Man Trap
Man trap applications are designed to allow controlled access to a vestibule area of a building.
Only one of the two doors may be open at any time.
| Components |
| A |
Power Supply
Includes terminals for both input and output devices, plus a battery backup system.
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| B |
Lock
Locking device with sensor that detects when door is in closed position.
Example locking devices:
Electrified lockset
Magnetic lock (shown in diagram)
Electric bolt
The sensor is a critical component to this system. Since only one door may be open at a time,
the power supply must know when each door is in the closed (locked) position.
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| C |
Input Devices
Sends a signal to the power supply to unlock one door.
Example input devices:
Keypad
Card swipe
Key switch
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| D |
Override Switch
On/Off switch that controls the entire man trap system (typically a key switch).
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Operation:
Both doors are normally locked.
Upon approaching the man trap area (from either side), the guard will activate an input device by entering a code or turning a key switch.
The input device sends a signal to the power supply to unlock that particular door, allowing entrance into the vestibule area.
Inside the vestibule, the occupants must wait until the open door is closed and locked before proceeding.
A sensor on the door (or lock) will tell the power supply when the door is locked. Only when both door are in the locked position will
the power supply accept a signal to unlock a door.
The guard then activates an input device at the next door, which then unlocks and allows egress out of the vestibule area.
Notes:
1. Most man trap systems are monitored at a remote station, a guard station for example.
This is accomplished by wiring two separate output signals from the power supply output terminals to a remote monitor.
The remote monitor will have 2 LED's per door. When closed and locked, each door will display the red LED.
Once a door becomes unlocked an open, the green LED will light notifying the guard that door is in use.
2. Local codes may require the man trap to have free egress in emergency situations.
In those applications, an input from a fire alarm system will cause the entire man trap system to unlock.
3. Many magnetic locks have the option of a built-in magnetic bond sensor. This allows a signal to be sent to the power supply when the door is locked.
The sensor not only ensures the door is closed, but is closed and in the locked position before sending the signal to a power supply box.
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