Civil Engineering June 2022 | Vol 30 No 5

4 June 2022 Civil Engineering oN THE COVER S izabantu started out as a trading company before becoming the marketing and sales agent for a major South African thermoplastic pipe manufacturer, and ultimately the Southern African agent for Molecor, a world leader in thermoplastic (PVC-O) pipe technology. Today, Sizabantu and Molecor are joint venture partners in a production facility located in the Richards Bay Industrial Development Zone. Significantly, Sizabantu’s management team, located throughout Southern Africa, consists of highly qualified and experienced experts who have been in the thermoplastic piping system industry for many years. Moreover, they know that quality products, customer service, product availability and commercial competitiveness are paramount in this highly competitive market. SA’S PVC HISTORY Sizabantu currently supplies high-quality, locally manufactured thermoplastic piping system products into the Southern African market. The maximum diameter and pres- sure rating of the PVC-O pipes currently available is substantially greater than previ- ously available and has enabled Sizabantu to compete in markets that were hitherto beyond the scope of previously available thermoplastic piping systems. PVC pressure pipes were first used in Germany about 85 years ago and were not enthusiastically received when introduced to South Africa 25 years later. However, things have changed, and today more than 95% of domestic sewerage reticulation pipes are PVC. Scientists, polymer technologists and processing engineers have enabled the allowable design stress (σ) for HDPE to be increased from 5 MPa to 8 MPa – a substantial 60% increase. However, the increase in PVC’s strength, enabled by improved technology, is even more substantial, increasing from 10 MPa to 36 MPa – an incredible 260% increase! In the 1970s the PVC industry entered the mining services market following a successful project, led by Dr Ken Hart, that developed a high-impact pipe PVC-HI (SANS 1283) that satisfied the mining industry’s requirements and enabled PVC pipes to be used for underground services. Following on from this work, another development project, led by Mike Osry, de- veloped PVC-M (SANS 966-2) in the mid- 1990s by adding impact modifiers, com- monly chlorinated polyethylene, rubber toughened acrylics, or a combination thereof, to the PVC material to increase its impact strength. This enabled the material to exhibit “tough” characteristics that facilitated the reduction of the design coef- ficient (C) from 2 to 1.4, thereby increasing σ from 12.5 MPa to 18 MPa. About 40 years ago PVC-O (oriented unplasticised poly vinyl chloride – SANS 16422) was developed. The molecular orientation process improves the physical and mechanical properties of the material. In the intervening 40 years, there have been improvements in PVC-O from a Classification 315 material initially to a Classification 500 material currently – the nomenclature is ten time the minimum required strength (MRS) of the material. The latest PVC-O material, Classification 500, must have an MRS of not less than 50 MPa at 50 years, that with a C of 1.4 gives a σ-value of 36 MPa, where σ = MRS/C. This is a substantial improve- ment that is twice the σ of PVC-M, made possible by improved in-line production technology that Sizabantu Piping Systems’ Spanish technology partner Molecor excels at. Their TOM® 500 PVC-O pipes are produced locally in Richards Bay. PVC-O OFFERING Innovation is one of Molecor’s core values, and with their technologically innovative TOM® 500 PVC-O branded pipes they increased the range of PVC-O pipes from the previous limit of 315 mm diameter PN16 Sizabantu celebrates 20 years of excellence 20 - Y E A R A N N I V E R S A R Y C E L E B R A T I O N - Sizabantu Piping Systems turned 20 in April 2022 and, having grown tremendously over the past two decades, has undertaken a remarkable journey in a very short time. Any other donations welcome! Our divisions alongwithvarious charity organisations throughout SouthAfrica, will be running a “20days of giving” campaign for our 20thbirthday . 2 0 D A Y S O F G I V I N G ! SPSCen|TanyaScott tanyas@sizabantu.com Join in today! Contact yournearest division toget involved SPSWC|AllisonGoosen allisong@sizabantu.com SPSEC|ElanaMatyityi receptionec@sizabantu.com SPSMP|ZanciavdWalt zanciavw@sizabantu.com SPSExp|LechalLouw lechal@sizabantu.com SPSGP|PraneshaMoothan pranesham@sizabantu.com SPSKZN|AlishaPather alishap@sizabantu.com SPSPLK|CandiceJooste candicej@sizabantu.com