Abstract: The threat of fire or other emergencies in high-rise buildings pose deadly fire challenges to fire department. The large numbers of persons in commercial high rise buildings, the nature of the occupancy and typical building geometry that is considered by many fire professionals presents an unacceptable risk. In reality, the fire department does not have capabilities to do much of anything above the fire floors that is beyond the reach of their super aerial ladder fire trucks. So, if a fire breaks out in a building taller than that, the consequences depend entirely on the in-built safety mechanisms. One of the in-built safety mechanisms is developing an evacuation plan.
What Is A High Building?
Most Building Code defines high buildings as those buildings with building height that are beyond the reach of the local aerial ladder fire truck. Generally, buildings of seven storeys or more in building height are considered as high buildings.
While high rise buildings are designed to be fire safe and are protected by the passive and active fire protection system, yet, high rise fire-fighting generally require more complicated operational approaches than most structure fires. It's a manpower-intensive operation. Tasks that are normally considered routine for most fire departments, such as locating and attacking the fire, evacuating occupants, and performing ventilation can become very difficult in high rises. Operations are affected by several specific challenges:
Access to floor levels that are beyond the reach of aerial apparatus is
generally limited to the interior stairways. The use of lifts is usually restricted or prohibited because of safety concerns. If the lifts are out, that meant carrying gear up and down flights of stairs and walking into a cement-walled apartment that heated up like "a furnace", and firefighters literally have to carry people who can't walk down the stairways. Rooftop helicopter rescue is dangerous.
Hundreds or even thousands of occupants may be exposed to the products of combustion while they are evacuating or unable to descend past a fire on a lower floor. Their exits may be limited to two narrow stairways, which are also the only access for firefighters coming up to assist with evacuation and to fight the fire.
The ability to contain and control the fire is increasingly dependent on the construction of the building and the ability of sprinkler and/or standpipe systems to deliver water to the fire area.
Ventilation can be much more complicated and critical in high-rises than in other types of structures. Vertical ventilation is often limited to stairways or lifts shafts, both of which may also have to be used to evacuate occupants. Horizontal ventilation, by breaking out windows, presents the risk of falling glass to those outside the building. The stack effect causes smoke to rise rapidly through the vertical passages and accumulate on upper floors.
Realistically, the evacuation from high rise buildings in a major emergency can only be effectively executed if there is an evacuation plan approved by the fire department to evacuate as many people as possible, as quickly and safely as possible prior to the arrival of the firefighters. The lack of plans and procedures for evacuation can lead to confusion among the occupants in the event of a large-scale evacuation.
High Building Fire Safety Concerns
Fire remains a major cause of death, injury and property damage. The rise in the number of fire and non-fire related incidents such as the terrorist threats, major energy power blackout and earthquakes worldwide clearly illustrated the need for high-rise buildings to be proficient if a total and sudden building evacuation becomes necessary. But, full-scale evacuations of high rise buildings are rare until a 'real' crisis occurs, little is known about how readily and rapidly these buildings can be evacuated and what factors serve as facilitators or barriers to the process.
Safety for people who work in the commercial high rises is a key issue after the 1993 bombing and 2001 World Trade Cente attack which led Fire and Building Regulators to review existing building code laws. The evacuation experiences of the WTC provided valuable lessons for change and innovation for high-rise and multi-complex buildings to be better prepared for probability of large-scale evacuations. Even a well-maintained intelligent or smart building with proper fire protection, security and surveillance systems cannot prevent threat of fire or other emergencies from happening.
Preparedness in evacuation is not a luxury but risks reduction strategy in the post 9/11 world. Creating emergency plans and procedures response to fire and other threats are needed to make sure all losses will be minimal in the event of worst case scenarios. The purpose of this article hopes to provide ideas to increase preparedness in evacuation that can help best provide for the care of getting everyone out, as quickly and safely as possible in the case of a major evacuation.
