The determination of the internal surface temperature in terms of critical surface humidity is determined using calculation (simulation) software in accordance with the standard:
EN ISO 13788:2012 Hygrothermal performance of building components and building elements. Internal surface temperature to avoid critical surface humidity and interstitial condensation. Calculation methods.
The purpose of this procedure is to determine the risk of mold growth on the internal surface of the tested connection of elements. According to the standard, the highest risk of mold growth is expected at the point of the lowest internal surface temperature. The internal surface temperature is calculated for an increased surface heat transfer resistance coefficient Rsi = 0.25 m2K/W. In the case of multidimensional heat flow at the connection of building elements, the temperature distribution is determined using simulation software. The choice of software depends on the geometry of the tested connection. The calculations require:
• information on the connection geometry,
• thermal properties of the component materials,
• calculation software for two- or three-dimensional thermal analysis in accordance with the requirements of the standard (EN ISO 10211, 2017).
The tests on the PM&VL7 test line included:
• Indresmat window frames,
• Indresmat sandwich panels,
• Flex&Robust connections,
• Flex&Robust injections,
• Flex&Robust layers.
In the case of the Indresmat sandwich panel, the thermal conductivity of the insulating core was based on measurements, and in the case of the other materials (steel and expansion tape) on tabulated values. According to (EN ISO 13788, 2012), the test result is positive when the value of the lowest temperature coefficient fRsi on the inner surface is higher than the required minimum value of the design temperature coefficient fRsi,min.