TABLE OF CONTENTS One of the problems in attempting rational design of fire safety systems for buildings is the development of an understanding of the relative effectiveness of fire safety systems that act in different ways. For example, comparisons of systems based on automatic sprinklers with those based on fire resistance ratings for structural elements and barriers are often frustrated, following a comprehensive comparison of the systems, by the question: But what happens if the sprinklers fail? .
An assumption behind this question is that while sprinklers may sometimes fail, other systems do not. It appears that this attitude stems from the historical development of fire safety systems in building regulations and the like. These systems appear to have initially been largely based on two principles:
Separation
Use of non-combustible materials.
Separation was achieved by requiring certain distances between buildings or by requiring solid masonry walls of certain thicknesses and details if the buildings had to be close together.
Sprinklers did not exist at that time and thus could not be specified.
However, in recent times sprinklers and various other subsystems and components have been specified in building regulations and the like, usually in addition to the existing requirements.
To evaluate the effectiveness of each system, subsystem or component we can look at the changes in outcomes when the systems are present. For some fire safety systems, subsystems and components data that enables the effectiveness in relation to certain objectives to be evaluated can be found in fire statistics [3].
