EN 15026:2007

Foreword
Introduction
1 Scope
2 Normative references
3 Terms, definitions, symbols and units
  3.1 Terms and definitions
  3.2 Symbols and units
4 Hygrothermal equations and material properties
  4.1 Assumptions
  4.2 Transport of heat and moisture
  4.3 Material properties
5 Boundary conditions
  5.1 Internal conditions
  5.2 External conditions
6 Documentation of input data and results
  6.1 General
  6.2 Problem description
  6.3 Hygrothermal model and numerical solution
  6.4 Calculation report
Annex A (normative) Benchmark example - Moisture uptake in
        a semi-infinite region
      A.1 General
      A.2 Problem description
      A.3 Results
Annex B (informative) Design of Moisture Reference Years
Annex C (informative) Internal boundary conditions
Bibliography

This standard specifies the equations to be used in a simulation method for calculating the non steady transfer of heat and moisture through building structures. It also provides a benchmark example intended to be used for validating a simulation method claiming conformity with this standard, together with the allowed tolerances.The equations in this standard take account of the following storage and one-dimensional transport phenomena:-heat storage in dry building materials and absorbed water;-heat transport by moisture-dependent thermal conduction;-latent heat transfer by vapour diffusion;-moisture storage by vapour sorption and capillary forces;-moisture transport by vapour diffusion; -moisture transport by liquid transport (surface diffusion and capillary flow).The equations described in this standard account for the following climatic variables:-internal and external temperature;-internal and external humidity;-solar and longwave radiation;-precipitation (normal and driving rain);-wind speed and direction.The hygrothermal equations described in this standard shall not be applied in cases where:-convection takes place through holes and cracks;-two-dimensional effects play an important part (e.g. rising damp, conditions around thermal bridges, effect of gravitational forces);•hydraulic, osmotic, electrophoretic forces are present;daily mean temperatures in the component exceed 50 °C.