Code Requirements Affecting Access Control Interface
The security system designer needs to consider the interface between the fire alarm system and the access control system as well as code requirements. The 2013 edition of NFPA 72 (National Fire Alarm and Signaling Code, Chapter 2, Emergency Control Functions) outlines specific requirements that will affect the security system design and installation. These include:
- Elevators for occupant controlled evacuation
- Elevator recall for Firefighters’ Service
- Door release service
- Electrically locked doors
In NFPA 72, 2002 and 2007 editions, the chapter is called “Protected Premises Fire Safety Functions.” Additional information for the design requirements for egress, doors and stairwells can be found in NFPA 101, 2012 edition, Life Safety Code, Chapter 7, Means of Egress. Chapter 21 of NFPA 72 covers emergency control function interfaces and the interconnection of nonfire alarm systems with fire alarm systems. As specified in NFPA 72, the fire alarm control panel must either monitor or control these nonfire systems, and relays must be located within three feet of the device being controlled.
When fail-safe locks are specified by the architect or owner, a dry relay contact from the fire alarm system can be used to release lock power, leaving certain doors unlocked but usually latched.
Many egress doors have push-to-exit “crash bars” that do not require an access card or release of an electric or magnetic lock to open. When fail-safe locks are specified by the architect or owner, a dry relay contact from the fire alarm system can be used to release lock power, leaving certain doors unlocked but usually latched. It is important for the security system designer to understand which doors are fail-safe or fail-secure. The terms “fail-safe” and “fail-secure” refer to the status of the secure side of the door. Fail-secure products are locked when power is removed while fail-safe products unlock when power is removed.
Stairway doors require additional consideration. For instance, magnetic locks are almost never used by themselves with stairway doors in buildings that are more than four stories high and required to stay latched while unlocked. Security systems should be designed to limit access in facilities such as hospitals or in mixed tenant high-rise facilities. When a fire alarm is initiated, bidirectional access — and not just egress access — is required to stairways. If only egress access is provided on every floor and the ground level floor egress is blocked, people will be trapped in the stairwells. This, of course, is unacceptable and not compliant with code.
Keeping Abreast of Code Requirements for Elevators
Many access control systems also enable elevator control. In buildings with elevators, proximity cards and readers are used to restrict people’s access to the floors needed for them to do their job. To limit tailgating, many high-rise buildings also require authorized and credentialed users to switch elevators to access sensitive floors such as data centers, storage areas for valuables or the executive suite. If the floor layout allows for it, doors into the sensitive spaces from the hallway with an access-controlled elevator should also require a credential for access.
When a fire alarm is initiated, the fire alarm system must override and take priority over any access control arrangement used for the elevator. The American National Standards Institute (ANSI A17.1) is the source for the safety code for elevators and escalators. It specifies that recall is required for elevators serving two or more floors. Some jurisdictions require elevators to be upgraded with recall features, whether or not a fire alarm system exists.
When designing the system to control elevator access, it is the security system designer’s responsibility to specify the interfaces and design the installation of the proximity card readers within the elevator cars. A terminal demarcation enclosure should be mounted within the elevator room with dry relay contacts provided outside the elevator machine room but within three feet as required by code. Th e access control system should be programmed to allow fl oor by fl oor access based on users’ credentials.
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