Research shows building with clay brick adds to thermal comfort and energy-efficiency of buildings.
Research conducted in South Africa, Australia and the USA continues to produce findings that endorse clay-brick construction’s pre-eminent status for sustainable housing construction in these countries.
Considering just energy-efficiency, the correlation in the findings of empirical, thermal modelling and parametric studies recognises the ability of clay-brick external wall constructions to outperform comparable lightweight walled structures. The empirical findings also confirm that clay-brick internal partition walls added further to the thermal comfort of the building, lowering energy usage no matter the external walling construction type.
During the last eight years of empirical study at the University of Newcastle’s Priority Research Centre for Energy, the performance of building modules that comprise different Australian wall construction types were continually measured under real-life conditions. The findings showed that:
• Insulated lightweight building, which has a high thermal resistance (R-value) with no thermal mass in the walls, was the worst performing in all seasons.
• Brick veneer, where brick is applied to the external skin of the outside wall, performed better than the lightweight construction.
• Insulated cavity brick performed the best.
When thermal mass was added in the form of internal partition walls to the 6m² x 6m² modules, the additional energy reductions were as follows:
• Insulated lightweight – 20%.
• Insulated reverse brick veneer – 8%.
• Insulated cavity brick – 6%.
While internal brick afforded benefits no matter the wall construction type, the reduction in energy usage was less prominent in the cavity brick modules compared to the lightweight modules because the masonry walled modules were already benefiting from the lower energy demand that the external thermal mass provided.
For more detail on the comparative performance of different wall construction types and why double-skin, clay-brick construction with the appropriate use of resistance for the climatic zone is the real deal for achieving optimal energy-efficiency in climates similar to South Africa, visit www.thinkbrick.com.au and reference “Energy-efficiency and the environment, The case for clay brick, Edition 4” and “A study of the thermal performance of Australian housing” – The Priority Research Centre for Energy, University of Newcastle, Australia .
It is to be noted that the findings of thermal modelling studies in both South Africa and Australia that used ASHRAE recognised and Agrement SA approved software [parametric studies confirm they have equations able to account for thermal resistance and the diffusivity of heat through thermal mass], were comparable to the Newcastle empirical research showing double skin clay brick with appropriate insulation outperformed comparable lightweight. Ecotect modelling software on the other hand, whose equations do not cope with thermal capacity and therefore thermal diffusivity; treat the wall R-value as the all-important thermal performance property for achieving energy efficiency, understandably producing findings in favour of lightweight.
Combine clay brick constructions energy efficiency with the materials robustness, inert qualities that assure low environmental impacts, cost effectiveness as built and propensity to provide lowest lifecycle cost, and clay brick’s continued use in construction makes perfect sense for sustainable house construction in South Africa.
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