Maintenance

The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure and supporting utilities in industrial, business, and residential installations.

[1][2] Over time, this has come to include multiple wordings that describe various cost-effective practices to keep equipment operational; these activities occur either before[3] or after a failure.

The United States Department of Defense uses the following definitions:[5] Maintenance is strictly connected to the utilization stage of the product or technical system, in which the concept of maintainability must be included.

This definition covers all activities for which aviation regulations require issuance of a maintenance release document (aircraft certificate of return to service – CRS).The marine and air transportation,[9] offshore structures,[10] industrial plant and facility management industries depend on maintenance, repair and overhaul (MRO) including scheduled or preventive paint maintenance programmes to maintain and restore coatings applied to steel in environments subject to attack from erosion, corrosion and environmental pollution.

[10] The basic types of maintenance falling under MRO include: Architectural conservation employs MRO to preserve, rehabilitate, restore, or reconstruct historical structures with stone, brick, glass, metal, and wood which match the original constituent materials where possible, or with suitable polymer technologies when not.

[12] Preventive maintenance (PM) is "a routine for periodically inspecting" with the goal of "noticing small problems and fixing them before major ones develop.

Maintenance activities include partial or complete overhauls at specified periods, oil changes, lubrication, minor adjustments, and so on.

In addition, workers can record equipment deterioration so they know to replace or repair worn parts before they cause system failure.

Specifically, planned maintenance is a scheduled service visit carried out by a competent and suitable agent, to ensure that an item of equipment is operating correctly and to therefore avoid any unscheduled breakdown and downtime.

This approach promises cost savings over routine or time-based preventive maintenance, because tasks are performed only when warranted.

[26] Usually it is a tax-benefit based [citation needed] replacement policy whereby expensive equipment or batches of individually inexpensive supply items are removed and donated on a predicted/fixed shelf life schedule.

A result of this cost is that the first generation of CBM in the oil and gas industry has only focused on vibration in heavy rotating equipment.

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.