With the increasing use of concrete panel construction for the entire range of buildings from simple residential to high-rise, whether the concrete panels are cast on-site or factory precast, some of the engineering design issues that should be considered in the use of this type of construction need to be addressed as much a the technology itself. The engineering design issues that should be considered include joint locations, technical skills transfer, on-site labour and machinery procurement, ease of use in situ and the whole gamut of green building considerations as well a price. Whilst most of the considerations largely rest on the technical and practical aspects of the particular panel system, it’s the green building considerations that will largely determine consumer appetite and regulatory approvals. In this regard, South Africa in on its way to approving Sans 10 400 XA. Compliance with the requirements of this document will be deemed to be compliance with the requirements of part XA of the National Building Regulations, issued in terms of the National Building Regulations and Building Standards Act, 1977 (Act No. 103 of 1977).
SANS 10 400 consists of the following parts, under the general title, The application of the National Building Regulations includes amongst others general principles and requirements of construction, structural design, public safety, site operations, excavations, foundations and walls. Moreover the new anticipated building standards call for the development modified thermal calculation software, certified by the Board of Agrément South Africa in terms of Agrément South Africa’s ‘Energy Software Protocols as being fit for thermal modelling or calculation purposes in terms of the National Building Regulations’. The rules also call for a competent person who is qualified by virtue of his education, training, experience and contextual knowledge to ‘make a determination regarding the performance of a building or part thereof in relation to a functional regulation or to undertake such duties as may be assigned to him in terms of the National Building Regulations’.
External walls are defined as the complete walling system, as measured from the outer skin exposed to the environment, to the inside of the inner skin exposed to the interior of the building, and do not include glazing. Designers should consider that interstitial condensation occurs in walling systems which are not able to accommodate moisture migration. The selection of vapour barriers and appropriate construction materials, including insulation, is important for the thermal efficiency of walling in climatic zones where damp and high relative humidity are experienced. Thermal resistance that is added to external walling with high thermal capacity should be placed in between layers, e.g. in the cavity of a masonry wall. Thermal resistance should not be added to the internal face of a wall with high thermal capacity.