The World Trade Centre (WTC) Evacuation Experiences
In 1993 the WTC suffered a terrorist attack that involved an explosion/fire in one of the towers that caused the failure of both the power and back-up power to the lighting and illuminated exit signs. Six people died and 1,042 were injured. Of those injured, 15 received traumatic injuries from the blast itself. Nearly 20 people complained of cardiac problems, and nearly 30 pregnant women were rescued. Eighty-eight firefighters (one requiring hospitalization), 35 police officers, and one EMS worker sustained injuries. It is estimated that approximately 50,000 people were evacuated in darkness from the WTC complex, including nearly 25,000 from each of the two towers. Fire alarm dispatchers received more than 1,000 phone calls, most reporting victims trapped on the upper floors of the towers. Search and evacuation of the towers finally were completed some 11 hours after the incident began.
Many lessons were learned by the FDNY, building management for the complex and the tenants of the WTC at this incident and formed the basis of revised procedures for high rise evacuations. After the 1993 bombing, the extensive fire safety improvements (e.g., improved signage and better lighting in stairwells) done at the two WTC towers were believed to have facilitated the 2001 evacuation process. The 1993 evacuation experiences led many tenants to enhance their own emergency plans, which might have helped evacuate their employees more rapidly in that tragic morning of 9/11.
In 2001 the WTC suffered another terrorist attack that involved two 747 -passenger jets crashed into the twin towers. The mass evacuations at WTC 2001 were unique - two towers, side by side, both with ten floors of fire and thousands of people trapped. According to reports, the September 11, 2001 attacks killed 2,749 people at the WTC. Out of that number, about 1,970 of the civilians who were trapped above the impact zones all died. The total number could have been as high as 14,000 had the buildings been full based on rough estimates using scientific models.
An estimated 13,000--15,000 persons successfully evacuated the two towers. Yet, the fatality figures were high. Even for people below the impact zones, going down was no piece of cake, with problems like evacuation initiation delay, evacuation interruption, and encountering obstacles in the evacuation path (environmental cues) such as smoke, water, or debris. In the North Tower, it said, the average survivor took longer to descend each floor than the slowest speed cited in fire-safety handbooks that engineer's use in designing buildings.
There were reports from those who successfully evacuated the towers who told of people using wheelchairs and walkers waiting at refuge areas to be rescued by the firefighters whom were coming up the stairs. They all perished as the building collapsed shortly after…. There were passing people who could not keep up (e.g., older people, people with respiratory conditions and limited endurance, and other people with no apparent disability) whose activity limitations prevented them from successfully evacuating.
Lessons Learned From The World Trade Centre (WTC) Evacuations
While one can hope that such acts of terrorism are rare and hope will never again, but the lessons learned from the WTC evacuations revealed so many shortcomings about the building egress systems (exit stairs and refuge areas) and raised so many questions.
Current building codes base the required number and location of exits on a ''phased'' evacuation strategy and do not assume that all occupants will leave at once. Such assumption could threaten lives. Current evacuation plan for people with disabilities was lethal to them: it consisted simply of requiring them to go to predetermined meeting sites within the building and wait for evacuation assistance (Center for Independence of the Disabled 2004). Such approach could threaten lives and had proven fatal to them in 9/11. Chances for people with disability of surviving could have significantly improved if evacuation plans had been in place that included them.
No building offers complete protection of its occupants from major
emergencies. Before 9/11, the traditional approach to the "Defend in Place" concept for high-rise emergencies would have work well in a "normal"
emergency. An important lesson building community learned after 9/11 was that this concept does not make sense when the building face with unusual events such as terrorist threats/attacks, bombs, unconventional fires, hazardous material releases, and aircraft crashes. Such unpredictable events underscore the need to look at the life safety issues of how to move all the building occupants out quickly in the event of the worst case high rise emergency scenarios.
How building management can best provide for the care of getting everyone out quick, including people whom may be trapped above a high-rise fire? In the aftermath of 9/11, building and fire authorities called for new research into how to construct buildings more safely and evacuate people more efficiently, including people with disabilities.
