Currently the only escape provisions in buildings are there for fire safety but as events at the World Trade Centre so clearly indicated these means of egress are used by people to escape the actions of terrorists, which may or may not result in fire. Are the current egress requirements in the codes adequate for addressing scenarios against the acts of terrorists, fire or otherwise that necessitate the simultaneous evacuation method of removal of all occupants rapidly from the building to a remote location? Evacuating a high-rise building is a big risk, what can be done to ensure that people desire to live and work among the clouds can get out quick under extreme conditions?
Introduction
Before September 11th 2001, modern high-rise building undermines evacuation procedures that there will never be a need to empty a high-rise quickly. For fires and other catastrophic events in skyscrapers, common practice has long been to tell people elsewhere in the building to stay where they are until they are told to evacuate. The view was that occupants away from the fire floor should stay put to avoid putting themselves in danger or interfering with emergency responders, and to await instructions. However, public should also realized that it may requires more time than is available for occupants to exit prior to their safety being threatened.
The terrorist attacks on the World Trade Center (WTC) and the Pentagon in the US have changed our perceptions concerning the evacuation and the relocation of occupants in high-rise building emergencies. High-rise building occupants are now more likely to evacuate on their own after the 9/11 incidents. People today will unlikely to obey an order over the public address system to stay in place. But when the stairs were not designed for the mass evacuation of thousands of people in tall buildings, would a simultaneous exit caused a stampede that may leave the stairs impassable? For this reason, staying in place during a fire emergency and prepare to evacuate if the fire begins to get out of control, or if the authorities order for evacuation is still considered by many fire safety experts the best thing to do for high-rise fires.
As the risk to our cities increases – through terrorism, war or accident is highly likely in the foreseeable future – public expectations to feel safe in buildings are increasingly unrealistic. In response to the growing threats, the “extra” safety initiatives that have been put in place to ensure “security” and “protection” measures of taller buildings have become prime importance across the world and would remain as long as there is a potential threat. Just like fire insurance, the preventive steps taken against a high consequence event would be worth the effort. Security and safety should be the last cost item to be budget to cut, not the first should there be a budget constraint.
All the security and safety measures would not guarantee that a terrorist attack would not occur. And to the certainty that future emergencies cannot be predicted, all stakeholders can do is to create emergency evacuation plans they hoped would never occur for uncontrollable events that requires total evacuation of building occupants at some point. When they do occur, a safe strategy would be to get as many people evacuated out of a blazing high-rise in a predetermined evacuation plan prior to the arrival of the fire services than having to depend on firefighters to perform search and rescue operations. This approach is the only acceptable way in guaranteeing life safety prevention and reduces risks for firefighters when condition is not safe for entry in the event of the worst conceivable scenario that could happen to a tall structure.
Some suggestions aimed at helping with such mass evacuation processes include wider stairs, multiple stairwells at strategic locations and determined fire service intervention at an early stage. In addition, harnessing technology to look beyond the normal stairways: research into lifts reliability and the safety of escape chutes to assist with full-scale evacuations is encouraged. It is hoped that such developments would help provide better escape procedures that allowed for the evacuation of a large number of people in a short space of time.
Building Fire Safety Features
Generally a fireproof building is a concrete building and there are generally no extensions to the floor above or to the adjacent apartments. The floors and ceilings are concrete to keep fire from spreading to other units. High-rise buildings are designed and constructed in this manner to prevent fire from spreading to nearby buildings, prevent premature collapse of the building and allow firefighters an opportunity to rescue people and extinguish the blaze in the quickest and safest way.
Most tall buildings are not designed for complete evacuation during a crisis because of the belief that built-in systems can contain and suppress fires, and because stairwells reduce the amount of rentable floor space. Most high-rise evacuation strategy assume smoke detectors, sprinkler systems and aggressive fire suppression will extinguish most fires without the need to empty more than a few floors. Collectively, these elements and measures worked together to provide fundamental beliefs in modern fire fighting and rescue strategy -- battling the blaze from the inside that requires firefighters to use the fire lift to quickly access the "fire floor" and conduct the operation from within. Firefighters adopt the internal fire fighting strategy to protect occupants from the initial fire development for a time sufficient enough to allow the occupants to evacuate, relocate, or defend in place.
