#### IfcStairFlight

Natural language names

##### Semantic definitions at the entity

Entity definition

Assembly of building components in a single "run" of stair steps (not interrupted by a landing). The stair steps and any stringers are included in this object. A winder is regarded as part of a stair flight.

An IfcStairFlight is normally aggregated by a stair (IfcStair) through the IfcRelAggregates relationship, the stair flight is then included in the set of IfcRelAggregates.RelatedObjects.

An IfcStairFlight normally connects the floor slab of zero to two different storeys (or partial storeys) within a building. The connection relationship between the IfcStairFlight and the IfcSlab is expressed using the IfcRelConnectsElements relationship.

> HISTORY: New Entity in IFC Release 2.0.

Property Set Use Definition:

The property sets relating to the IfcStairFlight are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcStairFlight are part of this IFC release:

- Pset_StairFlightCommon: common property set for all stair flight occurrences

Geometry Use Definitions:

The geometric representation of IfcStairFlight is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are:

Local placement

The local placement for IfcStairFlight is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations.

- The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level.
- If the IfcStairFlight, however, is used by an IfcStair, and this container class defines its own local placement, then the PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the aggregate.

Standard Geometric Representation

The standard geometric representation of IfcStair is defined using the following multiple shape representations for its definition:

- WalkingLine: A two-dimensional open curve (IfcBoundedCurve) defining the walking line for the stair flight.
- Boundary: A two-dimensional closed curve (IfcBoundedCurve) defining the boundary of the stair flight.
- Body: A Brep representation (subtypes of IfcManifoldSolidBrep) defining the 3D shape of the stair flight

First Representation: WalkingLine

The walking line is represented by a two-dimensional open curve within a particular shape representation. The curve is directed (direction has to be interpreted as specified at the subtypes of IfcCurve).

| IfcShapeRepresentation RepresentationIdentifier : 'WalkingLine' RepresentationType : 'GeometricSet' In case of straight flights the curve set shall consists of a single item of type IfcPolyline. In case of winding flights the curve set shall consists of a single item of type IfcCompositeCurve. In case of a curved flight or a spiral flight the curve set shall consists of a single item of type IfcTrimmedCurve.

Second Representation: Boundary

The flight boundary is represented by a two-dimensional closed curve within a particular shape representation.

| IfcShapeRepresentation RepresentationIdentifier : 'Boundary' RepresentationType : 'GeometricSet' In case of straight flights the curve set shall consists of a single item of type IfcPolyline. In case of winding flights or curved flights the curve set shall consists of a single item of type IfcCompositeCurve. In case of a spiral flight the curve set shall consists of a single item of type IfcConic or IfcPolyline.

Third Representation: Body

The three dimensional shape of the flight is represented by a Brep representation.

| IfcShapeRepresentation RepresentationIdentifier : 'Body' RepresentationType : 'Brep'

Attribute definitions

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
9 | NumberOfRiser | - |  | This attribute is out of scope for this model view definition and shall not be set. |
10 | NumberOfTreads | - |  | This attribute is out of scope for this model view definition and shall not be set. |
11 | RiserHeight | - |  | This attribute is out of scope for this model view definition and shall not be set. |
12 | TreadLength | - |  | This attribute is out of scope for this model view definition and shall not be set. |

