials.

“This new Act, together with the amendment to the National Environmental Management: Waste Act (No. 59 of 2008) that banned all waste electronic and electrical equipment from landfill as of 2021, will result in an increased demand for solutions for solar PV waste,” says EnviroServ Regional Manager Ryan van Heerden.

“We can expect to see more solar farms being established now, and if incorrectly disposed of, solar panels and lithium batteries used to store electricity can leach poisonous substances into our water system and the environment, causing permanent damage.”

28 IMIESA September 2024

NEW LEGISLATION HIGHLIGHTS NEED FOR SOLAR WASTE MANAGEMENT SOLUTIONS

EnviroSer v has seen an increase in enquiries for solar PV disposal in the past year as well as lithium batteries used for electricity storage in solar plants. Many of the queries are from the Northern Cape, which is known for its sunshine.

“As a responsible waste management company compliance is key for us and we assist our customers around the country in ensuring their solar waste is correctly disassembled and recyclable materials reclaimed before the non-recyclable components are taken to a compliant waste management facility,” Van Heerden continues, adding that a recycling certificate is issued after the process is completed.

Van Heerden says there is a need for more awareness around the importance of proper, legal disposal of solar waste.

“Solar plants must have a budget in place for their decommissioning, and the Extended

Solar plants must have a budget in place for their decommissioning, and the Extended Producer Responsibility framework legally holds producers responsible for the entire life cycle of their products, from design to end of life

Producer Responsibility framework legally holds producers responsible for the entire life cycle of their products, from design to end of life.” This legislation includes the cost of recycling and legal disposal of the items if they are damaged or no longer functional.

As the renewable energy sector expands, there is a need for stakeholders to prioritise effective solar waste management strategies to safeguard the environment. “This will ensure that clean energy advancements are beneficial to society rather than a potential health hazard awaiting us in decades to come,” Van Heerden concludes.

Xylem SA attained a new milestone recently when it successfully achieved certification in ISO 14001 and 45001 management systems, covering Health, Safety, and Environment.

WATER & WASTEWATER

Xylem SA achieves certification in ISO 14001 and ISO 45001

S

uch achievements uphold Xylem’s reputation as the world’s leading pure water technology company, helping countries, companies, and people across the globe to improve access to water and manage the challenges facing the planet’s most precious natural resource.

Operating in Africa for over 60 years, Xylem Africa has regional hubs in South Africa, Morocco, Ivory Coast, Kenya and Egypt, and has dozens of partners covering most of the continent’s countries. Globally, Xylem employs around 23 000 people and earned a combined revenue of US$8,1 billion in 2023.

“ISO certification is not just a piece of paper.

Achieving ISO 14001 and 45001 certification represents tremendous effort by Xylem SA’s staff across a multi-year process that required numerous adaptations and improvements,” says Chetan Mistry, Strategy and Marketing Manager at Xylem Africa.

“Their dedication and effort brought us here, supported by our seriousness around employee safety, environmental protection, quality control, and our focus on customers. Congratulations to the Xylem team members who made this cer tification a reality, and we’ll continue enhancing our ability to serve our employees, partners, and customers.”

The ISO 14001 and 45001 management systems standards are developed and enforced by the International Organisation for Standardisation (ISO), the globe’s primary creator of voluntary International Standards.

Established in 1946, it is one of the oldest non-gover nmental inter national organisations. Each standard is designed on the feedback and consensus of industr y experts, enabling trustworthy Chetan Mistry, Strategy and Marketing Manager at Xylem Africa.

trade and cooperation. Companies undergo rigorous scrutiny and testing to align with a specific standard, ensuring that ISO certification represents focus, care, and diligence in that area.

RoSPA recognition for safety

Helping every drop count

Globally, Xylem was also recently acknowledged at the internationally renowned Royal Society for the Prevention of Accidents (RoSPA) Health and Safety Awards for its unwavering commitment to protecting lives. During the 2024 ceremony, Xylem received an incredible 42 RoSPA awards, representing 18 countries. This sweep triples Xylem’s 14 RoSPA Health and Safety Awards, which were received last year and represented eight countries.

RoSPA announced Xylem’s achievement in June 2024, making the water solutions leader part of a legacy that values dedication to high safety standards and the well-being of individuals and signifies a commitment to excellence.

The awards are even more notable given the competition, selected from a pool of nearly 2 000 entrants from 50 countries.

“RoSPA’s criteria encompass a comprehensive assessment of health and safety management systems, leadership, employee engagement, risk assessment and continuous improvement initiatives. Participating in the programme is an invaluable oppor tunity for us to benchmark our health and safety per formance against industr y best practices, learn from leading safety practitioners, identify areas for improvement, and amplify our efforts to create a safe and healthy work environment for our colleagues,” says Autumn Crum, Xylem’s Director of Environment, Health, Safety and Operational Sustainability.

Xylem is at the forefront of modern water solutions, both commercially and in altruistic work through its Watermark social investment branch. The name “Xylem” refers to an organic membrane that helps move water in plants, and like its namesake, Xylem strives to connect communities and water through innovation and partnerships.

Xylem’s range of pumps, which includes market-leading brands such as Lowara, Flygt, and Bell & Gossett, are renowned for their efficiency, reliability, and advanced technological features.

In addition, Xylem provides consultation, design, installation, engineering, repair, and equipment rental services directly and through its network of experienced partners.

In recent years, the Xylem stable of brands has become synonymous with modernising wastewater facilities, detecting leaks in elaborate pipeline networks, providing dewatering solutions to mines, enabling efficient water use for agriculture, and delivering cutting-edge solutions such as solar pumps and UV sanitisation.

In a world of steadily declining supplies, fundamentally inefficient infrastructure, easily contaminated resources, and increasingly unpredictable weather, Xylem strives to bring together water’s economic and social benefits.

It suppor ts the United Nations’ Sustainable Development Goals, specifically SDG 6 (clean water and sanitation for all), but with the view that water underpins all development goals.

By achieving cer tification in ISO 14001 and 45001 management systems, Xylem SA demonstrates that it takes these goals seriously, striving for a world that provides clean water to everyone.

IMIESA September 2024

29

WATER & WASTEWATER

MANAGING YOUR GARDEN THE WATER WISE WAY Despite being the 30th driest nation in the world, most of our gardens are not planned with water conser vation in mind. In South Africa, the agricultural industr y, which includes plant production, uses over 50% of the countr y’s water resources, with water losses ranging from 30% to 40%.

W

ater management is, therefore, very important in the countr y, and gardeners who water their plants often are not doing their part for the environment. It is now time for gardeners to under take strategies to maximise water efficiency and embrace water-saving practices to reduce water waste in their gardens.

SAVING TIPS OF WATER MANAGEMENT IN YOUR GARDEN

1 Understanding your soil type

Understanding the soil type in your garden will minimise runoff and maximise water retention.

Compacted soil reduces porosity and waterholding capacity and occurs most frequently on clay soil. Sandy soils absorb water quickly, so water with a strong flow rate. Also, water more frequently, as water passes through sandy soil quickly. Increase soil water retention by adding lots of organic matter, such as compost. Loamy soils are best as they hold water around plant roots. Water with a moderate flow rate, but less frequently than sandy soils.

2 Installing permeable paving

Increase water holding capacity by installing permeable paving to let rainwater seep through the subsurface beneath pathways and other

Grouping plants with similar water requirements together is essential to achieve effective zoning

30 IMIESA September 2024

Increase water holding capacity by installing permeable paving to let rainwater seep through the subsurface beneath pathways and other hard surfaces

hard surfaces. Using compost as a mulch can reduce watering by up to 70%. Permeable paving is a maintenance-free gardening option which requires no annual planting, no watering, and no fertilising! If this style of gardening suits you, consider installing more paved areas in your garden, for example, a driveway, an entertainment area around the pool, a patio extension or replacing the lawn in areas of heavy usage such as alleyways.

3 Consider the slope of the garden

Gardens situated on steep slopes are more vulnerable to downslope flooding. As the rainy season approaches, the natural topography of the garden can also be used to capture rainwater and divert it to storage tanks for use during dry periods.

4 Plant groupings (hydrozoning)

Grouping plants with similar water requirements together is essential to achieve effective zoning.

