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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 superhighrise 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 here.

For underground station buildings, a passive safety system is proposed for energy conservation under daily use and for evacuation safety in case of a fire. The stack effect by a solar chimney and the ambient air cooling effect by dry mist, which have been examined in recent years, are used in the proposed system. During any period of the year, the proposed system controls the air current in the direction of "outside air → staircase → concourse and platform → solar chimney → outside air ". If a fire occurs under this status, the safety of staircases will be secured because smoke will be discharged through chimneys. When adopting this system for an underground station building, it is necessary to check the boundary conditions in the building for effective system operation. Therefore, in the present study, a model as small as 1/20 the size of an actual station building was fabricated, and experiments were conducted using scaling laws.

The Japanese Ministry of Construction's Notification 1441 (2000) on "Verification Method for Egress Safety from a Fire Floor" is composed of a set of prescribed characteristic input values for fire load density, occupant density, etc., coupled with a set of simplified formulae to calculate fire and evacuation behavior. The nominal egress time margin is calculated by combining these values and formulae with building design variables, such as room area and ceiling height. To clarify the degree of safety implemented in the verification method, the stochastic variability in input values and uncertainties in calculation formulae have been examined. Based on existing research and survey results, variability and uncertainty are expressed in terms of probability density functions. The target levels of egress from a fire room and a fire floor were also discussed in this study. The calculation method was analyzed using the methods of Reliability Engineering. The Limit State Function was selected as the difference between the nominal time margin of egress safety and the actual, stochastic time margin of egress safety. By examining the safety level of Limit State Function, the Target Safety Index and the Acceptable Probabity of Failure implied in the Verification Method is clarified for typical office building in Japan. This work has clarified that: (1) Two variables which contain inevitable stochastic variation (Fire Load Density and Occupant Density) are recognized as Type A variables, and six variables which contain uncertainties due to the incompleteness of the prediction method (Walking Velocity, Specific Flow Rate, Time to Start the Evacuation, Fire Growth Rate over combustible contents, Fire Growth Rate over lining materials, and Smoke Filling Time) are recognized as Type B variables. (2) The coefficients of variation are large in both Type A and Type B variables, ranging from 13 to 235 %. There is a need to reduce the uncertainties associated with Type B variables. (3) The Partial Safety Factors vary in the range of - 0.45 to 4.97. (4) The implied safety index of the calculation method is in the range of 1 to 3 depending on the method of smoke control and floor area on the condition of egress from a fire room, and in the range of 2 to 3 it is fairly independent on the method of smoke control and floor area on the condition of egress from a fire floor. (5) In comparison with Type A variability, the effect of Type B uncertainties (prediction error) is not negligible. (6) Possible combination of partial safety factors are proposed by 0.2, 2-6, 0.9 for fire load density, escape start time and smoke filling time on the condition of egress from a fire room for typical office buildings with single side corridor in Japan, and by 0.7, 4.8, 2.6 and 0.9 for fire load density, escape start time, fire growth rate and smoke filling time on the condition of egress from a fire floor.

A series of full-scale experiments were carried out to investigate the smoke propagation behavior for t²-fires. The effect of corridor arrangement (size and smoke curtains) were analyzed. The corridor size and smoke curtains have beneficial effect to delay the smoke propagation to downstream corridors. In the experiments, quick mixing of smoke after the decay of fire was observed that result in blockage of corridors. In the prediction of smoke layer by using zone models, this effect is not taken into account. Thus there is a need to revise zone type equations to include smoke-air mixing during post decay period.