Property

ThermalTransmittance

Namespace URI

http://identifier.buildingsmart.org/uri/buildingsmart/ifc-4.3/prop/ThermalTransmittance

Domain

IFC

Domain version

4.3

Description

Thermal transmittance coefficient (U-Value) of an element, within the direction of the thermal flow (including all materials).

DataType

Real

PropertyValueKind

Single

Classifications

An IfcBeam is typically a horizontal, or nearly horizontal, structural member that is capable of withstanding load primarily by resisting bending. It may also represent such a member from an architectural point of view. It is not required to be load bearing.There are two main representations for beam occurrences:IfcBeam with IfcMaterialProfileSetUsage is used for all occurrences of beams, that have a profile defined that is swept along a directrix. The profile might change uniformly by a taper definition along the directrix. The profile parameter and its cardinal point of insertion can be fully described by the IfcMaterialProfileSetUsage. These beams are always represented geometricly by an 'Axis' and a 'SweptSolid' or 'AdvancedSweptSolid' shape representation (or by a 'Clipping' geometry based on the swept solid), if a 3D geometric representation is assigned. IfcBeam without IfcMaterialProfileSetUsage is used for all other occurrences of beams, particularly for beams with non-uniformly changing profile sizes along the sweep, or beams having only 'AdvancedBrep', 'Brep', or 'SurfaceModel' geometry, if a more parametric representation is not intended.For any other longitudinal structural member, not constrained to be predominately horizontal nor vertical, or where this semantic information is irrelevant, the entity IfcMember should be used.REFERENCE Definition according to ISO 6707-1: structural member for carrying load(s) between or beyond points of support, usually narrow in relation to its length and horizontal or nearly so. NOTE The entity IfcBeamStandardCase has been deleted, IfcBeam with IfcMaterialProfileSetUsage is used instead. NOTE The representation of load-bearing beams in a structural analysis model is provided by subtypes of IfcStructuralMember (with IfcStructuralCurveMember being mostly applicable) as part of an IfcStructuralAnalysisModel. The camber of a beam may be defined by assigning an IfcStructuralCurveMember with displacement coordinates. Multiple sets of camber ordinates may be provided that are qualified by the particular load case, where full dead load would typically be used for fabrication, and other scenarios used for other loading conditions such as during construction. HISTORY New entity in IFC1.0

The IfcBuildingElementProxy is a proxy definition that provides the same functionality as subtypes of IfcBuildingElement, but without having a predefined meaning of the special type of building element it represents.IfcBuildingElementProxy may be used:To exchange special types of building elements for which the current specification does not yet provide a semantic definition. To represent building elements for which the participating applications can not provide a semantic definition.IFC4.3.0.0 CHANGE IfcBuildingElementProxy should no longer be used as spatial placeholders or provisions. Use IfcVirtualElement instead. HISTORY New entity in IFC2x.

Chimneys are typically vertical, or as near as vertical, parts of the construction of a building and part of the building fabric. Often constructed by pre-cast or insitu concrete, today seldom by bricks.{ .extDef}NOTE Definition according to ISO 6707-1: construction containing one or more flues. Flue: Duct designed to convey the products of combustion to the open air. Chimney stack: Part of the chimney that projects above a roof. HISTORY New entity in IFC4.