Zoning is not only done when new gardens are

Using compost as a mulch can reduce watering by up to 70%

designed but can be applied to existing gardens by moving plants in their dormant period to a more appropriate zone. Zoning the garden can be applied to any size garden, from a balcony to a townhouse garden, to a garden of a few acres. What changes is the scale and size of the individual zones (three pots on a balcony could have plants from each zone, as would a large garden have three different zones).

5 Efficient watering systems

South Africa’s summers are expected to become hotter and drier, with extreme weather events such as freak storms and flash floods becoming more frequent as a result of climate change. Deep soakings encourage roots to grow downwards and utilise moisture deep in the ground. The plants are then more drought resistant. Ensure that water reaches the expected root depth – 20 cm for lawns, vegetables and herbs; 60-90 cm for trees and shrubs (taken down by capillary action).

Allow the top 8-10 cm of soil to dry out before watering again. When planting a tree, place a water pipe from the base of the tree roots to just above the soil surface. Watering into this pipe will take the water directly to the tree roots and encourage deep rooting.

A water wise garden is a wise investment, which will result in reduced maintenance, long term sustainability and reduced budget.

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LEGAL

TWO-STAGE TENDERING IN SA’S CONSTRUCTION SECTOR NEEDS COLLABORATION Construction projects in South Africa are often concluded in a single stage – designs (usually incomplete) are used by the main contractor to provide tenders for constructing the project. However, two-stage contracting is a growing trend, where engineers work in concert with the preferred contractor to finalise the design, typically from an early stage in the project life cycle.

T

he combined effort upfront allows for quicker finalisation of the design and ultimately results in an improved construction process,” says Euan Massey, director at MDA Attorneys.

“Instead of dictating to the contractor, who then must execute the project works, two-stage tendering allows for practical and realistic prequalification based on the contractor’s preferred method of working. Any changes can be ironed out early, reducing the likelihood of variations during project execution.”

Two-stage procurement in South Africa’s public sector The concept of two-stage procurement has been in place in South Africa for a while. An example is the two-envelope system used in public sector projects. This system involves an initial technical proposal without costs, aimed at establishing that tendering companies have the necessary skills and capacity to undertake the project. Once the bidders have been narrowed down to those with the skills and capacity, the second “envelope” containing costs is considered, providing the ability to rule out contractors who are not proficient.

MDA Attorneys is also seeing another benefit par ticular to South Africa in examples where contractors have developed relationships with local communities and subcontractors. Two-stage procurement can enable the adjudication and negotiation of contracts Euan Massey, Director: MDA Attorneys

32 IMIESA September 2024

based on the contractor’s track record in uplifting these local communities.

Better scoping, lower risks On a two-stage contract, a contractor or group of contractors is brought on board to determine and cost works while carrying out preliminary activities (usually confined to the client’s design team). They do this while collaborating with the client and supply chain. The same contractor is not guaranteed to win the second stage, but it is usually in the best interests of both parties for it to continue with the contract.

As Massey explains, two-stage contracts allow the contractor to properly understand the scope, raise questions regarding constructability and other risks, such as ground conditions, and to price the work before it starts on site.

Under two-stage contracts, clients will pay more up front before appointing a main contractor. However, Massey says this additional cost should be seen in context – without the early contractor involvement, tendering contractors will include contingency in

their prices for the perceived risks in the project, resulting in additional costs to the client. Even if the contractors do not include these contingencies due to work scarcity, for instance, they will pursue variations and claims when changes and risks do materialise, and this will again result in higher costs for the client.

“Thus, advocates of two-stage contracts say it is in everyone’s interest to work closely together, citing the fundamental principle that planning ahead can usually save costs later on. This applies to construction more than most businesses because the costs of delay are so high. As with all relationships it will work far better if the par ties work in a genuinely collaborative and trusting way,” Massey continues.

Narrow margins, greater risks Depending on the nature of the works, contractors on a single-stage tender are unlikely to get more accurate pricing than around 10% of the final price. Overheads and profit will be priced at between 5-10%, making this a high-risk strategy. “You’ll be happy if you get it right, but if you get it wrong, it’s a disaster,” says Massey.

With two-stage contracting, clients also run the risk that contractors are unrealistic in their initial pitch during the first stage to get into the second stage and then hike up their prices.

“MDA Attorneys has always advocated a collaborative approach to contracting and this is crucial in two-stage contracting. Contractors operate in a really challenging market with high risk but if the client, consultant and contractor are working collaboratively from the star t, there should be fewer surprises, as their risk assessments should already have factored in higher prices,” Massey concludes.

ROADS & BRIDGES

TEXAS BRIDGE INSTALLED IN UNDER 24 HOURS

Engineers decided on a method which utilised a gantr y system with a jack and slide system on top. This would enable three directional movement to fine-tune adjustments during setting and account for misalignments.

Preassembled for installation

T

he solution came in the form of the only known S-curved, network tied bridge in the world – which was efficiently set overnight by heavy-lifting specialist, Mammoet.

Prior to its installation, the heavily travelled Northaven Trail on the west side of U.S. 75 and the Cottonwood Creek and White Rock Creek trails on the east side abruptly halted at the roadway. In order to access the trails on the opposite side of one of Texas’ busiest highways, cyclists and pedestrians had to detour through a dim underpass.

Mammoet teams worked with Ragle, Inc. and bridge designer HNTB to carefully plan the execution, considering multiple options to find the best fit. Installation with a crane would prove risky and complex, with no suitable area

Mammoet's teams moved the Northaven Trail Bridge into place over a weekend

In Dallas, Texas, the Northaven Trail Bridge has been installed as a crucial connection for multiple regional bicycle and pedestrian pathways.

to set the crane without causing a significant impact on area traffic and road closures.

Additionally, the bridge’s design would require a complex bracing system if supported at midspan, so the use of a jacking system was also ruled out.

The 61 m long bridge was assembled away from its installation location. On the Friday evening of the installation weekend, it was jacked up and loaded onto a pair of double 8-line SPMT trailers, then moved to the edge of the road. The length and width of the bridge required the use of turntables on top of the trailers for added manoeuvrability.

On Saturday night, once the highway was fully closed to traffic, the bridge was transported to its installation position and the gantries were built around it. To ensure disruption was kept to an absolute minimum, at least one frontage road remained open, allowing traffic to move along U.S. 75 without a significant detour.

The bridge was then lifted off the trailers using the gantr y/track combination.

Steadily the bridge was raised above the road surface, skidded over, and set on its piers at about 11h00 on Sunday morning – a highly choreographed move that was executed flawlessly over a total of 20 hours.

The Northaven Trail Bridge has established a crucial connection for multiple regional bicycle and pedestrian pathways

IMIESA September 2024

33

ROADS & BRIDGES

Signs of extensive flood damage on the northbound dual-carriageway section of the Mhlali River Bridge. Following its immediate closure for repair, vehicles were diverted onto the southbound carriageway bridge, with one lane open in each direction

REHABILITATION OF THE FLOOD DAMAGED MHLALI RIVER BRIDGE The catastrophic KwaZulu-Natal floods of April 2022 caused extensive damage to the Mhlali River Bridge, located along the northbound carriageway of SANRAL’s National Route 2 (N2) when large volumes of waterborne debris caused significant blockages to the hydraulic opening, resulting in the overtopping of the structure.

A

s a result, the 123 m long concrete deck became buoyant and was unseated off its bearings, shifting some 600 mm downstream. The concrete approach slabs of the bridge were left unsupported as the fill behind the abutments had been scoured out by the flood water,” explains Kerusha Ayer, a structural civil engineer within Naidu Consulting’s Bridges and Buildings Division. Naidu Consulting was subsequently appointed by SANRAL to provide consulting engineering services and construction supervision for the emergency repair.

Given the severity of the damage, the nor thbound section at the bridge was immediately closed to traffic pending its rehabilitation. This resulted in significant

During the April 2022 floods, the 123 m long concrete deck of the northbound dual-carriageway bridge became buoyant and was unseated off its bearings, shifting some 600 mm downstream. Signs of debris can be seen lodged in the bridge soffit

34 IMIESA September 2024

socioeconomic impact and disruption as the route is a vital economic link to the port of Durban from areas north and south of the countr y and into other Southern African countries. Toll fee collection at the nearby Tongaat Toll Plaza was also suspended, resulting in a loss of revenue for SANRAL. In the interim, vehicles were diverted onto the southbound carriageway bridge, with one lane open in each direction. Compounding the issue, a nearby alternative route was also closed due to another bridge being damaged in the same floods. This caused significant traffic buildup along the N2 in the vicinity.

