BY HOSSAM SHALABI
Human behavior in fire situations is a function of physiology and psychology. When fires occur, to ensure the evacuee’s safety, the required safe egress time (RSET) should be less than the available safe egress time (ASET). The start time of evacuation (TS) is a significant part of RSET. During fires, many factors affect TS, so its numerical value is uncertain.
Many factors affect evacuation time, such as heat, smoke and toxic gases, noise, and the characteristics of the building. These factors will also stimulate and irritate human physiology and psychology. In a fire, impaired people need more time to react and evacuate than those who are not. The impairment may be attributed to disability, disease, sleep deprivation, alcohol, or drugs.
Evacuation behavior is generally divided into preevacuation and evacuation. Preevacuation concerns behaviors prior to evacuating; evacuation covers those behaviors during the physical evacuation.
Preevacuation activities include behavior in which a person begins to vacate the floor he is on (the starting floor) before entering the staircase; he returns to his office to collect his belongings. Likewise, such behavior includes an occupant who moves to a different room to seek shelter.1
During a fire, people’s psychic stress levels may already be high because their information processing capacity has been exceeded2 or because they are confronted with an unfamiliar situation.3 The additional stress of finding the exit must be avoided; too much psychic stress can impair cognitive processes and the person’s response to fire. (2) Fire response performance is the human ability to perceive and interpret danger signals and make and carry out decisions aimed at surviving a fire situation.4
John Leach’s Dynamic Disaster Model
Evacuation models include input variables, a simulation model, and output variables. John Leach’s Survival Psychology5 offers the best theory in disaster psychology. The human behavior is specific for each phase.
Before the disaster’s impact, people are aware of the coming impact but ignore or deny the facts, ignore uneasy feelings of danger, and are apathetic with respect to the real danger.
During the impact, people’s information processing is hampered and confused, emotional systems are upset and out of control, and behavior is reflexive and mechanical.
After the impact, people are aware of the damage of the impact but try to suppress realities; express strong, irrational emotions; and develop emotional disorders. (5)
Statistically, Leach found that in the impact phase, 15 percent of the population exhibited overactive (aggressive), noneffective behavior and were out of emotional control. Another 75 percent were apathetic, were nervous, and showed a lack of initiative. However, 10 percent remained calm, considered the overall picture, acted vigorously, and demonstrated potential leadership. (5)
Extreme Behavior
Based on the published survivor accounts and an analysis of human behavior during the World Trade Center (WTC) attacks of September 11, 2001, extreme behavior (including the classic panic actions or people behaving irrationally) was only noted in 1/124 (0.8 percent) cases. (1)6 The assumption that occupants will panic during a fire should be reconsidered. Social scientists have considered the possibility of panic behavior in a fire a myth since the 1970s.7-9
Fire Characteristics
The human senses present many cues that fire is present. Visual cues include flames; smoke color and thickness; and the deflection of a wall, a ceiling, or a floor. Olfactory cues include the acrid smell of something burning, and audible cues include the sounds of fire crackling, glass breaking, and objects falling.
The evacuation start time TS depends on what people are doing in the fire building-i.e., working, sleeping, eating, shopping, or watching a show. The occupants’ response times depend on their knowledge and experience, their familiarity with the building, their past fire experience, and their fire safety and other emergency training.
The impact of the building’s architecture on the evacuation depends on the number and size of floors, the exit and stairwell locations, the space’s complexity and obstacles to way finding, the building’s shape, and visual access.
The effect of the occupancy type depends on whether it is residential (low-, mid-, or high-rise), an office, a factory, a hospital, a hotel, a cinema, a college, or a shopping center.
The fire safety features are among the most important factors: the fire alarm signal’s type, audibility, its location, and the frequency of nuisance alarms; the voice communication system; the fire safety plan; the trained staff; and the refuge area.
Each occupant’s gender, age, ability, and health condition (e.g., whether under the influence of drugs, alcohol, or medication) also affect the evacuation. Also, consider the occupant’s personality type and whether the occupant is a visitor, an employee, or an owner.
The fire’s characteristics also affect the occupant response. During a fire, people perceive different cues from the fire; and their interpretation of the situation will change rapidly, influencing their behavior.
Preevacuation Behaviors
An investigation of 68 survivors of a high-rise building fire revealed that 10 percent evacuated because there was smoke in the room, one percent because of smoke on the veranda, 34 percent because they were pushed by others (panic), nine percent gave no answer, and 46 percent cited other reasons.10
A study of two 1997 fires in two Hong Kong high-rise residential buildings, the Carado Garden in Shatin (S) and Tai Po Centre in Tai Po (T) looked into occupant behaviors (Table 1).11
Table 1 illustrates the relationship between occupant investigation and first actions of humans in the event of a fire. Twenty-three people (T1) had carried out an investigation; 22 (T2) did not. In the T1 group, five people (21.7 percent) evacuated compared to 16 (72.7 percent) in T2. In T1, 52.2 percent informed others, whereas only 9.1 percent in T2 did. Of the 21.7 percent in T1 who did not evacuate the building, 8.7 percent ignored the fire, another 8.7 percent got wet towels, and 4.3 percent went to get their personal identification. The T2 group did well compared with the T1 group in the evacuation rate and the closing of windows and doors.
