TABLE OF CONTENTS The entire process from an initial accidental event to the final end events, determined by consideration of the performance of protective systems and the responses of equipment and structures, is sometimes called the 'escalation process'. This is the widest interpretation of 'escalation'. Under this interpretation, escalation thus involves determination of different accident sequences and the related loads and responses applicable to each sequence.
A narrower interpretation of 'escalation' is to describe it as the secondary failure of containment, due to accidental effects. This is the interpretation of 'escalation' used in this book, and the wide interpretation is replaced by the term 'accident sequence' modelling or analysis.
It may be important to carry out escalation analysis if the risk to assets is being considered. An alternative, which may be carried out independently of the escalation analysis, is the so-called impairment analysis, which involves an assessment of the frequencies of impairment of the main safety functions. Both escalation analysis and impairment analysis are focused on response to accidental loading, mainly to fire and explosion loads.
Escalation of fire from one area to another is required to predict whether a fire spreads out of the original area. Secondary fire effects such as smoke or radiation stemming from the original fire are not considered as escalation. It is assumed that fires may escalate due to damage to the fire walls, by direct flow of fuel to the adjacent area or by external flames. Escalation to other...
