In the world of business security, the humble door has evolved. Gone are the days of simple locks and keys. Modern commercial security relies on access control systems—intelligent networks that manage who can enter a space, when, and where. Whether you’re a facility manager, a business owner, or a security installer, understanding the components and requirements is crucial.

This guide breaks down everything you need to know about commercial door access control.

Core Components of an Access Control System

A single access-controlled door is a symphony of interconnected parts. Here’s a breakdown of the key players:

1. The Credential & Reader

This is how you identify yourself to the system.

• Credentials: Key fobs, proximity cards, smart cards, or even biometrics (fingerprint, retina).

• Reader: The device that reads the credential. It can be a keypad (for PIN codes), a card/fob reader, or a biometric scanner.

2. The Access Control Panel (or Controller)

This is the brain of the operation. It’s a small cabinet, often located in a secure closet or above the ceiling, that houses the computer boards. The panel:

• Stores the permissions database (which cards work on which doors and at what times).

• Makes the grant/deny decision when a credential is presented.

• Logs all entry and exit events.

3. The Locking Device (The “Door Strike”)

This is the physical mechanism that locks and unlocks the door. The type you choose depends on your door and frame.

• Electric Strike: The most common solution for wooden or aluminum framed doors. It replaces the strike plate in the door frame. When powered, it releases the latch, allowing the door to open. When unpowered, it remains locked.

• Electromagnetic Lock (Maglock): An extremely powerful lock consisting of an electromagnet on the frame and a steel armature plate on the door. It requires constant power to stay locked and unlocks when power is removed. Important: Maglocks are fail-safe, meaning they unlock during a power outage, which is a key fire safety consideration.

• Electric Mortise Lock: A full lock body that replaces the existing mechanical mortise lock. It’s a self-contained unit with a motor that throws or retracts the bolt. Ideal for doors where you don’t want to modify the frame for an electric strike.

4. The Request-to-Exit (REX) Device

For safety and building code compliance, people must always be able to exit freely. A REX device signals the system to unlock the door from the inside.

• Push-to-Exit Button: A simple, durable button mounted on the wall inside the secure area.

• Motion Sensor (Exit Sensor): A passive infrared (PIR) sensor that detects motion approaching the door from the inside and automatically triggers an unlock.

5. Door Position Switch (DPS)

A small sensor, usually recessed into the door frame, that tells the system whether the door is Open or Closed. This is critical for alarm monitoring and ensuring the door is secure.

Understanding Door Types & Their Impact

The door itself dictates which hardware you can use.

• Full-Glass Doors (Aluminum Framed): Ideal for electric strikes or surface-mounted maglocks. The glass and frame cannot typically support a heavy electric mortise lock.

• Wooden/Steel Doors (Hollow or Solid Core): Can use electric strikes (requires frame modification), electric mortise locks, or maglocks.

• Double Doors (Pairs): One door is typically the active leaf (with the lock), and the other is the inactive leaf. You may need coordinating devices like a “flush bolt” to secure the inactive leaf. For double egress pairs, specialized hardware is required.

• Fire-Rated Doors: Crucial! Any modification to a fire-rated door or its frame (like installing an electric strike) must be done in compliance with local fire codes and often requires a “fire label service” to re-certify the door.

Putting It All Together: A Standard Single-Door Setup

1. A user presents their card to the reader.

2. The reader sends the card data to the access control panel.

3. The panel verifies the credential and, if valid, sends a signal to power the electric strike or unpower the maglock.

4. The user hears a “click” and can push the door open.

5. From the inside, a user can either push the REX button or walk toward the door (triggering the REX motion sensor), which also triggers the unlock.

6. The Door Position Switch logs that the door was opened and then sends a “secure” signal once it’s closed again.

Plan for Success

A successful commercial access control system is built on careful planning. Start by assessing your door types, understanding local fire and safety codes, and choosing the right components for your security and operational needs. By understanding the role of each part and the wiring that connects them, you can ensure a secure, reliable, and code-compliant installation that protects your people and assets for years to come.