An IfcColumn is a vertical structural or architectural member which often is aligned with a structural grid intersection. In most cases it represents a vertical, or nearly vertical, structural member that transmits, through compression, the weight of the structure above to other structural elements below. It may also represent such a member from an architectural point of view in which case it may represent a non load bearing element. Whether it is a structural load bearing element or a non-load bearing element is determined by the Pset_ColumnCommon.LoadBearing property.There are two main representations for column occurrences:IfcColumn with IfcMaterialProfileSetUsage is used for all occurrences of columns, that have a profile defined that is swept along a directrix. The profile might change uniformly by a taper definition along the directrix. The profile parameter and its cardinal point of insertion can be fully described by the IfcMaterialProfileSetUsage. These columns are always represented geometricly by an 'Axis' and a 'SweptSolid' or 'AdvancedSweptSolid' shape representation (or by a 'Clipping' geometry based on the swept solid), if a 3D geometric representation is assigned. IfcColumn is used for all other occurrences of columns, particularly for columns with changing profile sizes along the extrusion, or columns defined by non-linear extrusion, or columns having only 'Brep', or 'SurfaceModel' geometry, if a more parametric representation is not intended.For any longitudial structural member, not constrained to be predominately horizontal nor vertical, or where this semantic information is irrelevant, the entity IfcMember exists.REFERENCE Definition according to ISO 6707-1 structural member of slender form, usually vertical, that transmits to its base the forces, primarily in compression, that are applied to it. NOTE The entity IfcColumnStandardCase has been deleted, IfcColumn with IfcMaterialProfileSetUsage is used instead. NOTE The representation of a column in a structural analysis model is provided by IfcStructuralCurveMember being part of an IfcStructuralAnalysisModel. HISTORY New entity in IFC1.0

A covering is an element which covers some part of another element and is fully dependent on that other element. The IfcCovering defines the occurrence of a covering type, that (if given) is expressed by the IfcCoveringType.{ .extDef}NOTE Definition according to ISO ISO 6707-1: final coverings and treatments of surfaces and their intersections.Coverings are elements with relationships to the covered element and the space on the other side, they may contain openings, assigned by IfcRelVoidsElement, material information, assigned by IfcRelAssociatesMaterial, and others.EXAMPLE Coverings include wall claddings, floorings, suspended ceilings, moldings and skirting boards. NOTE A more basic information about claddings, floorings, and ceilings of a space can be attached to IfcSpace's using the Pset_SpaceCommon properties. Then only a name can be provided and the covering quantities would be interpreted from the space quantities.Coverings can be assigned toa space represented by IfcSpace using the inverse relationship CoversSpaces pointing to IfcRelCoversSpaces. The space is then accessible via IfcRelCoversSpaces.RelatedSpace. It defines to which space a covering is facing towards. a space boundary represented by IfcRelSpaceBoundary using the inverse relationship ProvidesBoundaries pointing to IfcRelSpaceBoundary. The space is then accessible via IfcRelSpaceBoundary.RelatingSpace. a building element represented by IfcBuildingElement using the inverse relationship Covers pointing to IfcRelCoversBldgElements. The building element is then accessible via IfcRelCoversBldgElements.RelatingBuildingElement.NOTE The mere containment relationship between an IfcCovering and an IfcSpace is created by using IfcRelContainedInSpatialStructureThe following guideline shall apply:(default) if the space has coverings that may not have their own shape representation and no defined relationships to the building elements they cover, then the IfcCovering shall be assigned to IfcSpace using the IfcRelCoversSpaces relationship, if the space has coverings that have an own shape representation and the space has defined space boundaries, then the covering, which relates to that space, shall be contained in the space using IfcRelContainedInSpatialStructure. It may be assigned to the space boundaries using the IfcRelSpaceBoundary. if the covering does not relate to a space, then the covering should be assigned to the building element or a distribution element using the IfcRelCoversBldgElements relationship.HISTORY New entity in IFC1.0.

