Special Issue

Mar 28 2013

FIRE INCIDENT REPORT (2)

“Wooshin Golden suites”in Busan

written by Young-sun Kim, Masayuki Mizuno and Yoshifumi Ohmiya (Center for Fire Science & Technology, Research Institute for Science & Technology,Tokyo University of Science, Japan)

INTRODUCTION
With rapid advance of construction technology, buildings have become much larger and higher. East Asian cities also have a forest of superhigh-rise buildings backed by their economic development. With many buildings, cities changed their skylines and superhigh-rise buildings with characteristic appearance are now regarded as the landmark of the city.
As superhigh-rise buildings are built by fully integrating state-of–the-art construction technology, construction of superhigh-rise buildings and formation of cities having those tall buildings represent the technological or economic strength of the nation. In fact many people believe they are the symbol of the nation.
To give some examples of superhigh-rise building fires in recent years, there are cases including destruction of World Trade Center by terrorism in New York, USA in 2001, Windsor building fire in Madrid, Spain in 2005 and CCTV high-rise building fire in Beijing, China in 2009 among others. As seen in these examples, fires in superhigh-rise buildings often burnt down and entirely destroyed the building, and yet the overcrowding trend of cities seems to continue.
Under such circumstances, South Korea entered the rush to build superhigh-rise residential buildings in 1990s mainly in Seoul starting with the construction of 30-story residential building in early 1990s. Eventually in 2000s, buildings principally designed for residential use including superhigh-rise residential and commercial complexes or officetels (buildings with units that can be used as either office or house) became higher than 70 stories.
South Korea shows different tendency from other advanced nations in situations that led to build superhigh-rise buildings. The reasons are described as follows.Firstly, lthough high-/superhigh-strength and high performance concrete is used as structural component of buildings in order to bear the vertical load, studies and accumulation of technology concerning its performance have yet been insufficient.
The rush to build residential and commercial complexes by leading constructors started before they learned enough knowledge and thus they are said to be too early to expand business. Secondly, because they have not reached social consensus on disaster prevention system such as appropriate disaster prevention equipment or laws and technical guidelines of interior/exterior materials, they have been just carrying out heuristic measures. Thirdly, development of legal system to control those heuristic measures is promoted so rapidly that even experts in concerned field cannot catch up with it.
In a situation that more and more superhigh-rise buildings are built one after another, a fire broke out in a 140-meter high and 38-story building (“Wooshin Golden Suites”) located in Marine City, the center area of Haeundae, Busan in South Korea in the morning of October 1, 2010. The fire rapidly spread to upper levels and burnt wide range of outside wall and inside of some floors. Although there was no loss of human live or serious damage to building structure, we found that combustible exterior material had certain influence at the time of fire. Therefore Tokyo University of Science Global COE Program conducted a field survey. This article presents the conditions of “Wooshin Golden Suites” fire and explores problems in superhigh-rise building fire.
OVERVIEW OF “WOOSHIN GOLDEN SUITES”

(“Wooshin Golden Suites” and around)

Building Structure
• Location : Haeundae district, Busan, South Korea
• Constructor : Wooshin Construction
• Completion : December 2005
• Floors : 38 stories above and 4 stories under ground
• Structure : SRC structure (S structure and RC structure in part)
• Height : Approximately 140 meters
• Floor Area : (Total) 68,917 m2
• Floor Area : (Standard Floor) 1,935m2

The course of the fire

11:21 a.m. Fire broke out (according to neighbors )
11:33 a.m. Report to the fire station
11:36 a.m. The first firefighting team arrived at the scene
11:44 a.m. Evacuation guidance and rescue efforts by firefighters began
12:10 p.m. Rescued 10 people using snorkel (ladder truck)
13:00 p.m. 9 people who had escaped onto the roof were rescued by helicopter
13:02 p.m. Extinguished fire around the fire origin floor
18:48 p.m. Fire of entire building was put out
MAJOR PROBLEMS IN THE FIRE
《Flammability of Outside Wall》

(Cross section of the outside wall structure)

In South Korea, there is no regulation on the use of combustible external material. The biggest problems in “Wooshin Golden Suites” fire was that outside wall using combustible material burnt intensely and the fire rapidly spread upward due to the surface shape and strong wind at the time.
Exterior finishing material used in the outside wall is called aluminum composite panel with small load and high usability in construction, which is especially effective to decrease structural load and reduce construction cost of superhigh-rise buildings. aluminum composite panel is connected to angles and then fixed to concrete wall.

(Pattern of aluminum composite panel〈the top faces to outside〉)

Figure shows the pattern of aluminum composite panel. On the core material made of combustible polyethylene resin, aluminum sheet, some kinds of coating material and protection film are piled up to ensure beautiful surface appearance as well as strength and resistance. Coating material and aluminum sheets are very thin and not fire-resistant as the melting point of aluminum is at about 660 ˚C. Also, considering that they have high thermal conduction rate and polyethylene ignite at 350 to 400 ˚C, it is very likely that they easily ignite and burn when exposed to heat expected in case of fire.
If incombustible material had been used in the outside wall, such a significant spread of fire could have been prevented. After “Wooshin Golden Suites” fire, the importance of fire-resistant capability of wall is recognized again in South Korea. On the contrary, since more than 80% of high-rise buildings in South Korea were built using combustible material, immediate response to this situation is strictly required.
《Difficulty in Evacuation and Rescue Activity》
The second problem is that lower than 50-story buildings in South Korea are not
subject to regulations requiring mid-level emergency evacuation space and other measures because they are classified as high-rise but not superhigh-rise buildings. Therefore, high-rise buildings having 16th to 40th levels where snorkels (pump truck with folding ladder) cannot reach are not covered by these regulations. Fortunately “Wooshin Golden Suites” fire did not take human lives, but some people in the building escaped onto the roof and were rescued by helicopter.
As the buildings become higher, vertical distance to escape become longer and people have to pay larger physical cost. Therefore, considering the features of superhigh-rise buildings, installation of mid-level evacuation space and immediate introduction of evacuation measures such as installing elevators exclusively for evacuation even in lower than 50-story high-rise buildings are strongly required.

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