Building Occupants - Should they stay, or should they go?
At the first indication there may be an emergency, many argue the best course of action is to evacuate all the occupants immediately, however, as buildings increase in size and complexity this question, like emergencies themselves, is challenging, and the best course of action is not straight forward. Thus, it is important to pre-plan an evacuation strategy prior to an emergency occurring.
For buildings required to have an emergency action plan, an evacuation procedure is required along with drills to ensure occupants (employees and guests) are aware of the approved strategy (NFPA 1 – Fire Code [1:10.8.2.1]). The development of an emergency action plan is the responsibility of the building owner; however, it must be approved by the AHJ (for more information about Emergency Action Plans check out this blog).
When a building is not required to have an emergency action plan, it is still important to pre-plan the evacuation procedure. There are four main strategies when it comes to occupant safety, each named for their intent:
- Total evacuation.
- Phased Evacuation.
- Occupant Relocation.
One of, if not the most common strategy is total evacuation where all the occupants are directed to immediately exit. Its most effective in less complex buildings, where evacuation occurs as emergency responders are in route. Since buildings are smaller and less complex, any potential conflicts with occupants exiting and access for responders are minimal. As building size and complexity increase, the number of occupants and time to total evacuation increases, making the total evacuation strategy less applicable.
An alternate to total evacuation is the phased evacuation where occupants are directed to exit in groups, typically starting with those closest to the emergency and working away. More often used in larger buildings such as high-rises, this strategy accounts for the increased time required to evacuate. Occupants closest to the emergency are given priority use of the exits, followed by those in less danger. Typically, the fire floor and one or two floors above and below are evacuated first. Additional floors are then evacuated as necessary, usually by doing one additional floor above and below at a time. Evacuation is often conducted over a longer period, requiring active management so that emergency responders are not competing for access while occupants exiting.
When occupants are incapable of evacuation possibly due to a medical conditions or physical restraint the occupant relocation strategy can be utilized. It is typically employed in buildings with both active (fire sprinkler) and passive (smoke/fire barriers) protection providing safe locations for occupants within the building during an emergency. This includes the use of areas of refuge as discussed in NFPA 101 Life Safety Code.
Like occupant relocation and phased evacuation, the shelter-in-place strategy involves utilizing the protection provided by the building, both passive and active, as well as the distance from the emergency to protect occupants in place. The difference being occupants are remaining in place, until the emergency is mitigated. Depending on the size of the building and type of emergency, evacuation may never be required. An example of this could be a residential high-rise where occupants several floors removed from the fire remain in their apartment until the fire is controlled.
The occupants away from the emergency. When a shelter-in-place strategy is employed emergency responders, in conjunction with facility personnel (if applicable) should continue to re-evaluate the situation and decision to employ said strategy. If the smoke/fire are spreading into occupied areas rescue from the fire department or total evacuation may be necessary. When occupants are directed to shelter in place it is important to communicate to the need to be patient as controlling the fire and removing the smoke can take an hour or longer.
In a fire or other emergency event, if occupants are located near the fire or emergency, they should be directed to take every action possible to remove themselves from that area. If safe exits are not available and the building can provide some protection facility personnel and emergency responders may choose to utilize another evacuation strategy. Communicating the strategy and practicing via drills ensures that everyone is familiar with increasing occupant safety in an emergency.
Every situation is slightly different making evacuation a complex decision. For more information on building evacuation check out these NFPA resources: