TABLE OF CONTENTS In 1991, the Commission for the EU initiated a project to develop 'an overall knowledge-based methodology for hazard identification'. A methodology was developed by the University of Sheffield in the UK and Ris National Laboratory in Denmark (Rasmussen and Whetton 1993), based on functional modelling of the system. This functional approach has been found to be very useful for Concept Hazard Analysis (CHA). The CHA methodology has also been described by Wells et al. (1993).
The CHA is a high-level hazard identification tool, and its output can be used for more detailed analysis of specific areas, as identified.
In the plant functional model, a function is an object comprising an 'intent', a list of more than one 'methods', which are used to satisfy the intent, and a list of zero or more 'constraints', which impose restrictions upon the Intent. Each element of the lists of methods and constraints can itself be treated as an object defining a new Intent with its associated methods and constraints. A simple schematic model is shown in Figure 4-7.
Hence, a plant model contains objects whose elements can be classified as follows:
Intents representing the functional goals of the specific plant activities in question
Methods representing items such as hardware, procedures and software that are used to carry out the Intent or operations that are carried out using those items.
Constraints describe items (physical laws,...
