Is it possible to create a radio frequency-based identification system that can be implemented at a factory to maintain a count of personnel entering and exiting the facility, which can then help in the case of emergency situations?
—Rameez, Karachi, Pakistan
This is possible with either an active or passive RFID system.
Akers Shipyard placed passive ultrahigh-frequency (UHF) tags on the backs of hardhats, as well as reader antennas next to gangplanks where workers boarded ships under construction, to monitor when employees entered and left the vessel. This was critical information in the event of a fire caused by welding (see Aker Yards Uses RFID to Ramp Up Worker Safety).
In addition, BP has deployed an active RFID system at its oil refinery in Cherry Point, to ensure that workers can be evacuated in the event of an emergency (see BP Refinery Uses RFID for Evacuation System).
Which system is best for your needs—active or passive—really depends on what information you need to collect, the physical environment in which you collect it and other factors. Passive tags can work well if the tag's location can be controlled, and if the workers pass through a fairly narrow gateway to enter a facility. Active tags, on the other hand, are better when you need to read tags over longer distances.
—Mark Roberti, Editor, RFID Journal