Introduction

It is becoming increasingly apparent to engineers that condition monitoring of machinery reduces operational and maintenance costs, and provides a significant improvement in plant availability. Condition monitoring involves the continuous or periodic assessment of the condition of a plant or a machine component whilst it is running, or a structural component whilst it is in service. It allows for fault detection and prediction of any anticipated failure, and it has significant benefits including (i) decreased maintenance costs, (ii) increased availability of machinery, (iii) reduced spare part stock holdings and (iv) improved safety.

Criticality and failure mode analysis techniques are commonly used to identify where improvements in machinery availability and reductions in maintenance costs can be achieved through the integration of condition monitoring techniques. This involves selecting the appropriate modes of condition monitoring (safety, online or offline vibration monitoring, and/or online or offline performance monitoring) based on the machine criticality and modes of failure, and also focuses on optimising the condition monitoring system to achieve specified objectives effectively and at least total cost. Criticality and failure mode analysis now also includes consideration of total production output and plant efficiency (in addition to breakdown/reliability), since these aspects of plant operation are equally important to total operating costs and production output, and hence bottom-line profits of large-scale petrochemical and power generation facilities. Consideration of total production output and plant efficiency represents the latest development in condition monitoring systems and is generically referred to as performance monitoring.