OARU model

OARU Model (Kjellen and Hovden, 1981, Kjellen and Larsson, 1981). 

The OARU model uses the term determining factors rather than causal factors. These are technical, organisational and social properties of the man-machine system and department that affect the accident sequence, but change only slowly in comparison with it. Figure 5.4 shows an example of an accident analysed by means of the OARU model. The distinction between the accident sequence and the underlying, determining factors is here made clear. 

Figure 5.4 Analysis of an accident at a construction site by means of the OARU model.

There are also other accident models that include a process component . Figure 5.5 shows that many of them distinguish between different phases in a way similar to the OARU model. 

Incidents rarely occur by pure chance. In the analysis of how incidents occur, we rely on the OARU model of Section 5.3. An incident is usually preceded by deviations at the workplace that increase its frequency and/or the consequences of it. SHE measures that eliminate existing deviations (e.g. repair of faulty safety equipment) will have an immediate effect on the risk of accidents. They will, however, not have lasting effects if the deviation may occur again. 

Modern process models distinguish between different phases of the accident sequence. A typical example is the OARU (Occupational Accident Research Unit) model (Kjellen and Larsson, 1981). The accident sequence is here divided into three phases the initial phase the concluding phase and the injury phase. There are thus four transitions between different phases ... 

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