Mantraps and Interlocks: Maximum Access Control

Sept. 2, 2020
Vestibules put an emphasis on physical safety in ultrahigh-security applications.

Mantraps and other high-security entrances originally were used under special conditions, such as by the military, law enforcement or correctional institutions. These applications generally were manned by security officers, and because of the applications, the emphasis was on security rather than safety.

Today, a mantrap (also known as a sally port) basically is an access control system that consists of a small space and at least two interlocking doors. The first door must close and lock before the second door unlocks and opens, ensuring that only one door is unlocked or open at a time. The person temporarily trapped in the space between the doors must wait for the first door to relock and then provide the necessary credentials to pass through the second door.

These vestibules can be operated manually or have an automatic system. In a manual system, a guard would lock and unlock the doors of the mantrap every time someone enters the room or building, which is cost- and labor-intensive. For automatic mantraps, some form of identification, such as a keycard, security code or biometric credential, is necessary to unlock each door.

Mantraps are used as physical-safety solutions for places that require a high level of security, such as banks, research labs, post offices, airports, health-care facilities and data centers. Another application is to prevent contamination of sterile environments or clean rooms. The demand for mantraps and interlocks has increased as the security industry attempts to mitigate the risks and threats posed by terrorists, criminals and, of course, pandemics.

My career began with serving the military and government markets, and I frequently was called upon to provide special-purpose systems for installations where you were more likely to encounter an armed marine that an electrified exit device.

Mantraps and interlocks soon transitioned into the commercial markets, and I recall episodes where what a client wanted conflicted with what codes allowed and what the public would tolerate. In civilian applications, life safety trumps security, so any such system must be code-compliant.

I rarely was known to say no to a customer who had money in their hand, but on more than one occasion I had to, because a shop owner requested that I trap customers in or out of their premises if they sensed a threat or suspected shoplifting. That’s a no-no.

In this article, we discuss modern “legal” systems, which are used in a wide variety of applications where life safety is of paramount importance, with security following a close second.

Where the occupancy codes permit, security can be factored with life safety, because under mitigating circumstances, the definition of life safety is redirected. For example, in a correctional institution, the safety of the guards or general public might be considered ahead of a dangerous criminal who is being transported through the mantrap.

The following is a listing of select mantrap products.

dormakaba Personal Interlocks

dormakaba’s electronically monitored Personal Interlocks protect sensitive building areas, ensuring that only one person at a time can pass through the entrance. This product series includes cylindrical or rectangular corridors. The Personal Interlocks allow passage in one direction.

The degree of separation can be accomplished by means of body weight, sensors or an additional biometric checkpoint for identification in the middle of the interlock. Alternative versions for high-security areas include bullet- and burglar-resistant designs.


  • Default position inside and outside closed (cylindrical), locked (cubic)
  • Emergency release button inside interlock prevents people from being trapped inside (cylindrical), optional manual override Fire-alarm integration (cylindrical)
  • ADA accessible (cubic)
  • Existing swing doors can be retrofit to include a mantrap (cubic)
  • Optional fire-rated doors (cubic)
  • Integrates with Keyscan, other networked access control systems
  • PIL Vision/anti-piggybacking
  • Interior biometrics
  • Passage widths: 20-1/2–35-13/16 in. (cylindrical), 31-1/2–47-1/4 in. (cubic)
  • Height: 82-11/16 in. (cylindrical), 89-3/8 in. (cubic)

More info:

Securitech RACHIE Entry & Exit Control Systems

RACHIE Entry & Exit Control Systems allow for keyed and electric release trim on each side of the mantrap door, with the option of fail-safe or fail-secure locking on any side of any door. This is to ensure that a person always can exit the mantrap in the event of a failure, which is useful, because lawsuits have been filed across the country by people trapped inside a mantrap.

Securitech also has created forced-entry mantraps by using its Auto Bolt automatic deadbolt series for jewelry manufacturing locations.

The code-compliant RACHIE system includes a basic two-door system as well customized systems that are aimed at psychiatric hospitals, detention facilities, laboratories, financial institutions, government facilities and retail stores, in configurations of two, three or more doors.

Standard mantraps and sally ports provide a controlled passageway where only one door in the passageway can be open at a time. However, Securitech’s RACHIE systems use dual-locking technology, so it can customize a mantrap to specifications.

RA-M100 series models include electrically and key-released trim, mortise locks and electromagnetic locks. The key override is restricted by the interlock control.

RA-E100 series models include electrically and key-released trim and mortise locks. The key overrides the interlock control at all times, so violations are possible.

Boards, relays and transmitters can be serviced or replaced without removing the control unit or disconnecting the wiring from the doors.

Different systems in each series reflect the individual trim function at loss of power (fail-safe or fail-secure).


