The last step of the workshop is to identify all the possible loss of-
control events that may occur during each working stage of the
activity, regardless of their likelihood.
Finally, the researchers compile a set of accident scenario types
(Table 1), and match each loss-of-control event recorded with one
or more types. Association with accident types is needed so that
the potential victims of each loss-of-control event can be identified
when a project’s risk levels are calculated. For any accident scenario
type, workers who are adjacent to the loss-of-control event,
below it, and/or above it may be exposed to the hazard. For some
types, only the workers performing the activity in question are exposed
– these are classified as ‘self impacting only’. The third column
of Table 1 provides these logical relationships.
In order to classify the accident scenario types, it must be possible
to calculate the level of exposure for each type as a function of
the geometric relationships between the locations and any equipment
involved. This requires a unique algorithm for each class of
accident types. The necessary exposure algorithms have been
developed and their application has been tested. Details can be
found in Sacks et al. (2009).