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keep it simple
Sub- master keys are available where every electrical and communication room on every floor can be accessed while the individual floor master keys can still operate that room on that specific floor. Why go through that effort when it usually is the same persons who need access into all those areas?
These areas should be periodically rekeyed and therefore should be keyed the same to keep it simple. When other vendors need access, special arrangements can be made to provide a temporary key and to arrange the proper return.
When rekeying suites of offices, not every office needs to be keyed different.
In the modern workplace, the trend is to get away from locked office doors and offices entirely, so it is possible to key all offices on a floor (or part of a floor) alike. This technique can drastically limit the number of wasted combinations when it comes to rekey.
As a department moves, key it all to pass
When an entire department moves to a new location within the building, gain approval from the head of the department to rekey in two passes. The chambers of all the cylinders or cores that would normally be keyed alike to conform to the floor master are filled; the rest of the chambers left open (see Figure 3).
A “common” floor key is developed using a change key dedicated to that floor. This key is generally issued to persons needing access.
As people settle in, most realize they do not need the added security. Those persons who need the added security can have their areas upgraded. The rest of the chambers are appropriately filled, essentially locking -out people with common keys.
This sensible approach results in a less complicated key strategy and wastes less overall combinations.
Label all doors
Use foilized-mylar labels with large sequential numbers. Consistently place the label on the flat surface of the top hinge on the active door. In this manner the label is out of site and protected. When there is a question about what door needs to be rekeyed, ask the requestor to open the door; and then read the number from the label on the hinge. (Foilized-mylar labels are available from printer supply companies.)
The numbers in Figure 4 are too small to read. Use at least quarter-inch high numbers. The best format I have found is three digits, followed by a hyphen, and then four digits.
Ask the requestor to read the phone number from the label. Research proves that seven digits are easier than five or six for humans to remember as we are pre-programmed to look at phone numbers.
Plans are available for all high-rises. The best means to obtain floor plans is to request electronic DWG or Cad drawings. From the Internet you can download free readers for these drawings and then cut and paste portions of the floor plans into your word processor or graphic programs.
Build a library of what you work on and it will streamline you effort. Additionally, these drawing can then be discussed with requestors of work to verify that everybody is on the same page.
It’s OK to Cross-Key
Effective rekey of high-rises is not for the faint of heart.
It is okay to cross-key a cylinder if you can predict the results. Existing combinations that will be affected need to be dealt with; and unused combinations that are affected need to be permanently isolated.
A cylinder might be cross-keyed so that manager who has offices on two different floors can access both offices with his change key. The cross-keying would allow the floor masters to operate properly.
The front entry door leading into a suite of offices might be cross-keyed so that all the different office keys could access the door. This is sometimes called Maison keying (French for house).
When a cylinder is cross-keyed, a “snapshot” of the pin stack needs to be recorded and archived.
Leaving Chambers Open
In theory, all master keyed cylinders should have all chambers filled, but this does not happen in the real world.
The entry door leading into a suite of offices might be keyed where several chambers in the lock cylinder or core are left empty (rather than filled with master wafers to accommodate Maison keying). The advantage of this is that there is less to go wrong with the pin stacks as there are less moving parts. The disadvantage is that more key combinations can access the cylinder (although these combinations would be from keys outside of the master key system).
Cylinders or cores where chambers are left open should be of very low security.
Certain locked restrooms might have lock cylinders or cores that have empty chambers. The chambers that are empty would normally distinguish which floor the restroom is on. The goal is that persons from one floor can access a restroom on another.
Some locked doors are used hundreds of times per day. A typical example is a bus terminal where the restroom is dedicated to the bus operators. Small-format interchangeable cores can wear out in less than 90 days under these circumstances. To increase the time between service calls on these areas, one lock shop leaves three chambers empty on these low security doors. This does prolong the life of the core.
Note: Remember if a door is opened on the average 20 times an hour, in a 24-hour operation that is 480 times a day or 43,200 times in 90 days. That is equivalent of 30 years worth of service on an office door.
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Choose and manage your high security key system carefully.