Going Up (in Smoke)

Electrical professionals understand that the purpose of a smoke detection and alarm system is generally to provide life safety for building occupants. They also understand that the goal of the fire alarm system is to provide occupants with as much escape time as possible. The system design can affect the amount of escape time, and emergency controls for certain devices or equipment will add to the life safety protection.

Many of us know some of these control functions quite well, and we often use them in a building’s overall life safety design. Magnetic door hold-open devices, which prop open smoke and fire doors but will release them in an alarm condition, are most common. However, one of the newest changes relates to a new building code requirement for “Occupant Evacuation Elevators.”

This specific function will require contractors to work well with the elevator contractors to ensure the elevators function correctly in a life safety situation. First, the elevators must be specifically designated and marked for occupant use during fires. Additionally, the outputs from the fire alarm system to the elevator controllers must be provided to implement elevator occupant evacuation operation in accordance with Section 2.27 of ASME A17.1/CSA B44 (2013), Safety Code for Elevators and Escalators. There are differing requirements for elevator operation depending on whether the intent is for partial or total evacuation.

For partial evacuation, the code requires the output signals to be provided to initiate elevator occupant evacuation operation upon automatic or manual detection of a fire on a specific floor or floors as a result of activation of any automatic fire alarm initiating device in the building. The code excludes an initiating device used for elevator Phase I Emergency Recall Operation in accordance with the ASME A17.1/CSA B44 (2013), and it excludes activation of manual means at the fire command center by authorized or emergency personnel. Notice this does not mention manual fire alarm boxes located throughout the building. The reason for this omission is they are typically activated at locations remote from the fire and could lead to misinformation about the fire’s location.

The floor identification becomes very important for the elevators to operate properly. For example, the code requires the output signals from the fire alarm system to automatically identify each floor to be evacuated and the identified floors to be a contiguous block of floors. This contiguous block of floors includes the following:

• The floor with the first activated automatic initiating device

• Floors with any subsequently activated automatic initiating device(s)

• Floors identified by manual means from the fire command center

• Two floors above the highest floor identified by the above criteria

• Two floors below the lowest floor identified by the above criteria

As stated in Annex A of the code, “The established block of floors is updated to reflect changing conditions as indicated by the output signal(s). This information is sent to the elevator system and also used for occupant notification. The output signals from the fire alarm system can be in the form of contact closures or serial communications. Coordination needs to be provided between the fire alarm system installer and the elevator system installer.”

The identified floors must also be displayed on a standard emergency services interface along with the other elevator status information.

The messaging required by the in-building fire emergency voice/alarm communications system must also transmit coordinated messages throughout the building. First, automatic voice evacuation messages must be transmitted to the floors identified to indicate the need to evacuate and that elevator service is available. Second, automatic voice messages must be transmitted to the floors not being evacuated to inform occupants of evacuation status and must indicate that elevator service is not available. Third, automatic voice messages must be transmitted to the floors identified to indicate that elevator service is not available when all elevators have been recalled on Phase I Emergency Recall Operation. All of these messages must be coordinated with the text displays provided separately by the elevator management system.

Note that elevator controls are not as simple as they used to be. You will want to consult Chapter 21 of NFPA 72 2012 to determine the interconnection requirements for a number of emergency control functions. There are other changes you should be aware of in the emergency control area to avoid project delays and cost overruns, so it will behoove you to own and read a copy of the latest code.

About the Author

Wayne D. Moore

Fire/Life Safety Columnist

Wayne D. Moore, a licensed fire protection engineer, frequent speaker, writer and expert in the life safety field, has been a principal member and chair of NFPA 72, Chapter 24, as well as a former principal member of NFPA 909 and NFPA 914. He is the...

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