Other Useful Concepts

There are a number of other, existing concepts within IFC that can be applied to geographical elements that extend the range of possibilities into new application areas. Because entities are being reused, this means that IFC support comes ‘for free’. Maybe not exactly free since guidance has to be given to implementers and the necessary view definitions specified but at least the model does not need further extension. Two key areas are given below. They are not the only possibilities; remember that the IFC model is large, competent and mature so much more may be feasible.

Permits

The concept of a permit to allow work to be done is captured through the IfcPermit entity. This has the specific attribute of a permit identity and also points to a document within which more specific information concerning the permit can be elaborated. Permits are occurrences of the general IfcControl capability that allows constraints or control measures to be applied to specific objects and can therefore be assigned by relationship (IfcRelAssigns) to any product or process. This could be to a building (as a building permit) or to a work order (to allow maintenance work in a sensitive or secure area).

Lifecycle Information

Lifecycle information about objects within a building is as relevant as such information about buildings and other external structures. To support maintenance and facilities management requirements, IFC added information about the service life of objects and the service life factors contributing to the service life determination as part of the IFC 2x2 release. Service life data capture is based on the specification set out in the relevant ISO standard.

As well as to individual objects, IFC also allows lifecycle information about assets (since an asset is considered to be a group of objects treated as a single entity for a given purpose; usually financial or operational).

Further supporting the lifecycle concept is the capture of the condition of objects and the ability to record condition in an event based log. Constraints can also be applied to objects to define trigger conditions at which point some specified action should be taken on the object.

IFC also contains a set of entities that enable cost models to be developed and these can be applied to enable lifecycle cost to be determined (or even the anticipated cost at any point in time given the effect of various influencing factors).

Environmental Impact Information Capture

The cost model in IFC proved to be particularly interesting when the idea of developing environmental impact information arose. It rapidly became clear that environmental impact could be treated in the same way as financial cost (only the units needing to be changed). This led to the development of a general idea known as an IfcAppliedValue. For environmental impact assessment, it can be used to determine things like CO2 emission, sulphur effects and much more.

Sensors

As part of the building controls capability of the IFC model, there is an IfcSensorType entity (whose equivalent occurrence is IfcDistributionControlElement). Various sensor types are predefined including CO2, fire, flow, gas, heat, humidity, light, moisture, movement, pressure, smoke, sound and temperature. Other types can be user defined. Most sensor types also have predefined property sets that handle ranges, set points and other relevant attributes. Sensors can be applied externally as well as internally and identified as sensing various types of external conditions. In conjunction with the new geographical capabilities of the model, this offers the potential to include pollution monitoring as a supported use case (even though it is not yet included on such a support list).