- Fail safe unlocks without power and protects people. Fail secure stays locked and protects property.
- Leaving must never depend on electronics working, in either mode.
- A maglock needs a hardware release that cuts the coil directly, not a controller request.
- Kill the power and walk every door. An untested mode is an unknown mode.
What the two terms mean
Fail safe means the door unlocks when power is lost. Safe refers to people. A magnetic lock is always fail safe because it cannot hold without power.
Fail secure means the door stays locked when power is lost. Secure refers to property. Most electric strikes are fail secure by default and many can be reconfigured either way with a jumper or a reversible plate.
Both are correct in the right place. A server room door should be fail secure so a power cut does not open it. A stairwell door on an exit route should be fail safe so a power cut does not trap anybody behind it.
Egress is never electronic
Whichever mode is chosen, leaving must never depend on the electronics working. That is the principle that resolves most arguments about this.
On a fail secure door the mechanical lever or exit device must still release the latch from the inside with no power and no credential. On a fail safe magnetic door there must be a hardware release path such as a break glass or a push to exit that cuts the magnet coil directly rather than asking a controller politely.
If the only way out of a room is for software to agree, the installation is wrong regardless of what mode it is in. That is the sentence to say out loud to a customer who wants a maglock with no mechanical release.
Documenting the decision
Write down, for every door, which mode it is in, why, what the release path is, and who approved it. Give the customer a copy and keep one.
That record is what protects everybody when a fire marshal inspects, when the building changes hands, or when somebody adds a door five years later and copies the wrong configuration.
And verify it physically. Kill the power at the panel and walk every door. Confirm that each one does what the document says it does. A mode that was set on a drawing and never tested on the door is a mode nobody actually knows.
Common Questions
Which one should I use?
Ask what happens in a power cut. If people must get out, fail safe. If the asset must stay locked and there is another way out, fail secure. The fire code usually settles it for you.
Is fail safe the same as unlocked?
Only when the power is off. With power on it holds normally. The name describes the failure state, not the everyday state, and that confuses people constantly.
Does a fail secure lock trap people inside?
It must not. The inside handle or push bar has to release it mechanically whatever the power is doing. If it does not, the installation is wrong and it is a life safety fault.
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