Maintenance of process plants requires application of good maintenance practice due to
a great level of complexity. From a plant maintenance point of view, the most significant activity
is turnaround, an activity carried out through project task with long planning process
period and very short execution period, which makes it one of the most complex projects
of maintenance in general. It is exactly this kind of maintenance that is based on multidisciplinarity
which has to be implemented through the system of quality management on all
levels of maintenance management. This paper defines the most significant factors determining
the process of turnaround projects quality management and its efficiency. Such relation
is observed through moderating influence of complexity on process management efficiency
in the turnaround project. The empirical research was conducted based on the survey of
turnaround project participants in five refineries in Croatia, Italy, Slovakia and Hungary.
For exploring the influence of research variables testing of the target relation is carried out
by applying logistical regression. Research results confirm the significance of complexity as
variable that significantly contributes to the project performance through the moderating
influence on success of the project, as well as the influence of an efficient management on
a plant turnaround project key results. Beside theoretical indications, practical implications
that arise from this research study mainly refers to management process of the industrial
plant maintenance project.