In some instances evacuation from an area or a building is required to protect the life-safety of its occupants. Supporting efficient and effective evacuation requires designers, building operators and emergency response personnel to consider numerous physical, psychological and temporal factors such as providing “refuge floors” at strategic levels. For example, during a fire emergency, occupants from the affected floors can take temporary refuge at the refuge floors and prepare to evacuate if the fire begins to get out of control, or if the authorities order for a total evacuation. In addition, firefighters can use the refuge floors serve as staging areas to mount search, rescue and fire-fighting operations.
Currently the only escape provisions in buildings are there for fire safety and most high-rise buildings offer routes for escape in an emergency that is based on the assumption of only a single fire source. This minimum egress requirement is in compliance with most, if not all fire codes, that assume multiple, simultaneous fire incidents in tall buildings will not occur. A single fire source equates to most occupancies of having a minimum of two means of egress from rooms or spaces that assume to be sufficient to facilitate the evacuation of the building occupants in phases. Hence, taller building has not been designed for full extreme emergency evacuation and are more difficult to tackle when seeking to evacuate in an effective way – one that allows for mass evacuation to take place simultaneously.
A Towering Concern
As buildings grow in both height and complexity, there is a growing concern over safety in a skyscraper when something goes wrong far below, particularly relating to evacuation in an extreme fire situation. The record of fires in high-rise building occupancies, with resultant fatalities, and heavy financial losses shows that life safety solutions are no longer restricted to fire detection and sprinkler systems, security surveillance and communication systems, and refuge floors. The potential for high human losses emphasizes the urgent need for instituting an effective evacuation programme for all people to get out quickly before conditions gets worse.
Imagine a hypothetical towering inferno. Fire Department may have strategy to tackle high-rise fire through internal fire fighting and may even have protocol requires firefighters to conduct a top-to-bottom stairway search while they fight the fire. But, how would the firefighters respond a rescue mission to get everybody out if fire and smoke spread rapidly from the thirtieth floor of a sixty-story building? The scenario may become even more complicated for the firefighters when some of the occupants are trapped above the fire floors. No one can say exactly how many people may be trapped inside but rescuing them will be an enormous challenge if stairwells are impassable because of smoke, heat or flames. Firefighters performing the search and rescue of saving lives could be left incapable of saving themselves once the buildings were deemed unsafe. Authorities rule out rooftop rescue by helicopter, and have no rescue plan for people trapped on the floors above the fire beyond the reach of the super-high aerial ladders or height rescue equipment. A helicopter rescue above the fire is not feasible and would be too dangerous to handle because hot gas and smoke rises and the heat from the flame below would interfere with the rotor system. Such a scenario offers a wide range of deadly problems for the building management, evacuees and for firefighters.
Fortunately, the rare occurrence of major hazards in high-rise building means that more often than not, the real-life experience of high-rise rescue, mass evacuation and evacuating people with disabilities under urgent circumstances is not tasted. But when they do occur, the only safest thing for building occupants to do in a blazing high-rise is to head for the nearest staircase on the floor to avoid being trapped and make their way down. However, research has shown that different people in a mixed ability population have different capabilities and limitations to egress a building. Hence, it is important to realize that in the context of high-rise evacuation, there are people among the building population who may have difficulty or no ability to walk down long flight of stairs and will need assistance to get out of the building.
As modern buildings have broadened access to ensure accessibility, the ranks of the aged and the disabled in tall buildings have expanded. Even though high-rise buildings are designed with fire safety provisions that will take care of the safety of the disabled during a fire emergency, but provision for their safety to get out has not. This pose a particular challenge for the disabled people to accessible means of egress since lifts, the standard means of access between floors, are typically taken out of service in emergencies for safety purposes. Although rescuers try not to use lifts, most fire services do allow the use of lifts for people with impaired mobility that need rescuing. But if the lifts are not in service during emergencies, the only way down is via the stairway. Clearly, any improvements to means of egress in tall buildings should include the means for those individuals who are not willing, or able, to walk down long flight of stairs due to impaired mobility or health reasons the ability to get down with minimum assistance. This approach maximizes their escape potential in getting out alive.
