Delayed egress locking arrangements basically delay egress through a subject opening for a pre-determined time. Most building codes require that delayed egress systems be connected to premises' fire alarm systems so that they unlock immediately if there is a fire alarm. Different building codes...
To access the remainder of this piece of premium content, you must be registered with Locksmith Ledger. Already have an account? Login
Register in seconds by connecting with your preferred Social Network.
Complete the registration form.
Delayed egress locking arrangements basically delay egress through a subject opening for a pre-determined time. Most building codes require that delayed egress systems be connected to premises' fire alarm systems so that they unlock immediately if there is a fire alarm. Different building codes set forth additional details of how the delayed system should operate, and what accessories are mandated or permitted.
Delayed egress is very useful for a variety of purposes. The signage which is typically required to be installed on a delayed egress door is a powerful deterrent to shoplifters and would-be miscreants in loss prevention applications.
For schools and medical facilities, delayed egress systems give caregivers a head start if a disoriented patient wanders, or a child decides to explore the wild unknown.
For access control applications, which are functionally an essential element of security and life safety, delayed egress does all the above, as well as provides a viable arrangement for using card readers for both entry and egress. By being able to monitor entry as well as egress, building security personnel can know who and how many people are inside a building and their approximate locations within the site at any point in time.
This information is vital if in an emergency, a decision must be made whether to send emergency rescue into a burning structure or otherwise hostile environment. If it is established that there are people inside to save, the information provided by the system can help to determine where in the structure these individuals are most likely to be and where to deploy manpower first.
Delayed egress systems are available in several configurations to suit a wide variety of door types, occupancies, and applications.
Standalone delayed egress bars combine a positive locking latch with an electronically controlled delay. Some models use battery power, battery backup with external power supply, or external power supply only.
Besides providing the benefit of a physical lock, they are fail-secure, so loss of power to the building does not mean the door will unlock as is the case with a failsafe lock. Some of these devices do incorporate features whereby if the bar is pressed while the power is off, the device unlocks immediately.
Other delayed egress systems combine an exit device with an electromagnetic lock. The exit device provides positive locking, a switched output to the electromagnetic lock, and audible annunciation.
Another family of delayed egress devices features an electromagnetic lock with all the electronics and annunciation built-in. These devices typically are able to be used in conjunction with mechanical exit devices, REX type switch bars, or by themselves, all depending on the building code and the particular system application.
The operating sequence usually includes:
- Pressure on the door or exit device by the person attempting to egress long enough to verify that it is a legitimate attempt to use the door
- Initiation of the typical 15-second countdown to unlock accompanied by an audible alarm and possibly remote annunciation
- Unlocking the door or enabling of the exit bar so that the person can exit
- Resetting and relocking the device.
Along with the increase in the use of special locking arrangements, the number of building codes addressing these installations have also increased. As is often the case, different code writers specify different requirements. Therefore, the installer must determine the requirements the local authority having jurisdiction (LAHJ) will be enforcing, before selecting and installing delayed egress.
Nuisance Delay Requirements
Is a time period programmed into the initiating circuit that ignores short pressure on the exit bar (or door if the door is part of the initiating device)? Such events may be caused by accidentally bumping into the door, or gusts of wind, etc. The intent of a nuisance alarm is to minimize false alarms and maintain security on the door. If an exit is demanded, the individual will maintain pressure on the bar (or door), and after the nuisance time has expired, the IRREVOCABLE release countdown will initiate. At the end of the count, normally 15 seconds in total, the lock will release.
Security Door Controls, Model #1511S Exit Check Delayed Egress Emlock combines features of several different models and adds code compliance at a new lower price point.