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"Towards estimating the cost premium of Green Star certified office buildings in South Africa
Hoffman, Daniël Johannes (University of Pretoria, 2023-12)
Global warming and climate change are concepts defining many aspects of life on earth during the 20th and 21st centuries. These topics are increasingly dominating public space and they are continuously being considered and debated by business leaders and governments worldwide. The extinction of many species of life on earth is being threatened by our modern lifestyle and the resulting effects of global warming and climate change. This predicament requires global action from all the nations of the world. Unfortunately, the political and economic will to take decisive action have in the past often been lacking. Making minor adjustments to a fundamentally flawed system of growth and development; but they will not succeed in addressing our challenge. The most severe environmental challenges to the natural world originate from cities, urban areas, and the global population's urbanisation. The built environment is a significant consumer of global resources consuming 40% of global energy use and generating up to 30% of global greenhouse gas emissions. The organised built environment responded by setting up councils and producing green building tools to evaluate and measure the environmental impact of buildings. The United States Green Building Council (USGBC) was formed in 1993, while the World Green Building Council (WGBC) was founded in 1999 by nine founding countries. Currently, the WGBC has more than 80 member countries. Member countries include the Green Building Council of South Africa (GBCSA), established in 2007. The most significant barrier to the growth of green building has been the perceived significant cost premium associated with green developments. Various local and international studies (Kats, 2003; Lockwood, 2008; Kats, 2010; WGBC, 2013; Coetzee and Brent, 2015; Morgan Stanley, 2016) have confirmed this as a significant barrier to green developments. Industry stakeholders often perceive green building cost premiums of more than 10% and as much as 20%. The widely held perception that green buildings cannot be justified from a cost-benefit perspective has created a significant obstacle to green design and building advancement. At the start of this study in 2014, no reliable cost data existed on the cost premium of South African green buildings. The GBCSA, the Association of South African Quantity Surveyors (ASAQS) and the University of Pretoria (UP) joined forces to address this challenge. The resulting study described the cost of green building in South Africa by evaluating the cost of Green Star-rated office buildings that were certified by the end of December 2018. The study has established that a GBCP did exist and described the extent thereof. The average GBCP was found to be 3,96% with a spread of 1,14 % - 14,24%. The study had to understand the cost of green buildings in general and specifically the cost premium over the cost of conventional code-compliant construction. The study, therefore, used eight generic features of office buildings closely linked to green building costs. These eight building features described the profile of the study population in terms of: 1. the Green Star certification level (4, 5 or 6 Star); 2. the geographical location of buildings; 3. the construction area of buildings; 4. the tenant mix of buildings; 5. the base building cost (R/m2) of buildings; 6. the façade : construction area ratio of buildings; 7. the Green Star certification date of buildings and 8. the Green Star certification rating of buildings (Design vs As Built). The study also proposed a scientific and rational methodology to estimate the cost premiums of proposed future green buildings based on the eight building features investigated. Describing and analysing the actual cost of green building in South Africa lessened the uncertainty and decreased the associated risk for decision-makers in the built environment surrounding green building costs. Lower risk creates a more favourable environment for real estate investors and developers and helps them to plan for the risk of undertaking green building developments. The study proposed an equation to estimate the combined effect of the eight features that affected the green building cost premium (GBCP). Using the baseline GBCP as a departure point, the estimated GBCP of a building was then calculated by allowing for the combined effect of the eight building features on the cost baseline. The study tested the proposed methodology by comparing the actual GBCP of buildings against their proposed estimated GBCP. The methodology proved to be more accurate in estimating GBCP values for projects with actual GBCP values 3,0% - 10,0% and less accurate with projects with extreme GBCP values of < 3,0% and > 10,0%. The study amended the proposed methodology and introduced an adjustment factor to secure estimated GBCP values that closely simulate the size and the spread of the actual GBCP values. The study concluded with several recommendations for further research to expand the knowledge and the insight into green building costs and the business case for green building.
A study protocol to assess the association between ambient air pollution and asthma and other respiratory health outcomes amongst children below 5 years of age in Alexandra township’s early childhood development centers, Johannesburg
Thompson, Velisha; Shirinde, Joyce; Masekameni, Masilu D.; Mbonane, Thokozani P. (MDPI, 2025-08-01)
Air pollution is linked to childhood mortality and morbidity in low- and middle-income countries globally. There is growing evidence linking air pollution to asthma and other respiratory diseases in children. Studies have shown that children are likely to experience asthma due to their narrow airways and their heightened sensitivity to environmental irritants. This study aims to investigate the relationship between ambient air pollution and respiratory diseases in children under the age of 5. The study will be conducted in the informal township of Alexandra, north of Johannesburg, South Africa. A quantitative approach will be used in this cross-sectional analytical study. Data will be collected using different tools that include a questionnaire to determine the prevalence of asthma and respiratory disease and potential risk factors. While environmental air pollution will be measured using Radiello passive samplers and Gillian pumps. Data will be analyzed using the latest version of the STATANow/MP 19.5 software. Furthermore, health risk assessment will be conducted for lifetime non-carcinogenic and carcinogenic risk estimation following the USEPA framework. The study will identify environmental triggers that exacerbate asthma and other respiratory conditions in other similar community settings and will contribute to the body of knowledge in public health. Ethical approval was obtained from the Research Ethics Committee, Faculty of Health Sciences at the University of Johannesburg.