Mass media often show that in many fatal fire incidents, people would risk injury and attempts to jump out of window or use any methods for escape, if available, to get out alive. While the use of lifts is not considered for evacuation, and the use of escape chute for evacuation is unconventional, yet members of the public will undoubtedly opt for the fastest means of escape if available. This decision is both the catalyst and symptom of panic and feelings of insecurity in the minds of those involved.
Evacuation Under Extreme Conditions
In the afternoon of February 26, 1993, more than 100 thousand of people were evacuated from the World Trade Center Plaza (WTC) in New York City after a bomb exploded in a basement-parking garage. In that total evacuation, tenants were sent running out onto the streets, with those in higher floors realizing the evacuation took quite long without using an elevator. We learned that it took as long 6 to 8 hours for the tens of thousands of building occupants traversed some five million person-flights of stairs through the smoky stairwell in darkness to successfully exit the buildings.
Even after the 1993 bombing at the WTC, the emergency planning there never anticipated a complete evacuation, according to officials. The improvements made to its stairwell lighting and exit-signs after the bombing incident appears to prove that the value of physical improvements done to the building exits enabled people to see their way out during 9/11 evacuation before the twin towers collapsed. Despite the loss of so many lives in 2001 WTC attack, many safety engineers who watched the towers fall remain astonished at how many people were able to escape in the hour and 45 minutes after the initial strike. It was estimated that there were between 16,000 and 18,000 people in the buildings when the planes struck at that morning. Had they been fully occupied with 50,000 people, a complete evacuation would have taken four hours, probers found.
With memories of the incidents of the 1993 bombing and the 2001 attack at the WTC are still fresh in the minds of many, it appears – for the time being at least – has become evident that everyone must be able to get out of tall buildings quickly in an emergency. The lessons that can be learnt from the evacuation of the WTC were that nearly everyone who could physically get out did. Numerous accounts show an unknown number--probably in the hundreds--made up their minds to flee despite receiving instructions to remain. Most people kept to the right of the stairwell to allow rescuers to climb up the left. In so doing, they saved their lives. For those who fled the upper floors, the staircases must have seemed endless — 100, 200, 1,000 steps, and more. Traumatized experiences in that evacuation show that people would take risks in attempting to get out of the building fast, such as using lifts if they were still running.
What about those occupants who were not willing, or able, to walk down long flight of stairs due to impaired mobility or health reasons? It was reported that people with disabilities who could be moved by colleagues or rescuers escaped. But how many of the less capable were still waiting to be rescued when the structures collapsed will probably never be known. At least 300 firefighters lugging heavy gear performing their duties of saving lives and property were presumed dead.
Almost three years after the collapsed of the WTC, some basic questions on the safe evacuation of people from high-rise buildings in the event of a major disaster remain unsettled. While several studies are already underway into structural issues, less attention has been paid to the way the buildings were evacuated. For examples, which elements in the towers' design helped or hindered people escape? Are the current egress requirements in the codes adequate for addressing scenarios that necessitate the simultaneous evacuation method of removal of all occupants rapidly from the skyscraper? How effective are skyscraper evacuation plans to get all people out quick under extreme situations when conditions does not permit safe entry for firefighters to perform search and rescue? How to get firefighters who are responding to search and rescue operations out quick when the building becoming unsafe? Evidence shown that firefighters were left incapable of saving themselves once the building was deemed unsafe.
Controlled and Uncontrolled Evacuation
Due to the significant numbers of occupants in tall buildings, evacuation is typically carried out through a ‘controlled process’ during a fire or similar emergency. Also known as ‘staged’ or ‘phased’, the evacuation method, with live voice messages and warden intercom points on each floor, allows for control centre or emergency services personnel to clear a building in a methodical way – controlling which floors are evacuated and when.
The fire alarms in high-rise buildings sound first on the floor of the fire and on the two above and the one below. The floor of the fire origin should be the first to be cleared, followed by other adjacent floors. If a fire grows, alarms spread to other floors.
