To properly specify the right type of ingress/egress to apply at each door in your access control system, it is best to start by understanding why controlled access is required on this particular opening. Is it a matter of privacy, such as protecting personnel and organization files? Is there a safety issue, such as providing access to and quick egress from the boiler room? Are there theft problems in the supplies area? Are there vandalism problems in the neighborhood?
To answer these very general questions, keep in mind that access control is simply the controlling of who can go where and when. Will there be many people or just a few? What kinds of doors are involved? Do you need audits and time features, such as letting some people through only at certain hours and on specified days? Will many people be coming at once, such as at the start of the work day?
By answering these questions, you can begin to flush out more details for selecting the appropriate access control solution.
Controlling the Who
To control people, they need to be identified. The simple key is a form of identification. When you give a maintenance worker a key, you are saying, in effect, the bearer of this piece of metal is authorized to enter the door with the lock matching this key.
Instead of keys and their management costs, you might consider using something the user knows for access — for example, numerical codes to work with electronic keypad locks. Codes can be easily added and deleted from electronic keypad locks, eliminating the high costs associated with re-keying a mechanical lockset. These locks are typically reasonably priced. Including installation, it typically costs $600-800 to secure an opening with an electronic keypad lock.
However, people can also forget or share codes. Think how many passwords and numerical codes you already have, from ATM codes to PC passwords. So they do not forget, people often write down passwords and codes, keeping them in sight, so they are easy to see and to steal.
For greater security, access may be limited to something the user holds that is difficult to duplicate. User credentials such as magnetic stripe cards and proximity fobs can be selected. A quick swipe or presentation of the credential to the reader, and the cardholder successfully gains access through the opening. However, an authorized credential does not necessarily mean the holder is authorized for access to the opening. Credentials can be lost or stolen. A missing credential could be in the possession of an individual with harmful intentions until that credential is removed from the system. That could be immediate for online access or hours or days for offline access.
For higher security, one may consider a linked access arrangement where an authorized user must hold the appropriate credential and know the appropriate numerical code associated or linked with that credential. This application is common with bank ATM cards. The card and a 4-digit personal identification code are required in order to gain access to the appropriate bank account. It significantly reduces the probability that a lost or stolen ATM card will compromise the security of the bank account.
Keep in mind that whatever the credential type used, there will be cost issues and logistical requirements associated with the administering of the credentials.
Lastly, you might want to consider a biometric, which looks for an unalterable personal attribute. A biometric verifies an individual’s actual identity. Additional benefits are that there are no credentials or codes to administer and biometrics ca not be shared, stolen, lost or left behind.
Once you determine how to identify who, you need to control them. You can provide momentary access to individuals. You might want to keep certain doors unlocked at some times and locked at other times. Perhaps you want a pass-through mode for VIPs, allowing them to come and go as they please. For temporary maintenance workers or volunteers, you may want to set up a one-time use.