What is the difference between fail-safe and fail-secure?

Fail-safe unlocks when power is lost, so it needs power to stay locked. Fail-secure stays locked when power is lost, so it needs power to release. Safe refers to life safety, meaning people can get out; secure refers to property, meaning people cannot get in.

Which should a suite entrance door use?

Usually fail-secure, provided exit is guaranteed mechanically. Where a reader controls entry and a lever handle always releases from the inside independent of power, a fail-secure strike keeps the door controlled during an outage without trapping anyone.

How do I find out what our doors do in a power cut?

Test them. Isolate power to the device and try the door from both sides, deliberately and in a planned way, recording the result per door. Configuration is often changeable on site, so a strike fitted years ago may not be in the mode the drawings assume.

Fail-Safe vs Fail-Secure Electric Locks

Q: Are magnetic locks always fail-safe?

Yes, inherently: they hold the door with an electromagnet, so no power means no hold. That is why they carry requirements around request-to-exit devices, a clearly marked release and release on fire alarm, and why a mag lock fitted without those provisions works until the day it matters.

The two terms describe what happens when a door loses power, and they are opposites. Getting them the wrong way round on an opening is one of the few access control mistakes that can be both a security failure and a life safety failure, depending on which way you got it wrong.

The two behaviours

Fail-safe means the device unlocks when power is removed. It requires power to stay locked. Lose power and the door is open.

Fail-secure means the device stays locked when power is removed. It requires power to release. Lose power and the door stays shut.

The naming is the source of most confusion, because both words sound reassuring. Safe refers to life safety, meaning people can get out. Secure refers to property, meaning people cannot get in.

Which one a door needs

The question to ask is what this door does in an emergency, and the answer usually comes from the egress requirement rather than from preference.

Fail-safe is normally correct where the door is part of an escape route and the electric device controls the direction people would leave through, or where the door has to release on a fire alarm. Stairwell doors that must unlock to let people out of a stair, and doors held by magnetic locks, are the common cases.

Fail-secure is normally correct on a perimeter or a controlled area where the electric device controls entry only and free exit is provided mechanically. A suite entrance with a card reader outside and a lever handle inside is the standard example: the reader controls coming in, the handle always lets you out, so the strike can safely stay locked in a power cut.

That last case is the important general principle. If exit is guaranteed mechanically, independent of power, then a fail-secure device on the entry side does not trap anybody.

Magnetic locks are a special case

A magnetic lock has no mechanical latch. It holds the door with an electromagnet, so it is inherently fail-safe: no power, no hold.

That makes it convenient and it makes it heavily regulated, because the entire security of the door depends on continuous power, and the entire egress depends on the release arrangement working. Mag-locked doors carry requirements around request-to-exit devices, a clearly marked release, and release on fire alarm activation.

The failure we see is a mag lock installed as a simple access control solution without those release provisions properly arranged. It works perfectly until the day it matters.

Electric strikes and electrified hardware

An electric strike replaces the fixed strike plate with one that can be released electrically. Most are available in either behaviour, and importantly, many can be configured on site, which means a strike fitted years ago may not be in the mode anyone assumes.

Electrified locksets and electrified exit devices do the same job inside the hardware rather than in the frame. On a fire rated assembly this matters, because the latch has to stay in place for the door to hold, so anything that would defeat latching is not permitted there.

The questions worth asking about your own doors

Which doors have electric locking at all? Many properties cannot list them, because they were installed at different times by different people.
How does each one behave when power is lost? Not what the drawing said, but what it does now.
How does somebody get out of each one with no power? If the answer involves anything other than pushing or turning a handle, that needs looking at.
What is on the fire alarm interface? Anything required to release on alarm should be tested as part of the alarm test, not assumed.
Is there battery backup, and what does it cover? A fail-secure door on backup power stays controlled. A fail-safe door on backup power stays locked, which may or may not be what you want during an evacuation.

Testing it, which almost nobody does

The behaviour is trivially testable: isolate the power to the device and try the door from both sides. Doing this deliberately, in a planned way, is far better than discovering the answer during an outage.

Miami loses power. Building it into a routine, and recording the result per door, turns an unknown into a documented position, and that record is exactly what an inspector or an insurer asks about.

Where we sit on this

The hardware is ours. Electric strikes, electrified locksets, mechanical locks, exit devices, door furniture, and confirming and recording what each opening does on loss of power are all performed by our own technicians, and no Florida contractor licence is required for that work.

The power supply, the wiring, the fire alarm interface and any connection into a panel are electrical work under Florida law at any job size, so a licensed electrician carries those out and we coordinate them. On this trade in particular the two halves have to be scoped together, because a strike in the correct mode wired to the wrong supply behaviour is still the wrong door.