“Therefore, the reinstatement of the bridge was urgently required and needed an ‘out-of-the-box’ approach for vertically and

horizontally jacking the bridge deck back into its original position and alignment,” Ayer continues.

Breather holes Naidu Consulting had incorporated into the rehabilitation solutions to increase the resilience of the bridge in the case of flood events of similar severity. The effect of buoyancy had resulted in the uplifting of the deck off the shear studs in the bridge’s line rocker bearings (at the time, the only lateral restraint connection of the deck to the substructure). To prevent this from reoccurring in future, “breather holes” were cored into the precast beams of the deck.

“This will allow trapped air between the beams to escape, thereby reducing the buoyancy effect on the deck in case of future extreme flood events,” Ayer explains, adding that shear restraint blocks were also proposed and accepted by the client.

These were constructed on the abutment and pier shelves to restrain the deck from lateral movement.

Jacking approach For the reinstatement phase, Naidu Consulting came up with a solution that allowed for the concrete deck to be jacked off a supporting frame with sized steel members, supported off the pile caps of the abutments and piers. This overcame the challenge of limited space on the abutments and pier shelves to place the jacks required for lifting the deck.

ROADS & BRIDGES

Another challenge was the requirement for the bridge deck to be realigned horizontally back into its original position. Naidu Consulting’s proposal incorporated the use of a horizontal jacking system bolted to the bridge piers and abutments. It was proposed that the deck be pulled into position using a steel spreader beam with a sliding surface, after levelling out the soffit of the deck using infill members below each of the precast beams.

The contractor decided to use a different jacking system during construction, which was accepted by the team. Their solution was for the deck to be suppor ted entirely by a temporar y works system bolted onto the abutments and piers. A steel jacking stub member was attached to the soffit of the spreader beam, allowing the horizontal jacks to bear against this sur face, shifting the whole beam and deck into its correct position.

“The precast beams of the bridge all sat on a camber (var ying soffit levels) resulting in the temporary works having to be designed to accommodate for this to ensure no cracking of the top slab of the deck,” Ayer explains.

These var ying sof fit levels, along with the var ying levels on the bridge deck sur facing due to the cross fall of the road, presented complexity in the method required to achieve the final levels of the bridge within the tolerances called for by the specifications. This was successfully achieved.

Work such as gabion construction, the construction of drains, clearing and grubbing, landscaping and planting of grass enabled the labour targets on the project to not only be achieved, but significantly exceeded

During the repositioning of the bridge, the deck was supported entirely by a temporary works system bolted onto the abutments and piers. A jacking stub member was attached to the soffit of the spreader beam, allowing the horizontal jacks to bear against this surface, shifting the whole beam and deck into its correct position. Some 98 bearings needed replacement

Restoration Restoration work, including crack injection, crack filling and concrete cleaning, formed part of the contract. Parapet coating work was also specified as the displacement of the deck caused damage to the parapets, which required portions of the concrete to be broken off and reinstated.

The large volume of debris carried by the river had also caused extensive damage to the environmentally sensitive area along the river course. To restore the area, labourintensive clearing was subsequently carried out by local community members, with extra care taken to ensure the preservation of the protected tree and plant species in the area.

In addition, landscaping, planting of grass, and gabion work was specified, ensuring the area around the bridge was not just reinstated, but also improved aesthetically.

Conclusion “This project is significant for various reasons. Due to the rarity of the work, there are no standard guidelines for horizontal bridge jacking. Significant risk was carried by the contractor as well as by the consultant due to the highly technical and specialised nature of the work being required in an emergency timeframe,” says Ayer. “For this reason, we had to work closely with the contractor to achieve the correct alignment and levels of the bridge.”

“The highly technical project was successfully completed in an emergency timeframe with no comprise on quality. Fasttracking the repair enabled the full reopening of the north and southbound sections in the shortest time possible, restoring full traffic flows on this vital socioeconomic corridor,” Ayer concludes.

Night shifts and weekend work were incorporated in the construction programme to meet the client’s deadline

TRENCHLESS TECHNOLOGY

Developments in design, construction and rehabilitation of sewers: Part 1 Developments continually take place in the world today. This also apples to sewer design, construction and rehabilitation.

When using new developments, there is a danger that the basics of past developments are not understood. Combining relevant aspects of the past and present creates a synergy that results in better understanding and implementation.

By Alaster Goyns, Pr Eng*

L

OPC/SIL pipe after 10 years with concrete corroded through at sides but not crown

OPC/SIL pipe after 12 years with the top half of the pipe, which was 84 mm thick, completely corroded away

CAC/SIL pipe after 24 years in Virginia sewer, which lost about 10 mm. Behind is an asbestos cement pipe with swollen wall

36 IMIESA September 2024

arge diameter outfall sewers installed in South Africa before 1940 were made of concrete and designed for a 40-year life.

However, in the early 1950s problems were experienced with the corrosion of these sewers. In discussions by members of the Institution of Municipal Engineers concerning this problem, it was agreed to sponsor a research project by the Council for Scientific and Industrial Research (CSIR) to investigate this issue and find solutions. Town councils and concrete pipe manufacturers contributed funding for the project.

The CSIR addressed the problem from three dif ferent angles, namely: the microbiological aspect of how the sulphuric acid was produced that attacked the concrete; the technical aspects of sewer design resulting in corrosion; and the possibility of construction materials that were more resistant to corrosion.

South Africa was not the only countr y experiencing this problem. Research was also being done in the USA and Australia.

In 1947, an American company, Ameron, started manufacturing PVC liners that were anchored into concrete pipes during the manufacturing process. Sewers using these pipes are still operating, but the costs of doing this in South Africa were exorbitant.

For several years, Dr Pomeroy in the USA studied the subject. He developed a theoretical model to predict corrosion depending on the conditions within the sewer and the concrete composition. Similar activities took place in Australia that produce the same output. However, this was published in a format for practical use only in the early 1970s. The Environmental Protection Agency in the USA and the American Concrete Pipe

Association both produced publications in 1974 that explained how this theory could be used in practice by designers.

Of significance is the practical approach based on the materials being used by the CSIR compared to international research. The output from the CSIR research was published in a book entitled “Corrosion of Concrete Sewers” (1959). This covered all three angles mentioned above. The most significant was the choice of material to improve sewer performance despite corrosive conditions.

Aggregate selection An alkaline aggregate was used that would be corroded by sulphuric acid, instead of an inert aggregate that would fall out of the concrete when the alkaline cementitious binder corroded. The combination of binder and aggregate both being alkaline resulted in a more uniform corrosion of the pipe surface and a significantly slower loss in wall thickness. By using an alkaline calcareous aggregate, such as limestone or dolomite, doubling the sewer’s life was anticipated.

The pipe manufacturers who were part of the project proposed an increase in cover to the pipe reinforcement by providing a sacrificial layer. As this was in excess of the standard cover to reinforcement, sewer pipes made with calcareous aggregate and a sacrificial layer could provide a ser vice life six to ten times longer than that of concrete pipes made before these changes were introduced.

Virginia sewer study In 1986, CSIR representatives involved in the earlier research questioned how their work and the theor y developed and published by Dr Pomeroy could be combined and checked in a practical situation. Pipe suppliers were invited to par ticipate. At the time, Ninham Shand Consulting Engineers was involved in a major sewer at Virginia in the Free State. They were invited to join the discussions.

As the downstream section of this sewer was fed by a rising main, serious corrosion was suspected and later confirmed. It was agreed that a trial section with several different pipe materials would be installed and periodically inspected to check the corrosion rates and compare these with the theoretical values.

TRENCHLESS TECHNOLOGY This 65 m trial section was installed in 1988, with an entr y pit at either end, and nine different pipe materials. An adjacent bypass line made it possible to physically inspect the trial section. The sewer was commissioned in 1989 and inspected annually for nearly a decade. Although material losses were observed and recorded, it was difficult to be sure of the real values as the actual internal diameters of the pipes had not been taken when the pipes were installed.

