What This Guide Covers and Who It Is For
A mantrap, also called a security vestibule or airlock entry, is a controlled access passage that uses two doors in sequence to prevent tailgating and unauthorized entry. Only one door can be open at a time. This guide helps security system integrators, commercial contractors, facility managers, and architects specify the door hardware and electrified components that actually make a mantrap function correctly. If you are designing a vestibule for a government facility, data center, financial institution, school office, or healthcare administration suite, the hardware decisions at each opening are more complex than a standard access-controlled door.
What Is a Mantrap Vestibule?
A mantrap (also called a sally port in some institutional contexts) is a small enclosed space with two independently controlled door assemblies. The core operating principle is interlocking: when the outer door is open, the inner door is locked, and vice versa. The access control system monitors the state of each door and enforces the interlock logic. The hardware on each door must be capable of receiving and responding to signals from that control system reliably and repeatedly.
Mantraps appear in:
- Bank vaults and financial back-office areas
- Data centers and server rooms requiring strict access logs
- School and campus main office entries (visitor management)
- Pharmacy and controlled-substance storage areas in healthcare
- Government and court facility secure zones
- Industrial facilities with restricted production or research areas
The Two Openings Are Not the Same Opening
One of the most common specification errors on mantrap projects is treating both doors as identical. In practice, the outer door and the inner door often have different hardware functions, different egress requirements, and different fire or life-safety classifications. Analyze each opening independently before building a hardware set.
Outer Door (Public Side to Vestibule)
- Typically requires free egress from the vestibule back to the public side at all times
- An electrified exit device or electric strike with a fail-safe configuration is often appropriate here
- Card reader, keypad, or intercom on the public approach side controls entry
- A door position switch (DPS) signals the access control panel whether this door is open or closed
- Door closer is required to ensure the door returns to a latched, secured position before the inner door can release
Inner Door (Vestibule to Secure Side)
- Higher security credential typically required: multi-factor authentication, PIN plus card, biometric plus card
- Electrified mortise lockset or electrified exit device depending on occupancy load and egress path
- Fail-secure configuration is common on the inner door to maintain the locked state on power loss
- Door position switch on this leaf feeds back to the interlock controller
- If the occupancy classification requires panic hardware, the exit device must allow free egress regardless of the electric lock state in the direction of egress
Hardware Categories You Need to Specify for Every Mantrap
Electrified Locksets and Exit Devices
The locking hardware on each door must accept an electric signal to lock or unlock on command. Options include electrified mortise locksets, electric strikes paired with mechanical locksets, and electrified exit devices for panic-hardware-required openings. Brands such as Sargent, Corbin Russwin, and Hager offer electrified mortise and cylindrical lock options well suited to high-cycle, institutional mantrap applications. For exit device applications, Sargent and Corbin Russwin offer electrified rim and mortise exit devices that integrate cleanly with interlock controllers.
Match your fail-safe versus fail-secure specification to what happens at each door during a fire alarm or power outage. The outer door serving an egress path typically needs to fail safe (unlock on power loss). The inner door securing a restricted zone may be specified fail secure depending on AHJ review and occupancy type.
Door Position Switches
The interlock logic lives in the access control panel, but the panel only knows what the door hardware tells it. A door position switch on each leaf reports the open or closed state in real time. Without reliable DPS signals, the interlock cannot function. Specify DPS devices that are recessed or concealed to prevent tampering and that are compatible with the access control system voltage and input type.
Request-to-Exit Devices
On the secure side of the inner door, occupants need a way to signal egress intent to the controller. A request-to-exit (REX) device, whether a push button, motion sensor, or a built-in switch in the exit device trim, sends the unlock signal and logs the exit event. Coordinate with the access control integrator on whether the REX bypasses the interlock or simply queues an unlock after the outer door confirms closed.
Door Closers
Both doors must close and latch positively every cycle. The interlock cannot confirm a door is secured if the closer is undersized or misadjusted and the latch fails to engage. Specify commercial-grade closers from lines such as Norton, Hager, or Accentra sized to the door weight and width. Adjust latch speed and backcheck carefully. On high-traffic mantraps, closer durability matters: choose a unit rated for the expected daily cycle count.
Power Transfer at the Opening
Getting power from the building to the electrified hardware requires a continuous electrical path through the door frame, the hinge area, and across the door to the lock or exit device. Electrified hinges or looped wiring harnesses in the hinge area are the two primary methods. Whichever approach the project uses, the wiring path must be coordinated between the door hardware supplier, the access control installer, and the low-voltage contractor before the door ships.
Hinges and Frame Prep
Mantrap doors are opened and closed far more frequently than typical interior doors. Specify heavy-duty ball-bearing hinges from lines such as Hager, McKinney, or Rockwood to handle the cycle load. If the hardware is electrified through the hinge, confirm the electrified hinge model is listed for the application and that the frame is prepped for the correct wire routing.
Code and Compliance Considerations
Mantrap vestibules exist at the intersection of security goals and life-safety code requirements. These two objectives are not always compatible out of the box.
- Egress must always be maintained. NFPA 101 and the IBC both require that occupants be able to leave a space. An interlock that traps a person inside a vestibule with no means of egress is a code violation. Coordinate with the AHJ before finalizing the interlock logic.
- Panic hardware requirements follow occupancy load. If either door serves an assembly occupancy or a space with an occupant load that triggers panic hardware, the exit device on that door must allow free egress by operation of the device regardless of the electronic lock state in the direction of egress.
- Fire-rated openings require fire-rated hardware. If either door in the vestibule is a fire-rated assembly, all hardware must be appropriate for fire door use. Electrified hardware on fire doors requires hardware that is listed for fire door applications. Confirm with the door and hardware manufacturer before specifying.
- ADA accessibility applies to the approach hardware. Card readers, keypads, and request-to-exit buttons must be mounted within ADA reach range limits. Hardware operating force limits apply to the door leaf itself.
What to Get Right Before You Order
Mantrap hardware fails in the field most often because the coordination was incomplete at the specification stage. Before placing an order, confirm:
- Fail-safe versus fail-secure decision documented for each door and reviewed by AHJ
- Interlock controller model identified and input/output requirements confirmed
- DPS type and voltage confirmed with access control integrator
- Power transfer method (electrified hinge or harness) confirmed and frame prep ordered accordingly
- Closer size and arm type confirmed for each door based on weight, width, and application
- Fire rating status of each opening documented
- ADA compliance of credential reader mounting heights confirmed
DoorwaysPlus Can Help You Build the Right Package
DoorwaysPlus.com carries the electrified locksets, exit devices, door closers, hinges, and accessory hardware needed to spec a complete mantrap installation from both openings. Our team works with commercial contractors, security integrators, and facility managers to make sure the hardware on each door matches the interlock logic before anything ships. Contact DoorwaysPlus to discuss your vestibule project and get a complete hardware package quoted.