Fail Safe vs Fail Secure: Which Lock Fits Your Door?
A fail safe lock unlocks when it loses power. A fail secure lock stays locked when it loses power. That is the whole difference, but it decides whether people can leave a building in an emergency and whether strangers can walk in during an outage. This guide explains how each type works, which doors need which, and how to decide before you buy or install.
TL;DR
Fail safe: power locks the door, so the door unlocks when power is cut. Think stairwells and doors that must open for escape or re-entry.
Fail secure: power unlocks the door, so the door stays locked in an outage. Think perimeter doors, storage rooms and most offices.
Both terms describe the outside (secure) side of the door. Free mechanical exit from the inside is normally still available on fail secure hardware.
Magnetic locks are always fail safe. Electric strikes on fire-rated doors must be fail secure.
Fire code can override your preference, so confirm the rule for your door before you choose.
Table of Contents
What fail safe and fail secure actually mean
These terms apply to electrified door hardware: electric strikes, electromechanical locks and electromagnetic locks. A plain mechanical deadbolt has no power state, so the question never comes up.
According to Allegion’s explanation of the two terms, fail safe products are unlocked when power is removed and need power to lock. Fail secure products are locked when power is removed and need power to unlock. The label describes the status of the secure side of the door, not the inside.
The names are easy to mix up because “safe” sounds like “secure.” A better way to remember them: fail safe protects people, because the door lets them through. Fail secure protects property, because the door holds.
Fail safe | Fail secure | |
Power on | Locked | Unlocked only when signaled |
Power lost | Unlocks | Stays locked |
Power needed to… | Keep the door locked | Open the door |
Priority | Life safety, quick exit or re-entry | Asset protection |
Typical door | Stairwell re-entry, controlled egress | Perimeter, storage, offices |
In plain terms, one setup spends electricity to keep a door shut and the other spends it to let someone in. That has real consequences for batteries, outages and running costs.
How each type behaves in a power failure
Imagine a storm knocks out power to a commercial building in Wilmington on a Friday night.
Fail safe doors release. People inside can leave and responders can enter, but anyone can walk through that door until power or backup returns.
Fail secure doors hold. The building stays protected, and people inside can still leave by operating the handle or push bar, because most electrified hardware is designed for free egress. Someone outside with a valid mechanical key can still get in.
That last point is a common misconception. Fail secure does not mean trapped. It means the outside stays locked.
Backup power matters more for fail safe
Because fail safe hardware needs continuous power to stay locked, a weak power supply is a security hole. Facilities that use it typically add battery backup, and a failed battery can leave a door open without anyone noticing. Fail secure hardware draws power only to unlock, so it is generally more energy efficient and usually simpler to maintain.
Which one goes on which door
A workable rule: start with the door’s job, then check the code.
Doors that usually call for fail safe
Stairwell doors that must allow re-entry. Under the 2024 International Building Code, stairwell re-entry doors are prescriptively required to use fail safe electrified locks, so they unlock on fire alarm or power loss.
Healthcare controlled egress doors.
Elevator lobby exit doors.
Any door fitted with a magnetic lock.
Doors that usually call for fail secure
Exterior and perimeter entrances.
Server rooms, supply rooms, cash rooms and records storage.
Hotel guest room doors, which fit the security-first posture while still allowing exit from inside.
Most residential and small commercial entry points.
A short checklist for deciding:
Does the code require people to be able to pass through this door when power is lost?
What is behind the door, and how bad is it if it opens during an outage?
Will the door be on a fire-rated assembly?
Can the door always be opened from the inside without a key or power?
Who handles the door during an alarm, and how do responders get in?
If question 1 is yes, you are in fail safe territory. If question 3 is yes and you want an electric strike, the choice is made for you, as the next section shows.
Hardware that limits your choice
Some products come in only one mode.
Electromagnetic locks hold by magnetism, so they release when power is cut. They are only made fail safe. That also means they need request-to-exit switches or fire alarm triggers to meet egress rules.
Electric latch retraction on panic hardware is only available fail secure, because the latch projects when power is removed.
Electric strikes come in both versions, but the fire door exception below applies.
The fire door rule people miss
Electric locks on fire doors are not all required to be fail secure. Electric strikes are different. Per NFPA 80, electric strikes on fire-rated doors must be fail secure, because a fail safe strike does not give the positive latching that keeps a fire door closed. The NIH technical bulletin on electronic locksets states the same requirement.
So a fail safe strike on a fire-rated stairwell door is the wrong product, even though stairwell logic might point you toward fail safe. This is exactly the kind of conflict to settle with a qualified professional before purchase, not after inspection.
Life safety, egress and the code
Security preference is the second question. Life safety comes first.
Special locking arrangements that restrict egress, including magnetic locks, must follow IBC and NFPA life safety codes. That includes manual release devices and integration with the fire alarm system. OSHA’s interpretation on building security and employee exit is worth reading if you manage a workplace.
