Rational Design

The Structure of Regulation XA Compliance Routes
Compliance Route options

To comply with the XA Energy Usage Regulations, either the Prescriptive or deemed-to-satisfy path to compliance, is followed or a Rational Design is performed which will involve either the Performance Route or The Reference building method which are outlined below:

Option 1: Prescriptive Route

Prescriptive route is often used by Architects to generate specification for building that will ensure compliance with Regulation XA.
The architect first produces the building design concept in accordance with the requirements of the client.
Calculations are done for the fenestration. If the first concept design does not comply, the following may be implemented to bring the design to compliance:

· reduce glazing ratio
· specify double glazing and performance glass
· implement horizontal shading devices

Insulation levels must be met for the roof, prescribed by the climate zone.
Shading provided by surrounding buildings may not be accounted for, and space use and the efficiency of energy systems may not be considered to show compliance.
Once the prescriptive boxes have been ticked, forms may be signed and submitted to council alongside building plans.

Option 2 : Performance Route

The Performance Route is a form of Rational Design and available for Commercial and Institutional buildings. It involves Energy modelling to demonstrate that the building will perform better than the requirements set out in Tables 3 & 4 of SANS 10400-XA This is a Rational Design which is performed by a Competent Person in terms of Regulation XA

Option 3: Reference Building Method

The Reference Building Method is a type of Rational Design that requires the building to be built, is made hypothetical by substituting in all aspects of the Prescriptive Route of SANS 10400-XA at which stage it is the subject of an Energy Modelling exercise.

The Energy Intensity and the Demand Intensity results from the Energy Modelling become the baseline against which improvement measures are evaluated in developing the improved building which is often termed the Rational Design.
If the improved building shows lower Energy Usage and Demand than the baseline Reference building, then the improved building can be said to be in compliance with SANS 10400-XA and hence with Regulation XA.

SP Energy Pty Ltd are experts and specialise in carrying out RATIONAL DESIGN and ENERGY MODELLING services countrywide.
Please contact us for further information.