Master key system

A master key system is the set of cylinders and keys that results from master keying: each door with its own key and, above that, keys that open groups of doors or all of them.

It normally has three levels:

• Individual key. Opens a single door, for example a flat or an office.
• Sub-master key. Opens a group, such as all the storerooms or one floor.
• Grand master key. Opens every door in the system.

It works well in communities, small hotels, offices and businesses with several rooms. What makes it secure is control: knowing how many keys there are at each level and who holds them. That is why it is always worked out with a keying chart. If you are thinking about one, our master keying page explains how we set it up.