IfcReal is a defined type of simple data type REAL. It is required since a select type (IfcSimpleValue), cannot directly include simple types in its select list.
In principle, the domain of IfcReal (being a Real) is all rational, irrational and scientific real numbers. Here the precision is unconstrained, but in practice it is implementation specific.
HISTORY New type in IFC1.5.1.
TYPE IfcReal = REAL;
References: IfcCartesianTransformationOperator IfcCartesianTransformationOperator2DnonUniform IfcCartesianTransformationOperator3DnonUniform IfcDirection IfcRationalBSplineCurveWithKnots IfcRationalBSplineSurfaceWithKnots IfcConversionBasedUnitWithOffset IfcSimpleValue IfcSurfaceStyleRefraction IfcTextureCoordinateGenerator IfcLightSourcePositional IfcLightSourceSpot IfcGeometricRepresentationContext IfcGeometricRepresentationSubContext IfcMapConversion