A preliminar y inspection done in 2000 indicated that man entr y would be unsafe.

The pipe manufacturers of the Concrete Manufacturers Association agreed to remove three full length pipes and six half-length pipe sections. Reasons for this were firstly to remove these samples and measure the actual section thicknesses and losses of the different materials, and secondly to construct manholes into which additional samples could be placed.

These circular samples consisted of 17 different sections each 300 mm long made from a range of different concretes. Two cuts were made at 120 degrees apart on the top of these samples so the top sections could be periodically removed and material losses measured. Sewage has been flowing through these samples since October 2004. An additional manhole was constructed in 2010 and 29 short pipe sections 200 mm in length, consisting of 29 different concretes, were installed.

At this time the University of Cape Town (UCT) and an international supplier of calcium aluminate cement took an active role in the project. Two UCT students obtained their master’s degree, and a third student obtained a doctorate based on this project. The latter – in particular – added to the understanding of the corrosion problem.

The information gathered from the Virginia project about the per formance of various concretes under aggressive conditions has provided extremely useful details about the choice of material that can be used in the design of sewers. The results show that using calcareous aggregate and increasing the cover to steel can increase the sewer life by ten times at ver y little increase in cost. For more severe conditions, calcium aluminate cement and calcareous aggregate can be used to add a lining to the standard concrete pipe.

This is particularly useful on smaller diameter pipes as it has less reduction than a thicker sacrificial layer with ordinary Portland cement.

This information shows how important it is to determine the corrosion potential when designing a new sewer, what concrete to use, and when to specify lined concrete pipes.

Site personnel measuring pipe ovality on a sewer line section prior to rehabilitation using cured-in-place pipe lining techniques.

(Source: eThekwini Municipality.)

In most cases where sewers are a metre and larger in diameter, corrosion is likely to be a problem and using lined pipes offers significant advantages.

Design manual

Upcoming SASTT webinar and Part 2 The Southern African Society for Trenchless Technology (SASTT) online webinar planned for 15th October 2024 will address new developments, and the significance of following international developments, we well as how these can be adapted to South African conditions.

For further information, and to register email Rina Stead at director@sastt.org.za and visit www.sastt.org.za.

Part 2 of this article will cover the practical aspects of sewer installation and rehabilitation based on the theoretical developments.

The concrete pipe manufacturers who are part of the Concrete Manufacturers Association published a design manual for concrete outfall sewers in 2009 incorporating information from the Virginia project and international research, as well as hydraulic and structural requirements. By applying the procedures in this manual, problems with corrosion in new sewers can be addressed. *Board member, Southern African Society for This is also significant when considering Trenchless Technology the rehabilitation of aging concrete sewers. (SASTT) Although tightly fitting linings, like cured-in-place pipe or Fold and Form, mean a slight reduction in pipeline diameter, Spirally they generally improve the wound liner being installed hydraulic capacity due to a in a rectangular smoother sur face and no host conduit joints, especially on the larger diameters where this may be as much as 20%.

However, if the interior of the host conduit is corroded, there could be a variable internal profile, including ovality, as well as some misalignment at joints. This could compromise the structural performance of the lining.

Under these circumstances, spirally wound linings which retain their internal profile are more effective and, from about 1 m diameter and larger, will also provide improved hydraulic performance.

SOUTHERN AFRICAN BITUMEN ASSOCIATION (SABITA)

The transition of South Africa from bitumen exporter to importer: Consequences for the road industry Bitumen is often considered the backbone of road infrastructure, ensuring connectivity, economic vitality, and social well-being worldwide. Its versatility and reusability make it the predominant choice of material for all types of road paving, from driveways, parking areas, and access roads to freeways and airport runways.

B

efore 2020 bitumen was readily available from four refineries in South Africa, serving not only local roadworks but also for export.

However, the post-2020 period marked a significant shift. The move to cleaner fuel specifications initiated by government in 2006, together with natural disasters, led to the closure of the two refineries in Durban. No bitumen is produced at the Cape Town refinery due to the change to lighter crude oil processing. The decline of South Africa’s local refinery system transformed the country from a net exporter to a net importer of bitumen.

This paper explores the background of South Africa’s road system, the evolution of the bitumen supply system and events leading to the major transition. It also discusses the challenges faced by the industry and the strategic responses adopted to ensure continued supply for road construction. The paper ends with risk mitigation measures to be considered by the road authorities when sourcing bitumen supplies.

Road system in South Africa South Africa’s total road network is estimated at 750 000 km (as shown in Table 1) and comprises of 618 081 km of proclaimed roads and approximately 131 919 km of unproclaimed roads. These un-proclaimed roads, predominantly located in rural areas, have not

38 IMIESA September 2024

been formally recorded in road inventories and as a result no tier of government is officially responsible for the maintenance and upkeep.

Table 1 highlights the relevant road authority responsible for the various par ts of the network, with the South African National Roads Agency (SANRAL), a national stateowned entity, managing the countr y’s national routes, while the remainder falls under the authority of either provincial or local government departments.

Clause 40 of the SANRAL Act of 1998 allows the Minister of Transport, with the approval of the appropriate provincial premier, to reclassify certain provincial or local roads as National Roads under the jurisdiction of SANRAL. Table 1 includes the recent delegation to SANRAL of 330 km from the Eastern Cape, 952 km from the Northern Cape and 20 km from the NorthWest Province during 2022 and 2023. The figures do not include the requests received of a further 1 650 km from the Eastern Cape and 1 486 km from the Limpopo provinces.

Despite the transfers to SANRAL, 85% of the proclaimed paved road network and 100% of the gravel network still reside under nine provinces and 255 municipalities, of which eight are metropolitan.

FIGURE 1 Historical refinery locations

Bitumen supply: Pre 2020 Prior to 2020, South Africa’s bitumen needs were met by four oil refineries, three of which were located at the coast. Table 2 illustrates the crude oil refining capacity and the bitumen processing capacity of these refineries at the time, whose location are indicated in Figure 1. Collectively, they had an estimated capacity of about 430 000 tons of bitumen per annum. However, these were aging facilities with the most recent commissioning being the SAPREF facility in 1971.

These oil refineries primarily impor ted crude oil to manufacture petrol and diesel for motor vehicles and trucks, with bitumen produced as a residue from the crude oil refining process. The percentage of crude oil converted to bitumen varied between 1 and 4%, depending on local demand for bitumen, and to a lesser extent, export opportunities.

The coastal refineries produced bitumen on a continuous basis because of their fuel and lubricant refining processes. In contrast, Natref could, and is still able to manufacture fuels, without producing bitumen and can also manufacture bitumen via a dedicated bitumen production mode.

Globally, the petroleum refining industry has undergone significant changes driven by decarbonisation strategies. The major oil companies have rationalised their operations, closing smaller and dated facilities and constructing mega refineries.

This, together with the catastrophic flooding and fire incidents experienced at two of the refineries (as indicated in Table 2), led to South Africa becoming a net bitumen importer. Australia, Europe and the United States have witnessed similar closures of several of their refineries, resulting in the increase of bitumen imports. Figure 2 clearly depicts the bitumen production evolution in South Africa.

Currently, only the Natref refinery remains operational with insufficient capacity to meet the national demand.

Its major maintenance shutdown in May and June 2023 resulted in zero bitumen production during that period.

SOUTHERN AFRICAN BITUMEN ASSOCIATION (SABITA) TABLE 1: South Africa’s Road Network

Road Length (km) and Percentage Split (%)

Authority

Paved Length (km)

Percentage

Gravel Length (km)

Percentage

Total

SANRAL

24,126

15%

0

0%

24,126

Provinces (9)

44,625

28%

226,273

49%

270,898

Metros (8)

51,682

33%

14,461

3%

66,143

District/Local Municipalities

37,691

24%

219,223

48%

256,914

TOTAL

158,124

100%

459,957

100%

618,081

Unproclaimed Estimate ESTIMATED TOTAL

158,124

Bitumen demand

131,919

131,919

591,876

750,000

FIGURE 2 Bitumen Production Evolution in South Africa

Local demand for bitumen has declined since the late 1980s, when an annual volume of up to 400 000 tons was consumed. Current demand fluctuates around the 250 000 tons mark. About 60% of the bitumen production capacity was concentrated in Durban, with surplus bitumen expor ted to the SADC region and Indian Ocean Islands. Demand for bitumen in the neighbouring SADC region has always been relatively small, estimated at approximately 80 000 tons per annum, and largely dictated by the availability of funding for road projects.

