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Security Vulnerabilities Created by Fire Department Key Boxes


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Many governmental agencies require that commercial businesses install key boxes on the exterior of their buildings to allow fire department access. These boxes are typically installed at primary building entrances and contain things such as master keys, access cards, and building floor plans. One major manufacturer of fire department key boxes is the Knox Company, so these key boxes are often called "Knox Boxes", even though several other manufacturers produce similar types of products.

Fire department key boxes are usually purchased and installed by the building owner, but come without the exterior lock. After the box has been installed, the owner arranges an appointment with the fire department, who comes out to the site and installs the exterior lock. At this time, the owner places building master keys, access cards, and floor plans into the box. Once the box has been locked by the fire department, the owner no longer has access, and it can only be accessed by the fire department.

All key boxes in a particular fire district zone are keyed alike. All fire department vehicles who respond to this zone carry a key that unlocks all of the key boxes in their zone. In a smaller city or town, there may be only one zone, so one key can unlock everything; in larger cities, there may be many different zones and many different keys.

The fire department key box is typically used when the building is closed and no one is around to let the fire department into the premises. The first responding emergency vehicle uses the fire department key to unlock the key box, and then removes the master keys and access cards from inside the box. These keys and cards are used by fire department personnel to gain entry to the premises, and to get inside of any locked rooms on the inside of the building.

Fire department key boxes are a weak spot in the building's overall security program because anyone who has access to the key box has access to every area of the building. An intruder who compromises the key box literally has the "keys to the castle" and can go almost anywhere that he wants.

There are two primary ways in which the fire department key box can be compromised. The first way is for the fire department's key to fall into the wrong hands. This could occur if the fire department key was lost or stolen from a fire department vehicle. This would give the person who took the key access to all buildings within the local fire zone (possibly hundreds of different businesses). Preventing this type of event from occurring is completely outside of the control of the property owner. 

One would hope that the fire department takes adequate precautions to keep fire department keys safe, and would quickly rekey the key box locks throughout the fire zone if a key to this zone was lost or stolen.

The second way for the fire department key box to be compromised is for it to be physically attacked. Most key boxes are well-constructed and designed to resist attack, but are not impenetrable. An intruder who has the proper tools and ample time can eventually compromise the key box. Some intruders actually remove the key box from the wall, and then take it to another location where they have more time to break-in to the box without being seen. They then return to the building to burglarize it once they have the master keys that were in the key box.

The most dangerous type of situation is where the intruder breaks-in to the key box surreptitiously without leaving any physical signs that the box has been tampered with. This can allow the intruder to steal keys and access cards and use them to make repeated entries into the premises over an extended period of time without being noticed. A creative intruder could even steal the original key box and replace it with a substitute key box to avoid the theft being noticed.


Here are some tips for providing improved security of your fire department key box:

  • When possible, arrange to have the fire department key box installed in a well-lit location that is visible from the street. Avoid having the fire department key box installed in hidden or out-of-the way places.

  • Recess-mounted key boxes are considerably more attack-resistant than surface mounted key boxes and should be used whenever possible. If you don't currently have a good place to install a recess-mounted box, consider constructing a concrete or masonry pillar next to the entrance just to hold the key box. An existing wall can also be faced with masonry veneer to provide a place where a recess-mounted box can be installed.

  • If the key box must be surface mounted, make sure that it is rigidly attached to a structural support member and not fastened to just the wallboard or siding.

  • Many key boxes offer an option that allows them to be through-bolted to the wall. This option should be used whenever possible.

  • Provide an alarm tamper switch within the fire department key box. Connect this switch to your intrusion alarm system or security management system. This system should be programmed to notify an off-site alarm monitoring station or on-site security officers anytime that the box has been opened.

  • If your facility has a video surveillance system, provide a camera that views the area where the fire department key box is located.

  • If you use a security guard or patrol service, have the security officer regularly check the fire department key box as a part of his nightly rounds.


For more information about how to provide improved security for your fire department key box, please contact us.

Also see related article: Security Vulnerabilities Created By Exterior Key Switches.

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