A curtain wall is a wall of a building which is an assembly of components, hung from the edge of the floor/roof structure rather than bearing on a floor. Curtain wall is represented as a building element assembly and implemented as a subtype of IfcBuildingElement that uses an IfcRelAggregates relationship. A curtain wall is often external, but using Pset_CurtainWallCommon.IsExternal can be used to define interior curtain walls.{ .extDef}NOTE Definition according to ISO 6707-1: non load bearing wall positioned on the outside of a building and enclosing it. HISTORY New entity in IFC2.0The geometric representation of IfcCurtainWall is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Independent 'Body' geometric representation, as described below, should only be used when the IfcCurtainWall is not defined as an aggregate. If defined as an aggregate, the geometric representation is the sum of the representations of the components within the aggregate.The geometric representation of IfcCurtainWall is defined using the following multiple shape representations for its definition:Axis: A two-dimensional open curve (for restrictions see below) defining the axis for the curtain wall. This is an optional representation for curtain walls. Body: A surface model or boundary representation model representation defining the 3D shape of the curtain wall. If the IfcCurtainWall has components (referenced by SELF\IfcObject.IsDecomposedBy) then no independent shape representation with RepresentationType = 'Body' shall be defined. The body of IfcCurtainWall is then geometrically represented by the shape representation of its components. The components are accessed via SELF\IfcObject.IsDecomposedBy[1].RelatedObjects. If the IfcCurtainWall has no components defined (empty set of SELF\IfcObject.IsDecomposedBy) then the IfcCurtainWall may be represented by an shape representation with the RepresentationIdentifier ='Body'.

The door is a built element that is predominately used to provide controlled access for people, goods, animals and vehicles. It includes constructions with hinged, pivoted, sliding, and additionally revolving and folding operations. A door can:be a "free standing" door, contained in an IfcSpatialElement such as an IfcBuildingStorey. fill an opening, typically in a wall. The door will then have a FillsVoids attribute which uses the IfcRelFillsElement relationship to relate the IfcDoor with the IfcOpeningElement; be part of an element assembly, typically an IfcCurtainWall. The door will then have a Decomposes attribute which uses the the IfcRelAggregates relationship to relate the door with the assembly of elements;There are two main representations for door occurrences:IfcDoor entities that have a 3D rectangle 'Profile' shape representation defined. This profile can then be used to parametrically generate the geometry of a door. If not provided, the profile of the IfcOpeningElement can be used if the door fills an opening. The parameters are specified on the relating IfcDoorType that references IfcDoorLiningProperties and IfcDoorPanelProperties for each panel in the door; IfcDoor entities that are not parametrically generated and have only 'Brep', or 'SurfaceModel' geometry.In addition, an IfcDoor may commonly include a 'FootPrint' representation defining the 2D shape of the door and its swing.The parameters of a door are defined by both the IfcDoor occurence and its IfcDoorType. The IfcDoor specifies:the door width and height the door opening direction (by the positive y-axis of the ObjectPlacement)The IfcDoorType specifies parameters which are common to all of its occurrences of IfcDoor:the operation type (single swing, double swing, revolving, etc.) the door hinge side (by using two different styles for right and left opening doors) the particular attributes for the lining by the IfcDoorLiningProperties the particular attributes for the panels by the IfcDoorPanelPropertiesREFERENCE Definition according to ISO 6707-1: construction for closing an opening, intended primarily for access with hinged, pivoted or sliding operation. NOTE The entity IfcDoorStandardCase has been deleted. Use an IfcDoor with a 'Profile' representation instead. The IfcDoor should also have an IfcDoorType with ParameterTakesPrecedence set to 'TRUE'. HISTORY New entity in IFC1.0.

An IfcMember is a structural member designed to carry loads between or beyond points of support. It is not required to be load bearing. The orientation of the member (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to IfcBeam and IfcColumn). An IfcMember represents a linear structural element from an architectural or structural modeling point of view and shall be used if it cannot be expressed more specifically as either an IfcBeam or an IfcColumn.There are two main representations for member occurrences:IfcMember with IfcMaterialProfileSetUsage is used for all occurrences of members, that have a profile defined that is swept along a directrix. The profile might be changed uniformly by a taper definition along the directrix. The profile parameter and its cardinal point of insertion can be fully described by the IfcMaterialProfileSetUsage. These members are always represented geometricly by an 'Axis' and a 'SweptSolid' or 'AdvancedSweptSolid' shape representation (or by a 'Clipping' geometry based on the swept solid), if a 3D geometric representation is assigned. IfcMember without IfcMaterialProfileSetUsage is used for all other occurrences of members, particularly for members with changing profile sizes along the extrusion, or members defined by non-linear extrusion, or members having only 'Brep', or 'SurfaceModel' geometry, or if a more parametric representation is not intended.NOTE The representation of a member in a structural analysis model is provided by IfcStructuralCurveMember being part of an IfcStructuralAnalysisModel. HISTORY New entity in IFC2x2 Addendum 1.

