An eight-storey building being used as a garment facility collapsed in Bangladesh on April 24. Hundreds died and the death toll continues to rise. In the past too, hundreds have lost their lives in fires in garment factories in Bangladesh. Even as these tragic events generate condolences and expressions of sympathy, they also provide a rare opportunity for the custodians of Nepal’s National Building Code (NBC-94) to engage in some much-needed introspection. Valuable lessons can be learnt from such incidents. This and other tragic incidents could spur modification, improvement and implementation of NBC-94. A sense of urgency is important since the media’s attention is fleeting and a sympathetic public’s memory short.
Could such man-made hazards take place in Nepal in general and Kathmandu in particular? On the weight of evidence, the answer is a definite ‘Yes’. Walk the streets and back alleys of Kathmandu and there is abundance of unmanaged construction and unplanned change in occupancy. Are these buildings being used as originally intended? Or were they even designed for any specific use?
AP
Tall building intended as apartments are being used as hotels; single-family residences have turned into offices, educational facilities, critical care health care facilities and schools; hotels are being converted to shopping malls. These conversions triggered perhaps by the changing business environment and societal demands overlook potentially deadly consequences. Stakeholders and authorities charged with public safety should be alarmed.
It will be premature to jump into conclusions on the collapse of the eight-storey building in Bangladesh. What we do know is that when buildings, designed for one purpose find another use without proper investigation and upgrade, occupants enter a different hazard level for earthquakes, fires and other ‘loads’. Structural components in buildings are designed for anticipated additional imposed loads (live loads) based on their intended use.
Consider a single-family residential facility. According to NBC, the uniform load for residential buildings ranges from 2.0 to 3.0 kilo-newton per meter square (KN/meter square), i.e. 40 to 60 pounds per square foot. Hotels, hostels, boarding house range from 2.0 to 4.0 KN/meter square. Educational buildings range from 3.0 to 5.0 KN/meter square. The California Building Code 2010, on the other hand, assigns a live load value of 40 pounds per square feet for single family residential building.
That same building if used as an apartment is designed for a live load of 50 pounds per square feet. These ‘live loading requirements’ are upgraded when structures find other ‘higher hazard category use’ such as educational institutions, restaurants. Designing buildings for ultimate unforeseen uses will however be uneconomical. Buildings with change in use should be evaluated through investigative engineering for their capacity to sustain a different load.
Proper enforcement of building codes could significantly reduce the chances of events like the recent Bangladesh tragedy. In Nepal’s context, this means proper revision of the NBC-94 to addresses “change of use or occupancy” issue. As things stand, NBC-94 is merely a document that fails to meet its singular and primary objective of ensuring public safety miserably.
Other well-established regulations recognize safety hazards and place limits on building heights, area and number of stories based on use and type of construction material. Such limitations allow for scientific analysis of structural and non-structural aspects of safety.
Tall building intended as apartments are being used as hotels. Single-family residences have turned into offices, educational and healthcare facilities.
Whether the eight-storey building in Bangladesh met the safety requirements for housing a garment factory remains questionable. But as noted in the media, it was constructed illegally. Obviously, safety codes were ignored, a practice that is all too common in Nepal as well.
The Bangladesh tragedy suggests the need for urgent reforms on safety issues that are inadequately addressed in NBC-94. One such issue is “escape mechanisms” from buildings. Principals of exiting from buildings, such as those found in the California Building Code, call for at least two continuous, unobstructed, undiminished access to exiting system from each floor, separated adequately from each other to allow choice of access for the people during emergencies. Properly and adequately designed and pre-engineered escape mechanisms in buildings—especially from taller buildings and building holding a large number of people—give ample time for escape during disasters. The NBC-94 needs urgent modification to deal with these issues. But this will happen only when the custodians of the Nepal National Building Code and development stakeholders learn important lessons regarding both structural and non-structural aspects of building safety from the tragic event at Bangladesh.
The author is a California-licensed professional engineer and visiting faculty at KU
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