A few points that save headaches:
Fail secure on a fire exit can trap people if the inside cannot be opened mechanically. A standard push bar or lever that always retracts the latch solves this.
Controlled or delayed egress is regulated. It requires specific safety measures and approval, and it is not a DIY decision.
Firefighters do not depend on your lock type. Responders have established ways in, such as key boxes and specialized tools, so choosing fail secure does not block emergency access.
In Delaware, the state’s own code sets baseline exit rules for places where crowds gather. Title 16, Chapter 75 of the Delaware Code requires buildings such as theatres, churches and public halls over one story to have outward-opening doors. Local and state fire marshal reviews and the adopted building code edition decide what applies to your specific building, so check with the authority having jurisdiction for your county or municipality.
If you are buying or selling a property and want the garage and other door safety systems tested, a garage door safety inspection is one way to get a documented review alongside your regular inspection. It does not replace a fire code review of electrified egress doors.
Common mistakes
Choosing fail safe for a perimeter door “for safety.” Without strong backup power, an outage turns that door into an open one.
Assuming fail secure blocks exit. It usually does not. The inside is normally free.
Ignoring the door’s fire rating. A fire-rated opening limits your strike options.
Skipping documentation. The choice balances life safety against asset protection, and it should be written into your security policy so the next manager or contractor understands why a door was set up that way.
Mixing up locks and safes. Readers sometimes search “fire safe vs burglary safe” after reading about fail safe. Those are about storage containers and what they resist, not about how an electrified lock behaves in a power outage. They are separate topics.
Our perspective on fail safe vs fail secure
Most of the calls we get are about getting people into cars and houses. Electrified door hardware comes up when a business manager, landlord or property manager wants more control than keys give them, and the first question is nearly always the same: “What happens if the power goes out?”
Our answer starts with the door, not the product. We ask what the door protects, who needs to use it, whether it is on a fire-rated frame and whether the inside always opens. For most storage rooms, back-of-house doors and exterior entries, we lean fail secure, because it holds through an outage and does not depend on batteries to stay locked. For stairwell re-entry and anywhere a code official requires release on alarm or power loss, we plan fail safe with proper release devices and a supply that is monitored.
We also push back on one thing: picking a lock mode because it sounds safer. The right setup is the one your building code, your fire marshal and your day-to-day traffic can all live with. Being a local, owner-operated team helps here, because you can talk to the person who will actually do the work and explain the door in plain terms, with no call center in between.
If a job needs a fire-code determination, we say so and expect you to involve the fire marshal or your design professional. We would rather install the right hardware once than redo a door after a failed inspection.
— Brian
Getting it installed in Delaware
Whether you are upgrading one office door or a whole suite, the installation matters as much as the lock mode. A fail secure strike that is misaligned will not latch. A magnetic lock with no request-to-exit device is a code problem. Panic hardware has its own rules: our guide to keeping your UL listing when installing a panic bar explains why the way it is installed counts.
Our mobile team handles commercial work including access control solutions, master key systems and panic bar installation. We come to your location anywhere in the state, including New Castle, Newark and Hockessin. You can see the full range on our locksmith services page. We do not publish fixed prices, so the quickest way to get a figure is to describe your doors and ask.
For homeowners, the same thinking applies at a smaller scale. A smart lock upgrade is a mechanical-plus-electronic decision, and our residential locksmith guide covers what to weigh. If you are locked out in the meantime, here is what you can do.
Questions to ask before you buy
Bring these to any installer, including us:
Is the lock fail safe or fail secure, and can it be changed later or is it fixed at order?
Is the door fire-rated, and is this product listed for that assembly?
How does someone exit from the inside if power fails?
What backup power is included, and who checks it?
How does the lock tie into the fire alarm, if required?
Who is the authority that approves the door in this building?
A clear answer to each one is a good sign. Vague answers on egress or fire rating are a reason to keep looking.
FAQ
Is a mag lock fail safe or fail secure?
A magnetic lock is fail safe. It holds the door with an electromagnet, so cutting power releases it. Because of that, it needs release devices such as request-to-exit switches and fire alarm integration to meet egress codes.
What is an example of a fail safe door?
A stairwell door that must let people re-enter a floor is a standard example. It unlocks on a fire alarm or power loss so people are not stranded in the stairwell. Controlled egress doors in healthcare settings and some elevator lobby exits work the same way.
What does fail secure mean for a front or perimeter door?
It means the outside of the door stays locked during a power outage and needs power to unlock electronically. People inside can normally still exit, since most electrified hardware allows free mechanical egress. It is the usual choice for exterior entries and storage areas.
Can I switch a lock from fail safe to fail secure later?
Sometimes. Some electrified locks must be specified in one mode at order and then stay that way, while others can be changed in the field. Check the product’s documentation first, and confirm the new mode still meets the fire code for that door.
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