The answer would depend on many factors, including the number of exits and whether you needed to know their precise location, or just that they had left the building. The technology choices would be different depending on what you wished to achieve, and costs would thus differ as well. One question to ask yourself is, Do you require continuous real-time tracking, or would it be enough to know that someone had left the building as soon as they passed through an exit? My guess is the latter would be sufficient.
You could use an active system to perform continuous real-time location tracking for individuals, but at $50 or more per tag, it would cost $2,000,000 just for the tags alone. That would make the deployment prohibitively expensive. Moreover, depending on the type of system you chose, there might be some issues with knowing whether someone was on a specific floor or inside or outside the building (though a good systems integrator could address those problems).
Let’s assume you don’t need to track everyone at all times, and that you don’t need to know the precise location, but rather just the floor on which someone might be located.
So let’s say you have four floors, with four stairwells and four exits (10,000 people per floor would likely dictate a need for more stairwells and exits, but let’s keep it simple).
There can be problems reading passive ultrahigh-frequency (UHF) tags close to a person’s body, but you could probably still do this with a passive UHF system. I would allot at least $80,000 for the passive UHF tags, because they are likely going to have to be encased in plastic, and should probably have the wearer’s image on it. Figure $2 per tag, though you might be able to get them for less.
To know which floor someone is on, you would need an RFID reader placed at each floor’s entrance to the stairwell, which would mean 16 interrogators (four sets of stairs, times four floors). Plus, you would need a reader to be placed at each of the four exits, bringing the total up to 20 readers. Figure $4,000 per interrogator, fully installed with antennas, Ethernet cable and power, which might require conduit to the stairwell.
You will need to feed the data into a server (at a cost of $2,000) running an application—for a ballpark of $10,000 for the application, or possibly less. You will also need someone to put the system together. Prices can be all over the map for services, but figure $25,000 to install the readers, run the cabling and set up the software.
So here are your totals:
• RFID ID badges: $80,000
• 20 RFID readers: $80,000
• Server: $2,000
• Software: $10,000
• Services: $25,000
These are just ballpark estimates, of course, but it should give you a rough idea of what is involved. If you were to deploy an active system for real-time locating, it would cost far more and probably not give you any additional value.
—Mark Roberti, Founder and Editor, RFID Journal
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