Engineers looked beyond the normal stairways, such as design route choices for vertical exit usability for all people, and alternative means of exit to the street to facilitate speedier evacuation in time of emergency. Experts elaborate on a series of new escape systems for high rise buildings under fire (or damaged by explosions) whose aim is to bypass impassable floors or blocked stairways. These would allow people trapped in higher elevations to escape safely to the street. They consider various types of devices, including those that can be deployed inside or on the exterior walls of the building.
Duty Of Care
Just as important as making buildings accessible to people with disabilities, building stakeholder has also a duty of care to provide adequate means of escape from a building for every people in the event of a fire. Super aerial ladders from the fire truck are not the sure way out of a burning high-rise because they have their limits. The safest way to get out from a blazing high-rise building is via stairway fire escapes and make way down.
But what constitutes adequate care if people have difficulty in identifying or getting to the escape routes in case of complete darkness due to failure of both the power and back-up power to the lighting and illuminated exit signs if the power system is damaged by fire/explosion. Further, it is estimated that about 20 percent of the building occupants living or working in high rise buildings would have difficulty in evacuating a building. Stairway evacuation is almost impossible – not just for people in wheelchairs, but also for people with walking difficulties, heart disease, epilepsy and so on.
Lifts are deemed to be unsafe for use in fire situation and should never be use for fire evacuation. Heat can activate lifts call buttons, sending the lifts to the fire floor, where dense smoke may interfere with the lift's light-sensitive eye and prevent the door from closing. Also, people may become trapped in the lifts if water from fire fighting operations create a power failure. In addition, firefighters require designated lifts to carry them and their equipment to the floor below the fire if the lift is still operational.
Successful evacuation is partly dependent on physical ability of individuals and other physical values, such as distance to travel, proportions of exits and density of smoke and partly on psychological values, such as communication processes, perception, conceptualization, understanding, evaluation and decision. Because of these factors, building managers have to do more to ensure safer and quicker escape of all occupants. But, what are the facilities needed for aiding building evacuation? What alternative means of escape are available to both the able bodied and to those with disabilities?
Facilities For Aiding Building Evacuation
Evacuation preparedness activities are needed when mitigation measures have not prevented disasters or cannot prevent them. The preparedness phase develops plans to save lives and minimize casualties. Preparedness measures also attempts to tackle the perceived difficulties and problems of building evacuation and to assess the need to provide adequate facilities to enhance evacuation response operation.
For example, a person who has to decide how to get out of a burning building is likely to be under significant psychological and even physical stress if he/she cannot locate the escape routes when power blackout. For an escape route to be effective and efficient, it is important that from anywhere in the building occupants have sight of a sign, or series of signs, which leads them to a place of safety even in complete darkness. Signs and stairways should be clearly identifiable and that each floor access is clearly numbered, and also indicating the nearest crossover floors, if certain floors are not accessible. The visibility of escape route signs will assist firefighters and other rescue teams to evacuate occupied areas during emergency situations.
Some of the facilities for aiding evacuation that are available in the market that the author has knowledge of when writing this article are:
An audible and visual fire alarm system is to warn people of an emergency and provide a general-purpose evacuation warning.
An adequate communication systems (e.g., public address system, inter-com system, and lifts telephone system) is to minimize heavy congestion on stairways by directing evacuees to move to a less congested staircase, and to quickly rescue those trapped inside the lifts.
Fire vents that open automatically in the event of a fire, maximize fire containment and life safety and minimize damage and material loss. The vents help to improve visibility inside the building to help occupants escape the fire and reduce the risk of smoke inhalation.
Creating better and safer protected stairwell design, such as: increasing number of exits, the width of doors, width of stairs, add on anti-slip nosing on steps of stairs, improved emergency lighting and signs, and smoke control in stairways.
The exterior fire escape stairs provide alternative egress for occupants and can also provide firefighters with access to, and escape routes from, upper floor of the fire building, when interior stairs are sometimes untenable or inadequate.
Emergency escape lighting, signage and safety way-guidance system, all electrically powered components with back-up power capable of being activated as directional information in the event of a power outage.
