BS EN ISO 13788:2012

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions, symbols and units
4 Input data for the calculations
5 Calculation of surface temperature to avoid critical
  surface humidity
6 Calculation of interstitial condensation
7 Calculation of drying of building components
Annex A (informative) - Internal boundary conditions
Annex B (informative) - Examples of calculation of the
        temperature factor at the internal surface
        to avoid critical surface humidity
Annex C (informative) - Examples of calculation of
        interstitial condensation
Annex D (informative) - Example of the calculation of the
        drying of a wetted layer
Annex E (informative) - Relationships governing moisture
        transfer and water vapour pressure
Bibliography

Provides simplified calculation methods for: a) The internal surface temperature of a building component or building element below which mould growth is likely, given the internal temperature and relative humidity. b) The assessment of the risk of interstitial condensation due to water vapour diffusion.

This International Standard gives simplified calculation methods for: The internal surface temperature of a building component or building element below which mould growth is likely, given the internal temperature and relative humidity. The method can also be used to assess the risk of other internal surface condensation problems. The assessment of the risk of interstitial condensation due to water vapour diffusion. The method used does not take account of a number of important physical phenomena including: the variation of material properties with moisture content; capillary suction and liquid moisture transfer within materials; air movement from within the building into the component through gaps or within air spaces; the hygroscopic moisture capacity of materials. Consequently, the method is applicable only where the effects of these phenomena can be considered to be negligible. The time taken for water, from any source, in a layer between two high vapour resistance layers to dry out and the risk of interstitial condensation occurring elsewhere in the component during the drying process.