Facilitating safe egress for occupants and providing access for firefighters are essential life safety tasks. The interior stairs are the preferred means of egress/access, but they are sometimes untenable or inadequate. Thus, protecting and providing safe means of egress from the fire building should include providing alternative exits for occupants to escape and firefighters to gain access.
Introduction
The greatest diversity in evacuation strategies lies in the provision of means of escape. Although there are some requirements for two independent escape routes, several countries allow rescue as a second route, and all allow a single escape route in various circumstances. The only absolute requirements for two independent escape routes are for tall buildings. Generally, building regulations do not include lifts in the provision of means of escape, with the exception of using firefighters lifts to transport the disabled people down when conditions permit.
Flexibility of allowing alternative routes are usually related to the heights of buildings, but some is also related to the protection of stairways or to travel distances. Rescue is allowed as an alternative route from dwellings in low-rise flats. The provision of alternative exits via windows, balconies, rooftops where firefighters can raise and position ground ladders to reach the target areas could provide additional means of escape from fire.
Fire Escape Options
Fire escape is a means of rapid egress from a building, primarily intended for use in case of fire. Several types of unconventional methods have been used: a knotted rope or rope ladder, descending devices, escape chutes, are all secured to an inside wall that are intended for self-rescue. Conventional methods are an open iron stairway on the building's exterior on iron balcony; and an enclosed fire- and smoke-proof stairway.
The iron stairway is the commonest because it can be added to the outside of buildings. This exterior iron stairway provide additional means of egress and can also provide firefighters with access to, and escape routes from, upper floor of the building. However, the iron stairway would need to be properly maintained for safe use during evacuation. If properly maintained, the iron stairway is safer to use than using fire department ladders.
It is sometimes necessary to establish alternative egress/access paths by raising fire department ground and/or aerial ladders when the interior fire escape routes and the exterior fire escape stairs are not passable. Firefighters raise and position ground ladders at strategic locations around the building to provide alternative means of escape for firefighters working inside a burning building. When available, the positioning of aerial ladder device from fire truck to reach the target areas can provide alternative means of egress for evacuees and access for firefighters is oftentimes a safer and better choice than ground ladders.
How would evacuees respond to the unconventional evacuation methods of fire escapes when the standard option of evacuating the building quickly may not be available if the normal means of egress, such as lifts, are not working and one or more stairways are impassable because of smoke, heat or flames? What would be the effect on evacuees? Would the occupants attempt to use the lack of familiarity with, or use of such systems if available to them?
Fire Escape Solutions
When building owners wish to select and adopt a fire escape system for their building, they would have to evaluate the occupancy load of the building and determine the shortest time needed to get everyone out of that premises to safety in case of an emergency. For instance, can an open iron stairway or an iron fire escape ladder that is less costly to provide meet the evacuation need? Can everyone got the physical ability to climb down the ladder without getting injured in the process? How long would it takes for a guy to get down from that height? How much time would be needed to get everyone out using that escape route? It will still boil down to how fast building owners want to totally clear all their building occupants from danger.
A fire-resistant escape chute provides another means of alternative egress that facilitate quick means of escape for occupants from upper floors to reach the ground. This is particularly helpful when occupants are located in buildings that are beyond the reach of aerial devices or where there is limited exterior access. When permanently available at a strategic location, fire escape chute provides a relative safe way for children, older adults and people with disabilities to reach the ground. Escaping from danger or fire has never been this easy and quick!
Fire Escape Chute
The escape chute is a non-traditional safety measure that provides possible solutions in an effort to salvage life in life and death situations. It is a near failsafe operation, even if the electrical supply to a building is lost during a fire it will still operate. The escape chute is intended as a supplement to the existing egress, provide redundancy and back-up as an alternative escape route. In Europe, safety chutes are commonly used on tall structures or heritage buildings that cannot have outside fire escapes added.
Most escape chute installations are of permanently fixed in one location served as emergency exits. There are several models of escape chutes, reusable preparedness solution to help evacuate occupants in building in the quickest timeframe possible, while maintaining safety. There is single-entry type mounted on the rooftop, balcony of corridor, and window, allows occupants gain access to the chute on that floor. The multi-entry type allows occupants gain access to the chute at each floor where several levels can be simultaneously evacuated.
Multiple-entry:
The multiple escape chute system is installed inside a fire 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 enclosure that is protected by fire rated door, one segment of chute per floor, 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.
In Nation Tower, at Bangkok in Thailand, for example, apart from meeting the minimum fire exit requirements in compliance to the building regulations, two multiple-entry chutes were installed at the core of the structure for emergency egress. These alternative escape routes not only provided the disabled another means of escape in the absence of lifts/elevators; evacuation times were significantly reduced.
Single-entry:
This exterior chute is for "outside of the box" evacuation ideas and is designed to offer the requisite level of protection that can be used for rapid, mass evacuation. It is a supplementary exit route designed for installation from two stories upward to maximum of 200m in height; best serves the occupants of that particular floor. The external evacuation system is packaged into a relatively small, unobtrusive container with frame of the platform that can be retrofitted into the window, balcony and rooftop of buildings. To activate the system, released a mechanism manually at the compact receptacle where the chute is stored and within seconds it unfolds the chute to fall vertically to ground.
In countries where no fire regulations are enforced, there will be situations where the minimum number of exits in a building or floor(s) may not be enough to cater for the occupants due to a change of occupancy classification or an increased in occupant load over the time. In many situations, the single-entry escape chutes are acceptable by fire authorities as a practical alternative exit in buildings where it is not possible to provide additional exits or increase the size of existing exits.
Unconventional Exit Strategy
The ability to evacuate occupants at a height level, should the building be at risk, seems sensible, especially if any emergency in a tall building effectively cuts off vertical evacuation routes and thus connection to the ground plane. Rather than concentrating on the conventional evacuation routes, which creates spatial dead-end, one possible way of providing redundancy system for means of evacuation is to have alternative evacuation route at height through the use of custom designed one-entry chute that can be retrofitted at a level.
This concept of evacuation at height provided additional escape routes, a method and means to rely on making total evacuation practical, 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.
In Intraco Office Towers, at Warsaw in Poland, for example, besides meeting the minimum exit requirements in compliance to the building regulations, several single-entry chutes were installed at strategic locations of different levels within the structure for emergency egress. Considering a high-density office tower with a floor capacity of 500 per floor, the system support continuous egress of the victims trapped on that particular floor, and would take not more than 20 minutes for all the evacuees to slide down to safety.
For high security buildings not open to the public where the goals associated with allowing authorized people in and keeping the wrong people out is primarily to limit entrances into the building at the ground level. This security approach must be weighed against the potential impact of hindering the compliment of building occupants who may need to quickly evacuate the premises. Locking of stairwell doors to prevent re-entry, installation of turnstiles at building entrance points and installation of screening equipment can restrict, or outright fire egress through previously available routes. Escape chute provided a secondary means of egress for high security buildings. The ability to evacuate occupants at height provided more than one means of exiting the building at various strategic levels that would have a huge impact on the security planning.
Escape chute can also serve as a secondary means of egress for air traffic control tower, communication tower, tower-restaurants and tower-entertainment where it has only one stairs for emergency egress.
Closing Remarks
How do you escape from the upper floors of a burning multi-story building when stairways are sometimes untenable or impassable? The provision of fire escapes would be the answer! While price is an important factor when considering the various fire escape options that are available in the market but buyers sometimes over-emphasise it, to the point that they often compromise it with safety. It will still boil down to how fast building owners want to totally clear all their building occupants from danger!
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