The use of photoluminescence emergency signage and way-finding systems intended to aid in evacuation from buildings in all risk situations where smoke is present and in the event of failure of both the power and back-up power to the lighting and illuminated exit signs. The photoluminescence egress system recommends these markings to be included throughout every stairwell, including around all landing perimeters, along the full length of every handrail, on each step, and around all obstacles to egress.
Personal ‘escape smoke hood’ can protect user for safe escape from smoke and fume during fire evacuation.
Portable and lightweight evacuating chairs enable trained helpers to move people with physical handicaps down a flight of stairs much easily that might not otherwise be possible.
Ramps can be helpful for wheelchair users in negotiating one or two steps.
Only use the special designed 'evacuation-lift' that is approved for use in fire evacuation by the fire department.
Only use escape chute that is accessible and usable by the greatest number of people, regardless of their capabilities, and is approved for permit safe evacuation in fire situations by fire research-testing institute. If deployed strategically inside or on the exterior walls of high building, allow people trapped in higher elevations to bypass impassable floors or blocked stairways to escape safely to the street, when building under fire (or damaged by explosions). This will give every person the ability of self-reliant escape.
The provision of appropriate facilities for aiding evacuation provides better opportunity for a safer, quicker and orderly evacuation. More importantly, reduce evacuation hazards and maximize the escape potential of people with disabilities of getting out alive.
Developing Evacuation Plans
Evacuation plans in general have always been an important operating feature of a building. Given that buildings have differences in structure design, construction, fire-resistant qualities, height, floor layout, usage, occupancy load, each building presents unique problems in emergency evacuations. For this reason, the fire department acknowledges that there is not a single recipe for handling evacuations for any one building, but the key is communication between building operators and firefighters.
A typical requirement of evacuation plans must account for a range of events and be robust enough to take all types of occupants into consideration:
Plans should include procedures for reporting emergencies that spell out occupant and staff response. For example, if people discover a fire, immediately activate red manual call point, leave the floor, and keep stairwell doors closed but unlocked at all times to preserve the safety of escape stairways.
The building calling for an evacuation when there is a known event. Only properly trained building manager or the chief engineer is authorized to order an evacuation on occasion when they have to make a decision ahead of the fire department. They should have the assigned authority to order evacuation of a given floor or several floors of the building to a refuge location prior to the arrival of the fire department. Additional floors, as well as total evacuation, may be evacuated at the direction of the local fire department.
Plans for evacuation during ‘bomb-threat’ or ‘non-fire’ related emergencies should be controlled by joint decision of the police and fire department in consultation with building management and tenants’ representatives.
Plans should detail the type and coverage of a building's fire protection system and other items required by the authority having jurisdiction. If additional facilities such as equipment and escape devices that are available for aiding evacuation and rescue, it should also be included in the evacuation plan.
Comprehensive floor plans and diagrams for evacuation routes. Floor plans with detail reveal the number of people who work in a specific office and whether or not that office has someone with special needs. Such floor plans that are available to on scene commanders of the fire department would be an extraordinarily valuable tool for firefighters.
Plans should include floor search to make sure that every person on a floor is aware of an emergency evacuation. The orderly movement of persons requires the utmost coordination of assigned emergency evacuation floor teams and central evacuation control. They must be encompassing, amenable to change, and applicable to a range of occupants with disabilities.
Building control will determine the safest and most efficient means of evacuation, depending on the nature of the emergency and scope of damage. For examples, Plan-1 evacuation should be accomplished by means of stairwell and make way down, the use of lifts for ‘bomb threat’ emergency evacuation can also be considered, but never for fire and earthquake emergencies. Plan-2 if evacuees encounter smoke while descending one stairwell, evacuees can cross over to the alternate stairwell that lead to other floors or transfer corridors giving access to separate buildings. Plan-3 for alternative escape routes when particular circumstances warrant rerouting of occupants to bypass impassable floors or blocked stairways because of hazards, such as smoke, heat, and gasses in the evacuation route. Procedures should advise skyscraper occupants never to flee towards the roof in a fire emergency because hot gas and smoke rises. The only exception to this rule is if the building has made provision of escape chute at the rooftop as an alternative means of escape route to the street.