A typical evacuating procedure advised occupants that in the event of an actual emergency, occupants should remain in place and wait for instructions, they would be directed to descend to at least two floors below the fire to await further instructions. By limiting the number of levels being evacuated at any one time, the process is efficient to prevent exits from being blocked, especially for those most at risk on the floor of the fire. The governing factor for use of staged evacuation is the reduction in numbers and width of the stairs required, therefore reducing core area and increasing net area for the entire building. This method of evacuation also reduces business interruption within affected buildings. However, this phased evacuation may require more time than is available for occupants to exit prior to their safety being threatened.
Another method of evacuation is the ‘uncontrolled’ or ‘simultaneous’ one. Here, all floors are alarmed at once with all occupants exiting via the stairs at the same time. During the complete evacuation of a taller building, it is likely that there would be significant congestion in the stairwells with a large number of occupants, when compared with occupant numbers during phased evacuations – at the same time as firefighters are travelling against the flow. Most low- and medium-rise buildings have a simultaneous evacuation process, as it is simpler and does not require significant warden input or a communication infrastructure.
Though uncontrolled evacuation is often rare today for high-rise buildings there are still some that opt for the simultaneous evacuation method in the case of an emergency. Therefore, are the egress requirements in the codes adequate for addressing scenarios, fire or otherwise that necessitate the removal of all occupants rapidly from the building to a remote location?
Recognition Of The Evacuation Problems
Staged evacuation, considered a valid egress strategy in the past, is now showing gaps in terms of situations planned for. Stakeholders are aware of the significant importance to include emergency response plans for the potential total evacuation of a building’s population from unpredictable non-fire related events like terrorist threats, electrical blackouts, hazardous material spills and other natural disasters that were previously deemed ‘unlikely’.
Lifts and exit stairs provide access and egress for inter-floor transportation during normal situation. But in a fire emergency situation, lifts are often shut down automatically, so exit stairs are the only way of escape. Since the tragic events at the WTC, building operators are requesting that fire safety engineers and building regulators investigate different methods of simultaneous evacuation and how to better equip buildings to handle catastrophic events.
One option is to increase the number or width of the stairwells – an extremely expensive solution, especially for existing buildings. In addition, descending the stairs is not something that all individuals can do with many struggling if the floor that they started on is above 100m. Therefore it is necessary for them to get down using other means. A viable option – but one that is also expensive – is to design lifts that are both fireproof and impact-proof, capable of providing a safe exit route for occupants and safe access for firefighters.
Another possible option, less expensive to adopt, is the concept of evacuation by escape chute. This form of vertical exit usability for all people to self-escape to ground with minimum assistance can provide additional escape routes without having to add fire escape stairs, hence saving a great deal of time, effort and space. This approach is similar to providing more lifeboats on a ship to increase the level of passengers offered the chance to escape in an extreme event.
If an existing building – one designed for staged evacuation is to be re-assessed for simultaneous evacuation, the most logical method of ensuring faster overall evacuation is to utilize the lifts and escape chutes with stairs. It is now clear that a rapid and yet orderly evacuation process should include the use of all of these methods. The question we now ask is whether such a combination egress methods will become a commonplace in tall buildings, be part of future egress design, and evacuation consideration in providing accessible means of egress to everyone?
Code changes do not arrive overnight and traditionally come about only after major disasters. Fire safety is more than a matter of code. It’s a matter of conscience. Property owners and facility managers in many countries have adopted voluntary safety standards to make their buildings egress accessible to everyone. This is a critical component of life safety that has a major influence on the success of complete egress in a total evacuation.
Emergency Plans and Drills
Egress efficiency during an emergency cannot be fully tested until a 'real' crisis occurs. Creating emergency plans and procedures response to fire and other threats are needed to make sure losses will be minimal in the event of fires or other emergencies. Conducting drills for rescue and evacuation under varying conditions not restricted to fires will help evacuate persons safely in the event of large-scale evacuations or major emergencies.
Because of differences in structure design, construction, fire-resistant qualities, height, floor layout, usage, and occupancy, each building presents unique problems in emergency evacuations. For this reason, there is no specific evacuation programme for any one building. However, evacuation planning for any one building should take into the consideration of how people will realistically react in an emergency situation.
