**2.1 Concepts and definitions**

The British Standard Glossary defined maintenance as "the combination of all technical and administrative actions, including supervision actions, intended to retain an item in, or restore it to, a state in which it can perform a required function" [18]. In addition, maintenance is a set of organized activities that are carried out in order to keep an item in its best operational condition with minimum cost required. Likewise, maintenance tasks are defined as "Sequence of elementary maintenance activities carried out for a given purpose. Examples include diagnosis, localization, function check-out, or combinations" [19].

Preventive maintenance is the performance of inspection and/or servicing tasks that have been pre-planned or scheduled for specific points in time in order to retain the functional capabilities of operating equipment or systems [20, 21]. Other standards such as ISO 13372:2012 [22] define preventive maintenance as "maintenance performed according to a fixed schedule, or according to a prescribed criterion, that detects or prevents degradation of a functional structure, system or component, in order to sustain or extend its useful life."

Corrective or reactive maintenance is carried out after fault recognition and intended to put an item into a state in which it can perform a required function [23]. This maintenance policy is also called failure-based maintenance because the asset is operated until it fails.

Predictive maintenance refers to the routine inspection of equipment, machines, or materials to prevent a failure. It is a type of proactive maintenance that focuses on determining the potential root causes of machine or material failure and dealing with those issues before problems occur. It is achieved by the measurement of some physical or performance variable [24].

Robert Davis defined asset management as "a mindset which sees physical assets not as inanimate and unchanging lumps of metal/plastic/concrete, but as objects and systems which respond to their environment, change and normally deteriorate with use, and progressively grow old, then fail, stop working, and eventually die" [25].

**Table 1** shows additional important concepts of maintenance management for reliability systems, in which the following four factors are recognized:


**7**

**Table 1.**

*Maintenance and Asset Life Cycle for Reliability Systems DOI: http://dx.doi.org/10.5772/intechopen.85845*

studies, opportunities, and returns on investment.

a.Instrumental (dispatch)

b.Operative

c.Tactical

d.Strategic

adjustments.

**Term Definitions**

**2.2 Fundamental aspects in the maintenance strategies**

Decisions associated with production maintenance are of four levels:

Maintenance decisions are of diverse natures and, depending on the level of impact, require proper identification and ranking. This is the starting point to develop suitable management policies and bring assertive strategies of reliability.

The strategic level incorporates the top direction of the organization and the maintenance implementation with tangible results in a time frame upward of 2 years. These decisions require important investments of resources and market

In operations and production, tactical decisions generate results within several months to 1 or 2 years. Tactical decisions are made by management and mid-level management, involve project modifications, and often are associated with important investments. Operation-specific decisions have immediate impact (from several days to a few months) and are made by technical personnel that do not require changes and investments in the operational budgets. Instrumental or dispatch decisions are also made by technical personnel. The costs related to these decisions are considered in the plans pertaining to preventive maintenance, and their impact is reflected in hours. The maintenance activities related to these decisions are called

Often, the governing bodies of the industries only stop to consider the need to restructure their departments or maintenance processes when faced with frequent expensive failures or costly downtimes that cause significant production losses. In addition to the above, performed research indicates that implied processes of documentation and registration processes are precarious, even though, in many cases, significant sums of money have been invested in information systems. When

Availability Ability to be in a state to perform as and when required, under given conditions, assuming

of condition monitoring and/or inspection and/or testing, analysis, and the ensuing

information that will assist the maintenance management in planning, organizing, and

information that will assist the maintenance management in planning, organizing, and

CBM Condition-based maintenance: preventive maintenance which includes a combination

CMMS Computerized maintenance management system: a system that can provide important

CMMS Computerized maintenance management system: a system that can provide important

that the necessary external resources are provided

maintenance actions

controlling maintenance actions

controlling maintenance actions

*Concepts for maintenance management for reliability systems [26].*