Evacuation planning should take into the consideration of how people will realistically react in an emergency situation. Lives are often lost through the irrational behavior of evacuees triggered by panic. Because of this, proper education of occupants on abiding to evacuation procedures and escape routes during regular drills hopes to eliminate panic when people are ignorant during an emergency evacuation.
Lastly, it is the building management’s responsibility and duty of care to ensure that the building evacuation plans can evacuate as many occupants including the less fortunate prior to the arrival of the fire department. If the system fails, the firefighters will then have to come to do a search and rescue for those left behind. From time to time, an evacuation plan shall be reviewed and updated as required by the authority having jurisdiction.
Developing A Disability Evacuation Plan
Who are people with disabilities? In disaster management activities, the term people with disabilities includes people who are “vulnerable” or “at risk” and cannot always comfortably or safely use some of the standard resources offered in disaster preparedness, relief, recovery and mitigation. They may include people who have a variety of visual, hearing, mobility, cognitive, emotional, and mental limitations, as well as older people, people who use life-support systems, people who use service animals, and people who are medically or chemically dependent, and people with situational disabilities.
All too often in emergency situations the legitimate concerns for evacuating of people with disabilities are overlooked or swept aside. Building evacuation plans are typically designed for people without disabilities, for whom escape or rescue involves walking, running, seeing, hearing, and quickly responding to directions. People with disabilities visiting, working and living in high rises would have few options to find a way out in times of emergency because the current evacuation plans rely so heavily on self-evacuation that the handicapped, old and the sick may have little chance of getting out on their own. Some may have a plan to provide evacuation assistance to people with special need. But many of those plans are inadequate - wait for assistance. Generally, they are relying on community support groups, such as buddies, emergency responders and firefighters to get them out. But, is "waiting for assistance" approach acceptable in a civilized society?
According to the U.S. Census of 2000, people with disabilities represent 19.3 percent of the 257.2 million people ages 5 and older in the civilian non-institutionalized population, or nearly one person in five. It is a general believe that individuals with disabilities make up a sizable portion of the growing ageing population. Given the high potential for future fire and non-fire related incidents such as the terrorist threats, energy power black out and other catastrophes, planning for the building evacuation of people with disabilities will definitely be one area should be urgently addressed.
Adopting a broad definition "Nobody Left Behind", and the imperative is clear that building managers address the broad spectrum of disability and activity limitation issues. The proper evacuation procedure for this group of persons would inevitably be different from other normal persons. But, they should be given the equal opportunity of getting out of high rise emergency as the other people of the building community. People with disabilities should be involved in the activities of preparedness and planning so that they are not excluded from evacuation available to the rest of the building community. Although they may need additional facilities or services, the building management must work to build provisions for these means and services into its plans otherwise people with disabilities would find evacuation inaccessible or difficult to manage. If planning does not embrace the value that everyone should survive, they will not.
A disability evacuation plan would need to address the survival needs of people with disabilities during a building evacuation. Where obstacles or physical features of a building makes it impossible or unreasonably difficult for disabled people to access/egress, building management must take reasonable steps to remove or alter the feature or provide a reasonable alternative method of overcoming the problem. Building emergency warning systems should be accessible by the greatest number of people, regardless of their capabilities, hearing or vision disabilities.
Depending on the type of building and its obstacles, such as stairs, certain equipment and signage may be needed. The provision of appropriate facilities to help those individuals who are not willing, or able, to walk down long flight of stairs due to impaired mobility or health reasons will maximize their escape potential in getting out alive. All primary function and public areas should have evacuation signs showing the means of egress and multiple paths of travel if the path to be taken by someone with a disability is different than the one used by the general public. Signs are for directional purposes should be simple for people to follow even under complete darkness.