Sabita Road Review To enable key insights, the Sabita Road Review is produced on an annual basis and provides Sabita members with a perspective of the South African road network and its impact on the bituminous product industry.

This review assists members in formulating their business plans and engaging with other organisations related to road provision, usage and maintenance programmes.

Data is compiled on road lengths, condition and usage, estimates of expenditure, road safety and projections of the bitumen market covering the specific period of the MediumTerm Expenditure Framework (MTEF).

Figures 3A and 3B extracted from the 2023 Sabita Roads Review illustrate the trends in South Africa’s bitumen market in relation to

the expenditure on national and provincial roads. The Sabita Road Review projects that the bitumen market will likely remain stable, with demand not expected to drop below current levels. Over the MTEF, demand could rise to around 315 000 tons, though it is not expected to exceed 362 000 tons over this period.

Bitumen imports and exports South Africa has recently become a net impor ter of bitumen, as illustrated

by Figures 4 and 5 which indicate the dramatic changes in the country’s import/ expor t balance. Prior to 2020, South Africa imported small amounts of bitumen

and was related to refinery maintenance shutdowns or the impor t of specially formulated bitumen products.

Globally the country was at about 120th position in bitumen imports. However, by 2023, South Africa had imported 275 000 tons of bitumen, rising to 15th place globally.

In contrast, bitumen exports have declined sharply, falling to 29 000 tons in 2023 (as shown in Figure 5).

This shift has required significant investments in dockside discharge and bulk storage facilities to accommodate imported bitumen. Since 2021, approximately 24 vessels have delivered bitumen to the country. Notable shipments include the

TABLE 2: Refineries in South Africa (pre-2020)

NAME

LOCATION

CAPACITY

OWNERSHIP

CAPACITY

TIMELINE TO NET EXPORT

ASTRON REF

Cape Town

100 000 b/d 1966

Astron Energy

54 000 tons Bit p.a.

Refinery closed Q3 2020.

Reopens in May 2023 processing only low sulphur (sweet) crude with no bitumen production.

ENREF

Durban

135 000 b/d 1954

Engen

198 000 tons Bit p.a.

Typically 160 tons with 50% into Africa

Refinery closed after a fire in December 2020.

NATREF

Sasolburg

110 000 b/d 1971

Sasol 64%/Total 36%

100 000 tons Bit. p.a.

For the foreseeable future only refinery producing bitumen.

SAPREF

Durban

180 000 b/d 1963

BP 50%/ Shell 50%

80 000 tons Bit. p.a.

Major floods closes refinery in 2020 and Shell divests from South Africa.

TOTAL 432 000 tons Bit. p.a.

IMIESA September 2024

39

SOUTHERN AFRICAN BITUMEN ASSOCIATION (SABITA) Figure 3A

refinery to storage within South Africa is shown in Figure 6.

The shift to imports locally has coincided with global price increases, with bitumen prices surging from R6 000 per ton in early 2021 to R14 000 per ton. This increase is driven by global refining trends, including the rise of mega-refineries and stringent fuel quality regulations. The war in Ukraine has further exacerbated these costs, impacting oil prices and transport expenses. Figure 7 shows the change in bitumen price from 2021 to 2023.

Traditionally, the price of locally produced bitumen had little to do with local production costs and inflation, but more so the cost of acquisition of crudes, which are globally determined and the price at Durban of a petroleum product, marine fuel oil (bunkers), which was regarded as an export parity procedure.

FIGURE 3A

Figure 3A FFIGURE igure 33B B

IMPACT ON THE ROADS SYSTEM The transition to being a net importer has introduced several challenges for the South African roads industry.

Source of supply

Figure 3Cadiz B Palanca from Colombia and the Viveka, which has made multiple deliveries to Cape Town and Durban. Investments in storage facilities by companies like Rubis, FFS and ARIAsphalt have played key roles in developing the necessary infrastructure.

Rubis, through FFS, has around 4 000 tons of storage capacity in Cape Town.

FFS is developing significant terminal storage infrastructure in Durban. Phase 1 of FFS’s Durban storage units went operational in February 2024. This facility includes 7 500 m3 of storage capacity with heating facilities, an import pipeline, and loading and weighbridge facilities. Phase 2, expected to be completed by June 2025, will add 12 000 m3 of storage capacity. ARIAsphalt has invested in 7 500 tons of bitumen storage tanks at their Durban facility in the Bayhead area and are also looking at expanding to 19 000 tons of bitumen storage in 2025. Masana has invested storage at both the customer and offsite with a total of 4 000 tons of storage.

40 IMIESA September 2024

Other importers have invested in bitutainer storage facilities that add a further 20 000 tons of bitumen storage to the national capacity. The impor tation process for bitumen, from production at an international FIGURE 4

The first challenge is for the potential bitumen impor ters to find bitumen of appropriate quality and consistency, and a reliable supplier. This involves appropriate due diligence on the supplier and the source refiner y. The supplier in many instances sources bitumen from different refineries and not all sources of crude oil are suitable for production of bitumen of appropriate quality and consistency for road paving purposes.

The bitumen importer also must ensure that there is no trade embargo in place preventing the importing of the bitumen from a specific source refinery.

SOUTHERN AFRICAN BITUMEN ASSOCIATION (SABITA) Market Demand Information The second major challenge is for the industry to provide adequate long-term, market demand information. Previously this was not a problem as bitumen was readily available to the market and the quality and consistency of supply were non-issues.

Importers need to have accurate data to understand bitumen demand, volumes required and proposed binder grades. Buyers need commitments so that ships can be timeously sourced due to specialised cargo handling requirements (heating, cargo pumps, tank and piping insulation, etc).

Bulk liquid bitumen is normally shipped in purpose-built tankers that are dedicated to bitumen service and on average around 5 000 tons. The economy of scale makes these ships expensive to operate and there are a limited number of vessels available for charter and the optimum quantity, timing and execution of bitumen orders is a critical factor to procuring material.

Forecasting production requirements will also be key to meeting client needs and importation has led to significant increases in product lead times. Most bona fide importers have invested large amounts in the financing of bitumen supply and the financing of capital storage and heating facilities, and the producers and client bodies to build partnerships and ensure there is constant engagement on supply requirements.

Constant quality checking and sample collection The quality of bitumen for the road industry must conform with the relevant specifications

FIGURE 5

of the producers and client bodies. In South Africa, the quality assurance of bitumen is done in accordance with the requirements of SANS 4001- BT1:2012, Edition 1.1 Penetration grade bitumen.

For several years South Africa has been transitioning to a specification system which strives to define bitumen properties more closely related to the performance of bituminous layers in a range of environments of climate and traffic. To facilitate the process of implementation of this per formance related specification, SABS has published a technical standard, SATS 3208 (2019) Per formance Grade (PG) specifications for bitumen in South Africa, which certain road authorities have adopted as a project specification and all bitumen must also meet

FIGURE 6 Importation process for bitumen – production to storage within South Africa

FIGURE 7

the requirements. All bitumen used for road pavements construction in South Africa should meet the specification requirements and, in most instances, both specifications are being specified.

The quality assurance process associated with imported product has meant a lengthy testing regime with the first tests conducted on refinery samples. This involves costs of collecting the samples and flying to South Africa for testing. The second and third tests are conducted on samples taken on loading and once the ship has reached port. In most cases, it seems that little testing is being outsourced to special agencies and the testing has kept local laboratories busy. Once the offloading of the vessel has occurred, the frequency of testing is recommended at least one test per 500 tons with the minimum test of G*/ Sin δ indicating acceptable results for the grade supplied.

Importers and producers are developing testing data libraries taken from samples across a host of source refineries to get a greater deal of comfort and understanding regarding the quality and consistency based on imported bitumen origins.

Samples are a critical part of the import process and not all importers treat it as such. Sometimes one must be alert to the issue of producing samples for product from questionable sources or producing test certificates for product from loading points where refineries don’t exist.