An IfcPlate is a planar and often flat part with constant thickness. A plate may carry loads between or beyond points of support, or provide stiffening. The location of the plate (being horizontal, vertical or sloped) is not relevant to its definition.Plates are normally made of steel, other metallic material, or by glass panels. However the definition of IfcPlate is material independent and specific material information shall be handled by using IfcAssociatesMaterial to assign a material specification to the IfcPlate.Plates are often add-on parts. This is represented by the IfcRelAggregates decomposition mechanism used to aggregate parts, such as IfcPlate, into a container element such as IfcElementAssembly or IfcCurtainWall.An instance of IfcPlate should preferably get its geometric representation and material assignment through the type definition by IfcPlateType assigned using the IfcRelDefinesByType relationship. This allows identical plates in a construction to be represented by the same instance of IfcPlateType.A plate may have openings, such as voids or recesses. They are defined by an IfcOpeningElement attached to the plate using the inverse relationship HasOpenings pointing to IfcRelVoidsElement. The position number of a plate as often used in steel construction is assigned through the attribute IfcElement.TagThere are two main representations for plate occurrences:IfcPlate with IfcMaterialLayerSetUsage is used for all occurrences of plates, that are prismatic and where the thickness parameter can be fully described by the IfcMaterialLayerSetUsage. These plates are always represented geometrically by a 'SweptSolid' geometry (or by a 'Clipping' geometry based on 'SweptSolid'), if a 3D geometric representation is assigned. IfcPlate without IfcMaterialLayerSetUsage is used for all other occurrences of plates, particularly for plates with changing thickness, or plates with non planar surfaces, and plates having only 'SurfaceModel' or 'Brep' geometry or if a more parametric representation is not intended.REFERENCE Definition according to ISO 6707-1: thin, rigid, flat, metal product, of a thickness greater than that of a sheet. NOTE The representation of a plate in a structural analysis model is provided by IfcStructuralSurfaceMember being part of an IfcStructuralAnalysisModel. HISTORY New entity in IFC2x2

A ramp is a vertical passageway which provides a human or vehicle circulation link between one floor level and another floor level at a different elevation. It may include a landing as an intermediate floor slab. A ramp normally does not include steps.{ .extDef}NOTE Definition according to ISO 6707-1: Inclined way or floor joining two surfaces at different levels.The IfcRamp shall either be represented:as a ramp assembly that aggregates all parts(ramp flight, landing, etc.) with own shape representations, or as a single ramp without decomposition including all shape representations directly at the ramp entity.NOTE In case of an IfcRamp being the assembly of all parts of the ramp the aggregation is handled by the IfcRelAggregates relationship, relating an IfcRamp with the related IfcRampFlight and landings, IfcSlab with PredefinedType=LANDING. IfcRailing's belonging to the ramp may also be included into the aggregation. NOTE Model View Definitions and implementer agreements may restrict the IfcRamp being an assembly to not have an independent shape representation, but to always require that the decomposed parts have a shape representation. In this case, at least the 'Body' geometric representations shall not be provided directly at IfcRamp if it is an assembly. The 'Body' geometric representation of the IfcRamp is then the sum of the 'Body' shape representation of the parts within the decomposition structure. HISTORY New entity in IFC2.0.

Show all classifications (16) »

Classifications of other domains

structural supporting object in a plane or curved surface form withstanding compression forces and bending moment

structural system terminating a space upwards

space access object for upright passage by persons

structural system terminating a space downwards

space access object of restricted size for passage of persons and goods

Show all classifications of other domains (26) »