# ISO 10211:2007 Thermal bridges in building construction. Test case A.3 validation

QuickField validation of the test case A.3 presented in ISO 10211:2007 Thermal bridges in building construction.

Problem Type:
3D problem of heat transfer.

Geometry:

all length units are in millimeters.

Given:
Thermal conductivity of AAC λ1 = 0.7 W/K·m.
Thermal conductivity of insulation λ2 = 0.04 W/K·m.
Thermal conductivity of brick λ3 = 1.0 W/K·m.
Thermal conductivity of concrete slab λ4 = 2.5 W/K·m.
Thermal conductivity of plaster λ5 = 1 W/K·m.

Problem:
The floor slab penetrates the wall near the corner and forms the cold bridge. Determine the flux and the thermal coupling coefficients.

Solution:
Air contact surface thermal resistance Rs is caused by the convection. The convection coefficient value is reciprocal to the surface resistance value:
α = 1 / Rs [W/(K·m2)].

Results:
Temperature distribution in the wall:

 Temperature in the corners: QuickField Reference %% First floor 11.12°C 11.11°C <0.1°C Second floor 11.37°C 11.32°C <0.1°C Heat flux: 59.4 W 59.98 W <1%

Thermal coupling coefficients (reference values are in the brackets).
 External First floor Second floor External (1.000) (0.000) (0.000) First floor 0.375 (0.378) 0.401 (0.399) 0.223 (0.223) Second floor 0.329 (0.331) 0.216 (0.214) 0.455 (0.455)

To comply with the ISO 10211:2007 the difference between calculated and reference heat flux should be less than 1% (0.1°C - for temperature). This simulation accuracy complies with the requirements of ISO 10211:2007.

See the iso_10211_2007_case3.pbm problem in the Examples folder.