Delayed egress systems are door locking systems which prevent a door from opening immediately when egress is attempted in a non-emergency situation.
One of the golden rules is of course that a lock is never supposed to impede egress, but there are specific situations where it is allowed with special approval from the Local Authority Having Jurisdiction (LAHJ), as long as the application is in accordance with the relevant building code.
Delayed egress has many important uses. For healthcare facilities, it can alert staff to a patient attempting to leave the premises or someone attempting to steal drugs.
In commercial applications, doors may be equipped with delayed egress to discourage shoplifting. At airports, doors leading to hazardous and flight line areas will be equipped with delayed egress.
In schools and childcare, delayed egress systems will deter abductions and delinquency.
In security environments where it is desired that a credential be used for passage in both directions, a delayed egress lock will allow locking of the door, encouraging the use of a credential, without potentially trapping individuals if there is a legitimate reason for them to exit.
It is imperative that the installer confirm the acceptability of a delayed egress system with the LAHJ prior to installation. In some geographical locations, and in some types of occupancies, more than one authority may have jurisdiction, for example a Fire Marshal as well as a Building Inspector. It is the responsibility of the installer to determine the hierarchy of LAHJs for a particular situation, and to take the necessary steps to assure compliance.
Delayed Egress systems are typically configured as:
An integrated Delayed Egress electromagnetic lock in which all logic and locking components are built into a single device
A Component System where locking, logic, annunciation and control devices are separate
A Delayed Egress Exit Device
Depending on the design, the delayed egress may be triggered by door movement or an external triggering device.
Building Codes vary with respect to requirements for Delayed Egress locking arrangements. However they all have a similar set of core safety requirements:
1. The delayed egress lock must be approved or listed and shall be permitted for installation on doors serving occupancy levels as specified per prevailing code (refer to your prevailing code and consult your LAHJ for complete details).
2. The doors must unlock upon activation of an automatic sprinkler system or automatic fire detection system.
3. The door(s) must unlock upon loss of power controlling the delayed egress locking device.
4. The delayed egress locks shall be unlocked by a signal from the fire command center.
Important Note: Some cities may also require a remotely located manual reset station attended at all times by trained personnel. 5. Applying no more than 15 lbs of pressure for a maximum of 1 second (1 second nuisance delay) will start an irreversible process to unlock the door in 15 seconds. The LAHJ may permit up to 30 seconds.
6. An alarm must sound at the opening upon initiation of the release process.
7. A sign must be applied to the door stating, “PUSH UNTIL ALARM SOUNDS. DOOR CAN BE OPENED IN 15 SECONDS.”. Letters must be one inch high x 1/8” stroke. The sign shall indicate 30 seconds where applicable.
8. Emergency lighting is required as prescribed per code.
9. The lock must be manually reset at the door.
10. A building occupant may not be required to pass through more than one delayed egress equipped door.
There are differences in the Building Codes as to what types of occupancy a delayed egress system may be installed.
The United State Fire Administration advises: The International Building Code® prohibits delayed egress locks in Group A, E, and H occupancies, while NFPA® 5000, Building Construction and Safety Code allows them in all occupancies except detention and correctional facilities.