Fire safety engineering. Methodology

Like all safety regulations, fire safety regulations were developed in response to catastrophic fires. The first French regulatory act was a royal decree in 1667, which imposed plaster cladding on the wooden framework of Parisian dwellings, following the Great Fire of London in 1666. Subsequently, regulatory requirements were gradually fleshed out, culminating in the regulations currently in force, depending on the type of activity: establishments open to the public, installations classified for environmental protection, homes... Of course, fire safety regulations are not confined to buildings; they also apply to civil engineering structures, air, sea and land transport...

Experience shows that some fires develop very quickly, while others are easily controlled. This is proof that it is possible to reduce the scale of losses by adopting appropriate design measures, integrating judiciously chosen materials and products or high-performance safety systems, so that these constructive or protective devices oppose the development and spread of fire.

When the first regulations dealing in detail with fire safety in buildings open to the public were drawn up, knowledge of how fires develop and of the fire behaviour of building materials and components was still extremely limited. It was therefore necessary to base requirements on simple principles and experimental verification. In the case of fire resistance, for example, the use of a single conventional fire is a case in point.

These regulatory requirements were therefore mainly descriptive in nature, to enable the various players in the construction industry to implement them without requiring in-depth knowledge of the chemical, physical and physiological phenomena governing fire and its effects.

Subsequently, verification tests on certain types of elements were replaced by analytical approaches. France was one of the first countries in the world to authorize calculations to determine the fire resistance of structural elements, with the decree of December 19, 1975.

At the same time, increasing knowledge of combustion, fluid mechanics, risk analysis, etc., now makes it possible to numerically model the development of fires and estimate their effects on people, property, structures and the environment...

Descriptive regulations are intended to cover the majority of construction cases that may arise, by requiring the implementation of means (devices considered to reduce the risk in the event of fire). The effectiveness of these various means has always been difficult to assess, and it is highly likely that some of them will have little or no effect on risk reduction: investment in these useless measures is therefore detrimental...