1. Performance of insulation foams over time
November 2004

2. Water Pick-up by Diffusion (SIA 279 70/0°C)
Water pick-up by diffusion over time
Time (Days)
Water Pick-up (%vol) 10 20 30 40 50 60 80
100
120
140
160
180
200
220
Water Pick-up by Diffusion (SIA /0°C)
PU 80 kg/m³
(100 mm)
XPS 45 kg/m³
Here PU 80kg/m³ is compared with XPS 45kg/m³ in terms of water pick-up by diffusion. After 120days PU shows a 10% higher moisture pick-up by diffusion than XPS.
After 200 days a difference of 20% can be detected.
November 2004

3. Thermal conductivity over time related to water pick-up by diffusion20 40 60 80
100
120
140
160
180
200
220
Thermal Conductivity (mW/mK)
Time (Days)
The Thermal Conductivity change in time
caused by water pickup by Diffusion
(SIA /0°C)
PU 80 kg/m3
(100 mm)
45 kg/m³
Comparison of PU 80kg/m³ versus XPS 45kg/m³ related to thermal conductivity over time considering water pick-up by diffusion. After 40 days the thermal conductivity of PU is already higher than XPS even if the start value is lower. During the first 40 days PU picks up 6% moisture by diffusion, XPS 2,5%.
November 2004

4. Calculation of water pick-up of different insulation materials versus thermal conductivity
The curve has been created based on the EN ISO It shows the influence of moisture content in insulation products on lambda. PU and Phenolic foam are very low in lambda but with increasing moisture content the thermal conductivity gets up. The increase of lambda in these cases is higher than with XPS.
November 2004

5. Mechanical strength under temperature influence
The chart shows the compressive strength of XPS and PU foam after exposure (24 hours) to different temperatures.
November 2004

6. Thermal Conductivity – comparison different BAs
The curves give a picture about the performance of thermal conductivity over time considering different blowing agents.
CO2-blown foam starts with a low lambda and reaches the max. value after approx.30 days. Maximum value means that the cells are completely filled with air.
152a provides a very low lambda-value if the foam is fresh. But it leads to a fast aging. After approx. 10 years the thermal conductivity is at its max. There is no 152a left in the foam after this time period.
134a provides long term lambda performance. The aging proceeds much slower meaning that the cell gas remains in the cell over long time period. The maximum level of thermal conductivity is reached after 25 years. Long-term lambda was the important argument for Dow to go for 134a.
curve based on calculation model
November 2004