For objects, when applicable, indicate whether the property IsExternal is TRUE or FALSE.  



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:

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.

TIP: Thermal insulation is always IsExternal=TRUE.