The energy efficiency standard for buildings has been developed and published to ensure that new buildings are designed and built to achieve a huge reduction in energy consumption using practical energy saving measures.

SANS 204 sets out the general requirements for achieving energy efficiency in all types of new buildings, both for naturally ventilated buildings and for artificially ventilated buildings.

SANS 204 – Consist of the following parts

• SANS 204-1 – General requirements for energy efficiency
• SANS 204-2 – Energy Efficiency for Naturally Ventilated Buildings
• SANS 204-3 – Energy Efficiency for Artificially Ventilated Buildings

There are two routes of compliance:

1. Through rational design in compliance with the tables in SANS 204-1 or by demonstration that the design is equal or better than the deemed-to-satisfy rules in (SANS 204 -2 & 3)
2. In compliance to the deemed-to-satisfy Rules in (SANS 204-2 & 3)

SANS 204 can also be used as a guide for voluntary energy efficient retrofits of existing buildings in order to reduce energy usage and thus electricity accounts.

• Maximum energy usage demand per building classification (occupancy) for each climatic zone
• Maximum annual consumption per building classification (occupancy) per building for each climatic zone

South Africa has been divided into six climatic zones according to the humidity and temperature variations.

 

The occupancies in the tables are as follows:

A1 Entertainment and public assembly
A2 Theatrical and indoor sport
A3 Places of instruction
A4 Worship
F1 Large shop (including shopping malls)
G1 Offices
H1 Hotel

	1	2	3	4	5	6
A1	85	80	90	80	80	85
A2	85	80	90	80	80	85
A3	80	75	85	75	75	80
A4	80	75	85	75	75	80
F1	90	85	95	85	85	90
G1	80	75	85	75	75	80
H1	90	85	95	85	85	90

Note:
The maximum demand shall be based on the sum of 12 consecutive monthly maximum demand values per area divided by 12 per square meter which refers to the net floor area.

	1	2	3	4	5	6
A1	420	400	440	80	400	420
A2	420	400	440	80	400	420
A3	420	400	440	75	400	420
A4	120	115	125	75	115	120
F1	240	245	260	85	260	255
G1	200	190	210	75	190	200
H1	650	600	585	85	620	630

Note :

1. The annual consumption per square metre shall be based on the sum of 12 months monthly consumption of consecutive months.
2. Non-electrical consumption, such as fossil fuels, shall be accounted for on a thermal equivalence basis by converting mega joules to kilowatt hours.

Isover recommends that when specifying a building solution it is important that the following criteria are considered.

• Climatic Zone
• Construction type
• Total R-value of the system
• Presence of water/water vapour
• Fire requirements

The standard is written according to how one would actually construct a building.

• Site and siting (Orientation & shading)
• Building design (Foundation, floor, walls, fenestration, ceiling & roof)
• Building sealing (Envelope, air filtration & leakage)
• Services (Lighting, power, hot water leakage & appliances)

This section stipulates the total R-value that must be achieved by the construction of the foundations, floors, walls, roofing system and services.

Floors and solutions

• Perimeter insulation R-value = 1.0
  • Exception1: buildings greater than 500 m2
  • Exception 2: Climatic Zone 5
• In-slab heating – insulated with R-value = 1.0
  • Water resistant
  • Continuous
• Perimeter insulation – suspended floor
  • Climatic Zones 1 & 2 – R-value = 1.5
  • Climatic Zones 3, 4 & 6 – R-value = 1.0
  • In-slab heating – R-value = 1.0

Walls – density less than 300 kg/m2

• Climatic Zones 1 & 6 Total R-value = 2.2
• Climatic Zones 2, 3, 4 & 5 Total R-value = 1.9

All hot water services shall be insulated in accordance with the information in the table above

Insulation shall:

a) be protected against the effects of weather and sunlight,
b) be able to withstand the temperatures within the piping

All chilled water, hot water and refrigeration piping, conditioned air duct work and flexible ducting shall be insulated to limit heat gain/loss to not more than 5% from source to furthest point of delivery on a system.
Picture courtesy of Liewellyn van Wyk Senior Researcher for CSIR

The standard is written to how one would actually construct a building:

• Site and siting (Orientation & shading)
• Building design (Foundation, floor, walls, fenestration, ceiling & roof)
• Building sealing (Envelope, air filtration & leakage)
• Services (Lighting, power, hot water leakage & appliances)

This section stipulates the total R-value that must be achieved by the foundations, floors, walls & roofing system.

Floors and solutions

• Perimeter insulation R-value = 1.0
• Exception1: buildings greater than 500 m2
• Exception 2: Climatic Zone 5
• In-slab heating – insulated with R-value = 1.0
• Water resistant
• Continuous
• Perimeter insulation – suspended floor
• Climatic Zones 1 & 2 – R-value = 1.5
• Climatic Zones 3, 4 & 6 – R-value = 1.0
• In-slab heating – R-value = 1.0

• Climatic Zones 1 & 6 Total R-value = 2.2
• Climatic Zones 2, 3, 4 & 5 Total R-value = 1.9

Insulation shall:

a) be protected against the effects of weather and sunlight,
b) be able to withstand the temperatures within the piping


All chilled water, hot water and refrigeration piping, conditioned air duct work and flexible ducting shall be insulated to limit heat gain/loss to not more than 5% from source to furthest point of delivery on a system.