Façade is the face of any building and today glazed facades are more in demand. But the glazed buildings are in much higher risk of fire hazard than brick and mortar façade buildings. This is majorly owing to the susceptibility of the complete disintegration of glazed façades in the event of major fires and the spread of fire through the external face of the building. This is established from several well-publicized fire accidents in high-rise buildings.
So architects and developers need to be made further aware of the same to ensure that the life-safety aspects of high-rise buildings are enhanced and not diminished by the façade.
Let's discuss fire risks associated with glass façades, their application concerning codes, and commercially available options to minimize the fire risks.
There can be many reasons for fire spreading in glass façade. Some of them are:
•Poke through effect: Spread of fire from external fire to internal areas of a building.
•Chimney effect: Spread of fire and smoke through the gap between glazing and the slab.
•Leap Frog effect: Spread of fire from internal areas to upper floors through external façade.
Before delving into the solutions for providing fire-rated façades, it is essential to be aware of the code requirements for the provision of fire-rated glass façades. The NBC code has listed out several norms for the fire safety of façades in high-rise buildings. Some key points brought out after studying clauses and codes are:
•For buildings with a distance greater than 9m from adjacent buildings, normal tempered glass or above, is acceptable as a fenestration material, provided the same is installed in a non-flammable assembly. Care should be taken that the PVB coatings, sealants, etc. are also non-flammable.
•Mandatory use of fire-resistant glass is restricted to usage in areas or elevations which require a specific fire rating.
•NBC acts as a guideline; however, the local fire authority is the final authority on fire norms to be followed.
•Providing openable panels is mandatory as per the codes.
New norms specified in the latest edition of NBC are a start and should be followed in all projects irrespective of commercial or residential. At present, there is a lot of ambiguity concerning the provision of codes and requirements of local authorities, where certain clauses of the code are ignored.
Some aspects have been quantified in various codes and standards for the selection of glass materials.
•Resilience to fire
•Rate of flame spread
•Time to ignition
•Chemical and convective heat release rates
•Mass loss rate
•Effective heat of combustion
•The heat of gasification and smoke yield
Not everyone is fully aware of these guideline and codes which is not a good thing. For more information on fire safety codes and measures to reduce spread of fire in glazed building read the article.
CO2 fire extinguisher discharges CO2 gas, also known as carbon dioxide.
This is stored in the extinguisher as a liquid, and the gas is created under pressure when the handle of the extinguisher is squeezed.This causes the CO2 gas to emerge at great speed, which is why CO2 fire extinguishers are not recommended for chip pan fires – they could literally blast the flames into surrounding areas.Unlike water and foam extinguishers, CO2 fire extinguishers do not work by cooling the fire and so are ineffective on fires involving flammable solids.Instead, CO2 extinguisher work by replacing the oxygen surrounding the flames with carbon dioxide, meaning the fire can no longer burn.
Precaution: Fire extinguisher refilling and maintenance is necessary once in a year.