A building's evacuation plans should include the designation of people willing to provide assistance to those who need help and their training in the type of evacuation devices supplied to facilitate speedier evacuation, save injury to evacuees and rescue workers. Emergency evacuation floor teams should have a current list of all visitors and occupants with physical handicaps, including those persons who cannot use stairs because of temporary illness or other impaired physical conditions. Unless the risk level of the emergency called for a total evacuation of all building occupants, fire wardens should simply evacuate their floor or area as normal and guide this group of occupants to a safe area of refuge. Depending on the life threat level of the emergency situations, at some point, rescue workers may have to get the disabled people out from the refuge location.
Fire authorities recognize the difficulties of evacuating people from high-rise buildings, especially elderly and disabled people in extreme emergency situations. Some fire departments have even approve the use of fire lifts for evacuation of people with mobility impairments, while others deem this method too risky. If the lifts are in service during emergencies, the evacuees should be moved down the staircase to the uppermost floor served by an uninvolved lift bank, and then be moved by lifts under the direction of firefighters. But if the lifts are not in service, the only way down is to move them via the stairway.
Evacuation Drills
The purpose of an evacuation drill is not a test for egress efficiency but enable building management to see how effective the plans and fire training have been conducted, identify problem areas and highlights things that should be better.
An evacuation drill programme should be established for periodic practice of ‘progressive movement’ and ‘total movement’ of occupants under varying conditions not restricted to fires. Chances for people with disability of getting out of high rise emergencies would be greater if evacuation plans is in place that included them, and that are regularly practiced by using both announced and unannounced drills for reviewing procedures. Combine training with drills allows occupants to become familiar with the emergency procedures, and that people with disabilities and activity limitations not be excused from participating. When drills are held, all occupants must know how to evacuate via routes that deviated from their normal paths and actually entered their designated stairwell. Such practices hope to eliminate panic when people are ignorant during an emergency evacuation. For building staff and fire wardens, they must practice their duties to ensure an orderly evacuation in case of fire, panic, or other emergency. They should also be taught how to use portable fire extinguishers, in-door fire-hoses, ‘egress facilities’ if any, such as evacuation chairs and the escape chutes properly.
The myth of evacuation time taken to empty a tall building during a fire drill cannot be a determine factor of how long it will take to evacuate the structure under actual emergency situation. When the real emergency occurs, the speed of egress can vary greatly depending on many factors, including the number of occupants, their mobility, their reaction and behavior, visibility and accessibility of escape routes, situational conditions and the distance they must travel. Will the building staff and fire wardens know what to do and perform their duties well? Are evacuation facilities in good working conditions to facilitate speedier evacuation?
Conclusion
Evacuation planning takes a ‘total approach’ at all levels: the individual, organizational, and building environmental. Preparedness in evacuation is a proactive and efficient state of readiness for a full-scale total building evacuation. Pre-planning, adequate communications capabilities, evacuation priorities and proper skill drills help eliminate mistakes and misunderstanding in coordination during actual emergency evacuation. Adequate training in the proper use of equipment and facilities for aiding evacuation should be incorporated as part of the evacuation drills.
Lives are not saved by codes; they are saved because people will have decided, with the help of codes, to assume responsibility for their own safety. For example, fire escape stairwells are legal in many jurisdictions but cannot guarantee that everyone can walk down the stairs quickly without injuries during emergency evacuation. In the context of the fire code, it is not required to provide facilities in a building for escape or rescue purposes. But facilities such as escape chute could have save more lives in extreme emergencies if stakeholder chose to provide them to enable more people to get out quickly where they are not required by law.
Measuring the success of a preventive program is difficult. Nevertheless, prevention and proactive is the key objective, not reactive. A building’s level of fire protection and preparedness for evacuation holds the highest level of importance for safety of the occupants and property within. Voluntary actions by stakeholders to enhance the level of safety and responsible actions taken by individuals to meet real threats have always been the best way to advance the cause of safety and preparedness for evacuation.
This article is contributed by Escape Consult Mobiltex (S) Pte Ltd - www.escapeconsult.com
