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Asia On The Mark Issue 26 (Summer 2008)
Fundamental of High Rise Building Fire Safety

Fundamental of High Rise Building Fire Safety

Knowledge in the field of fire protection is undergoing development and recognition that will enable buildings to be designed for fire safety more rationally and efficiently. After years of trial and error, we are able to develop concepts and criteria that enable us to build high rise buildings that are safe. More over this vertical expansion is also due to the increasing population and restrictions towards horizontal expansion. Much activity is taking place today regarding fire safe building design. The general thrust is directed towards quantification procedure and identification of a rational design methodology to parallel or supplement the traditional "go or no go" specification approach. Adequate fire prevention and protection lead to the safety of occupations and buildings. To mitigate the sources of fire and losses due to it, planning at the architects' table enables us to design a fire safe building. Both active and passive fire defenses provide reasonable safety from the effects of fire. Hence a well knit plan, its implementation in the design and construction of a high-rise residential building executes a fire safe structure.

Objectives

Effective fire safe design begins with conscious analysis and decision-making early in the design process. To effectively incorporate the building fire defenses into the design the fire safety objective must first be identified.

The acceptable levels of safety and the focus of fire safety analysis and design process objectives are concentrated in the following areas.

Life safety
Property protection
Continuity of operation
Environmental protection

Fire Safety Design Strategy

Fire safety objective can be met if fire ignition can be prevented or if, given ignition, the fire can be managed. Evaluating a design for building fire safety represent a systematic approach to the fire safety strategy. These strategies can be identified as follows:

1. Prevent fire ignitionn

The first opportunity to achieve fire safety in a building is through fire prevention, which involves separating potential heat sources from potential fuels. Major building fires are started by heat sources and ignitable materials that are brought into the building, not built into it. This means the design of the building, from the architects and builder’s standpoint provides limited potential leverage on building future fire experience.

For design purposes fire prevention is enhanced by careful observance of codes and standards in the design and installation of electrical and lighting system, the heating system and any other built in equipment such as cooking, refrigeration air conditioning and clothes washing and drying. Venting system is also needed to be designed carefully to carry carbon monoxide and potential fuels along protected paths.

Protection from lightning and exposure fires affects the external design of the building. A fire in one building creates an external fire hazard to neighboring structure by exposing those structures to heat by radiation, and possibility by convention currents, as well as to the danger of flying branch of fire.

2. Control combustion Process

The control combustion process is concerned with slowing the fire to provide other fire safety measures with sufficient time to be effective. A systematic design for this purpose should address the possible way that hazards can grow rapidly.

The building fire safety system can be organized around fire growth and its resulting production of combustion i.e. flame, heat smoke ad gases. The ease of generation and movement of these products is influenced by counter measure provided by the building. The effectiveness of the building fire safety system determines the speed, quantity and paths of movement of these products of combustion.

The main factors that influence the control of combustion process are

i. Fuel load
ii. Interior finish of the room
iii. Air supply
iv Size shape and construction of the room
v. Fire Load

3. Control fire by construction

Fire Resistance Barriers such as walls, partition and floors, separate building spaces. These barriers also delay or prevent fire from propagation from one place to another. In addition, barriers are important features in any fire fighting operation because they dictate the size of fire.

The effectiveness of a barrier depends upon its inherent fire resistance construction and its penetration. Use of flame retardant paints, fire stop barriers, firewalls, fire doors and windows. Other few methods for controlling the fires by construction in building.

4. Fire detection and alarms

Fire detection is needed so that automatic or manual fires suppression will be initiated, any other active fire protection system will be activated and occupants will have time to move to safe locations typically outside the building.

One reason for concern over any rapid initial fire growth is that it can shrink the time available after detection for the life and property saving responses. Whatever type of detection system is chosen, it is important that, for each area of a building, a realistic assessment be made of the implication for response time after the fire is detected and before a lethal or other high hazard condition develop.

Alarm provision need not be linked to the detection sensor location but should be designed to tell occupants what they need to do based on where they are and their ability to respond. This would include the use of central annunciation panels and monitors to inform responsible staff.

5. Automatic suppression

To accomplish automatic suppression, both detecting the fire and applying sufficient suppressant are necessary. For nearly a century and a half automatic sprinkler have been the most important single system for automatic control of hostile fires in building. Among the advantageous of automatic sprinkler is the fact that they operate directly over a fire and are not affected by smoke, toxic gases and reduced visibility. In addition much less water is used because only those sprinkles fused by the heat of fire operate. The major elements of determining the automatic extinguishing system are

i. Its presence or absence
ii. If present, its reliability
iii. If reliability its designing and extinguishing effectiveness

6. Manual suppression

The major aspect of this part of building design include

i. Fire department’s distance from building
ii. Initial agent application
iii. Fire extinguishment
iv. Ventilation
v. Water storage and use
vi. Water removable
vii. Barrier effectiveness

7. Managing the exposed

Fire impact can be lessened by managing the exposed i.e. people property, operations, environment or heritage depending on the design aspects being considered. The exposed people or property may be safeguarded either moving them to a safe area or refuge or by defending them in a place. The design for life safety may involve one or combination of

i. Evacuation of the occupants
ii. Defending the occupants in place
iii. Providing an effective area of refuge
iv. Practicing Evacuation drill.

Role of UL in high-rise building fire safety

 
   
Underwriters Laboratories is the first laboratory in the world to have a testing facility for large variety of building construction materials with over a century experience. UL has a number of standards and codes for effective Fire Resistance components of Building like fire doors, dampers, smoke exactors, fire walls, flame retardant paints, flame retardant building materials, roofing materials, through penetration stops etc. and Fire Suppression components like Fire Extinguishers, Fire Extinguishing system Units, Pumps, Engines, Hose & Hose valves, Sprinklers, Deluge valves, Water Mist nozzles etc. These codes and standards help in a long way in the containment & extinguishment of the fire and smoke spread and thereby protecting and saving lives.

By Sumit Khanna, Safety Evaluation Engineer

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In this Issue
Fundamental of High Rise Building Fire Safety
UL's Water Program Makes its Indian Debut at The Everything About Water Expo in New Delhi
Functional Safety
Creating the Future of Fire Risk Management
UL 864, 9th Edition
GS Mark — Polycyclic Aromatic Hydrocarbons (PAH)
UL Expands Global Photovoltaic Footprint to China
UL offers One Step for reaching all North American markets
Recent Changes to the MDD
UL University
UL Standards
News Bites


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