Glossary | LLumin CMMS

Maintenance Terminology & Definitions

Maintenance Terminology & Definitions






Asset Management:

The systematic management of assets to maximize their value and performance.

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Asset Naming Convention:

A systematic method for identifying and labeling assets within an organization. Often, this convention includes coding that makes it easy to identify the type of asset and where it resides. In addition, proper naming ensures consistency, simplifies asset tracking, and enhances communication about assets among team members.

Asset Lifecycle Management:

Managing assets throughout their entire lifecycle, from acquisition to disposal.

Alternative Fuels:

Fuels other than traditional gasoline or diesel, such as natural gas, propane, or electric power.

Asset Integrity Management (AIM):

Ensuring the reliability and integrity of industrial assets throughout their lifecycle.

Asset Performance Management (APM):

Managing and optimizing the performance of physical assets using data-driven insights.

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An instrument used to analyze and measure the composition of a substance, such as gas analyzers.

Arc Flash:

A dangerous release of energy caused by an electric arc, often associated with electrical faults.


The proportion of time that a system is operational and available for use.

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Accelerated Life Testing:

Exposing a system to conditions that simulate years of use in a shorter period to predict its reliability over time.

Advanced Analytics:

The use of sophisticated statistical analysis and machine learning to derive insights and make prescriptive maintenance recommendations.

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Autonomous Maintenance (AM):

Empowering operators to perform routine maintenance tasks on their equipment to enhance overall equipment effectiveness.

ABC Analysis:

Classifying MRO items into categories based on their importance, often using criteria such as usage frequency and criticality.

Acoustic Analysis:

A technique used to assess the condition of machinery and equipment by analyzing the sound and associated patterns of sound, it emits. This can help in early detection of potential failures or malfunctions.

Asset Hierarchy:

An organizational framework that categorizes assets based on key attributes important to the organizational entity. Typically, asset hierarchies identify where assets reside, how assets are interconnected, their parent child relationships, and often the hierarchy illustrates critical components that are necessary for performance. This structure aids in managing and maintaining assets more efficiently by understanding their interrelationships.

Asset Utilization:

A measure or parameter that indicates the levels of use an asset has associated with it. Utilization levels and percentages can be used to create proactive maintenance schedules and measure how effectively an organization’s assets are used to produce output. High asset utilization indicates efficient use of resources, while low utilization may signal inefficiencies.



Comparing the performance of your facility’s maintenance practices against industry standards or best practices.


The use of barcode technology to track and manage tool inventory efficiently.

Breakdown Maintenance:

Also known as corrective or unplanned maintenance, this is the repair or work involved in the replacement of equipment, after it has failed. This approach can lead to higher costs and downtime for high criticality assets. However, an approach can be chosen for assets deemed low cost and non-critical.


Corrective Maintenance:

Unplanned maintenance carried out to fix equipment or facility issues.

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Condition Monitoring:

Monitoring equipment condition in real-time to predict and prevent failures.

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Condition-Based Maintenance (CBM):

Maintenance activities performed based on the current condition of the equipment.

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CMMS (Computerized Maintenance Management System):

Software used to manage and schedule maintenance activities.

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Corrosion Control:

Strategies and techniques to prevent or mitigate corrosion in industrial equipment.

Critical Equipment:

Machinery or systems essential to the operation of the plant, requiring special attention and maintenance.


Adjusting and verifying the accuracy of measurement instruments.

Confined Space Entry:

Procedures and precautions for working in confined spaces.

Control Valve:

A valve used to control the flow of a fluid in an industrial process.


The flow of electric charge, measured in amperes (amps).


A closed loop or path through which an electric current can flow.


Material that allows the flow of electric current, typically metals like copper or aluminum.

Criticality Analysis:

Evaluating the importance of different components in a system based on their impact on overall performance.

Cost-Benefit Analysis:

An evaluation method that compares the costs of an action to its expected benefits to determine its economic feasibility.


A leader or advocate for TPM initiatives within the organization.

CNC Machining:

Computer Numerical Control machining, where tools and machines are controlled by computers for precision manufacturing.

CAM (Computer-Aided Manufacturing):

Software that aids in the creation of toolpaths for CNC machining based on CAD designs.

