Maintenance Terms

Below are a list of terms that are commonly used when talking about maintenance and maintenance operations. To learn more about individual terms, follow the links to a page that elaborates on how the term is used in the field of maintenance.

Bill of Materials: a detailed list of the parts and their respective quantities required to complete a project

Breakdown Maintenance: maintenance performed on equipment that has broken down, faulted, or otherwise cannot be operated

CMMS: A computerized maintenance management system (CMMS) is software that stores data about maintenance performed on equipment, machinery, and other assets.

Condition-Based Maintenance (CbM): uses sensor devices to collect real-time measurements (ie. pressure, temperature, or vibration) on a piece of equipment to help maintenance personnel perform maintenance at the exact moment it is needed

Corrective Maintenance: occurs when a maintenance technician discovers a problem while completing a preventive maintenance, inspection, general, or emergency work order

Deferred Maintenance: repairs to infrastructure and assets that get delayed and backlogged because of budget limitations and lack of funding

Downtime: the amount of time that equipment is not operating, whether that’s a result of unplanned equipment failure (like a fault or broken part) or planned downtime (like necessary downtime for preventive maintenance)

EAM Software: enterprise asset management (EAM) software is a type of maintenance software that collects and analyzes data for physical assets during all phases of the asset lifecycle, including the acquisition, maintenance, and disposal phase

Emergency Maintenance: a type of reactive maintenance that is used to prevent a threat to lives, property, profitability, or viability of an organization

Failure Finding Task: an inspection that reveals hidden failures or potential failures within an asset

FMEA: a process that is available to organizations to identify potential failures with assets and other areas of business

Industry 4.0: the latest trend in industrial production characterized by the use of interconnected cyber-physical systems (CPS)

Inspection: tasks that check the condition of equipment and determine what tools, materials, and labor are required to service them

Lean Six Sigma: a process that aims to systematically eliminate waste and reduce variation

Lockout Tagout (LOTO): safety practices and procedures that ensure dangerous machines are properly shut off and are not able to unexpectedly release hazardous energy during maintenance activities

Maintenance Backlog: a measure of required maintenance work that has not been completed

Maintenance Log: a document that records activities that have been performed on an asset

Maintenance Repair and Overhaul (MRO): includes all the components required to keep a company focused on its core mission, which includes tests and repairs as well as the supplies and equipment required to keep all the individual components, machines, and equipment running

Mean Time Between Failure (MTBF): a metric that defines the average time that equipment is operating between breakdowns or stoppages

Mean Time to Repair (MTR or MTTR): the average time it takes for equipment to be diagnosed, repaired, and recovered after experiencing a failure

Operation and Maintenance Manual: a comprehensive document that provides all the details necessary about a physical plant as well as individual pieces of equipment to help the maintenance staff keep everything running smoothly

Overall Equipment Effectiveness (OEE): a standard used for measuring plant performance

P-F Curve: a graph that shows the health of equipment over time to identify the interval between potential failure and functional failure

Periodic Maintenance: activities performed on equipment based on a set time interval

Planned Maintenance: the process of determining what work needs to be completed and how it is to be done

Planned Maintenance Optimization: a method of improving maintenance strategies based on existing preventive maintenance (PM) routines and available failure history

Planned Maintenance Percentage (PMP): a percentage that describes the amount of maintenance time used towards planned maintenance tasks, which is measured against the total amount of maintenance hours in a given time period (weeks, months, years)

Precision Maintenance: describes the maintenance culture in a facility

Predictive Maintenance (PdM): a type of condition-based maintenance in which assets are monitored with sensor devices that supply data (i.e. vibrational frequency) about the asset’s condition which is used to predict when the asset will require maintenance

Preventive Maintenance: a type of proactive maintenance that keeps assets in good order and reduces unscheduled downtime and major repairs

Proactive Maintenance: a maintenance strategy that performs corrective action to conditions that can lead to equipment failure

Reactive Maintenance: the process of repairing assets and restoring them to normal operating conditions after a breakdown or observances of unusual performance

Reliability Centered Maintenance (RCM): a process for determining the level of maintenance that’s needed for a company to operate effectively in terms of overall cost, production availability, spare parts stockholding, and other factors

Root Cause Analysis: a systematic process of identifying the origin of an incident

Routine Maintenance: the regular inspection and servicing of machines and systems that keep operations running smoothly

Run to Failure Maintenance (RTF): a maintenance strategy that is sometimes more appropriately called “Fit and Forget” because there is no maintenance plan beyond complete replacement upon failure

SCADA: Supervisory control and data acquisition (SCADA) is a computer system used to monitor and control plant processes

Schedule Compliance: a maintenance metric that measures the percentage of time that scheduled work orders are completed over a period of time

Scheduled Discard Task: involves replacing a specific part or component of a piece of equipment at regular time intervals, regardless of its performance quality

Scheduled Maintenance: any repair and upkeep work performed within a set timeframe that details when maintenance tasks are performed and by whom

Scheduled Restoration Task: a complete overhaul of machinery or equipment that is performed on a predetermined schedule regardless of the condition of the equipment

Total Productive Maintenance (TPM): a maintenance strategy that requires total participation of the organization and maximizes equipment effectiveness by engaging multiple departments, including every single employee from top management down to the workforce

Useful Life: an estimate of the number of years an asset will remain in profitable service

Work Order: a formal document (digital or paper) that describes maintenance work that is approved for execution (i.e. an approved work request)

Work Request: a formal document (digital or paper) that describes maintenance work that needs completed