Fail-safe vs fail-secure locks: what is the difference?
When choosing an electric lock for an access control system, one of the most important things to understand is the difference between fail-safe and fail-secure operation. These two terms describe what the lock does when power is removed.
Choosing the wrong type can affect security, safety, access control operation and emergency exit arrangements. This guide explains the difference between fail-safe and fail-secure locks, where each type is commonly used, and what to consider before choosing a locking device for your door.
What does fail-safe mean?
A fail-safe lock unlocks when power is removed.
This means the lock needs power to stay locked. If the power supply fails, the access control system loses power, or the lock circuit is interrupted, the door will release.
Magnetic locks are the most common example of fail-safe locking. A maglock uses an electromagnet to hold the door closed. When power is applied, the magnet holds the armature plate. When power is removed, the magnetic force is lost and the door can be opened.
Fail-safe locking is often used where safe exit is important, especially on access-controlled doors that form part of an escape route. However, the full system must be correctly designed and installed with suitable exit buttons, emergency door release units, fire alarm interfaces and power supplies where required.
What does fail-secure mean?
A fail-secure lock stays locked when power is removed.
This means the lock normally requires power to unlock, rather than power to stay locked. If the power supply fails, the door remains secured from the outside.
Fail-secure operation is commonly used with many electric strikes, electric releases and door locking devices where maintaining security during a power failure is important.
For example, a storeroom, office, restricted area or external entrance may need to remain locked if power is lost. In these cases, a fail-secure lock may be suitable, provided safe exit from the inside is still available where required.
The main difference between fail-safe and fail-secure locks
The easiest way to remember the difference is:
Fail-safe means unlocked without power.
Fail-secure means locked without power.
Fail-safe locks prioritise release when power is removed. Fail-secure locks prioritise security when power is removed.
Neither option is automatically better than the other. The correct choice depends on the door, building, escape route, user requirements, fire safety design and level of security needed.
Common examples of fail-safe locks
Fail-safe locks are commonly used in access control systems where the door needs to release if power is lost or if an emergency release condition occurs.
Common fail-safe products include:
- Magnetic locks
- Some electric strikes
- Some electric release locks
- Some solenoid bolts
- Certain specialist access control locks
Magnetic locks are normally fail-safe by design because they rely on power to create the magnetic holding force.
Fail-safe locks are commonly used on:
- Access-controlled entrance doors
- Internal office doors
- Escape route doors
- Communal entrance doors
- Reception areas
- Education and healthcare buildings
- Commercial access control systems
- Doors connected to fire alarm release systems
Where a fail-safe lock is used on an escape route, the installation may also require a press to exit button, emergency door release unit, fire alarm interface and suitable system wiring.
Common examples of fail-secure locks
Fail-secure locks are commonly used where the door should remain locked if power is removed.
Common fail-secure products include:
- Fail-secure electric strikes
- Fail-secure electric releases
- Some cabinet locks
- Some specialist electric locking devices
Fail-secure locks are often used on doors where the inside handle or mechanical escape method still allows exit, but outside access remains controlled.
Fail-secure locks are commonly used on:
- Store rooms
- Staff-only areas
- Office doors
- External doors with suitable mechanical escape hardware
- Door entry systems
- Restricted access rooms
- Areas where security must be maintained during power loss
A fail-secure lock should only be used where the door can still be operated safely and legally for the building and application.
Fail-safe locks and magnetic locks
Magnetic locks are one of the most widely used fail-safe locking devices in access control.
They are popular because they are simple, reliable and provide strong holding force. They are often used with keypads, proximity readers, door controllers, press to exit buttons and emergency door release units.
Because a magnetic lock releases when power is removed, it is important to use the correct power supply, control equipment and safety devices. On many escape route applications, the maglock may need to release when the fire alarm operates, when power fails, or when the emergency door release unit is activated.
Fire-rated doors and escape routes should always be assessed carefully before electronic locking equipment is installed.
Fail-secure locks and electric strikes
Electric strikes and electric releases are often available in fail-safe or fail-secure versions.
A fail-secure electric strike remains locked when power is removed and unlocks when power is applied. This can be useful where outside access needs to remain secure during a power failure.
In many installations, the electric strike works with an existing latch or lock case. The door remains mechanically latched, and the strike releases the latch when access is granted by a keypad, reader, intercom or access control system.
This makes electric strikes a popular choice for offices, apartment entrances, commercial doors and door entry applications.
Which lock type should you choose?
The best choice depends on the door and what the system needs to achieve.
Choose fail-safe where safe release on power failure is required, especially where the door is part of an escape route or access-controlled exit path.
Choose fail-secure where maintaining security during power failure is important, provided the door still allows safe exit where required.
Before choosing, consider:
- Is the door on an escape route?
- Does the door need to unlock during a fire alarm activation?
- Should the door remain locked if power fails?
- Is the door internal or external?
- What type of door and frame are being used?
- Is there an existing latch or lock case?
- Will the system use a keypad, reader, intercom or controller?
- Is a press to exit button required?
- Is an emergency door release unit required?
- What voltage and current does the lock need?
- Is monitoring required?
These questions help determine whether a magnetic lock, electric strike, electric release, solenoid bolt or another locking device is the right choice.
Access control safety considerations
Electronic locking systems should always be designed with safe exit in mind.
A door may need more than just a lock and reader. Depending on the installation, the system may require a press to exit button, emergency door release unit, fire alarm interface, timer relay, access control controller and suitable power supply.
For escape routes, fire doors and public access areas, the locking arrangement should be checked by a competent person. The correct solution depends on the building, door hardware, fire strategy and relevant safety requirements.
Key buying checklist
Before buying a fail-safe or fail-secure lock, check:
- Whether the lock is fail-safe or fail-secure
- The voltage required, such as 12VDC or 24VDC
- The current draw of the lock
- The type of door and frame
- Whether the door is on an escape route
- Whether fire alarm release is required
- Whether a press to exit button is required
- Whether an emergency door release unit is required
- Whether the lock works with your access control system
- Whether monitoring outputs are needed
- Whether suitable brackets, faceplates or accessories are required
Checking these points before ordering can help avoid compatibility issues and installation problems.
Final thoughts
Fail-safe and fail-secure locks both have important roles in access control and door security.
A fail-safe lock unlocks when power is removed, making it suitable for many access control and emergency release applications. A fail-secure lock remains locked when power is removed, making it suitable where security needs to be maintained during power failure.
The right choice depends on the door, building, user requirements, escape route design and access control system.
Browse our range of magnetic locks, electric strikes, electric releases, access control systems, press to exit buttons, emergency door release units and power supplies to find suitable products for your installation.