Pre-planning, evacuation priorities and proper skill drills help eliminate mistakes and misunderstanding during actual emergency evacuation. Drawings, diagrams, evacuation routes, procedures, and information related to evacuation should be included in the building’s emergency evacuation plans. In the event of fire, the building manager or the chief engineer should have the assigned authority to order evacuation of a given floor or several floors of the building to a refuge location. Additional floors, as well as total evacuation, may be evacuated at the direction of the local fire department. Building control will determine the safest and most efficient means of evacuation, depending on the nature of the emergency and scope of damage. Floor search to make sure that every person on a floor is aware of an emergency evacuation and the orderly movement of persons requires the utmost coordination of assigned emergency evacuation floor teams and central evacuation control.
Plans for evacuation during fire emergencies should be accomplished by means of fire stairwells and make way down. Plans should include possible alternate routes when particular circumstances warrant rerouting of occupants because of hazards, such as smoke, heat, and gasses in the evacuation route. Plans 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 escape route to ground.
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. In addition to evacuation by means of stairwell, the use of lifts for ‘bomb threat’ emergency evacuation can also be considered, but never for fire emergencies.
Evacuation planning should also include a need assessment to provide different equipment that is appropriate to help those individuals who are not willing, or able, to walk down long flight of stairs due to impaired mobility or health reasons to maximize their escape potential in getting out alive. 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 firefighters.
Emergency evacuation floor teams should have a current list of all occupants with physical handicaps, including those persons who cannot use stairwells or fire escapes because of temporary illness or other impaired physical conditions. This group of occupants should be moved down the fire stairwell to the uppermost floor served by an uninvolved lift bank, and then be moved by lift under the direction of firefighters. But if the lifts are not in service during emergencies, the only way down is to move them via the stairway. The use of special designed ‘evacuation chairs’ can enable helpers to move those occupants with physical handicaps down a flight of stairs much easily that might not otherwise be possible. However, it can also slow stairwell traffic if travel dozens of floors during large-scale high-rise evacuation. The provision of escape chutes at strategic locations within the building will give them the ability of self-reliant escape.
An evacuation drill programme should be established that would include periodic practice of ‘progressive movement’ and ‘total movement’ of occupants. Such practices hope to eliminate panic when people are ignorant during an emergency evacuation. Drills should be conducted often enough to allow all people to become familiar with the emergency procedures, and for building staff and fire wardens who 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 and other manual fire suppression equipment properly. The purpose of a 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.
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, dimension of the egress components 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 available to facilitate speedier evacuation?
Building Egress (Exit Stairs)
In the aftermath of 11 September 2001, much attention was paid to creating better and safer building egress, in particular exit stairs. Many improvements could be made to the current emergency egress requirements, such as increasing the number of exits, wider stairs with smoke control in stairwells, enhance marking of stairs and exits with evacuation guidance system, improving emergency lighting, installing communication and surveillance system to monitor evacuation process, etc. While such structural modification that can be made to stairways served their purpose as the primary means of escape and no doubt saved many lives, they do however, have some deficiencies. Such improvements will not help to speed up the process of evacuation in the case of taller buildings and when fatigue becomes a limiting factor to the physical act of descending long flight of stairs that requires the most time. Search and rescue of the remaining evacuees taking refuge at the stair landing of the upper floors will still be needed. Clearly, it is not enough in opting for one means of escape that cannot be used by everyone in a total evacuation.
Lifts For Evacuation
In the past lifts have provided one of the safest forms of vertical transportation. However, despite their successes people have fallen victim to fire while using them to escape. It is precisely because of these instances that many of the world’s fire services discourage the use of such equipment as means of escape. In fact, around the world it is widely understood that lifts should not be used during fires, supported by warning signs in most buildings.
However, there is a present trend in countries, such as Australia, the US and the UK, to investigate using lifts to rapidly increase evacuation speed. Several research groups, charged with looking into the possibility of using lifts as a means of evacuation have concluded that the use of protected lifts is feasible. In certain emergencies, emergency personnel may operate standard lifts through the use of a special key and in such cases, it may be possible to evacuate people with disabilities in this manner. This, however, is not always an option.