Logistics and planning A major challenge to the importer is to ensure that all the logistics and planning issues are dealt with timeously. The timing of the vessel arrivals into port depends on upfront planning with the port authorities for berth and traffic

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SOUTHERN AFRICAN BITUMEN ASSOCIATION (SABITA)

clearances. The roads industry is unfamiliar with the time constraints and logistics and in many cases the experienced importer supplies the storage.

Importers must contend with issues such as late arrivals of vessels due to storms and the possibility of having 50 to 60 hauliers waiting and the operations extending past the weekend, resulting in mounting costs. There have been instances where the temperature of the bitumen at arrival was 110oC and heating delays must be considered.

Adequate pricing models Finding a pricing model for imported binders that industry agrees on will minimise contract delays as local supply will continue to be severely constrained. The client and engineer need to understand the new cost complexities of bitumen transpor t and some of the risks and outcomes as solid motivations for additional costs. Currently there is no standard of the acceptance of monthly published prices from the local oil refineries, and the relatively small volumes available from NATREF has little bearing and relevance on the cost of product being imported, stored, heated and distributed.

ISSUES FOR CONSIDERATION BY THE ROAD AUTHORITIES Source confidence The refinery source of the bitumen is an important and critical element of information for both importers and the client body, the road authority. The source affects the bitumen compliance, quality, consistency and ultimately contributes to the durability and long-term performance of the pavement.

Road authorities need the source information to manage their risks, meet their specification requirements and to ensure a successful project outcome. The road authority will need to ensure that the refinery source stability and reliability does not impact on the supply chain.

Whichever specification is specified by the road authority, Performance Grade (PG) or penetration grade or both, knowing the refinery source will assist in giving some comfort in complying with the specifications, and if the project suffers from pavement performance issues, the traceability back to the source refinery assist in the investigation and root cause analysis.

Knowing the source assists in regulatory compliance, be it meeting trade embargo restrictions or being aware of differing regional environmental standards allowing permissible levels of compounds.

42 IMIESA September 2024

Experienced consignor/importer

Conclusion

Experienced and reputable consignors and importers provide road authorities with high levels of expertise in quality assurance, supply chain management, risk mitigation, cost management, and technical support.

Such impor ters have access to good testing facilities and can ensure that the bitumen meets the required specifications and per formance standards, conducting regular quality checks both before shipment and upon arrival. Their established quality control protocols can quickly identify any quality issues.

The experienced impor ters also understand international logistics and supply chain matters and have adequate mitigation measures in place. They have good relationships with their suppliers, and they can provide clear and transparent pricing to their client bodies. Experienced and reputable impor ters are those with significant investments in storage or gantries for ship to truck.

Traders in the market typically act only as intermediaries, sourcing bitumen from multiple suppliers and may not have direct control over the quality of the bitumen, relying on the supplier’s quality assurances without independent verification. Traders typically are not transparent with their pricing and unable to negotiate better deals with their suppliers.

Lots of traders have zero interest in the market and make the product a commodity with profits never seen in SA.

Post-2020 has witnessed a marked shift in South Africa’s bitumen supply chain. The closure of the Durban refineries, driven by regulatory changes and natural disasters, and the shift to lighter fuel processing at the Cape Town refinery, have fundamentally altered the country’s position from a net expor ter to a net impor ter of bitumen.

This shift reflects broader global trends in the petroleum refining industry, where decarbonisation strategies have led to the closure of smaller refineries and the construction of mega-refineries.

The period has introduced some complex challenges for the roads industry, including the securing of consistent, high-quality bitumen supplies. Long-term planning, quality assurance processes, and logistical coordination are now critical to ensure reliable bitumen imports. Adequate storage and temperature control remain essential for maintaining bitumen quality and mitigating potential supply shortages. This has resulted in significant investments in dockside discharge and bulk storage facilities.

The road authorities have a critical role to play in actively engaging in the quality assurance process, working closely with importers to assess refinery standards, testing protocols, and logistics management.

The complexities of bitumen pricing and transpor tation have to be understood so that informed decisions can be made about project costs – planning for potential risks such as supply disruptions or inconsistent quality and the implementation of mitigation strategies.

By maintaining close collaboration with experienced consignors and importers, road authorities can ensure that the materials used in road construction meet safety and per formance standards, ultimately contributing to the success of infrastructure projects across the country.

Bitumen importers and the road authorities need to adapt to the new realities of South Africa’s bitumen market to ensure the long-term per formance of the nation’s road infrastructure.

Sabita, in pursuit of excellence, will render support to the industry in navigating these new realities. This includes suppor ting trustworthy, reputable importers investing in the industr y in the interest of the production of a consistently quality product and will do what it can to guard against unscrupulous practices and traders causing short-term disruption.

Storage facilities/testing capabilities Importers of bitumen need to have good local storage and testing facilities. Bitumen needs to be stored at specific temperatures and proper temperature control prevents hardening and premature ageing and remain free from contamination. Adequate storage capacity provides some level of confidence regarding supply shortages and ensures adequate stock rotation.

Importers with access to good testing facilities can verify the bitumen meeting specifications on arrival and provide regular testing for consistency of product quality.

In this new regime of South Africa being a net importer of bitumen, importers who have invested in local storage and testing facilities give comfort to the road authorities that the bitumen supplied will be of consistent and high quality. Bona fide importers who have invested and are willing to understand the players and stakeholders in the industry build a strong market reputation.

CEMENT & CONCRETE | MILESTONE PROJECTS Some of the precast columns at Cape Concrete’s production yard

Precast concrete an essential component in boutique winery construction Concrete Manufacturers Association (CMA) member, Cape Concrete Works, played a crucial role in the construction of a winery at Taaibosch Wines – situated on the lower slopes of the Hottentots Holland Mountain range just outside Stellenbosch – ensuring that it was built in time to process the 2019/20 harvest.

Precast retaining walls and precast columns

T

aaibosch Wines was bought in 2017 by a European consortium when the estate was then known as Cordoba. It offered ideal soil, a cool climate and an outstanding quality of grape varietals, elements which today contribute to the crafting of exceptional boutique-quality wines.

Process engineering was the focal point of the project and every element, from the wine processing equipment to the precast concrete elements, was custom designed. This not only meant trouble-free construction and plant assembly, but also proved to be the most costeffective option.

Unlike many construction projects where problems are only unearthed on site and costly to remedy, the planning stage on this project took two years such that the smallest details were incorporated into the design and building schedule. This is why when it was completed in February 2020, actual construction and plant assembly only took a year.

The project began with the appointment of Schalk Willem Joubert, one of the country’s most experienced winemakers as its managing

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CEMENT & CONCRETE | MILESTONE PROJECTS

A precast panel with two protruding feet for vertical alignment

director, together with a team of professionals with the enviable reputation of bringing the Ruper t and Rothschild Classique Winer y and some other high-end winer y ventures on stream.

The professional line-up was as follows: consultC Engineering, process engineers and principal agents; Malherbe Rust Architects; MPro Consulting Engineers, structural and civil engineers; Hennie Kleynhans QS, quantity surveyors; CSV Construction, main contractors; and Cape Concrete Works, precast concrete producers.

According to Charl de Kock of consultC Engineering, meeting all the building and plant assembly deadlines was vital to the success of the project. “Our schedule was simply too tight to allow for any changes during construction.

Precast assisted us in this regard, which is why we planned its use from the outset.

Moreover, it is easier to programme and eliminates rain delays.”

The 1 600 m² winemaking plant was built on sloping land at the bottom end of the estate. It comprises a 1 000 m² twin-storey processing plant and cellar, which was attached to an existing 600 m² warehouse.

“One of our major challenges was converting the warehouse into an integral part of a hi-tech winery. Apart from the roof, it was completely gutted and rebuilt,” said de Kock.

The upper level of the new building is being used for the early wine-making stages such as grape crushing and initial cooling, and the lower ground floor section for maturation and ageing. In addition, a doublestorey brick and mortar office building was erected adjacent to the crushing plant on the upper level.

Earthworks and retaining walls A large volume of ear th had to be shifted to create a platform for the new building,

44 IMIESA September 2024

which was built on the same level as the existing warehouse. The excavation left a soil embankment approximately 7 m metres high, which had to be retained. Rather than build a separate retaining wall, the rear wall of the new structure and half of one of the gable-end walls doubled as retaining walls. In addition, half the opposing gable-end elevation was also constructed using precast slabs in order to maintain architectural symmetry.

