The 2010 edition of the National Fire Alarm and Signaling Code has three new chapters, one of which, Chapter 21, is devoted to emergency control functions and interfaces. This new chapter finally brings all of the integrated safety systems that are monitored or controlled by the fire alarm system (FAS) into one location to make it easier for you to find and understand the installation requirements for the following interfaces: elevator recall for firefighters’ service; elevator shutdown; first responders use of elevators; elevators for occupant-controlled evacuation; heating, ventilating and air conditioning (HVAC) systems; door-release service; electrically locked doors; and exit marking audible notification systems.
The code allows each of these interfaces to be performed automatically, but they shall not interfere with power for lighting, other operations of the FAS or operating elevators. One of the issues that seems to crop up on many installations is the question of acceptable methods of interconnection of the control relay that is interconnected to the fire alarm control unit (FACU). The code requires that a listed relay or other listed appliance connected to the FAS used to initiate control of protected premises emergency-control functions be located within 3 feet of the controlled circuit or appliance. This means the wiring from the FACU to the relay must be a circuit that is monitored for integrity and meets the requirements of the National Electrical Code (NEC) Article 760. The wiring from the relay to the controlled circuit or appliance is limited to a maximum of 3 feet because it is not monitored for integrity and must meet the requirements of the NEC’s Article 725. The other option when wiring an interfaced system is to use what is now labeled in NFPA 72-2010 as a Class D circuit. A Class D circuit operates in a fail-safe manner, where no fault is annunciated, but the intended operation is performed in the event of a circuit or pathway failure.
Typically, most contractors, when installing FAS, are familiar with the interfaces they encounter most often, such as elevator recall for firefighters’ service, elevator shutdown, door release service and HVAC control. For example, most contractors know that, unless otherwise required by the authority having jurisdiction, only the elevator lobby, elevator hoistway, and elevator machine room smoke detectors and initiating devices used for initiating shutdown of elevator power can be used to recall elevators for firefighters’ service. And smoke detectors must not be installed in elevator hoistways that don’t have sprinklers, unless they are installed to activate the elevator hoistway smoke-relief equipment.
Smoke detectors mounted in the air ducts of HVAC systems are allowed to initiate either an alarm signal at the protected premises or a supervisory signal at a constantly attended location or supervising station.
Two interfaces that may not be as familiar to contractors are new to the code: first responders’ use of elevators and elevators for occupant-controlled evacuation. Both of these interfaces were added to the code to accommodate their requirement by the latest edition of the building codes and Life Safety Code.
NFPA 72-2010 states that where one or more elevators are specifically designated and marked for use by first responders during fires, the conditions for the elevators, associated lobbies and machine rooms shall be continuously monitored during any such use and their status displayed on a standard emergency services interface complying with the code. The conditions monitored and displayed include, but are not limited to, the following:
1. Availability of main and emergency power to operate the elevator(s), elevator controller(s), and machine room (if provided) ventilation
2. Status of the elevator(s), including location within the hoistway, direction of travel, position of landing doors and whether they are occupied
3. Temperature and presence of smoke in associated lobbies and machine room (if provided)
Where one or more elevators are specifically designated and marked for use by occupants for evacuation during fires, they must also comply with all of the conditions outlined above.
In addition, the lobbies of elevators used by occupants for evacuation in fires must be provided with a status indicator complying with the code’s Chapter 18, and the required status indicator must display an illuminated green light and the message, “Elevators available for occupant evacuation,” while the elevators are operating under normal service and the fire alarm system is in an alarm condition, but before Phase I Emergency Recall Operation in accordance with ANSI/ASME A.17.1a/CSA B44a, Safety Code for Elevators and Escalators, has been initiated. The required status indicator must display an illuminated red light and the message, “Elevators out of service, use exit stairs,” once the elevators are under Phase I or Phase II operation in accordance with the Safety Code For Elevators and Escalators.
These new interfaces will take some time to both understand and find their way into new buildings, but the professional contractor should be aware of their existence and how the installation must be accomplished. The new chapter in the NFPA 72-2010 will go a long way in helping that awareness.
MOORE, a licensed fire protection engineer, frequent speaker and an expert in the life safety field, is a co-editor of the current National Fire Alarm Code Handbook. Moore is a principal with Hughes Associates Inc. at the Warwick, R.I., office.