A lift system, intended for evacuation, must offer protection of lift vestibules with fire rated separations against heat, flames, smoke, and water, overheating of machine room equipment and loss of electrical power. A further concern is seismic activity. Attention needs to be paid to earthquake design in areas deemed to be at high risk.
Concerns over the continued operational abilities of a lift system in the event of such a disaster have meant that lifts are not generally viewed as an acceptable tool for evacuation. Though technological advances now appear to have improved performance levels under these conditions, further research is still needed to make it safer for use in real fire situations and the overall safety to evacuees.
Escape Chutes
Technology always advances faster than the development of codes, specifications, and standards. One potential means of rapid emergency egress that can be used by everyone is the escape chute – suitable for building-exit strategies for a different future. Chute works on the principle of gravity, allow all occupants to slide down to the ground quickly and relative safely. Such equipment was developed more than 100 years ago and has advanced quite significantly since then, although the concept remains the same. The latest versions, capitalizing on advances in technology, are being patented around the world and permit evacuation from high-rise structures during an emergency.
Currently there are no standards for the design and construction of escape chutes or similar devices, nor are there mandatory requirements for placing them in structures for aiding rescue or evacuation purposes. If current fire regulations do not require buildings to provide escape chutes, often question ask is should they be used? Given the opinion that lifts are unsafe for fire egress and stair travel is taxing and potentially dangerous for the aged and people with mobility impaired, evacuation via escape chutes provide the answer to make building egress accessible to everyone. In Europe, safety chutes are commonly used for providing additional means of egress to buildings that do not meet the minimum exit requirements by codes and cannot have additional means of escape or outside fire escapes added.
In principle, the escape chutes or similar devices should be manufactured in conformance to its performance as tested by a fire research institute. Chutes are designed and constructed in such a way that is failsafe to use in fire situations, safeguard those who are most vulnerable in an emergency: children, the elderly, the injured, and the disabled. It should allow the users to have the ability to control the speed of one’s descend and also to allow external means to control the speed of one’s descend. The chute is designed for reusable preparedness solution, quick to deploy for user-friendly operations and also for easy retrieval of chute after its use.
While the idea of a chute evacuation may not be very appealing to some, it is slowly gaining popularity in an effort to raise the level of occupant safety. In fact, when occupants acknowledged that escape chutes are there as an alternative escape route when the conventional exits are no longer available, serviceable and useable, it increases their feelings of security in trying circumstances. With frequent practice, occupants will even feel safer descending down the long chute than negotiating the long flight of stairs during mass evacuation in emergencies.
Alternative Means of Escape
In many ways the escape chute is a near failsafe operation. It needs no electrical supply to operate, allowing it to be operational for evacuation during power outage. The chute is designed to act as an alternative escape route in building, by providing back up to those that are there already. This means that if lifts are not working or stairs are impassable because of smoke, heat or flames, chutes can be deployed offering an opportunity for occupants to escape.
There are several types of escape chute installations and applications currently on the market with most being permanently fixed at one location, reusable preparedness solution in the quickest timeframe possible, while maintaining safety to help evacuate occupants from high structures:
Single-Entry Chute: The one-entry escape chute is installed at old or existing building at window, balcony, terrace and rooftop of multi-floor buildings from two stories upward to maximum of 200m in height, best serves occupants of that particular floor. This concept of evacuation at height provided additional escape routes, without having to add on fire escape stairs from the design, which would otherwise have been needed, a significant space was saved. This approach is similar to provide more lifeboats on the ship to increase the level of the passengers’ ability to escape from an extreme event.
Multiple-Entry Chute: The multiple escape chutes is installed inside a protected vertical shaft enclosure in a new building or retrofitted in an existing building. The installation is constructed in accordance to international fire code that provides protection from fire effects for evacuees so that it can be used safely for emergency egress. The chute is permanently available at each level inside the fire protected shaft, one segment of 2-layers chute per floor level, from the highest floor to the ground floor on the same vertical line with no length and height constraints. Evacuation takes place inside the building and occupants can gain access to the chute at each floor where several levels can be simultaneously evacuated.