The retaining walls were built with precast panels measuring 7 m x 2.4 m x 345 mm and the void between the walls and embankment was filled with soil and compacted. The remaining halves of the gable-end walls and the other wall were built with conventional brick and mortar masonry between the columns.

A considerable advantage of the winery’s design is that the upper floor and the top of the embankment are level, which means grape-laden containers and other vehicles can be wheeled directly off the embankment onto the upper floor without the need for an access ramp. Furthermore, once crushed, grapes can be gravity-fed from the upper level to the ground level processing section.

One of the column concrete bases showing the templates for rebar alignment

Oval columns The upper level floor comprises a reinforced insitu structure supported by 32 six metre high oval-shaped precast columns.

“Aesthetically pleasing finishes were impor tant project elements, which is why we opted for oval columns,” said de Kock.

“They are more easily produced with precast manufacture and the nice thing about them is that when looked at side-on they appear to be only 140 mm thick. And of course, being precast, their quick installation enabled the upper floor level to be cast much sooner.”

“Given our time constraints, this project would have been impossible without the use of precast concrete,” said Servaas de Kock of Malherbe Rust Architects. “A major advantage is that it can be produced while other building activities are under way, and this saves time.

It may appear more expensive than in-situ on a direct item-for-item basis but when timesaving, quality, reliability and safety aspects form part of the equation it wins hands down.”

Keeping it modular “One of the main challenges in using precast is keeping it modular. We could have opted for innumerable shapes and sizes, but this would have proved too expensive. Instead, we devoted a considerable amount of time in finetuning our precast designs before the first moulds were built and having Cape Concrete on board from the outset made this process much easier; once the moulds were made it was just a matter of repeated casting,” he explained.

Structural engineer, Henk Burger of MPro Consulting said the precast panels were installed using inver ted construction. This involved first casting a blinding layer and then lifting the panels into position with a 130 tonne mobile crane. Each panel was cast with two 360 mm x 345 mm feet at the bottom end flanked with starter bars. The feet came to

CEMENT & CONCRETE | MILESTONE PROJECTS

35MPa, the screed was sloped to create falls to stainless steel drainage slots so that solids can be washed off the floor. The tiling was done by highly skilled ar tisans, who created channels between tiles for water drainage.

Some of the oval columns prior to the assembly of shuttering for the first floor

Wine tanks

rest on the blinding layer, and steel shims were inserted under the feet for vertical alignment.

Once foundation reinforcing had been installed, concrete was poured around the base of each panel, which remained propped until the upper floor section had been cast.

“The only downside with this approach was that we had to prop the walls a little longer than usual, due to the walls being designed as propped cantilevers,” said Burger.

The panels were also cast with keys on each vertical joint. These formed ducts for grouting the panels together.

“It’s much easier to build accurately with precast walls. Not only is it more difficult to achieve the same accuracy with in-situ construction, but it’s also much more time consuming, given that precast elements can be manufactured while preparation work and foundations are continuing on site. Moreover, with in-situ ever y shutter board can be out of line so the chance of error is far greater.

By contrast, if in the unlikely event that a precast panel or column does not meet design specifications it can be simply exchanged for another,” said Burger.

position, the columns were vertically aligned with fibre-cement shims.”

Another major consideration was that the winer y’s upper level floor had to be 100% waterproof and it was designed to accommodate this proviso. Cast in-situ with high-strength reinforced concrete, the floor has a loading capacity of 16 kN or 1,6 tonnes per m² and binds together with the walls. After the initial curing, the entire slab was covered with a layer of water for 10 days to ensure even curing and no cracking. The shuttering was stripped off the deck only once the concrete was fully cured.

Special hard-wearing ceramic tiles impor ted from Germany were used to line the floor. To avoid air pockets, they were laid as an integral part of the floor structure on a 100 mm cementitious screed. Rated at

Besides the precast panels and columns, there is a third precast and equally important concrete element in this project, namely, precast concrete wine tanks. Imported from Italy, initially 10 tanks were fitted for the first season. Another 26 tanks were installed and ready for the second har vest.

As Charl de Kock explained, concrete wine tanks exhibit far fewer temperature fluctuations than their stainless steel equivalent, which display hot and cold spots.

“Quality gains using concrete tanks are huge. Stainless steel tanks are better suited to the initial fermentation process when the wine is moving,” he added.

In order to ensure that the plant was fully functional by the end of Februar y 2020, some of the wine processing equipment was installed in September 2019 even though not all of the building work had been completed.

Other aspects of the programme such as the building of roads, the upgrading of water and electricity supply, installation of Wi-Fi, inter alia, all took place in tandem with the execution of the winery to complete this world class project, which set a new benchmark for precast construction.

Column installation A different method was used to install the columns. They were cast with corrugated grouting ducts rather than protruding rebar and were lowered onto star ter bars set in concrete bases and then grouted in position.

“The advantage of this process is that once the columns are grouted in position, the props can be removed within 24-hrs,” explained Burger. “However, the grouting ducts had to be cast with a tight tolerance of 2 to 3 mm so that they could match the starter bar alignment.

And Cape Concrete supplied CSV Construction with steel templates to ensure that the starter bars were cast with the required degree of accuracy to match the column ducting. Once in

Cape Concrete’s oval precast columns look fit for purpose at Taaibosch Winery’s processing cellar

IMIESA September 2024

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AECOM siphokuhle.dlamini@aecom.com AFI Consult banie@afri-infra.com ARRB Systems info@arrbsystemssa.com Asla Construction (Pty) Ltd johanv@asla.co.za BMK Group brian@bmkgroup.co.za Bosch Projects (Pty) Ltd mail@boschprojects.co.za BVI Consulting Engineers marketing@bviho.co.za CCG puhumudzo@ccgsytems.co.za / info@ccgsystems.co.za Civtech Engineers (Pty) Ltd admin@civtech.biz Corrosion Institute of Southern Africa secretary@corrosioninstitute.org.za Dlamindlovu Consulting Engineers & Project Managers info@dlami-ndlovu.co.za EFG Engineers info@efgeng.co.za Elster Kent Metering Mark.Shamley@Honeywell.com EMS Solutions paul@emssolutions.co.za ENsync Engineers info@ensync.africa ERWAT mail@erwat.co.za Gabion Baskets mail@gabionbaskets.co.za GIBB marketing@gibb.co.za GIGSA secretary@gigsa.org GLS Consulting info@gls.co.za Gorman Rupp Cordeiro@gormanrupp.co.za Gudunkomo Investments & Consulting info@gudunkomo.co.za Hatch Africa (Pty) Ltd info@hatch.co.za HB Glass Filter Media info@hardybulkinglass.com Herrenknecht schiewe.helene@herrenknecht.de HSA Technology (Pty) Ltd cs@hubersa.com Hydro-comp Enterprises info@edams.co.za IMQS Software (Pty) Ltd shemine.adams@imqs.co.za Infrachamps Consulting info@infrachamps.co.za INFRATEC info@infratec.co.za Institute of Waste Management of Southern Africa iwmsa@iwmsa.co.za IQHINA Consulting Engineers & Project Managers info@iqhina.co.za iX engineers (Pty) Ltd hans.k@ixengineers.co.za Izinga Holdings info@izingalabezi.co.za JG Afrika DennyC@jgafrika.com KABE Consulting Engineers info@kabe.co.za Kago Consulting Engineers kagocon@kago.co.za Kantey & Templer (K&T) Consulting Engineers ccherry@ct.kanteys.co.za Kitso Botlhale Consulting Engineers info@kitsobce.co.za KSB Pumps and Valves (Pty) Ltd salesza@ksb.com KUREMA Engineering (Pty) Ltd info@kurema.co.za Lektratek Water general@lwt.co.za Loshini Projects muzi@loshini.co.za Makhaotse Narasimulu & Associates mmakhaotse@mna-sa.co.za Mariswe (Pty) Ltd neshniec@mariswe.com Martin & East gbyron@martin-east.co.za M & C Consulting Engineers (Pty) Ltd info@mcconsulting.co.za Mhiduve adminpotch@mhiduve.co.za MPAMOT (Pty) Ltd mpumem@mpamot.com Mvubu Consulting & Project Managers miranda@mvubu.net Nyeleti Consulting naidoot@nyeleti.co.za Prociv Consulting & Projects Management amarunga@prociv.co.za Rainbow Reservoirs quin@rainbowres.com Re-Solve Consulting (Pty) Ltd maura@re-solve.co.za Ribicon Consulting Group (Pty) Ltd info@ribicon.co.za Royal HaskoningDHV francisg@rhdv.com SABITA info@sabita.co.za SAFRIPOL mberry@safripol.com SAGI annette@sagi.co.za SALGA info@salga.org.za SAPPMA admin@sappma.co.za / willem@sappma.co.za SARF administrator@sarf.org.za.co.za SBS Water Systems marketing@sbstanks.co.za Silulumanzi Antoinette.Diphoko@silulumanzi.com Siroccon International (Pty) Ltd admin@siroccon.co.za SiVEST SA info@sivest.co.za Sizabantu Piping Systems (Pty) Ltd proudly@sizabantu.com Siza Water (RF) Pty Ltd PA@sizawater.com Sky High Consulting Engineers (Pty) Ltd info@shconsultong.co.za SKYV Consulting Engineers (Pty) Ltd kamesh@skyv.co.za Smartlock jp.alkema@smartlock.net SMEC capetown@smec.com SOUTH AFRICAN VALUE EDUCATION Sabiha@savegroup.co.za Southern African Society for Trenchless Technology director@sasst.org.za SRK Consulting jomar@srk.co.za Structa Group info@structatech.co.za TPA Consulting roger@tpa.co.za Ultra Control Valves peter@ultravalves.co.za V3 Consulting Engineers (Pty) Ltd info@v3consulting.co.za VIP Consulting Engineers esme@vipconsulting.co.za VNA info@vnac.co.za Water Institute of Southern Africa wisa@wisa.org.za Wam Technology CC support@wamsys.co.za Wilo South Africa marketingsa@wilo.co.za WRCON ben@wrcon.co.za Zutari charmaine.achour@zutari.com

