Fire resistance
Concrete is completely non-combustible and outperform both steel and timber in any test. It does not burn, it cannot be 'set on fire' like other materials in a building and it does not emit any toxic fumes, smoke or drip molten particles when exposed to fire.
Concrete and its mineral constituents enjoy the highest fire resistance classificatioin (class A1) under EN 13501-1.
The excellent fire performance is due in the main to concrete's constituent materials (ie, cement and aggregates) which, when chemically combined, form a material that is essentially inert and has poor thermal conductivity. It is this slow rate of heat transfer that enables concrete to act as an effective fire shield not only between adjacent spaces but also to protect itself from fire damage.
For any building or structure, regardless of its complexity, design for fire safety should address the following four principal objectives:
- to ensure stability of the loadbearing construction elements over a specific period of time
- to limit the generation and spread of fire and smoke
- to assist the evacuation of occupants and ensure the safety of rescue teams
- to facilitate the intervention of fire fighters and other rescue parties
Good practice in design for fire safety incorporates these aspects and more in what is termed 'fire engineering' for large, complex structures that warrant additional design effort. Although prescribed data (such as dimensions for thickness and cover) may be used, the aim of fire engineered structures is to move away from the traditional methods and create a fire strategy dedicated to the project in hand, based on the building's design, how it will be used, fuel load and the probability of a fire occurring. For this reason, computer software is used to perform a probability analysis of the behaviour of both fire and people.
From a whole building standpoint, concrete can satisfy the four principal objectives of fire safety through its inherent fire resistance and the utilisation of its structural continuity in fire engineered design.
Information provided by The Concrete Centre www.concretecentre.com
