Push bar doors (also called panic bar or crash bar doors) are designed to always open from the inside, but locking them from the outside depends on the type of exterior trim installed on your door. Most commercial push bar doors can be locked from the outside using a key cylinder built into the exterior trim hardware. The method varies based on your door’s specific function setting.
How Exterior Trim Controls Outside Locking
The push bar itself is only on the inside of the door. On the outside, you’ll find one of several types of trim: a lever handle, a pull handle, a thumb piece, or sometimes just a flat plate with a key cylinder. This exterior trim is what determines whether and how the door locks from the outside.
Every push bar door has a “function” that defines its locking behavior. The two most relevant for outside locking are:
- Night Latch (NL): The outside is always locked by default. Turning a key retracts the latch momentarily to allow entry. Once you remove the key, the latch extends again and the door re-locks automatically. This is the simplest option if you want the door locked from the outside at all times.
- Classroom (or Lock/Unlock): Turning a key unlocks the outside lever, and it stays unlocked until you re-lock it with the key. This gives you the flexibility to toggle between locked and unlocked without the key each time someone needs in.
If your door has a thumb piece instead of a lever, it works similarly to the classroom function: a key locks or unlocks the thumb piece on the outside. The key distinction between these functions is whether the door stays unlocked after you use the key (classroom) or immediately re-locks when the key is removed (night latch). Choosing the right function depends on whether you want the door permanently secured from the outside or only locked during certain hours.
Locking the Door Step by Step
For most push bar doors with a key cylinder on the exterior trim, the process is straightforward. Insert your key into the cylinder on the outside of the door and turn it. On night latch hardware, you don’t need to do anything extra because the outside is locked by default. You’d only use the key to temporarily unlock it for someone to enter.
On classroom-function hardware, turn the key to the locked position (typically a quarter turn). The outside lever or thumb piece will no longer retract the latch, meaning no one can pull the door open from outside. The push bar on the inside still works normally, which is required by fire code.
Some doors also have a feature called cylinder dogging. This uses a key cylinder (usually on the push bar side) to hold the push bar in the depressed position so the door can swing freely in both directions, often used during business hours. To lock the door from the outside, you first need to make sure the push bar is not dogged down. Turn the dogging key clockwise to release the bar back to its normal position, then lock the exterior trim as described above.
Why the Inside Push Bar Always Works
No matter how you lock the outside, the push bar on the interior side must always allow people to exit. This is a core requirement of NFPA 101, the Life Safety Code. Egress doors must open readily from the inside whenever a building is occupied. Locking a door from the outside, or the “non-egress side,” is generally permitted specifically to prevent unauthorized entry. But any modification that would prevent the push bar from opening the door from the inside violates fire code and creates a serious safety hazard.
Key-operated locks on the outside of commercial doors are explicitly recognized as acceptable by NFPA 101, particularly for storefronts and offices that need after-hours security. The rule is simple: lock the outside all you want, but never restrict the inside.
When the Door Won’t Lock From Outside
If you’re turning the key and the door still won’t stay latched, the problem is usually mechanical alignment rather than the lock itself. The most common cause is that the door has sagged or the building has settled slightly, pushing the latch and the strike plate out of alignment. The latch bolt extends but doesn’t catch in the strike.
For a standard rim-style push bar (the most common type, with a single latch near the top of the door), loosen the screws on the strike plate mounted to the door frame. Most strike plates have slotted screw holes that let you slide the plate up, down, or side to side. Adjust it until the latch clicks securely into the strike without dragging.
Vertical rod devices, which you’ll often see on double doors, are trickier. These use rods that connect the push bar to latches at the top and bottom of the door frame. Even slight shifts in door alignment can prevent one of those latches from catching. If the bottom rod drags on the floor, shorten it by threading it further into its connector. If the top latch isn’t reaching the strike, lengthen the top rod. These adjustments often require removing the push bar’s cover plate to access the rod connections.
Another common issue: the key cylinder on the exterior trim is worn or the wrong key is being used. If the cylinder turns but feels loose or doesn’t engage the latch, the cam inside the cylinder may have shifted or broken. A locksmith can replace just the cylinder without swapping the entire trim assembly.
Choosing the Right Hardware Grade
If you’re installing new exterior trim or upgrading your push bar’s locking capability, the hardware’s ANSI/BHMA grade matters. Commercial door hardware is rated in three tiers. Grade 1 is the highest performance level, tested to one million open-close cycles and built to withstand significant force. In security testing, Grade 1 hardware must survive 10 blows at 75 foot-pounds of force to the cylinder face. Grade 2 handles 5 blows at that same force. Grade 3, the entry level, survives only 2.
For an exterior door that you’re relying on for security, Grade 1 hardware is worth the investment. For interior doors where the push bar is primarily for fire egress and the outside lock is just for access control, Grade 2 is typically sufficient.
What You Can’t Do Legally
You cannot chain, padlock, or otherwise physically block a push bar door in a way that prevents it from opening from the inside. You also cannot disable the push bar mechanism to create a “locked from both sides” situation during occupied hours. If your goal is to restrict the door from opening from the inside during certain conditions, you’d need a specialized access control system (like delayed egress or controlled egress hardware) that meets specific code requirements and includes alarms, timers, and integration with the fire alarm system. These are not DIY installations.
For straightforward outside-only locking, the correct exterior trim with the right function setting handles everything you need. If your current push bar has no exterior trim at all (just a flat plate with no key cylinder), a locksmith can retrofit compatible keyed trim to your existing device without replacing the entire push bar assembly.