CEMENT & CONCRETE

Impact-resistant flooring upgrade completed for Department of Basic Education

T

he Department of Basic Education partnered with Transfrontier Projects to replace their worn-out flooring with new, impact-resistant coatings that ensure longevity and durability.

The project involved the application of various high-performance products from Sika, a global leader in construction chemicals, to provide a robust and lasting solution for the department’s flooring needs.

The primary goal of this project was to replace the existing worn floor coating in all high-traffic areas where examination and education materials are frequently moved with trolleys. The process began by removing the existing coating with diamond grinders, resulting in an open pore concrete surface, which is conducive to bonding the new screed to the concrete substrate. Good preparation is crucial for the effective application of all new coatings and screeds.

High traffic areas:

• Shrinkage crack repairs: Sikadur®-52 ZA, a low-viscosity epoxy resin with high strength, was used to repair cracks by means of gravity feed into the cracks before applying the final coats.

• Scratchcoat and screed: Sikafloor®-21 PurCem®, a high-performance, impactresistant polyurethane hybrid self-smoothing screed designed for heavy traffic areas, was used as both a 1 mm scratch coat and final 5 mm screed layer.

After the initial preparation process, the 1 mm scraper coat was applied to seal off the open pore surface and prepare it for the final screed application.

Sikafloor®-21 PurCem® was then applied at 5 mm thickness and finished off by spike rolling to remove bubbles and imperfections from the wet surface for a smooth, seamless finish.

Medium traffic areas:

• Passages and offices: For these areas, Sikafloor®-263 SL ZA, a 2-part epoxy self-smoothing coating for smooth and broadcasted flooring surfaces, was used. The same surface preparation was done, and Sikafloor®-263 SL ZA was poured, spread evenly with a serrated trowel, then levelled and any entrapped air was removed with a spiked roller. After about 15 minutes (at +20°C) but before 30 minutes (at +20°C), quartz sand was broadcast, first lightly and then to excess, and Sikafloor®-263 SL ZA was roller-applied in two coats.

Light traffic areas:

• Storerooms and UPS rooms: In these areas, Sikafloor® Garage, a versatile, easy-to-apply water-based coating ideal for light to medium traffic areas, was used.

The same preparation process was done, and Sikafloor® Garage was roller-applied in two coats.

Parking decks:

• Damaged concrete: Damaged concrete surfaces were cut out, and defective areas were primed with Sika MonoTop®-1010 ZA, a cementitious bonding primer, which was brush-applied as a prime coat. Sika MonoTop®-412 NFG, a highstrength, shrinkage-compensated repair mortar, was used to level out the primed areas using a trowel, ensuring a neat finish.

Joint sealing All existing sealants were raked out of the joints. All joints were cleaned and then primed with Sika® Primer-3 N to ensure bonding of the new sealants to the sides of the joints. Sikaflex®-11FC Purform® was used to fill in all joints.

With the successful completion of this flooring upgrade, the Department of Basic Education now benefits from durable, high-performance surfaces designed to withstand heavy use and maintain aesthetic appeal. The partnership between Transfrontier Projects and Sika has delivered a robust solution tailored to the unique needs of various traffic areas, enhancing both functionality and longevity.

This project exemplifies a commitment to quality and resilience in educational environments, setting a new standard for future upgrades.

IMIESA September 2024

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VEHICLES & EQUIPMENT The Titan T200 has a maximum feed size of 220 mm and throughput capacities from 100 up to 260 mtph

The production of Astec Industries’ tough, high-per formance Titan T200 cone crusher is moving to South Africa.

T

he group’s Johannesburg-based Astec South Africa division will star t manufacturing this exceptional machine at its stateof-the-art Elandsfontein facility from 2025.

This strategy is geared towards simplifying and focusing Astec business units, developing product lines on a company-wide basis and maximising efficiencies within Astec’s Materials Solutions group. It also forms part of Astec’s drive to consolidate operations, and to become more flexible in production capabilities to meet customers’ demands within the regions.

“We are delighted to have the opportunity to contribute to the continued growth of the strong Astec brand and to manufacture the innovative Titan T200 in South Africa,” says

A Proudly South African Titan A Proudly South African Titan Martin Botha, product manager for crushers at Astec industries.

A locally produced Titan T200 is good news for South African and African gravel producers, as well as quarrying and recycling operations.

The cone crusher can be configured for a range of industrial operations.

Optimum throughput capacities The Titan T200 has a maximum feed size of 220 mm and throughput capacities from 100 up to 260 mtph. This makes it ideal for secondary and tertiary circuit positions in aggregates, crushed stone production and recycling applications.

Weighing in at just under 10 tons and with a head diameter of 915 mm, the Titan T200 The Titan T200 has large clearing circuits that safely allow uncrushable material to pass. This minimises costly damage and maintenance downtime

is engineered to deliver uncompromising productivity, safety and ease-of-maintenance for maximum uptime in tough, abrasive applications. The cone crusher’s hybrid thrust bearing design ensures improved static and dynamic lift. It can crush at lower horsepower without compromising production, and this design allows for easy bearing inspection.

The Titan T200 has large clearing circuits that safely allow uncrushable material to pass. This minimises costly damage and maintenance downtime. The hydraulic anti-spin system prevents head spin to extend the manganese life. The machine’s automatic reset feature requires no parts replacement or repair time.

Stationary and portable configurations With a small footprint, the Titan T200 can easily replace existing cone crushers while providing high production and an excellent product size and shape. Available in both stationary and portable configurations, the Titan T200 can be used in series with Astec jaw crushers and screens.

The concave retention system, simple topservice disassembly and the optional TRAC10 control system are other noteworthy features of this latest-generation cone crusher that will be “built in South Africa for the world,” Botha states.

The rest of the range of Titan cone crushers will follow very soon after the T200. This includes the T300, T400 and T500.

INDEX TO ADVERTISERS

APE Pumps Gabion Baskets IMESA

48 IMIESA September 2024

12 OFC, 6 2, 4 & 46

KSB Rainbow Reservoirs Rand Water

OBC

SAPPMA

21

25

Sizabantu

IFC

Xylem

31

15, 30

IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa www.imesa.org.za

INFRASTRUCTURE DEVELOPMENT • BUILDING • MAINTENANCE SERVICE DELIVERY • UTILITIES MANAGEMENT • ROADS • ENERGY

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