How Are the Good Designing and Fire Safety Connected in the Tall Buildings - Essay Example

THE IMPACT OF GOOD DESIGN ON FIRE SAFETY IN TALL BUILDINGS A tall building, more popularly known as a high rise, is a building which is 75 feet to 491 feet tall (23 m to 150 m), while those that extend beyond this are known as skyscrapers. Although there are different interpretations for the term, the International Conference on Fire Safety in High Rise Buildings defines a high rise as “any structure where the height can have a serious impact on evacuation”. INTRODUCTION Tall buildings and structures have multiple functions and meanings depending upon various factors. Till recently, only the religious structures such as the churches and the mosques dominated the skylines of European countries and other parts of the western world. Tall buildings often symbolize the dominance and power of one country over another in respect of its varied architecture and strong economy. It is a symbol of prosperity combined with the urge to make a mark on the world while some others have evolved as a part of creating history. The current trend to create taller buildings is a bid to reflect the impact of globalization on the development of the modern world. Major cities of the world literally compete on a global stage to have the tallest building which announces their dominance over others as it reflects their respective country’s strong economies. In terms of fire safety, a high rise building could be defined as a building taller than four stories or 75 feet simply because the aerial ladders of the fire department can barely reach up to that level. These huge structures, sometimes pose a serious danger to the firefighters in case of emergencies because of their designs such as the building standpipe system, HVAC (Heating, Ventilation, and Air Conditioning) system, fire sprinkler system etc. Also the usual fire escape routes such as stairwell or elevator evacuations too can be fatal and cause damage to millions of lives and property. According to some estimates, every year there are about 7,000 fires that break out in high rise office buildings causing serious damage. This damage could be significantly reduced by implementing better fire prevention methods, better informed designs of high rises and detailed planning. With globalization and industrial development, more and more buildings are getting taller with little or no change in the evacuation methods. The tallest telescopic ladder, for example, barely reaches the 12th floor leaving the people trapped with no option other than escaping through stairs. But this too isn’t a viable option, because as the fire catches, the smoke starts to spread in all directions turning the escape routes (staircases and elevators) into a gigantic chimney. The use of sprinklers in putting out fire is a good idea in case of normal fires. But in high rise buildings the sprinkler systems need to be designed more intricately and utmost precautionary measures should be taken to safeguard the water supplies of the buildings and keep them away from damage caused by fire. Use of Fire fighting shafts is a common practice in UK, which consists of three main elements stairs, lifts and lobby. Fire catches rapidly and during such a calamity, one cannot rely only on the age old safety measures such as the escape ladders, fire extinguishers or helicopters. Thus it is absolutely necessary to device model methods to combat fire and ensure the minimum damage. The buildings should be intricately designed to survive a full burn out without having to depend on the sprinkler systems. The escape routes should be protected from smoke which can be done by ensuring proper ventilation systems. The use of elevators should be planned diligently as it contributes to a large extent in reducing the evacuation time by almost 50%. Extra care should be taken to safeguard the vulnerable parts of the building like the power supply. NEW TECHNIQUES FOR EVACUATION PLAN FOR HIGH RISES Using natural ventilation is by far the best possible alternative as it saves the valuable floor space which could otherwise be taken up by heavy equipments like ducts or shafts. Use of lifts for escape Using lifts as an evacuation option is a viable option as it reduced evacuation time to a significant extent. Moreover it is the most logical and practical means of escape for people with disabilities. So irrespective of warnings or recommendations of not using the lifts for escape during fire would work as that is the only reasonable option available to them. Proper measures should be taken to while using lifts as a means of evacuation which includes robust lift shaft construction, well guarded power supply, protecting the lift shaft from smoke, fire lifts to be used only for fire fighting operations and warning the people in advance over the PA/VA systems. (source: K Martin, Fire in High Rise, May 4, 2008) One such invention, useful in case of evacuation during fires is the Gravitational elevator, invented by G.Vilchinsky. When a person gets on it, the elastic chambers shrink, driving excessive pressure through the pipe line into the reservoir. The piston moves, compressing the spring .When a person exits the receiving chamber, the spring brings the piston to its initial position, air enters the crushed chambers expanding them. 1. Elastic chamber 2. Pipe line 3. Reservoir 4. Piston 5. Spring 6. Receiving chamber (Source: T.Nakagawa, Staircase design of High Rise Buildings Preparing against Fire, May 4,2008 ) Skid out highrise fire escape device (US patent December 1,1987) This invention relating to the fire escape device, is used in multi-floor structures, such as, highrise buildings. One or more vertical skid tracks are fixedly mounted on a front of a building in the range of escape windows which in turn allows the building occupants to exit safely in the event of an emergency especially when the conventional ways of