EN 15026:2007 – Hygrothermal performance of building components and building elements – Assessment of moisture transfer by numerical simulation
1 Scope
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.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 12664, Thermal performance of building materials and products — Determination of thermal resistance by means of guarded hot plate and heat flow meter methods — Dry and moist products of medium and low thermal resistance
EN 12667, Thermal performance of building materials and products — Determination of thermal resistance by means of guarded hot plate and heat flow meter methods — Products of high and medium thermal resistance
EN 12939, Thermal performance of building materials and products — Determination of thermal resistance by means of guarded hot plate and heat flow meter methods — Thick products of high and medium thermal resistance
EN ISO 7345, Thermal insulation – Physical quantities and definitions (ISO 7345:1987)
prEN ISO 9346:2005, Hygrothermal performance of buildings and building materials – Mass transfer – Physical quantities and definitions (ISO/DIS 9346:2005)
prEN ISO 10456, Building materials and products – Hygrothermal properties -Tabulated design values and procedures for determining declared and design thermal values (ISO/DIS 10456:2005)
EN ISO 12571, Hygrothermal performance of building materials and products – Determination of hygroscopic sorption properties (ISO 12571:2000)
EN ISO 12572, Hygrothermal performance of building materials and products – Determination of water vapour transmission properties (ISO 12572:2001)
prEN ISO 15927-3, Hygrothermal performance of buildings – Calculation and presentation of climatic data – Part 3: Calculation of a driving rain index for vertical surfaces from hourly wind and rain data (ISO/DIS 15927- 3:2006)
EN 15026:2007 – Hygrothermal performance of building components and building elements – Assessment of moisture transfer by numerical simulation