shadow11612 wrote:LFIC are not "interchangeable", but are more truthfully described as removable cores. Schlages are really easy to see this as the top and bottom halves are different sizes. If you have LFIC housings for a Schlage system, not other manufacture's LFIC core will fit. Granted there are some generic locks that will interchange, but most of the big names LFIC's are different.
There is nothing in any requirement that I know of which says an IC must be "universally interchangeable" across a variety of manufacturers... The SFIC "standard" came from Best's original design when the patent on the design itself expired... Like you state it is more compatible with a greater variety of product lines but that is by no means a requirement for the designation "interchangeable cores"..
"Removable Core" is a deceptive term, as it only implies that the cylinder core itself can be removed and separated from the lock... Such a description doesn't infer nor imply that such removal is easy or accomplished with a key (it might require taking the lock apart with tools) NOR that a removable core can fit into any other type of lock other than the exact model of the one it was removed from...
LFIC is an interchangeable core system with a proprietary design common only within one manufacturer's product lines... Said products are still interchange within their own manufacturer's product lines which provide the proper compatible housings... Compare this with a non-IC system where you can have bored locksets which may need several different specific types of replacement cylinders depending on what model of lock it is to upgrade to a new high security product or keyway with locks that support standard rim/mortise cylinders... It is MUCH easier to swap out rim/mortise cylinders for something new that it is to do the same with locksets which require a special purpose cylinder...
One rationale for having interchangeable core locks besides the ability to have non-skilled personnel being able to re-key a lock without the need for tools in order to quickly restore security in the event of a lost key or terminated employee... Another is the ability in certain environments to "scramble" the lock cores to different departments or sections of a building in a large facility rather than having to retire a master key group due to high employee turnover rate or a reconfiguration of the use of the space...
Think of a hospital where departments might move around and if the locking hardware was not of the interchangeable core type that might mean a lot of labor to physically disassemble other types of locks and re-key them to the existing keys rather than just removing the cores with a control key and reinstalling them in the doors at the new location...
Think of a college or university dormitory where it is NOT desirable UNDER ANY CIRCUMSTANCES to have the same change key operate the same door location from one year to the next... (That sort of situation often inspires the college student occupants of the space to want to make unauthorized copies of their keys...) Sure a lot of college locking hardware is using a mortise type cylinder but that is quite labor intensive to open the door, unscrew the cover plate screws, loosen the cylinder retention screw, unscrew the mortise cylinder itself to remove it from the lock, then proceed to follow those steps in reverse order after verifying that the cylinder properly operates with a key after screwing the 'new' one for that door into the lock... It is MUCH quicker to use a control key, swap the core out for one you have and move onto the next door... In fact since all the keys work (someone would have complained if one didn't) all the locksmith needs to do is take a second to examine all the keys for wear as they are being prepared into their envelopes marked for distribution for the new academic year, any replacement keys can be made and swapped in for worn ones at that time... It is all a matter of recording what cores are swapped into which doors during the scramble...
If you had different door locks requiring different types of cylinders your possibility of swapping cylinders without having to disassemble them and re-key would be limited... In fact in a college/university setting where you have several buildings with nearly identical layouts you can switch every core between them and have any given building on a different building master key (which the building users have not seen before) each year if that was required... Interchangeable cores also allow for additional groups of cores to be available in case a floor master key goes missing and an entire floor must be quickly re-keyed... In fact in a larger college/university it is not uncommon to have cores prepared in case a building master key is lost or compromised...
Without IC type locks in use that is an awful lot of man hours of labor which must be performed when the rekeying work is demanded, sometimes after hours by one person, rather than having "retired" or unused sets of cores around the lock shop to work on at a leisurely pace all academic year when the workload might not be as intense during slower periods (a.k.a. "busy work")...
~~ Evan
