Technical Note #15 SANS 204 compliance for masonry walling


The objective of the Technical Note is to provide a concise explanation of the walling provisions in the SANS204 standard, and indicate how this can be used to the advantage of end-users/owners.

Compliance for Clay Brick Masonry Walling

The South African National Standard (SANS) 10400-XA and the SANS 204 Regulations are an attempt made by government to regulate energy use and encourage energy efficiency in building.

SANS 204: Energy efficiency in buildings, introduces sensible and practical measures that save energy when new buildings are both designed and built. By eventually making the three parts of this standard mandatory, the government will slowly but surely begin to achieve savings in energy and savings in the cost of providing that energy.

SANS 204 was published as a voluntary National Standard for “Energy Efficiency in Buildings” in October 2008 and updated in August 2010 to fulfil the requirements of the National Building Regulations for the Construction Sector, i.e. SANS 10400, of which Part XA specifies the minimum deemed-to-satisfy requirements for compliance to Energy Usage in Buildings.  It contains requirements that are higher than SANS 10400-XA and defines the minimum requirements that must be adhered to, to achieve a Green Building rating.

It covers Site and building orientation, Shading, Building design (Floors and External walls), Fenestration, Roof Assemblies, Roof lights, Building Sealing/Mechanical Ventilation and Air Conditioning and Services.

  • Please download the attached technical note for the full specification


The thermal performance of walling as indicted by the CR-value corresponds with the property of thermal diffusivity which is the product of thermal conductivity and the specific heat of any material. The thermal diffusivity takes the time for transfer of heat through a building element into consideration.

The tool in SANS 204 provides only for double-brick cavity wall constructions. However, by calculating in terms of a Rational Design, building professionals can achieve a similar CR-value result as those of Table 2.

Designers can check the CR-value of various combinations of high mass walling and thermal insulation products by making use of the online CR-value calculator available at:

The most energy efficient walling systems can be designed and specified for South Africa’s climatic conditions by making use of the CR-value tool in SANS 204.


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