462 ITU‐T's Technical Reports and Specifications transportation systems, such as airports, highways, police checkpoints or customs applications. Nobody thinks twice about the information presented on luggage carousels at airports, which change continuously (and are not always 100% accurate) and the concept of having time‐dependent signage or situation‐dependent signage does not come as a surprise. Thus, particularly in Europe, where great emphasis is placed on visitors to buildings being well‐informed upon arrival, of how they may need to exit if an emergency arises, automated signage is widespread. For example, electronic signage can be changed in an instant, should a building evacuation be necessary, so as to point out the emergency stairs as opposed to the elevators. 1.7 Building condition monitoring Intelligent building technologies open the opportunity to facilitate the monitoring of a building's condition. Transducers and sensors are available to measure most building related parameters and in any given situation, there may be particular needs driving their specific use. Under appropriate conditions some or all of the following may be appropriate and would then be communicated to a central monitoring facility. Areas with heavy snowfalls or other weather extremes may wish to monitor snow load or wind load on roofs; Exhibition halls or bridges may wish to monitor key structural components affected by wind loads, suspension of exhibits, loudspeakers (in musical performance facilities); Moisture detectors can be laid beneath membranes protecting roofs (especially green roofs which are now mandated in many cities) or bridges; Monitoring the temperatures of electrical panels, switch gear and transformers; Metering current flow in electrical conductors; Providing sub‐metering for tenants; Monitoring oil condition in bearings, transmissions, etc.; Monitoring pressure drop across filters, etc.; Measuring hours of usage of many components, such as filters, belts, lamps, pumps; and Routine testing of critical devices such as pumps, loudspeakers, alarms etc. No further comment needs to be made with respect to some disasters which have occurred and which might have been prevented in the event that some or all of the building monitoring technologies alluded to above might have been in place. Clearly it can be added that these concepts are consistent with measuring and monitoring practices which have evolved dramatically within recent years.