AUG 12 -
Good morning, Kathmandu. You are at a crossroads. You must wake up to the hazards and risks from earthquakes and fires.
Modern and tall buildings are mushrooming. Infrastructure is inadequate. Upgrade is dismal. Geological realities already pose potential catastrophic earthquake risks. Fires often follow earthquakes. Electrical short-circuits, gas cylinders, candles and other igniters in homes, apartments, hotels, offices, theaters and other spaces also start fires. Fire safety cannot be ignored.
Safe evacuation from fires is possible only when spaces and buildings are analysed, designed and constructed
per acceptable, recognised standards of exiting. Engineered exiting systems permit safe passage from fires and deadly smoke.
Exiting, one of the many non-structural components of building design, is of major concern. Code-complying exiting systems save lives by reducing potential fire and smoke risks through local and global exit pathways. Fire safety is achieved by appraising the use or occupancy of spaces, the location of individuals within spaces, the building’s type of construction, fire-fighting capabilities inside and outside the building and other issues. The maximum potential number of people (occupants) in each space and the entire building is considered. Because codes recognised panic behaviour, safe exiting systems provide continuous, unobstructed, undiminished and secure paths to open public spaces. Exiting systems can be complex and their design cumbersome, but it cannot be marginalised. A certified “safe building” comprehensively satisfies both structural and non-structural safety requirements.
The exits in single family homes are designed differently from those within tall buildings, restaurants or movie halls. Living in upper floors is more hazardous than living at ground level. Building codes, such as the California Building Code (CBC), recognise this. Mandates ensure access to a minimum of two adequately protected, adequately separated, sufficiently wide exits from upper floors when potential occupants exceed threshold numbers, thus insuring alternative escape paths to an exit.
A restaurant space with 50 or more potential occupants requires a minimum of two adequately separated exits through a continuous and uncompromised exit system. Exit convergence is prohibited.
Correctly designed exiting systems result in dimensional modifications, as well as building and loading configuration changes. Exiting systems may impact a building’s structural design and costs. Ineffective, improper, inadequate exiting systems, however, cause preventable deaths.
Code authorities are trustees and guarantors of public safety. Viable, comprehensive, enforceable building and land development codes are their tools. Ineffective codes trivialise hazards and risks and create a false sense of security from both structural and non-structural hazards.
Firstly, hats off to the Nepal National Building Code (NBC)-1994 developers. Some rules are in place now. However, challenges abound, and NBC remains a helpless adolescent infant.
NBC, the legal controlling regulatory document, enforces safety in living and working environments. Revisions are currently underway, and it is a timely moment to enhance its provisions—both structural and non-structural—for greater public safety. Input from all stakeholders (government agencies, architects, engineers, planners, contractors, developers, politicians, the public, members of the disabled community, financiers and many others) is crucial. Public safety hinges on NBC’s provisions and implementation.
Let’s attempt to evaluate awareness, consciousness and potential safeguards from fires by seeking answers in NBC-1994. A few observations:
According to the NBC-1994 preface on the requirements for state-of-the-art design, the building code was prepared in 1993 “as part of a bigger project to mitigate the effect of earthquakes on the buildings of Nepal”.
As far as non-structural safety issues are concerned, the NBC section on provisional recommendations on fire safety states: “This standard covers the basic requirement for fire safety in the design of ordinary buildings. This standard, with due consideration to the severe limitations on the issue of fire protection in Nepal conditions,
takes a modest approach. It deals only with the minimum requirements of exits from and access to ordinary residential buildings from the fire safety point of view. Designers are encouraged, wherever possible, to incorporate higher levels of fire safety in their design by following relevant reference, standards or codes”.
This current legal language is insufficient in that it limits concerns to “ordinary residential buildings”. What are “ordinary residential buildings”? Are they single family homes or tall apartment buildings? What are the safety impacts—non-structural and structural—when these “ordinary residential buildings” find other unapproved uses such as schools, hospitals, colleges and offices?
On the other hand, The NBC preface on architectural design requirements states, “The module of Nepal National Building Code covers general building design requirements in accordance with the principles stated in the Bhawan Ain-2055 (Building Act). The principal focus is on the safety of occupants in a building during earthquakes, fires and natural disasters. Due to the limited technical manpower in the country’s construction industry, the code has been simplified for the ease of use and implementation. It is hoped that with the development of manpower and modernisation of construction processes, it will be possible to release a more sophisticated set of building planning guides in the future”.
Unclear, ambiguous, legally-binding language fails to insure public safety. Margins for misinterpretation, misrepresentation and unenforceability are infinite. Thus the perception: non-structural safety aspects, including disabled access issues, are inadequate or misunderstood in NBC.
Grand visions for a modern metropolitan Kathmandu shall mandate strong, viable and enforceable fire-safety, building and land development codes to insure public safety.
Codes have many components: administrative, enforcement, fire-life safety (non-structural), structural, mechanical, electrical, land & infrastructure development and environmental. Each component is uniquely important yet intertwined. Public safety is insured through judicious collective application and enforcement of codes.
NBC revisions must include comprehensive non-structural requirements for exiting systems based on the classification of buildings; consideration of uses or occupancy; type of construction; area, height and stories limitations; and fire-resistive requirements. Non-structural exiting systems cannot be accomplished in a few NBC pages.
Life is precious. The revised NBC must pass the fire test and address Nepal’s unique challenges arising from several World Heritage sites; a rich mix of historical, cultural and archeological sites; and the demand for modernisation.
Baidya is a licensed California engineer and currently a visiting faculty teaching engineering codes at Kathmandu University
Posted on: 2012-08-12 08:24