By incorporating the multiple-chute system at the core of a protective staircase enclosure, such escape way provides evacuation route choices for vertical exits at each level within the building. When fire occurs, the disabled and the severe mobility impaired will have to make their way, assist or unassisted, and take temporary refuge inside this enhanced stair enclosure while waiting for rescue. They can either choose to use the chute inside the stair enclosure that would get them to the ground floor or to be assisted by helpers down the stairs. This egress design feature is a classic example of building-exit strategy that is above the required minimum of an exit stairwell accessible to everyone that can be incorporated in the early stages of a building’s design.
Mobile/Portable-Rescue Chute: The dual functions in one unit portable rescue chute has become standard rescue equipment used by many Fire Services Department worldwide for high rise rescue operations. One unique feature of the rescue chute is its flexibility of extending or shortening the chute length to the desired height for the rescue. The quick deployment of mobile rescue unit mounted on the bucket of hydraulic platform or aerial ladder of fire truck allows the rescuers the speed to quickly provide victims a safer means of rapid vertical escape from bucket to ground. The portability and versatility of the rescue chute allows the rescuers to carry the rescue unit to the desired floor, positioned at the parapet of balcony and window for quick rescue use.
It is suggested that fire services worldwide have no objections to the installation of escape chutes at buildings. If an evacuation is required the chute can support other means of escape to minimize the time taken for occupants to egress buildings during emergencies. Essentially meaning that the building can be cleared in a fast and effective way whilst providing an opportunity for firefighters to get in and deal with the event. Such evacuation plans would not only give people with disabilities the best chance of survival but also rescue workers who would not have to put themselves at undue risk to conduct a search for victims when conditions do not permit safe entry.
Even without regulatory changes for buildings, escape chute systems are gaining a following through demand from stakeholders. Property owners and facility managers in many countries have voluntary provided chutes for emergency egress as a preventive programme to enhance their building's emergency preparedness for mass evacuation. Most owners of chute installations have either seen or experienced a large-scale evacuation incident. While the success and effectiveness of such a preventive programme can only be measured when a 'real' crisis occurs, nevertheless prevention is the key objective rather than adopting a reactive approach.
Conclusion
Presently, there are no codes around the world, which permit the use of lifts in an evacuation caused by fire. Neither are there codes that require buildings to have escape chutes as a secondary means of emergency egress for all occupants. Yet, it is not enough in opting for one means of escape -- exit stairs that cannot be used by all in a total evacuation. However, it is evident that lifts and escape chutes do offer an additional means of escape in instances where an extreme event is imminent and rapid, simultaneous evacuation is warranted. It is also clear that many opportunities exist to enhance the role of lifts and the use of escape chutes to minimize the time taken for occupants to leave buildings.
Given that the potential for building emergencies is worldwide, it is therefore appropriate to address these evacuation issues at a global level, such as the International Standards Organization or an ‘international research institute for fire safety engineering’. Clearly, the results of any research work could significantly influence the next generation of performance based building codes and the design of accessible means of egress to make equal opportunity in evacuation in buildings possible. It could also guide new policies and emergency procedures and, ultimately, have the potential to save many lives. For example, rules establishing standards, procedures and requirements for the orderly evacuation of persons necessitated by fire, explosion, biological, chemical or hazardous material incident or release, natural disaster or other emergency, or the threat thereof from any office building or public building in the interests of public safety.
Besides complying with codes, the building industry will also have to address the issues surrounding evacuation for taller buildings. It must voluntarily look at what needs to be done in order to improve the physical means of egress in an effort to raise the level of occupant safety and providing appropriate evacuation facilities to facilitate speedier evacuation in the event of a mass evacuation. Ideally, the planning for such events and the methods to be used must be accessible to everyone in the early stages of a building’s design. For example, by designing accessible emergency evacuation methods into the basic structure of building, the emergency action plan can work with the building, taking advantage of various design features and safety practices of the evacuation planning. This would reduce the risk of having to further adapt a building at a later date. Often, when egress features are added as an afterthought to correct the egress deficiencies, a significant amount of effort and cost is spent to make it right. Even then it does not fit quite right.
This article contributes by Escape Consult Mobiltex (S) Pte Ltd. For more information on the escape chute evacuation system, please visit website: www.escapeconsult.com or email: mobiltex@singnet.com.sg
