Publish Time: 2025-12-26 Origin: Site
If you manage a commercial building, a school, or a public facility, you are likely familiar with the horizontal bars across your exit doors. Known as panic bars, crash bars, or door push bars, these devices are essential for safety compliance. But a common question arises for building managers and security personnel: How do you lock a push bar door from the inside without violating safety codes?
Balancing security with safety is a delicate act. You need to keep intruders out while ensuring that occupants can leave quickly during an emergency. This guide explores the mechanics of door push bars, the different locking functions available, and how to secure your facility effectively without compromising life safety standards.
Before diving into locking mechanisms, it is crucial to understand why door push bars exist. Originally designed to prevent crowd crushing during emergencies, these devices allow a door to open outward with simple body pressure.
According to safety regulations like the Life Safety Code (NFPA 101), exit doors in assembly occupancies generally must be equipped with panic hardware. The primary rule is that egress must always be free. This means that from the inside, a person should be able to walk up to the door, push the bar, and exit without needing a key, a code, or special knowledge.
Therefore, when we ask "how to lock a push bar door from the inside," we usually mean one of two things:
Dogging the device: Holding the latch retracted so the door operates as a push/pull door during business hours.
Locking the outside trim: Preventing entry from the exterior while maintaining free exit from the interior.
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One of the most common ways to control a door push bar is through a feature called "dogging." This doesn't technically "lock" the door in the sense of securing it against exit; rather, it locks the latch in a retracted position.
Cylinder dogging uses a key cylinder located on the push bar itself. When you turn the key, it retracts the latch bolt and holds the push pad in the depressed position.
High Traffic Flow: Ideal for main entrances during business hours. It turns the door into a simple push-pull passage, reducing wear and tear on the latch mechanism.
Noise Reduction: Eliminates the "clack-clack" sound of the latch hitting the strike every time someone enters or exits.
Security Risk: When the device is dogged, the door is unlatched. It relies on the door closer to keep the door shut, but wind or pressure can blow it open. It offers zero security against intruders until undogged.
Fire Door Restrictions: You generally cannot use mechanical dogging on fire-rated doors. Fire doors must latch positively to prevent the spread of fire and smoke.
Similar to cylinder dogging, hex key dogging retracts the latch to allow free passage. The difference lies in the tool used.
Instead of a key cylinder, there is a small hole in the push bar assembly. You insert a hex key (Allen wrench), push the bar in, and turn the key to lock the bar in the retracted position. To re-secure the door (so it latches), you simply turn the hex key in the opposite direction.
This is a cost-effective solution often found on non-fire-rated exit doors in low-security areas or interior cross-corridor doors.
For modern access control systems, Electrified Latch Retraction (ELR) is the superior choice. This method allows you to "lock" and "unlock" the operation of the door remotely.
A motor or solenoid inside the door push bar is connected to your building's access control system.
Unlock Schedule: During business hours, the system powers the motor to pull the latch back (dogging it electronically). The door swings freely.
Lock Schedule: At the end of the day, the power cuts, the latch extends, and the door is secure from the outside.
The biggest advantage of ELR is that you can integrate it with card readers or keypads. From the inside, the bar always allows egress. From the outside, the door remains locked until a valid credential is presented, at which point the latch retracts momentarily.
To help you decide which method suits your facility, here is a comparison of the three primary methods for controlling door push bars:
Feature | Cylinder Dogging | Hex Key Dogging | Electrified Retraction |
|---|---|---|---|
Primary Use | High traffic, non-fire doors | Low budget, non-fire doors | High security, automated access |
Tool Needed | Standard Key | Hex / Allen Key | Access Control System |
Security Level | Low (when dogged) | Low (when dogged) | High |
Fire Door Allowed? | No | No | Yes (if latch extends on fire alarm) |
Cost | Medium | Low | High |
There is a dangerous misconception that you should be able to lock an exit door so that nobody can leave. This is almost always a code violation.
You should never use a chain and padlock on a door push bar while the building is occupied. This creates a trap. If a fire breaks out, confused occupants may be unable to remove the chain in thick smoke or panic. Chains are only acceptable on specific doors when the building is completely unoccupied, and the "This Door to Remain Unlocked When Building is Occupied" signage is usually required.
Placing furniture, boxes, or security bars across the push pad is illegal. The path of egress must remain unobstructed at all times.
While we have focused on the inside operation, securing the door push bar against outside entry is equally important. This is usually handled by the "trim"—the handle or lever on the exterior side of the door.
Night Latch Function: The exterior lever is rigid and only opens the door when a key is turned. Once the key is removed, the door is locked again.
Classroom Function: The exterior lever can be locked or unlocked using a key. If unlocked, anyone can enter. If locked, the lever is rigid, but the inside push bar still works for exiting.
Storeroom Function: The exterior lever is always rigid. Entry is only possible with a key, but the door is always ready for exit from the inside.
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Selecting the correct locking mechanism depends on your specific building requirements, fire codes, and budget.
For example, D&D Hardware offers a range of certified solutions that cater to different security levels:
UL Listed Panic Hardware: Ideal for US and Canadian markets, ensuring compliance with UL 305 and UL 10C standards.
CE EN1125 Panic Exit Devices: Designed for the European market, tested for over 200,000 cycles to ensure durability in high-traffic areas.
If you are equipping a fire door, remember that you need fire-rated hardware (often labeled as "Fire Exit Hardware" rather than just "Panic Hardware"). These devices do not have mechanical dogging features because the door must remain latched to prevent fire spread.
Locking a push bar door from the inside is less about preventing exit and more about controlling the latch mechanism. Whether you choose simple mechanical dogging for convenience or electrified retraction for high-level security, the golden rule remains: safety first.
Never compromise the ability to exit freely in an emergency. By choosing the right door push bars and trim functions, you can maintain a secure facility that protects both your assets and your people.
If you are unsure which device is right for your metal or wooden doors, or if you need to upgrade your current system to meet fire codes, consult with a certified hardware supplier.