Designing for fire safety

Approaches

Destruction of whole cities by fire may have been common in the past, but it is not the case nowadays – although our cities and buildings have grown considerably in size. Fire safety is a standard part of building design process. For some building types and occupancies it is a mandatory part with high importance.

Prescriptive approach

Setting requirements in terms of fire characteristics of building parts and materials is now the traditional way of securing a certain level of fire safety. The requirements may often originate from experience and have been implemented as a consequence of past disastrous fire cases.

Performance-based approach

Over the past few decades we can see a rapid development in a new way of building design – a valuable set of scientific tools called Fire Safety Engineering.
This method may be the only possible way to construct very large and special buildings. Elements of this approach are often used in conjunction with traditional prescriptive way – for example modelling of evacuation and smoke spread.

Although predictions of fire growth and smoke movement are made using the anticipated building content and building use, they do not usually take into account two facts:

  • The building structure may give out heat and contribute to fire,
  • The building structure may emit significant amount of toxic smoke and gases.

Hence it should be assumed that only building structures which do not release heat and smoke can be used if this approach has been applied during the building design.

Given the fact that fire – and human reaction to it – is a disastrous and hardly to predict phenomenon, it is beneficial to have certain level of robustness and reliability as part of the building design.

Safety margins are used in every aspect of building design and there is no reason why they should not exist in assumptions and procedures aimed at saving human lives.