IfcStairFlight

IfcStairFlight

Definition from IAI: 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.

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

A stair flight (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
ISSUES: See issue and change log for changes made in IFC Release 2x.

Geometry Use Definitions:

The geometric representation of IfcStairFlight is given by the IfcProductDefinitionShape, allowing multiple geometric representation. 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 , which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that.
If the IfcStairFlight, however, is used by an IfcStair, and this container class defines its own local placement, than 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 (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'

EXPRESS specification:

ENTITY IfcStairFlight

SUBTYPE OF (

IfcBuildingElement);

NumberOfRiser

OPTIONAL INTEGER;

NumberOfTreads

OPTIONAL INTEGER;

RiserHeight

OPTIONAL IfcPositiveLengthMeasure;

TreadLength

OPTIONAL IfcPositiveLengthMeasure;

END_ENTITY;

Attribute definitions:

NumberOfRiser	:	Number of the risers included in the stair flight.
NumberOfTreads	:	Number of treads included in the stair flight.
RiserHeight	:	Vertical distance from tread to tread. The riser height is supposed to be equal for all stairs in a stair flight.
TreadLength	:	Horizontal distance from the front to the back of the tread. The tread length is supposed to be equal for all steps of the stair flight.

References (1):

Name

Type

Referred through

Express-G

IfcBuildingElement

Entity

Subtype

Diagram 1

Inheritance graph

ENTITY IfcStairFlight;

ENTITY IfcRoot;

GlobalId

IfcGloballyUniqueId;

OwnerHistory

IfcOwnerHistory;

Name

OPTIONAL IfcLabel;

Description

OPTIONAL IfcText;

ENTITY IfcObject;

ObjectType

OPTIONAL IfcLabel;

INVERSE

IsDefinedBy

SET OF IfcRelDefines FOR RelatedObjects;

HasAssociations

SET OF IfcRelAssociates FOR RelatedObjects;

HasAssignments

SET OF IfcRelAssigns FOR RelatedObjects;

Decomposes

SET OF IfcRelDecomposes FOR RelatedObjects;

IsDecomposedBy

SET [0:1] OF IfcRelDecomposes FOR RelatingObject;

ENTITY IfcProduct;

ObjectPlacement

OPTIONAL IfcObjectPlacement;

Representation

OPTIONAL IfcProductRepresentation;

INVERSE

ReferencedBy

SET OF IfcRelAssignsToProduct FOR RelatingProduct;

ENTITY IfcElement;

Tag

OPTIONAL IfcIdentifier;

INVERSE

ConnectedTo

SET OF IfcRelConnectsElements FOR RelatingElement;

ConnectedFrom

SET OF IfcRelConnectsElements FOR RelatedElement;

ContainedInStructure

SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;

ENTITY IfcBuildingElement;

INVERSE

ProvidesBoundaries

SET OF IfcRelSpaceBoundary FOR RelatedBuildingElement;

HasOpenings

SET OF IfcRelVoidsElement FOR RelatingBuildingElement;

FillsVoids

SET [0:1] OF IfcRelFillsElement FOR RelatedBuildingElement;

ENTITY IfcStairFlight;

NumberOfRiser

OPTIONAL INTEGER;

NumberOfTreads

OPTIONAL INTEGER;

RiserHeight

OPTIONAL IfcPositiveLengthMeasure;

TreadLength

OPTIONAL IfcPositiveLengthMeasure;

END_ENTITY;