# 7.1.3.3 IfcPermeableCoveringProperties

## 7.1.3.3.1 Semantic definition

This entity is a description of a panel within a door or window (as fillers for opening) which allows for air flow. It is given by its properties (IfcPermeableCoveringProperties). A permeable covering is a casement, such as a component, fixed or opening, consisting essentially of a frame and the infilling. The infilling is normally a grill, a louver or a screen. The way of operation is defined in the operation type.

The IfcPermeableCoveringProperties are included in the list of properties (HasPropertySets) of the IfcWindowType or the IfcDoorType. More information about the permeable covering can be included in the same list of the window or door style using the IfcPropertySet for dynamic extensions. This particularly applies for additional properties for the various operation types

The IfcPermeableCoveringProperties does not hold a geometric representation. However it defines parameters which can be used to create the shape of the IfcWindowType (which is inserted by the IfcWindow into the spatial context of the project), or of the IfcDoorType (which is inserted by the IfcDoor).

The parameters at the IfcPermeableCoveringProperties define a standard permeable covering. The outer boundary of the panel is determined by the occurrence parameter assigned to the IfcWindow or IfcDoor. It has to take the lining parameter into account as well. The position of the permeable covering within the overall window or door is determined by the PanelPosition attribute.

Figure 7.1.3.3.A illustrates the panel applied to the position within the lining, as defined by the panel position attribute. The following parameters apply to that panel: FrameDepth, FrameThickness.

## 7.1.3.3.5 Formal representation

ENTITY IfcPermeableCoveringProperties
SUBTYPE OF (IfcPreDefinedPropertySet);
OperationType : IfcPermeableCoveringOperationEnum;
PanelPosition : IfcWindowPanelPositionEnum;
FrameDepth : OPTIONAL IfcPositiveLengthMeasure;
FrameThickness : OPTIONAL IfcPositiveLengthMeasure;
ShapeAspectStyle : OPTIONAL IfcShapeAspect;
END_ENTITY;