Doors – Fire Safety
Using Fire Doors to Maintain Fire Safety
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hen loss to human life and property bring about grief, we invest our resources to ensure such losses do not occur again. For decades, countries and jurisdictions have been writing and evolving guidance documents (building codes) to build-in safety measures in construction to prevent loss to life. These codes give requirements ranging from structural requirements, fire initiation and growth prevention requirements, and even requirements for the design of plumbing systems to ensure the health of building occupants. The development and implementation of such codes in many countries is usually driven by manufacturers of products who believe very strongly in prevention of loss. The ethos of such companies drives them to aid the adoption and localisation of such codes written internationally. FIRE SAFETY CODES They are guidance documents which usually divide construction of different types of buildings by grouping them into what is called occupancies (the occupants and use of the building) as it helps to predict the behaviour of people if there is a fire. Fire Safety Code requirements provide the framework and boundaries to architects and consultants for designing buildings. The codes also help: a) Material suppliers to produce standard materials
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WFM | MAY-JUNE 2019
b) Contractors to objectively price and plan for construction work, and c) Authorities and regulators to objectively evaluate how fire safety will be implemented for buildings which are competing to differentiate themselves from other buildings. For the majority of the codes followed in the world, a twopronged approach for fire safety is commonly followed. One, they aim to prevent a fire from initiating and spreading beyond the area where it began (passive fire protection). Two, to have measures in place to detect, and if possible, suppress a fire (active fire protection). As the use of combustible materials in construction has been increasing over the past few decades; fire rated doors (and wall and roof systems) have been enabling the containment of fire within a compartment until the fire brigade reaches the building and the occupants can be safely evacuated to prevent a loss of life. WHAT ARE FIRE DOORS? Passive fire protection creates a strategy of compartmentalising the occurrence of a fire within a small area so that the fire does not spread rapidly. Figure 1, explains how a compartment can be designed on a typical floor plan for an apartment building. The solid purple lines show the area where the walls might be designed to contain the fire and the red
circles show doors that might be required to be fire rated. The words ‘might be’ are used as the type of occupancy (where the building is constructed and who occupies it) defines what the fire strategy is designed and how it is deployed. A fire door assembly is a complete set of door-frame, doorleaf, door-hardware and associated fixing details. It is this complete combination that need to contain a fire in a room/compartment. As per a published report on “analysis of changing residential fire dynamics” by Underwriters Laboratories, experiments show that living room fires now have flashover times of less than 5 minutes when previously, they used to be around 30 minutes. The time between the initiation of a fire (dropping a burning matchstick or a cigarette stub as an example) to the time when major combustible items like sofa or mattress, etc. are burning creating high temperature and pressure is defined as a flashover time. Beyond flashover time is when it becomes very challenging to control and suppress the fire. To validate the effectiveness of a fire door assembly, such a condition is replicated in a fire testing furnace. Figure 2 shows a fire resistance test of a glass partition system in progress. Here you can see the inside of a fire testing furnace. TESTING A FIRE DOOR ASSEMBLY Testing laboratories need to be able to simulate the conditions defined