exit from the building are either blocked or rendered useless owing to the smoke emitted by fire. Sophisticated Software Sophisticated softwares, to analyze the behavior of fire in accordance with the given space, can be used to develop performance-based designs.. The National Institute of Standards and Technology (NIST) has played an important role in this work. In its World Trade Center Investigation Final Report, NIST says “performance-based methods are an alternative to prescriptive design methods.” (source: James Carrigan, Sophisticated Softwares Helps Analyse Behaviour of Fires) For example, fire-modeling programs available through the NIST Fire Research Division helps in analyzing the effect of smoke control systems and smoke movement based on a variety of fire conditions within a building. The programs can also effectively determine the approximate time required for carrying out an evacuation operation as well as evaluate how the use of elevators and stairways can reduce overall evacuation time in non-fire situations. The Fire Dynamics Simulator numerically models smoke and gas movement, accurately predicts gas temperatures, heat fluxes, gas velocities and sprinkler activation times. The Smokeview feature allows the user to graphically visualize the data which provides more understanding and hence develop methods to prevent casualties in large numbers. Similar programs can be successfully adopted and incorporated in the High Rises, thereby reducing the risk of lives to a significant extent. Another way of dealing with fire in high rises could be an emergency escape/fire fighting and building maintenance system with columns mounted to the exterior of a building for guiding the escape slider, fireman or the maintenance lift. Each column comes with an an inner and outer face that assists in controlling the rate of descent of the escape slider or assisting the fireman in climbing the columns. The slider includes a harness and a body member The body member comes with a brake pad surface which provides automatic braking system in case the user fails to maintain the desired escape posture and control his descending speed. In addition, a manual braking system is also added to the alternate slider designs. This slider can be used by able persons who are physically strong mainly because the descending speed of the slider is required to be controlled by the user himself. After this system is placed into service, plans are being made to design sliders for persons with physical disabilities. (source: High rise building fire escape/fire fighting and building maintenance system, May 4,2008) The following diagram shows a perspective view of an emergency escape/fire fighting and building maintenance system according to the present invention.(source: United States Patent, June 23,1987) CASE STUDIES Garley Fire – Hong Kong 1996 fatalities: 39 This 16 storey high rise in Hong Kong, caught fire on 21st November 1996, during welding work in an elevator shaft. The fire spread upwards at lightning speed through the elevator shaft filling the rooms as well as the escape routes with immense heat and smoke as a result all the charred bodies were found on the 15th floor although more than 90 people were rescued. Atlanta High Rise Fire, 1989 In Atlanta, an electrical fire originating from the 6th floor destroyed hundreds of lives on June 30, 1989. One woman was reported to have jumped from the 6th floor even before the fire department personnel could arrive on the venue. Approximately 14 people were rescued using the aerial ladders while yet others were rescued from within the building. The electric closet, where the fire was reported to have originated, opened directly into the exit corridor as a result when the fire broke out; the corridor was immediately blocked trapping the victims inside. The fire in high rise buildings and the various case studies, stresses the need for automatic sprinkler protection and the resultant impact the fire can have on the occupants behavior. CONCLUSION The events following the attacks in New York City were among the world’s most ghastly disasters one had ever seen, which claimed millions of lives. The events is recorded to have caused the largest loss of life and property in any single event in history of building collapse. Many of the systems designed to combat fire failed including the sprinkler system, fire protection to steel work, escape stairs, lifts, communication systems and the works. The collapse of the twin towers also damaged the local water mains and blocked access to the adjacent buildings. This event, makes us even more aware about our vulnerability towards dealing with such sudden events, either man made or natural, and urges us to think and give more importance to the designs of the high rises so that in future the loss to life and property is reduced to the minimum possible level. But this can only be ensured by good structural architecture of the high rises and incorporating latest technology such as sophisticated softwares which can detect the fire and help the victims take immediate action. REFERENCES May 4, 2008. Available from: K Martin, Fire in High Rise, May 4, 2008, Available from: T.Nakagawa, Staircase Design of High-rise Buildings Preparing against Fire May 4, 2008.Available from :< http://www.triz-journal.com/archives/2001/04/a/index.htm> May 4, 2008. Available from :< http://www.freepatentsonline.com/US4828072.html> Operational Aspects of High Rise Firefighting, May 4, 2008.Available from :< http://www.firetactics.com/HIGH-RISE1.pdf> C. James, Sophisticated Software Helps Analyze Behaviour of Fires, May 4, 2008. Available from :< http://www.facilitiesnet.com/bom/article.asp?id=5224> Logendran, Subramaniam, Fire Safety in Tall Buildings, University Technology, Malaysia. Dr. H J Visscher, Dr F.M. Meijer, Buildings Regulations of Fire Safety in Europe, International Conference on Tall Buildings, 8th May 2003, Malaysia Read More