What Defines a FA Selective-Evacuation Zone?

4/9/2024

Sometimes we would not want to evacuate entire buildings in a fire alarm condition, even outside of healthcare facilities.

If a fire alarm is programmed to evacuate only "affected" areas, what defines the boundaries of the affected area?

What building features are required to implement a defend-in-place strategy, in a large Industrial Facility F-1?

Where can I find the specific rating requirements for the fire and smoke barriers separating "affected areas"/zones?

Looking to understand this concept and the requirements around it better; thanks in advance.

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6 Comments

Pete H

4/9/2024 02:02:36 pm

Not my field so I doubt I'll be of much help, but here's what I got:

From NFPA 101 (2018 Edition)
9.6.3.6.2 Where total evacuation of occupants is impractical due to building configuration, only the occupants in the affected zones shall be initially notified, and provisions shall be made to selectively notify occupants in other zones to afford orderly evacuation of the entire building, provided that such arrangement is approved by the authority having jurisdiction

A.9.6.3.6.2 To approve an evacuation plan to selectively notify building occupants, the authority having jurisdiction should consider several building parameters, including building compartmentation, detection, and suppression system zones, occupant loads, and the number and arrangement of the means of egress.

In high-rise buildings, it is typical to evacuate the fire floor, the floor(s) above, and the floor immediately below. Other areas are then evacuated as the fire develops.

--

Okay, let's dig into that annex. Compartmentation seems obvious as a method to identify separate zones, as do separate floors.

Detection and suppression zones work for our field. Suppression zones sound like individual sprinkler systems. So area under the control of the same sprinkler riser and/or control valve assembly sound like they would be one zone.

Same for areas controlled by the same fire alarm detection/notification assemblies. But as stated, that is not my field so I'm not sure how to break that up and the few class notes I've kept of the basics aren't pointing me in an obvious direction.

Brett

4/10/2024 10:27:32 am

Thanks for that. I've been finding a lot of the same. Nothing specific, i.e. specific requirements to define a zone.

The intention would be to continue operations in all "unaffected areas," rather than shutting all operations down. Especially if it's not a critical threat to the entire building or false alarm.

Unless it's just up to the AHJ, I'm assuming there's likely a definition for what the barrier must be, to consider an area "separate" from the affected area, and protected well enough to continue operations.

Glenn Berger

4/10/2024 06:34:43 pm

IMO, would require horizontal fire barriers at a minimum. Look at design criteria / solutions used at hospitals (specifically patient rooms, where there is insufficient staff to evacuate everybody).

Todd E Wyatt

4/12/2024 02:21:52 pm

SUMMARY
Fire Alarm (FA) “zones” are typically separated by 1-Hour Smoke Barriers (1SB) in Group I Institutional Occupancy Classifications (OC).
Recommend discussing this “defend-in-place” scenario with the AHJ (e.g. Fire Marshal) as it is not specifically prescribed by the scoping Code (e.g. IBC-2021).

EXPLANATION
The “defend-in-place” scenario for a Group F-1 Moderate-hazard Factory Industrial OC may require AHJ approval even if a Fire Alarm & Detection System is not required per IBC-2021 907.2.4 Group F (see REFERENCES below).

This modified “occupant notification” for a Group F-1 is based on ones for Group I OCs (e.g. Hospitals, Nursing Homes, Correctional Facilities) which is based on trained personnel assisting occupants to a safe, adjacent Smoke Compartment (SC) that is protected by 1SB. SCs have additional egress requirements so that occupants that are (temporarily) evacuated horizontally to a SC have a Means of Egress to an Exit without egressing through the SC that has the fire emergency. Since this Group F-1 building may not have “trained personnel assisting occupants to a safe, adjacent SC”, you may get push back from the AHJ.

Q1 : What defines the boundaries of the affected area?
A1 : The scoping Code (e.g. IBC-2021) references “notification zones” (An area within a building or facility covered by notification appliances which are activated simultaneously.) but does not prescribe how these NZs are to be separated from one another.

The FA could annunciate per (1) of (4) initiating devices (Manual fire alarm boxes, Automatic fire detectors, Automatic sprinkler system waterflow devices, and/or Automatic fire-extinguishing systems). Because some of these could be observed by the occupants (e.g. manual fire alarm box), occupants would have an “expectation” of their function and of the FA. For instance, even if a building is not required to be protected by an automatic sprinkler system (ASPS), the installation of visible ASPS heads that are not functional is not permitted since the occupants have an “expectation” that the building is protected by an ASPS.

Todd E Wyatt

4/12/2024 02:22:19 pm

REFERENCES
IBC-2021
Chapter 9 Fire Protection and Life Safety Systems
Section 907 Fire Alarm and Detection Systems
907.2 Where Required—New Buildings and Structures
907.2.4 Group F
A manual fire alarm system that activates the occupant notification system in accordance with Section 907.5 shall be installed in Group F occupancies where both of the following conditions exist:
1. The Group F occupancy is two or more stories in height.
2. The Group F occupancy has a combined occupant load of 500 or more above or below the lowest level of exit discharge.
Exception: Manual fire alarm boxes are not required where the building is equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1 and the occupant notification appliances will activate throughout the notification zones upon sprinkler water flow.
907.4 Initiating Devices
Where a fire alarm system is required by another section of this code, occupant notification in accordance with Section 907.5 shall be initiated by one or more of the following. Initiating devices shall be installed in accordance with Sections 907.4.1 through 907.4.3.1.
1. Manual fire alarm boxes.
2. Automatic fire detectors.
3. Automatic sprinkler system waterflow devices.
4. Automatic fire-extinguishing systems.

Author

4/12/2024 04:05:56 pm

Thank you for all of that information. It is helpful.

More additional context may be helpful for further discussion...

This occupancy is F-1.
Fire suppression and fire alarm are in the design.
Voice evac system is included.
Areas do included rated barriers and horizontal exits.
There will be trained staff on site 24/7 to assist with evacuation procedures.
The FD is nearby.

This inquiry is mainly to define what is an adequate barrier for a "separate compartments" that allows for partial evacuation (1hr, 2hr 3hr). The fire alarm is capable of providing different messaging instructions for occupant actions.

What Defines a FA Selective-Evacuation Zone?

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