DC ferrochrome smelting : the arcing zone and its influence on energy transport and exergy dissipation
Oterdoom, Harmen; Reuter, Markus; Zietsman, Johannes Hendrik (Springer, 2025-02)
Phenomena between the electrode tip, the arc attachment zone (AAZ), and the bath below the AAZ—taken together as arc attachment volume (AAV)—have a significant impact on the performance and efficiency of DC arc furnaces. This paper investigates the phenomena in the AAV in detail. Phenomena are analyzed with reference to industrial scale furnace viz. a Kazakh DC ferrochrome furnace. The impact of the various reactions in the AAV under different conditions both from an energy and exergy flow perspective is analyzed. The temperature, carbon in feed (thus the carbon to feed ratio called RC), and slag from the slag bath are investigated as the significant variables affecting phenomena in the AAV. Results show that alloy can become the reductant to fume specifically Mg(g), SiO(g), Cr(g) and even Fe(g) from slag containing MgO SiO2, FeOx and Cr2O3. The implications and resulting mass and energy transfer by these fumes can play a significant role in understanding open-bath ferrochrome smelting better as well as the energy balance of the arc and its impact on overall furnace efficiency. The irreversibility of the fuming reactions and reoxidation of metal vapor has a significant negative impact on furnace operation if the temperature in the AAV is not managed well due to poor operation regarding charging of feed. This implies not only that the average slag and metal temperature are of importance, but especially the actual AAV temperature is crucial. To fully understand the effect of chemical potential of the gases coming from the AAV, an exergy analysis uniquely showed that the fumes can be essential to reduce energy consumption if managed well, especially if the chemical potential energy can be harnessed in other zones within the furnace. This investigation is also relevant to other open-bath processes with fumable oxides, for example in smelting of ferronickel, titania slag, direct reduced iron, or even iron ore. Understanding the reaction mechanisms in the AAV in detail will be significant to push efficiencies of these applications to their thermodynamic, kinetic, and technological limits to ensure that their green metallurgical impact is fully realized.
Methionine, threonine and glutamic acid adapted pathways in captive cheetahs on a glycine-supplemented diet
Van Boom, Kathryn Merle; Kohn, Tertius Abraham; Tordiffe, Adrian Stephen Wolferstan (Springer, 2025-04-23)
BACKGROUND : Captive cheetahs are prone to a range of unusual diseases potentially linked to unnatural diets high in muscle meat and low in collagen-rich animal fibre. In the wild, cheetahs typically eat whole prey diets not easily replicated in a captive setting. Glycine is the most abundant amino acid in collagen with a key role in several metabolic pathways such as collagen biosynthesis. Several recent studies suggest that endogenous glycine production may be limited in several species. OBJECTIVES : Using untargeted 1H- nuclear magnetic resonance, the metabolic changes in the urine and serum of 10 adult captive cheetahs on a glycine-supplemented diet were investigated. METHODS : Cheetahs were fed either a meat only (control) or glycine-supplemented meat diet (30 g glycine per 1 kg meat) for four weeks, followed by a four-week cross-over. Urine and blood samples were collected at baseline and after each intervention. RESULTS : A total of 151 and 60 metabolites were identified in the urine and serum, respectively. Specifically, dimethylsulphone, proline, fructose, dimethylamine, trimethylamine, pyroglutamic acid, 1,3-diaminopropane, dihydrothymine, methylmalonic acid and pimelic acid contributed to metabolome differences in the urine. In serum, glutamic acid, threonine, α-aminobutyric acid, glucose-6-phosphate, ethanolamine, methionine and propionic acid were highlighted. These metabolites play various metabolic roles in energy production, immune function, protein and collagen biosynthesis or as products of gut microbiome fermentation. CONCLUSION : Glycine supplementation influenced threonine sparing, pyrimidine biosynthesis pathways and bacterial fermentation products, although the implications of these findings on the health of captive cheetahs is unknown. Future studies should use a targeted approach to further elaborate on these pathways.
Treatment of industrial brine using a poly (vinylidene fluoride) membrane modified with carbon nanotubes
Tshauambea, Tshifhiwa T.; Malinga, Soraya P.; Ndungu, Patrick Gathura (MDPI, 2025-07-23)
This study explores using polyvinylidene fluoride (PVDF) membranes modified with multi-walled carbon nanotubes (MWCNTs) to treat simulated and industrial brine from coal power stations. The MWCNTs were acid-treated and characterized using Fourier Transform Infrared Spectroscopy (FTIR), Raman, and nitrogen sorption at 77 K, Thermogravimetric analysis (TGA), and Transmission electron microscopy (TEM). The desired membranes were obtained by casting from a solution of N-Methyl-2-pyrrolidone, PVDF, various weight percentages of MWCNTs, and a small amount of polyvinylpyrrolidone. The acid treatment of the MWCNTs introduced oxygen moieties on the surface, and increased pore volume and surface area while maintaining crystallinity and structural integrity remain preserved. The maximum rejection rate achieved was 41.82% with 1 wt.% of acid-treated MWCNTs in the PVDF membrane. Acid-treated MWCNTs loaded membranes had an improved rejection rate, which was 5× higher than membranes without MWCNTs.