Editor –
As the Clay Brick Association of South Africa, we refer to the report in the Engineering News of September 26, 2012, titled
‘Group mitigates poverty with alternative building technology’.
The last paragraph quotes Sven Graef, of Sasol ChemCity, as saying that “brick and mortar do not comply with SANS204 standards; we believe that alternative building technologies (ABT) is the way forward for the building construction environment”.
Graef was either misquoted or is misinformed. The SANS204 energy efficiency standard treats masonry construction differently from ABT. Regarding SANS204 for ABT, a minimum ‘deemed- to-satisfy’ wall R-value of either 1.9 or 2.2 is prescribed for the different climatic zones. SANS204 in respect of masonry construction takes into account the value of thermal capacity (derived from the thermal mass of clay bricks) in moderating indoor thermal comfort across all six major climatic zones of South Africa.
Accordingly, ‘deemed-to-satisfy’ CR product values (that is, product of combinations of thermal capacity ‘C’ and resistance ‘R’) have been set for compliance by masonry walling in each of these six climatic zones. For Graef to say that ‘brick and mortar’ does not comply with SANS204 is therefore incorrect.
Clay brick construction’s superiority in affording indoor thermal comfort is evident in the correlation of findings of major thermal modelling studies that compared clay brick houses in accordance with SANS204 DTS standards and various alternate lightweight building technologies (both SANS517 and SANS204 compliant). Notably, ABT SANS204-compliant houses provided suboptimal thermal efficiency outcomes relative to the best of clay-brick alternates. The clay-brick house also provided best financial payback over a 50-year life cycle.
Further endorsement of clay brick construction’s superior life-cycle value is evident in the findings of the Life Cycle Assessment by Energetics, Australia. The clay-brick house with insulation in the cavity afforded a lower ‘total’ energy (embodied plus heating and cooling energy) consumed over a 50-year life cycle than an ABT insulated weatherboard alternative in every situation.
To better understand the relative contribution of clay brick construction in terms of the environmental, economic and social dimensions to some of the more established ABTs, the Clay Brick Association is on track with commissioning a full life-cycle assessment.
At Coetzee
Executive Director, Clay Brick Association
Tel: 011 805 4206