The analysis of the life cycle environmental impacts of clay brick walling in South Africa shows a clear result: that the use-phase of the bricks, meaning the impacts deriving from the electricity production required for the heating and cooling of brick buildings, has a far bigger impact on the environment than the production of bricks.
A first step towards improving the sustainability of building materials is to understand the extent and source of the environmental and socio-economic impacts, which is why the Clay Brick Association of Southern Africa (CBA) commissioned an industry-wide lifecycle assessment (LCA) of clay-brick products in the country – the first of its kind.
The research, stretching over four years, was done by the University of Pretoria and coordinated by the CBA technical team. The analysis was conducted in accordance with the ISO 14040 and 14044 standards with an external review. The study evaluates all major environmental impacts as defined by the highly-regarded Impact 2002+ methodology with respect to the production of 1 kg of fired brick.
“Energy used during production is just a fraction of the total life cycle considerations of a building material,” CBA technical team leader, Nico Mienie point out. “The clay brick industry LCA will allow architects to accurately calculate the lifetime environmental impact of using clay brick in a building, compared against other construction materials. Access to accurate data will make it easier to design green buildings that are naturally energy efficient,” he says.
The results will further allow property developers and building owners to make fact-based decisions in the context of building and operating sustainable, energy-efficient buildings.
The study followed a holistic approach, evaluating all major environmental impacts including damages to human health, to ecosystem quality, the contribution to climate change and the consumption of non-renewable resources for the six main brick manufacturing technologies with respect to the production of 1 kg of fired brick.
The South African clay brick industry Life Cycle Assessment:
• Calculates the resources consumed and emissions produced over the entire life cycle of clay brick.
• Assesses the impact of different methods of clay brick production against specific environmental factors such as human health, climate change and damage to ecosystems. The study used specific production data from 86 out of the 102 clay brick production sites in South Africa, ensuring the results are a relevant and valid assessment of the industry.
• Quantifies the energy efficiency of six common walling materials across South Africa’s six climate zones and three types of building types (low cost residential, residential and commercial). It compares heating and cooling costs during the 50 year use or occupation phase.
• Measures a range of socio-economic factors such as health and job creation (social Life Cycle Assessment).
From cradle to gate
The impact of the production of one standard clay brick in South Africa is equal to boiling a kettle five times, based on a weighted average, with the production of 1kg of clay bricks in South Africa requiring on average 3,46MJ of fossil energy. Per year, local brick production adds up to about 2,6 million tons of CO2 emitted, equal to the annual emissions of approximately half a million passenger vehicles on the road.
The most significant environmental impacts from the production and use of bricks are contribution to global climate change, consumption of non-renewable resources and emissions of substances that cause respiratory diseases. All three of these are a consequence of the use of fossil fuels, primarily coal, which is the raw material used for combustion during firing. Since the country also relies on coal burning technology for electricity generation, switching to electric kiln technologies would not help to reduce the environmental impact.
From gate to grave
However, over the entire lifecycle of 1m2 of wall, the contribution from the production and construction phases is small compared to the use-phase. Assumed to last 50 years, by far the greatest share of climate and health impacts occurs during use-phase of brick, due to the fact that electricity used for the heating and cooling of buildings in South Africa is predominantly generated by coal-fired power stations.
The study considered annual operational energy, which is the sum of all heating, cooling and ventilation electricity costs accumulated over all four seasons in one year, and were based on a thermal comfort measurement of between 19°C and 25°C.
In addition, a thermal performance study carried out in conjunction with this LCA found that residential buildings constructed with clay-brick walls have the lowest heating and cooling requirements compared to other commonly employed walling systems in South Africa.
In the temperate climate zones, residential buildings built with 220mm solid brick walls can potentially save 30% relative to those built with 150mm hollow concrete blocks, whilst savings of 70% were found if walls were built with insulated cavity brick walls. Even higher savings are evident in the hotter regions of South Africa.
For the social LCA assessed how all stakeholders in brick manufacturing, workers, the community and the consumer are affected in terms of socio-economic factors, such as human rights, working conditions and health and safety. Some 89 manufacturers contributed data, representing a 78% response rate.
It was found that the brick manufacturing sector provides four jobs per million bricks produced, seeing that it takes 26 man-hours to produce a thousand bricks. These employment opportunities are particularly in rural communities where it is most needed.
Brick producers are also actively engaged in community development programmes, with on average R65 000 spent per million bricks produced, and the sector is a significant supporter of SMMEs with 74% of supplies provided by small businesses.
A particular strong-point is that there is transparency and communication about the industry’s environmental and social performance. Areas for improvement include equal opportunities for employment at higher education levels, and equal remuneration across gender and race.
The benefit of LCA studies
This report on the environmental and socio-economic impact of clay bricks in South Africa sets a benchmark for clay brick, and allows architects and property owners to calculate and compare the impact of clay-brick building against other building materials. Future studies can also refer to these results as a baseline against which improvements or changes can be measured.
The LCA is central to goals of The Energy Efficient Clay Brick Project (EECB) – a CBA initiative to foster sustainable technologies to increase energy efficiency in brick-making.
Over the last four years, the EECB project’s energy-efficiency initiatives already resulted in a 10-15% reduction in the industry’s greenhouse gas emissions with several local brick manufactures having reduced their energy consumption since the LCA’s data collection period.
The EECB project was originally funded by the Swiss Agency for Development and Cooperation (SDC) and implemented in South Africa by Swisscontact. The project was handed over to the CBA for ongoing implementation in 2017.
“The Clay Brick Association of Southern Africa has led research in brick production and brick building design for 54 years,” notes CBA president Musa Shangase.
“This Life Cycle Assessment is part of a larger sustainability initiative that commits the clay brick sector to continuous improvement in terms of water and energy saving, as well as limiting the use of coal as a firing fuel. The LCA will guide our members who want locally-relevant statistics on which technologies offer reduced fuel use, improved air quality and low environmental impact.”
A regular South African Brick Industry Sustainability Report will be prepared to show how the clay brick sector in South Africa is performing against its collective sustainability strategy. It will demonstrate progress against the targets set in the areas of fossil fuel use, waste and resource consumption.
Full thanks and acknowledgement are given to the Clay Brick Association of Southern Africa for the information given to write this article.