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New building regulations and thermal insulation.

1. Climatic Zones Map
2. Energy Demand per Building Classification

Occupancy classification & building description

Max. Energy Demand
VA/m2

ZONE

1

2

3

4

5

6

A1

Entertainment &
public assembly

85

80

90

80

80

85

A2

Theatrical &
indoor sport

85

80

90

80

80

85

A3

Educational

80

75

85

75

75

80

A4

Worship

80

75

85

75

75

80

F1

Large Shops &
Shopping Malls

90

85

95

85

85

90

G1

Offices

80

75

85

75

75

80

H1

Hotels

90

85

95

85

85

90

Based the sum of 12 consecutive monthly maximum demand values

3. Consumption per Building Classification

Occupancy classification & building description

Max. Energy Consumption
kWh/(m2.a)

ZONE

1

2

3

4

5

6

A1

Entertainment &
public assembly

420

400

440

390

400

420

A2

Theatrical &
indoor sport

420

400

440

390

400

420

A3

Educational

420

400

440

390

400

420

A4

Worship

120

115

125

110

115

120

F1

Large Shops &
Shopping Malls

240

245

260

240

260

255

G1

Offices

200

190

210

185

190

200

H1

Hotels

650

600

585

600

620

630

Based the sum of 12 consecutive monthly maximum consumption

4. Deem-to-satisfy SANS 100400 XA — ROOFS

Deem-to-satisfy SANS 100400 XA clause 4.4
ROOFS

ZONE

Description

1

2

3

4

5

6

Minimum required
Total R-value (m².K/W)

3.7

3.2

2.7

3.7

2.7

3.5

Direction of
heat flow

Up

Up

Down
& Up

Up

Down

Up

IsoBoard R-value equivalent (mm)

100

80

70

100

65

90

5. Deem-to-satisfy SANS 100400 XA — WALLS

Deem-to-satisfy SANS 100400 XA clause 4.4
External Walls (non-masonary)
Note: Double-skin masonry and 140mm plastered and rendered walls comply.

ZONE

Description

1

2

3

4

5

6

Minimum required
Total R-value (m².K/W)

2.2

1.9

1.9

1.9

1.9

2.2

IsoBoard R-value equivalent (mm)

100

80

70

100

65

90

6. Deem-to-satisfy SANS 100400 XA — FLOORS

Deem-to-satisfy SANS 100400 XA clause 4.4
Floors with under-floor heating
Note: If no under-floor heating, no floor insulation required.

ZONE

Description

1

2

3

4

5

6

Minimum required
Total R-value (m².K/W)

1.0

1.0

1.0

1.0

1.0

1.0

IsoBoard R-value equivalent (mm)

30

30

30

30

30

30

7. Deem-to-satisfy vs IsoBoard Rational Design

Building description
Roofing/Ceiling

Deem to Satisfy vs Rational Design
IsoBoard Thickness Required (mm)

ZONE

1

2

3

4

5

6

(Deem to satisfy)

(100)

(80)

(70)

(100)

(65)

(90)

Small shop/
Strip Mall

40

30

30

30

30

40

High Rise Office

40

40

40

40

40

40

Low Rise Office

30

30

30

30

30

40

Residential >132m²

40

40

40

40

40

40

Subsidy Housing

40

30

30

40

30

40

Hospital

40

40

40

40

40

40

Hotel

40

30

40

30

40

40

Retail Shops &
Malls

40

40

40

40

40

40

As of the 10th November 2011, the National Building Regulations (South African National Standard 10 400 XA) require mandatory interventions to reduce energy consumption in new buildings and additions to existing structures. Amongst the stipulations are alternative options to achieving compliance using thermal insulation included in the building envelope.

The building owner is the person vested with the responsibility for ensuring compliance with the stipulations of the National Building Regulations. However, this responsibility can be delegated to appointed building professionals such as architects and engineers, and competent people can be appointed by either the owner or building professional to ensure design compliance of specific aspects, such as thermal insulation.

To determine the applicable standard required, one needs to establish where the building is located as per the defined climatic zones, and know the building occupancy classification, as certain building types require specific energy demand and consumption targets are met.

The adjacent tables 2 and 3 indicate the maximum permissible annual electrical demand in VA per m2, as well as the maximum permissible electrical consumption in kw per m2 for specific building occupancy classes.

These buildings generally have HVAC (Heating, Ventilation, Air Conditioning)systems, as well as other energy consumers such as escalators and elevators. The design for these buildings would most likely vest with a team including architects, mechanical or electrical engineers, as well as competent specialists.

Other building occupancy classes may either follow the Deemed–to-satisfy provisions for thermal insulation as indicated in the adjacent tables 4, 5 and 6, or may be the subject of a rational design by a competent person.

The Deemed to satisfy provisions are conservative, and will certainly reduce the energy required for heating and cooling to a comfortable living temperature. However, IsoBoard believes the comfort effects of the thermal insulation can be achieved through a Rational Design for each building, resulting in the equivalent energy usage as per the Deemed to satisfy provisions, for a lower intervention cost.

In adjacent table 7, an example is provided of the difference between the IsoBoard thickness intervention required per region for Deemed-to-satisfy and calculated Rational Designs, for roofing/ceilings of different building types.

Following Rational design, the same level of energy conservation can be achieved with lower thickness specifications of thermal insulation, at a considerable cost saving.

© Isoboard 2012