Generally speaking, there are two types of maintenance in use:
- Preventive or scheduled maintenance, where equipment or facilities are inspected, maintained and protected before break down or other problems occur.
- Corrective maintenance where equipment is repaired or replaced after wear, malfunction or break down.
Architectural conservation is another type of maintenance involving the preservation, rehabilitation, restoration or reconstruction of historical structures made from stone, brick, glass, metal, and wood with MRO materials which match the original constituent materials where possible, or with suitable polymer technologies.
Preventive maintenance & repair
Preventive maintenance is maintenance performed with the intent of avoiding failures, safety violations, unnecessary production costs and losses, and to conserve original materials of fabrication. The effectiveness of a preventive maintenance schedule depends on the RCM analysis which it was based on, and the ground rules used for cost efficacy.
Corrective maintenance & repair
Corrective maintenance of equipment after equipment break down or malfunction is often most expensive – not only can worn equipment damage other parts and cause multiple damage, but consequential repair/replacement costs and loss of revenues due to down time during overhaul can be significant. Rebuilding and resurfacing of equipment and infrastructure damaged by erosion and corrosion as part of corrective or preventive maintenance programmes involves conventional processes such as welding and metal flame-spraying, as well as engineered solutions with thermoset polymeric materials.
Predictive maintenance & repair
More recently, advances in sensing and computing technology have given rise to ‘predictive maintenance’. This maintenance strategy uses sensors to monitor key parameters within a machine or system, and uses this data in conjunction with analysed historical trends to continuously evaluate the system health and predict a breakdown before it happens. This strategy allows maintenance to be performed more efficiently, since more up-to-date data is obtained about how close the product is to failure.