  • Requires 110 VAC electric connection
  • Printed circuit boards with microprocessors assure trouble-free operation
  • Optional battery backup
  • Tamper alarms available

More info:

Boon Edam Circlelock Solo

The venerable Circlelock Solo owes its longevity to its ability to deliver on the true intent of multifactor authentication, which is that only one person, and the right person, can enter a secure area. The portal integrates with any access control system, and biometric scanning technologies can be mounted inside the portal on an optional, supportive post.

A user presents one credential to enter the portal, which scans the interior to ensure that the user is alone, and then present their face, iris, fingerprint or hand to confirm their identity before the second door opens.

The Circlelock Solo combines premium construction with the intelligence of a sophisticated, near-infrared detection technology that’s placed in the ceiling, called StereoVision 2. When a user steps into the portal, StereoVision 2 scans the compartment to verify that a user is alone before allowing them to enter a secure facility.

Unlike conventional, site-built mantraps, the Circlelock Solo mantrap portal is a fully tested, turnkey solution that can be installed in two days. There is no need for mounting sensors or cameras and continual testing to check for blind spots. In addition, the integrated hardware and software of the Circlelock Solo delivers the highest levels of reliable security without the necessity for guard supervision.

A popular option is the use of bullet-resistant glass for the mantrap’s cylindrical walls and sliding doors.

More info:

Boon Edam Circlelock Combi

The new Circlelock Combi was designed as a convenient retrofit option to address the risk that exists with any type of swinging door: After a swinging door is opened by an authorized user, any number of people also might gain access to a secure area. This is known as “tailgating” or “piggybacking”.

The Circlelock Combi “half portal” solution attaches to an existing fire-rated swing door, converting it into a mantrap solution that prevents piggybacking 24/7 and eliminates the necessity for manned supervision, all while maintaining the fire-rated benefits of the swing door. The Combi also saves considerable space compared with traditional mantrap vestibules that use standard walls and two swinging doors.

The Circlelock Combi is a cylindrical solution that has a single sliding door. The opening on the other end is mounted to an existing wall and swing door. The Combi uses StereoVision 2 detection technology in the ceiling to scan the compartment and ensure that a user is alone prior to unlocking the swing door. Security managers can choose to prevent piggybacking for inbound and outbound traffic. 

The Circlelock Combi enables deployment of multifactor authentication to ensure the identity of the user. Users present their first credential to enter the portal and then a second biometric credential, such as an iris scanner or facial or hand recognition, to unlock the second door. Virtually any verification technology can be mounted inside the Combi on an optional, floor-to-ceiling post. 

The Circlelock Combi can process five people per minute and is ideal for sensitive interior locations, such as data centers, government buildings, airports, legal- or patient-record areas and executive suites.  

More info:

Dortronics mantraps

Dortronics is involved in door interlock projects for security (mantraps) as well as environmental (airlock) applications. These custom-built systems use Dortronics’ interlocking door controllers. electronic locks, indicator lights and alarm devices.

The 44211-LU 2-Door Interlocking Controller provides power and control for two doors that have electric locks, which makes it suitable for environmental laboratory airlocks or mantrap security control. The door interlock logic allows only one door to be unsecured at a time. The controller can be configured to have both doors locked, unlocked or alternating one locked and one unlocked, depending upon the customer application. The 44211 onboard heavy-duty power supply assures reliability for extended use.

More info:

Farpointe Data Ranger

The Data Ranger long-range receivers and transmitters can be used to create a simple mantrap.

Data Ranger transmitters are available in a two- or four-button configuration, with each button corresponding with the Wiegand output on the Ranger receiver.

For example, Data Ranger receivers can be wired so the output from channel one, corresponding with button one on the transmitter, controls the outside door of the mantrap; and the output from channel two, corresponding with button two on the transmitter, controls the inside door. So, a single Data Ranger transmitter and receiver can be used to create a convenient, touchless mantrap.

This system also allows each transmitter to integrate the convenience of long-range identification with traditional proximity access control.

For example, if a site required employees to access the first door of a mantrap and then a second door, the Data Ranger solution enables users to access the long-range and proximity applications though a single transmitter.

For the first door, the user presses the transmitter button and, when gaining access at that door, they simply present the transmitter to the building’s proximity reader. Because identical data is transmitted upon a button press or presentation, each user has to be enrolled only once in the access control system.

Data Ranger receivers are a long-range radio frequency ID solution that operates at the frequency of 433 megahertz and delivers transmission ranges of up to 200 feet.

More info:

Tim O’Leary is an experienced security consultant and a regular contributor to Locksmith Ledger.

About the Author

Tim O'Leary

Tim O'Leary is a security consultant, trainer and technician who has also been writing articles on all areas of locksmithing & physical security for many years.