INSULATION THICKNESS CALCULATOR

ENERGY EFFICIENCY PERFORMANCE PRINCIPLES

THE BUILDING ENVELOPE

Components that constitute the building envelope are:

1. Roofs2. Fenestration3. Walls4. Floors

• A well designed building envelope controls heat gain and loss in the hotter and colder seasons of the year.

• Maximize cooling air movement • Limits exposure to direct sunlight in summer• Trap and store heat from the sun in winter• Minimise heat loss to the external environment

SECTIONAL ELEVATION OF A ROOM SHOWING EXTENT OF SUN PENETRATION AND HEAT LOSS/GAIN THROUGH THE BUILDING

ENVELOPE

BUILDING REGULATIONS SANS 204 AND SANS 10400XA

CORE ASPECTS OF THE STANDARDS ARE THE FOLLOWING:• Site orientation• Building orientation• Shading• Building design ( external walls, floors, fenestration, shading, roof

assemblies and roof lights)• Building sealing ( building envelope, air infiltration and leakage and

permissible air leakages)• Services (lighting and power, hot water services and appliances)• Mechanical ventilation and air conditioning• Installed equipment.

MAP OF CLIMATIC ZONES OF SOUTH AFRICA

FLOORS

With the exception of zone 5 (climatic zones), buildings with a floor area of less than 500 m2 with, a concrete slab on ground shall have insulation around the vertical edge of its perimeter which shall:

• Have an R-value of not less than 1.0• Resist water penetration in order to retain its thermal properties• Be continuous from the adjacent finish ground level a) to a depth of not less than 300 mm b) for the full depth of the vertical edge of the concrete slab-on-ground

Application criteria

Table 1: Perimeter insulation required (mm)

Climatic zone 1 2 3 4 5 6

Minimum required R-values for perimeter insulation m2 K/W

1 1 1 1 - 1

FLOORS

Where an in-slab or in-screed heating system is installed it shall be insulated underneath the slab with insulation having a minimum R-value of not less than 1,0.

Application criteria

Table 2: installed under floor heating

Climatic zone 1 2 3 4 5 6

Minimum required R-values for perimeter insulation m2 K/W

1 1 1 1 1 1

FLOORS

With the exception of climatic zone 5, a suspended floor that is part of a building’s envelope shall have insulation that shall retain its thermal properties under moist conditions and be installed:

• For climatic zones 1 and 2, with partially or completely unenclosed exterior perimeter, and shall achieve a total R-value of 1,5:

• For climatic zones 3, 4 and 6, with a partially or completely unenclosed exterior perimeter, shall achieve a total R-value of 1,0.

• With an in-slab heating system, and shall be insulated around the vertical edge of its perimeter and underneath with insulation having a minimum R-value of not less than 1,0.

Table 3: suspended floor that is part of the building envelope

Climatic zone 1 2 3 4 5 6

Minimum required R-values for perimeter insulation m2 K/W

1,5

1,5

1 1 - 1

FLOORS

Detail 1: heat loss through un-insulated floor slabs and walls

FLOORS

Detail 2: perimeter and under slab insulation

FLOORS

Detail 3: perimeter and cavity insulation

FLOORS

Detail 4: cavity insulation and under screed insulation

FLOORS

Detail 5: suspended timber floor

EXTERNAL WALLS

Non- masonry walls shall achieve a minimum total R-value of

• Climatic zones 1 and 6: 2,2• Climatic zones 2, 3, 4 and 5: 1,9

Application criteria

Table 4: Light weight external walls surface density less than 180 Kg/m2 deemed-to-satisfy minimum total R-Values for each climate

Climatic zone 1 2 3 4 5 6

Minimum required total R-values for light weight walls insulation m2 K/W

2.2

1,9

1,9 1,9 1,9 2,2

EXTERNAL WALLS

Masonry walls. For walls with a surface density greater than 180 kg/m2, table 5 sets out the minimum CR product requirements and their application:

• CR product –the time constant property (hours) of a composite element, such as a wall, and being the arithmetical product of the total C-value and the total R-value)

• The thermal capacity of a material is known as the “C-value” and it reflects the ability to store heat during the hot period and to radiate the heat during the cool period. This process is also known as thermal lagging, and masonry products such as bricks

Application criteria

Table 5: DEEMED TO SATISFY Minimum thermal capacity and resistance CR product, in hours, for external walling

occupancies

CR-Value per Climatic zone

1 2 3 4 5 6

Residential: E1-E3, H1 –H5 100 80 80 100 60 90

Office and institutional: A1-A4, C1-C2, B1-B3, G1 80 80 100 100 80 80

Retail: D1-D4, F1-F3, J1-J3 80 80 120 80 60 100

Unclassified: A5, J4 NR NR NR NR NR NRNote: NR= No requirement

EXTERNAL WALLS

Detail 6: Wall insulation types

ROOFS AND CEILINGS

A roof assembly shall achieve the minimum total R-value specified in table 6 for the direction of heat flow.

Table 6 Minimum required R-Value (m2.K/W) for Roofs

Climatic zones 1 2 3 4 5 6

Minimum required total R-values for roof solar absorptance of more than 0.55.

3.7 3.2 2.7 3.7 2.7 3.5

Dominant direction of heat flow. Up Up Down & Up

Up down UP

The tool kit is meant to support the decision making process that determines the use of insulation as energy-saving measures in new and existing buildings, with a focus of the three BASF insulation products (Neopor, Elastopor and Elastospray).

This tool for determining recommended insulation levels is to be used in conjunction with other energy efficient design principles such as

1. Design for climate 2. Building orientation, main living areas towards the north3. Insulation of geysers and pipes4. Positioning of windows to allow cross ventilation and accommodate glass

selection.

BASF TOOL KIT

TOOL CONCEPTUAL CHART

TOOL LAYOUT

DETERMINING REQUIRED INSULATION THICKNESS

Roof Construction

Align with Climatic zone dial, Choose the climatic zone e.g. 2

Align with the minimum R-Values required from either the regulation or the rational calculations. See the required R-

ValueMatch to the available R-values from Product manufacturer

Product thickness mm

PLEASE TEST THE SAMPLE CALCULATOR