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
IfcRoot
1 | GlobalId | IfcGloballyUniqueId | [1:1] | Assignment of a globally unique identifier within the entire software world. | X
2 | OwnerHistory | IfcOwnerHistory | [1:1] | Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE: only the last modification in stored. | X
3 | Name | IfcLabel | [0:1] | Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule. | X
4 | Description | IfcText | [0:1] | Optional description, provided for exchanging informative comments. | X
IfcObjectDefinition
| IsDecomposedBy | IfcRelDecomposes @RelatingObject | S[0:?] | Reference to the decomposition relationship, that allows this object to be the composition of other objects. An object can be decomposed by several other objects. | X
| Decomposes | IfcRelDecomposes @RelatedObjects | S[0:1] | References to the decomposition relationship, that allows this object to be a part of the decomposition. An object can only be part of a single decomposition (to allow hierarchical strutures only). | X
| HasAssociations | IfcRelAssociates @RelatedObjects | S[0:?] | Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification. | X
IfcObject
5 | ObjectType | IfcLabel | [0:1] | The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute PredefinedType is set to USERDEFINED. | X
| IsDefinedBy | IfcRelDefines @RelatedObjects | S[0:?] | Set of relationships to type or property (statically or dynamically defined) information that further define the object. In case of type information, the associated IfcTypeObject contains the specific information (or type, or style), that is common to all instances of IfcObject referring to the same type. | X
IfcProduct
6 | ObjectPlacement | IfcObjectPlacement | [0:1] | Placement of the product in space, the placement can either be absolute (relative to the world coordinate system), relative (relative to the object placement of another product), or constraint (e.g. relative to grid axes). It is determined by the various subtypes of IfcObjectPlacement, which includes the axis placement information to determine the transformation for the object coordinate system. | X
7 | Representation | IfcProductRepresentation | [0:1] | Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement. | X
IfcElement
8 | Tag | - |  | This attribute is out of scope for this model view definition and shall not be set. |
| ConnectedTo | IfcRelConnectsElements @RelatingElement | S[0:?] | Reference to the element connection relationship. The relationship then refers to the other element to which this element is connected to. |
| HasOpenings | IfcRelVoidsElement @RelatingBuildingElement | S[0:?] | Reference to the Voids Relationship that creates an opening in an element. An element can incorporate zero-to-many openings. | X
| IsConnectionRealization | IfcRelConnectsWithRealizingElements @RealizingElements | S[0:?] | Reference to the connection relationship with realizing element. The relationship then refers to the realizing element which provides the physical manifestation of the connection relationship. | X
| ConnectedFrom | IfcRelConnectsElements @RelatedElement | S[0:?] | Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element. | X
| ContainedInStructure | IfcRelContainedInSpatialStructure @RelatedElements | S[0:1] | Containment relationship to the spatial structure element, to which the element is primarily associated. | X
IfcBuildingElement
IfcStairFlight
9 | NumberOfRiser | - |  | This attribute is out of scope for this model view definition and shall not be set. |
10 | NumberOfTreads | - |  | This attribute is out of scope for this model view definition and shall not be set. |
11 | RiserHeight | - |  | This attribute is out of scope for this model view definition and shall not be set. |
12 | TreadLength | - |  | This attribute is out of scope for this model view definition and shall not be set. |

##### Definitions applying to AISC Model View

Instance diagram

Concept usage

Properties on Occurrences

The Properties on Occurrences concept applies to this entity as shown in Table 28.

Property
AISC_EM11_Pset_PieceIdentification
AISC_EM11_Pset_Feature
AISC_EM11_Pset_ToleranceForLayout
AISC_EM11_Pset_Material
AISC_EM11_Pset_SurfaceTreatment
AISC_EM11_Pset_StatusInformation
AISC_EM11_Pset_VersionInformation
Table 28 — IfcStairFlight Properties on Occurrences

Exchange |
--- | ---
Import | O
Export | O

Placement

The Placement concept applies to this entity.

Exchange |
--- | ---
Import | R
Export | R

Body Geometry

The Body Geometry concept applies to this entity.

Exchange |
--- | ---
Import | R
Export | R

Concept alternates

Body Profile Extruded Area Solid

The Body Profile Extruded Area Solid concept applies to this entity.

Exchange |
--- | ---
Import | O
Export | O

Body Brep Geometry PolyLoop

The Body Brep Geometry PolyLoop concept applies to this entity.

Exchange |
--- | ---
Import | O
Export | O

Feature Substraction

The Feature Substraction concept applies to this entity as shown in Table 29.

FeatureObjectType | Description
--- | ---
BoltHole | Represents an instance of Bolt Hole
SlotHole | Represents an instance of a Slot Hole
Cope | Represents an instance of a Cope
Opening | Represents an instance of an Opening
SkewedEnd | Represents an instance of a Skewed End, which has two axis of rotation
WeldPreparation | Represents an instance of a Weld Preparation
Table 29 — IfcStairFlight Feature Substraction

Exchange |
--- | ---
Import | O
Export | O

Mapped Geometry

The Mapped Geometry concept applies to this entity.

Exchange |
--- | ---
Import | O
Export | O

Concept inheritance

# | Concept | Model View
--- | --- | ---
IfcStairFlight
| Properties on Occurrences | AISC Model View
| Placement | AISC Model View
| Body Geometry | AISC Model View
| Feature Substraction | AISC Model View
| Mapped Geometry | AISC Model View

##### Formal representations

XSD Specification
`<xs:element name="IfcStairFlight" type="ifc:IfcStairFlight" substitutionGroup="ifc:IfcBuildingElement" nillable="true"/>
<xs:complexType name="IfcStairFlight">
<xs:complexContent>
<xs:extension base="ifc:IfcBuildingElement"/>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcStairFlight
SUBTYPE OF (IfcBuildingElement);
NumberOfRiser : OPTIONAL IfcStrippedOptional;
NumberOfTreads : OPTIONAL IfcStrippedOptional;
RiserHeight : OPTIONAL IfcStrippedOptional;
TreadLength : OPTIONAL IfcStrippedOptional;
END_ENTITY;

EXPRESS-G diagram

`

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