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Regulations

FOR COMPLIANCE THAT’S BUILT-IN.

All new buildings or additions to existing buildings must comply with National Building Regulations in terms of reducing energy use. Thermal insulation – like the kind Summit provides – is one of the officially recommended ways to achieve this.

What is the R-value?

The R-value is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat. The higher the R-value, the more resistant a product is to heat flow. The R-value applies only to specific materials – so to calculate the overall R-value of an entire system (such as a wall system), the R-values of all components must be added together.

Thickness
XPSboards
Thickness
M
Thermal
conductivity
dry 90 day
aged
Thermal
conductivity
dry 5 year
aged
Thermal
Conductivity
90% RH
25mm0.025 0.0240.0280.03
30mm0.030.0240.0280.03
40mm0.040.0240.0280.03
50mm0.050.0240.0280.03
60mm0.060.0240.0280.03
70mm0.070.0240.0280.03
80mm0.080.0240.0280.03
Thickness
XPSboards
Thickness
M
R- Value dry
90 day aged
R- Value
5 year
aged
R- Value 90%
RH
25mm0.025 1.0420.8930.833
30mm0.031.2501.0711.00
40mm0.041.6671.4291.333
50mm0.052.0831.7861.667
60mm0.062.52.142.0
70mm0.072.922.502.33
80mm0.083.3332.8572.667

Use these values for SANS 10400XA R-Value calculations

What are “up” and “down” R-values?

“Up” values measure the flow of heat rising up through the insulation, while “down” values measure the amount of heat passing down through the insulation. These are also sometimes known as winter and summer values, respectively. These measurements are especially important when dealing with reflective insulation.

MINIMUM TOTAL R-VALUE OF ROOF ASSEMBLIES
DescriptionClimate zones
123456
Minimum required total
R-value (m2 K/W)
3.73.22.73.72.73.5
Direction of feat
flow
UpUpDown
and
Up
UpDownUp
METAL SHEETING ROOF ASSEMBLIES
DescriptionClimate zones
123456
Direction of featUpUpDown
and
Up
UpDownUp
R-value (M2 K/W) of roof
covering material
0.300.360.30
R-value of celling0.05
Adding R-value of
insulation
3.352.852.353.352.293.15
CLAY TILE ROOF ASSEMBLIES
DescriptionClimate zones
123456
Direction of feat
flow
UpUpDown
and
Up
UpDownUp
R-value (M2 K/W) of roof
covering material
0.350.460.35
R-value of celling0.05
Adding R-value of
insulation
3.302.802.303.302.172.8
Fire test

Summit XPS insulation board will be classified as B/B1/2/H&V in terms of SANS 428, which means that although it is combustible, it poses no flame-spread hazard.
Summit XPS can be installed horizontally or vertically in any building type – even those without a sprinkler system – with the exception of regulated buildings that require non-combustible materials. Exposed to fire, Summit XPS insulation board shrinks away from the heat source, with no flaming droplets or flame spread.

Properties:

  • Density = 28-36kg/m³
  • Compressive strength = 160-310kPa
  • Coefficient of linear thermal expansion = -10°C to 60°C;
  • 0.067mm per m per °C
  • Thermal conductivity = 0.024W per m per °C

climatic-zones

WHERE TO FIND US
STOCKIST

FIND YOUR STORE

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