When assessing your keying and security requirements, another option to consider is Master Keys. Put simply, a master-keyed lock is one that is designed to be opened by individual keys but can also be opened by using a higher access master key.
The main distinction of a master key system is that access can be controlled. It allows only approved individuals to use their keys to enter specific areas. For the person who is authorized to use the master key, it can greatly reduce the number of keys that must be carried, which is named as one of the greatest benefits that come with this lock security method. Fewer keys to carry means less time fumbling to find the right one; it also greatly lightens the load for facilities managers and others who would otherwise be weighed down with a massive ring of keys.
To use a master key system, there is some planning required to determine the individuals who need access, and at what level. For example, keys in a master system are typically distributed to give the minimum level of access needed, with incrementally increased access based on title, rank or responsibility. Typical master lock systems involve these specific keys, presented in order of lowest to highest access privileges:
Also called the sub-master key. It will open one lock and only locks that are exactly the same. The lock that the change key opens will also open when used along with the master key, and any key above that rank.
Without a master key, there is only one key for a lock. This is the necessary key to change a simple lock into a master-keyed lock. In some systems, this will be the highest-ranking key, and will sometimes be stamped ‘MK’.
Grand Master Key
A grand master key enables access to multiple master key systems. This key will open every master system under it, as well as the change keys under those systems. These keys may be stamped ‘GMK’.
Great Grand Master Key
The great grand master key will open all the grand master key systems under it, the master key systems under those, and the change keys under those. The schematic can become increasingly more complex depending on security needs and objectives.
Even intricately designed master key systems are not designed to last indefinitely. A good rule of thumb is to re-evaluate and replace the system within 10 years of initial use. Employee turnover, changing and improved lock technology and security peace of mind are worth the time and expense of following this recommendation.
The convenience of a master key system does bring some sacrifices in the area of security and risk, for example, they are easier to decode and pick. Assessing risk and deciding if the master key system is suitable for your situation is best left to the experts, your local locksmith.