Other Case Studies
On the whole, in a study of the WTC attacks of 9/11, it was noted that occupants in WTC2 had shorter response times than those in WTC1. Data analysis suggests that this may have been because WTC2 occupants had better knowledge of the event than those in WTC1. (6)
According to the survivors, the major purpose for making the phone calls was to give information to family members (9/24, or 38 percent of calls). Calling simply to give emotional support, to get more information, or to warn other people of danger was infrequent (Table 2).
Annual evacuation drills were also studied in three Canadian government office buildings.12 The occupants were not warned of these exercises. Video cameras recorded the individual time-to-start of more than 1,000 occupants. The mean TS for the three buildings was 50 seconds. Although all of these workers were trained in and fully aware of the evacuation procedure, they still spent time finishing phone calls, saving data on their computers, securing files, and getting belongings before leaving their desks. Many had to be encouraged to move by their local fire wardens.
This is a typical case of occupants ignoring the event or delaying the TS. All of the occupants have been trained and do fire drills annually, and the buildings have emergency procedures and a fire warden, but occupants still do not take the event seriously. The fire wardens were the main catalysts to get the occupants moving.
A study of TS in an underground transport system13 showed the impact of cue received in speeding up the occupants’ evacuation. In the station underground levels, the passengers didn’t start to evacuate when the fire alarm activated. They kept waiting for their trains, reading, and standing but did not move to evacuate. Only when staff showed up to expedite the movement did passengers comply immediately. Using the voice communication system received the same positive response. The messages informed the passengers of the type of incident and its location and told them what to do. Only 15 seconds after the voice communication message, passengers started to move.
It’s apparent that when occupants get the confirmation that the event is a real fire and not a drill, they tend to comply immediately. Using voice communications and fire wardens are very efficient methods to confirm such an emergency to occupants.
It is essential to reduce the time delay of occupants starting to evacuate in fires. The key strategy to achieve this is providing information to the occupants as early as possible. The first step should be installing a voice communication and a fire alarm signal that emits a Temporal-Three evacuation signal, as described in International Organization for Standardization’s (ISO’s) audible evacuation signal standard, ISO 8201.14
References
1. Galea ER, Blake SJ, Westeng H, and Dixon AJP. (September 2004) “An Analysis of Human Behaviour During the WTC Disaster of 11 September 2001 Based On Published Survivor Accounts.” University of Greenwich, United Kingdom. http://bit.ly/2f8bws6.
2. Proulx G. (June 1993) “A stress model for people facing a fire.” Journal of Environmental Psychology (13) 2, 137-147.
3. Verwey, WB. (2004) “Psychologische Functieleer en Cognitieve Ergonomie: een Siamese tweeling?” [“Experimental psychology and cognitive ergonomics: a Siamese twin?”]. Tijdschrift voor Ergonomie (29) 2, 4-9.
4. Kobes, M. (2008) “Zelfredzaamheid bij brand. Kritische factoren voor het veilig vluchten uit gebouwen.” [“Fire response performance. The critical factors for a safe escape out of buildings.”] Boom Juridische uitgevers, Den Haag, The Netherlands.
5. Leach, J. (1994) Survival Psychology. Palgrave.
6. Galea ER, and Blake SJ. (2004) “Collection and Analysis of Data Appearing in the Mass Media Relating to the Evacuation of the World Trade Centre Buildings on 11 September 2001.” Building Disaster Assessment Group (BDAG), Office of the Deputy Prime Minister. London, United Kingdom. http://bit.ly/2gznVqc.
7. Sime, J. (1980) “The concept of panic” in D. Canter (Ed.), Fires and Human Behaviour, John Wiley & Sons, Chichester, UK, 63-81.
8. Keating, JP. (May 1982) “The myth of panic,” Fire Journal, pp. 57-61.
9. Quarantelli, EL. (1977) “Panic behavior: some empirical observations,” in D.J. Conway (Ed.), Human Response to Tall Buildings, Stroudsburg, Pa., Dowden Hutchinson & Ross, 336-350.
10. Sekizawa, A, Ebihara M, Notake, H. (1999) “Occupants’ Behaviour in Response to the High-Rise Apartments Fire in Hiroshima City.” Fire and Materials, 23, 297.
11. Lo, SM, Lam, KC, Yuen, KK, Fang, Z. (2001).” A Pre-evacuation Behavioural Study for the People in a High-Rise Residential Building under Fire Situations.” International Journal on Engineering Performance-Based Fire Codes, 2, 143.
12. Proulx, G, Pineau, J. (1996) “Differences in the Evacuation Behaviour of Office and Apartment Building Occupants.” Proceedings of the Human Factors and Ergonomics Society 40th Annual Meeting, Philadelphia, USA.
13. Proulx, G, Sime, JD. (1991) “To prevent panic in an underground emergency, why not tell people the truth?” Proceedings of the Third International Symposium on Fire Safety Science, Elsevier, London, UK.
14. International Organization for Standardization. (1987) “ISO 8201:1987 Acoustics-Audible emergency evacuation signal.” Switzerland.
HOSSAM (SAM) SHALABI has more than 10 years of experience in applying fire safety engineering principles and techniques in the nuclear, oil and gas, and manufacturing industries, including experimental and field work, teaching, data analysis, computer simulation/modeling, and risk assessment. He is the subject matter expert at Canadian Nuclear Laboratories (CNL) for fire PRA & fire modeling. He has a bachelor’s degree in applied science (chemical engineering) from the University of Ottawa, a master’s degree in fire safety engineering (Carleton University), and a master’s degree in engineering management (University of Ottawa) and is a Ph.D. candidate for fire safety engineering (Carleton University).
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