The property IsExternal is marked as TRUE (outside/external) or FALSE (inside/internal) to provide a rough demarcation in the models. These include material conservation and the possibility of separating the thermal skin from the shell, for example, for planning (wind and water tightness) and building physics calculations.
If an object is indicated as IsExternal:TRUE, this can have the following consequences:
- In relation to material:
- steel and wood: TRUE = other preservation required
- concrete: TRUE = consequences for the environmental class
- External facade package: other building physics calculations
- For use in planning: determine construction sequence (LoadBearing first, then wind and water tightness)
Rules of thumb
There are several ways to rationalise IsExternal. As a rule of thumb, consider the spatial function to which the object abuts or in which the object is located (Figure 4.4.1). Another useful rule of thumb: use IsExternal for objects with materials that require a degree of preservation, such as metals, concrete, wood and plastics.
Figure 4.4.1 IsExternal is rationalised through its spatial function
IsExternal always applies to floors, walls and roofs (including openings). Make additional agreements with your project team about which other components are also IsExternal=TRUE or IsExternal=FALSE.