In a fire emergency situation, cooler heads prevail. And in fully-sprinklered, non-combustible construction, commercial high-rise buildings with two-stage fire alarms and emergency voice paging systems, it is extremely important not to let the building time into a general alarm.
A full-building evacuation should only be initiated at the insistence of the fire department after their assessment indicates it is necessary. If there are staff members in the building, one of the first priorities upon alarm activation – aside from calling 911 – should be to press the acknowledge switch to keep the fire alarm from timing into general alarm and forcing a full evacuation of the building. If a fire is confirmed, then it is only necessary that the three floors in alarm evacuate down to the nearest cross-over floor and await further instructions from fire authorities. Exterior evacuation should only be initiated if the fire/alarm is on the bottom four floors.
In a fully-sprinklered building, it is unlikely that a fire will spread beyond the room it starts in. The arguments against a full-building evacuation, either automatically by the fire alarm (second stage time-in) or upon the initial discovery of a fire, are as follows:
- Stairwells are not designed to handle the volume of a full-building evacuation. Back-up to the roof was observed in all cases during large numbers of full-building evacuation drills conducted by WPS following 9/11.
- All stairwell doors open at once during full evacuation. This compromises stair pressurization, both natural (stack action) and mechanical. As well, building code pressurization design specifications assume no more than two doors into the stairwells will be open at the same time.
- Stairwells will become impassable once the fire department accesses the fire floor via the stairwells and keeps the stairwell door propped open on the fire floor so their fire hoses can get from the standpipes located in the stairwells to the fire. There will not be enough time to evacuate all of the occupants of a high-rise building before stairwells are compromised by the fire department. There is ample time to clear only three floors.
- Evacuating the entire building simultaneously means that the occupants on lower floors below the fire floor, who are in no danger from smoke and toxic gases, are clogging the stairwells for those on and above the fire floor, who are in greater danger from toxic gases migrating up and into the stairwells.
- Evacuating all building occupants may hamper the fire department’s response, both inside the exit stairwells and outside of the building.
- Evacuating all building occupants simultaneously puts all evacuees into potential debris field outside the building, especially if the fire is up against window glass.
- Full evacuation exposes all evacuees to the elements in adverse weather. For example, hypothermia can be an issue in less than 20 minutes in colder months with sub-zero temperatures.
- Occupants are resistant to going down 20 to 30 flights of stairs unless they are in imminent danger. Most can handle going down two to six flights (six flights would be the maximum that they would go down to reach a cross-over floor not in alarm if the acknowledge switch is activated).
- Fire drills will be less disruptive and have less impact upon commerce as occupants going down a couple of floors to a cross-over floor and then back up to their original work location take far less time than evacuating down 30 flights of stairs, proceeding at least a block away to the assembly area, being accounted for, walking at least a block back to the building, and then waiting in line for the elevators. Right now, less than 20 per cent of building occupants, on average, participate in fire drills. That number will increase dramatically if there are less demands on the occupants during the fire drill process.
Case study: Cook Country high-rise building
In 2003, a fire in a Cook County high-rise office tower killed six people when an untrained, or improperly trained, security supervisor strayed away from Chicago policy and used the fire alarm/emergency voice paging system to evacuate the entire building into the stairwells where the victims succumbed to smoke inhalation while within the stairwells. The Chicago Fire Dept. policy was to relocate the occupants on the affected floors down to unaffected floors where they would then determine if further evacuation was necessary.
The property management company paid an out-of- court settlement to the victims’ families of $24 million, while the building owner paid $9 million in damages. The city of Chicago had to pay $50 million in damages to the victims’ families. Those deaths would not have occurred had the building not been put into full evacuation mode during this fire emergency.
Terry Bruns is CEO at WPS Disaster Management Solutions.