A Complete Guide On Door Interlocking Systems
  • Introduction
  • What is the Door Interlocking System?
  • Types of Door interlocking system
  • Applications of Door interlocking systems
  • What factors to consider while selecting a door interlock system?


They say the doors we open and close each day decide the lives we live. Well, doors are one of the vital assets when it comes to protecting a building or any place for that matter from trespassers or threats. Take the case of a bank, the manager has to trust the doors and the respective locks it possesses to protect everything stored inside the bank's lockers. With the doors, the manager can blindly trust the installed locks without any need for manual intervention

Door interlocking systems have been the prime choice for security over the years; gone are the days when guards stood by the entrance. Over the years, the type of threats has alarmingly increased and one has started to rely on machines and technology more than an actual workforce.

What is the Door Interlocking System?

Now with technology pacing, door interlocking systems have developed as well. The doors now have locks and multiple in-built alarms and SOS services that can alert the nearby surroundings. Now looking towards the proper definition of a door interlocking system, a set of two doors interlinked to work in such a way that they open and close when one door is done performing a particular action. Now access to these doors can vary depending upon the system and the type of institution that uses it. Some use key cards, or biometrics, or punching in codes that allows maximum security and avoids all kinds of threats. Different door interlocking systems serve various purposes; some prevent piggybacking and intrusion, while some protect from major attacks like ballistic and blasts. Many door interlocking systems have pre-installed sensors and detectors which record data at regular intervals that can be retrieved and analyzed any time one wants. A door interlock system not only saves money but also provides top-grade security without needing any over-the-top efforts. Now let’s take a look at the types of door interlocking systems in detail.

Types of Door interlocking system:

A door interlocking system is classified into mainly two types, namely:

  • Air Lock Control Systems
  • Secure entry or free egress system
  • Restricted entry and exit

Air Lock Control Systems

The most straightforward system amongst the types, Airlock control systems are mostly preferred for places where the lowest security is needed. With the basic operation of unlocking, an airlock control system can access one entry at a time. This system does not have doors interlinked with each other and provides hassle-free movement across the doors. With two or more doors accessible simultaneously, airlock control systems offer the least security.

Secure Entry system

The secure entry system, also known as the free egress system, is a powerful combination of complex locked and simple unlocking doors that provide a more secure entry or exit system than the air control system type. These entry systems have two sets of doors having a secured exterior and a simple secondary door for admission. The access can be either a card scan or swipes to unlock, which again clasps back when gained access. The secondary door opens only when the first door locks once someone enters. There are some systems where both the doors require a person to swipe one by one, which provides more security and prevents tailgating and piggybacking in entry or punching in. But this system does not require credentials to make an exit

Restricted entry and exit

This system provides the highest type of security by allowing one entry at a time. When making an entry or exit, one needs to use their credentials like biometric or card access each time. The security is highest because one door is unlocked at a time while others remain unlocked. With that, restricted entry and exit also work simultaneously. Now let’s roll over to the applications of door interlocking systems.

Applications of Door interlocking systems

There are many applications of the door interlocking systems, majorly places where security is the topmost priority, like banks, and shops, malls, and educational institutions. Majorly they can be noticed in airports and offices where every entry and exit needs to be monitored round the clock. Apart from these applications, a door interlocking system is also used widely in clean rooms, where it is a must-have according to industry standards. This ensures to meet the necessary standards and ensures the quality remains intact without any external influence by providing security.

In public places like malls, where metal detectors and sensors are a must since a large population passes by, a door interlock system is what any place needs. With features to alarm the environment and send out SOS, or to detect any theft or arms, a door interlock system though simple, allows tracking and securing a more straightforward job. In case of emergencies when power failure is a common issue, door interlock systems are built to work in almost all scenarios possible. Their inbuilt emergency override allows it to be manually opened or closed to make the evacuation easier in case needed.

While on the other hand, correctional systems are considered to be the best example to understand the working of a door interlock system. Where each entry, exit needs to be monitored and made sure no accidents or escape happens, a door interlock system helps the judicial system a lot in matters of these. By providing multiple features of alarms and detecting almost every possible detail, the interlock system makes the job way much easier.

What factors to consider while selecting a door interlock system?

When choosing a door interlock system, there are many factors to be kept in mind. Various parameters and requirements of the institution play a significant role when it comes to selecting a system. The kind of service or valuables to protect and to monitor is one of them. Like in a bank again, there are various things to keep in mind. Metal detectors to detect the arms and locks to ensure access is restricted to the general public, making sure no trespassing occurs. With many valuables like cash and documents, special sensors and credentials are needed. Punch codes, card swipes, and biometrics like retina scan and fingerprint ensure only authorized personnel are allowed.

In corporate workplaces, door interlocking systems require a controller to record each employee's sign-in time. Apart from the type of monitoring systems and detectors, selecting a door interlocking system also involves:

  • The number of doors required
  • Types of doors to be used
  • Type of access for the building

A single device can control independent interlocking systems in most scenarios, depending upon how far the doors have been separated from each other. Many parameters and devices to record door status, monitor the latch, push buttons to exit, sensor to detect and grant access are needed in a door interlocking system. Depending upon the number of doors required, the outputs can either be mapped to single doors or multiple doors with a common controller. The kind of output one expects also determines a major factor in choosing a system. While some doors provide alarms and beeps, others give a signal through light indicators while any form of entry or exit is happening. Indicating locks when latched open and closed to record the same or to signal through sound to alert.


Wrapping things up, even though seemingly simple in structure, door interlocking systems have become the requirement in almost every place needing to be monitored. A door interlocking systems isn’t something we should take for granted. With eliminating manual intervention and saving money, an interlock system is all one needs for hassle-free security.


Mr. Mayuresh Choudhari

Head- Pharma