In the world of access control, few decisions are more critical—and more misunderstood—than choosing between fail safe and fail secure locking hardware. Whether you’re designing a new system or retrofitting an existing building, this choice has direct implications for safety, security, and code compliance.
Understanding how fail safe vs fail secure locks function during a power outage or fire alarm is essential for security dealers and integrators who want to reduce liability and ensure client safety. In this post, we’ll break down the difference, explore real-world applications, and show you how to make the right call for each opening.
What’s the Difference Between Fail Safe and Fail Secure?
These terms describe how an electrified locking device behaves when power is lost—either through a power failure or when released intentionally by a fire alarm or emergency system.
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Fail Safe: The lock unlocks when power is lost. It requires electricity to remain secure.
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Fail Secure: The lock stays locked when power is lost. It requires electricity to unlock.
In simple terms:
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Fail Safe = safe exit during power loss
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Fail Secure = secure property during power loss
But don’t let the names mislead you. “Fail safe” doesn’t always mean “safe,” and “fail secure” doesn’t always mean “more secure.” The correct application depends on the purpose of the door, the life safety code, and fire alarm system integration.
Where to Use Fail Safe vs Fail Secure Hardware
Fail Safe: Life Safety Priority
Fail safe hardware is typically used on:
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Exit doors and egress paths
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Stairwell doors in multi-story buildings
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Lobby or vestibule doors with fire-rated glass
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Doors where people may be trapped during a fire or power outage
Since fail safe devices unlock when power is lost, they allow immediate exit, which is a requirement under most building and fire codes. These doors may still be monitored with delayed egress, alarms, or integrated access control—but they must always allow people to evacuate safely.
Fail safe locks are required on fire-rated doors used for egress. This ensures the door will unlock during a fire alarm, allowing first responders and occupants safe passage.
Examples:
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A glass lobby door using an electric strike or magnetic lock.
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A controlled access stairwell that must unlock during a fire alarm to allow exit.
Fail Secure: Security Priority
Fail secure hardware is typically used on:
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Exterior doors to prevent unauthorized entry
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IT rooms, data centers, and evidence rooms
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Employee-only entrances or security closets
Fail secure devices remain locked when power is lost, preventing unwanted access. These are ideal when keeping intruders out is more critical than providing free exit, such as in areas with sensitive assets.
But here’s the key: fail secure locks still need mechanical free egress from the inside. For example, a door may use an electrified strike or mortise lock that remains locked from the outside but still opens from the inside with a lever or push bar.
Examples:
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A card-access employee entrance that must remain secure during a blackout.
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A telecom room or cash vault that must remain locked during emergencies.
Fire Alarm Integration: Code Compliance Matters
When fire alarms are activated, life safety takes precedence over security. That’s why many fail secure doors must be tied into the fire alarm system and temporarily unlock during an alarm event—even if their default behavior is fail secure.
Maglocks (often fail safe by design) are also required by NFPA 101 and IBC to release upon:
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Fire alarm activation
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Loss of power
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Actuation of a motion sensor
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Manual release (e.g., emergency push-to-exit button)
Security dealers must confirm that their access control system complies with local AHJ (Authority Having Jurisdiction) requirements, which often vary based on occupancy type, building use, and local fire code interpretation.
Bottom line: Always work closely with the fire marshal, building inspector, and facilities team during system design.
Best Practices for Dealers and Integrators
Choosing the right fail mode isn’t just about security—it’s about safety, liability, and code compliance. Here’s how dealers can navigate the decision:
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Evaluate the purpose of each door: Is it primarily for entry, exit, or access to a sensitive area?
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Check if the door is fire-rated: Most fire-rated doors require fail safe hardware.
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Consult life safety codes: NFPA 101, IBC, and ADA have specific rules.
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Design with power failure in mind: What happens to your system if there’s a blackout or battery failure?
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Test fire alarm integration: Ensure all access-controlled doors respond correctly to alarm signals.
Technical Summary
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Fail Safe Devices (Unlock When Power is Lost)
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Typical Types: Magnetic locks, some electric strikes
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Application: Glass doors, egress paths, stairwells
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Power Draw: Requires constant power to stay locked
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Fail Secure Devices (Stay Locked When Power is Lost)
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Typical Types: Electrified strikes, electrified lever sets, electrified mortise locks
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Application: Perimeter doors, data rooms, restricted areas
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Power Draw: Only uses power to unlock
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Many electrified locks are field-selectable or available in both fail safe and fail secure versions. Dealers should consult datasheets and wiring guides during design and installation.
Partner with SESP for Your Access Control Projects
Southeast Security Products represents best-in-class manufacturers across the Southeast U.S., offering hands-on support, product expertise, and dealer-focused programs to help you grow your business. Whether you’re upgrading a client’s building for fire safety, adding new access control hardware, or retrofitting a mixed-use facility, we can help you select the right fail safe and fail secure solutions for each application. Contact us today for design support, pricing, or help navigating code compliance.
Visit sesproducts.com or reach out to learn more about how we can support your next project.