Cycle Counting:

A method of regularly counting a subset of inventory items to ensure accuracy.


Items that are used up or worn out during regular operations, such as cutting tools or abrasives.


Adhering to legal, regulatory, and internal policies when procuring MRO items.

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The period during which equipment or a facility is not operational.

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Distributed Control System (DCS):

A control system used to control multiple processes or systems in a distributed manner.

Design for Reliability (DfR):

The practice of designing products and systems with reliability in mind from the beginning.

Digital Twin:

A digital replica of physical assets or systems, used for monitoring and analysis in predictive maintenance.

Data Analytics:

The use of advanced analytics tools to analyze large datasets, often collected through sensors, for predictive maintenance insights.

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Diagnostic Tools:

Instruments or equipment used to diagnose the condition of machinery or systems.

Demand Forecasting:

Predicting the future demand for specific tools to optimize inventory levels.

Deferred Maintenance:

Maintenance activities that have been postponed or delayed, often due to budget constraints or prioritization of other tasks. This can lead to increased future unplanned breakdown costs and asset failure operations downtime risks.

Data Collection Standardization:

A process of establishing uniform procedures and formats for gathering data across within an organization or specific operation. This helps ensure consistency in data collection practices, enabling easier and more accurate analysis and interpretation of resultant data sets.


The decrease in the value of an asset over time, due to wear and tear, obsolescence, or age. This concept is important for financial reporting, cost of ownership reporting, and maintenance budgeting.

DOT Compliance:

Adherence to regulations set by the Department of Transportation, including safety standards and record-keeping.

Driver Vehicle Inspection Report (DVIR):

Document completed by drivers to report any vehicle issues or defects.


Equipment Reliability:

Maintaining the dependability and performance of machinery and equipment.

Emergency Shutdown (ESD) System:

Automated systems designed to shut down critical processes in emergency situations.

Energy Management System (EnMS):

Strategies and practices to optimize energy usage in manufacturing.

Electrical Troubleshooting:

Identifying and resolving electrical issues in equipment and systems.

Electrical Panel:

Also known as a breaker panel or distribution board, it houses circuit breakers or fuses for controlling and distributing electrical power.

Electrical Disconnect Switch:

A switch used to isolate electrical equipment for maintenance or repair.

Electrical Grounding System:

A network of conductors and grounding electrodes used to connect electrical systems to the earth.

Early Equipment Management (EEM):

Involving maintenance teams in the early stages of equipment design and procurement to enhance reliability and maintainability.

ERP (Enterprise Resource Planning):

Software that integrates various business processes, including inventory management, into a unified system.


The use of electronic systems and technology for the procurement of MRO items.

Emergency Maintenance:

Unplanned repairs must be done immediately to avoid significant impacts on safety, environment, or operations. This type of maintenance usually incurs high costs due to its urgent nature.

Enterprise Asset Management

EAM is a systematic approach to managing physical assets and infrastructure over their entire lifespan, from capital planning to procurement, maintenance, compliance, risk management, to disposal.

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Fleet Maintenance Management:

Managing maintenance and repairs on vehicles or heavy assets in the fleet.

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Fuel Efficiency Optimization:

Implementing practices to maximize fuel efficiency and reduce operational costs.

Failure Reporting, Analysis, and Corrective Action System (FRACAS):

A system for tracking and analyzing failures to improve reliability.

Fault Tree Analysis (FTA):

A systematic method for analyzing the causes of system failures.


A communication protocol used in industrial automation to connect field devices.


A device used to measure the flow rate of liquids or gases.


A safety device containing a metal wire that melts and breaks the circuit when excessive current flows through it.

Failure Analysis:

The process of investigating and understanding the root causes of failures.

Fault Detection and Diagnostics (FDD):

Systems and tools that automatically detect faults and diagnose issues in equipment.

Failure Prediction Models:

Mathematical models developed to predict the likelihood of equipment failures based on historical data.

Focused Equipment Reliability Improvement (FERI):

Targeting specific equipment for reliability improvement efforts within the TPM framework.

Fixture Design:

Creating plans for the production of fixtures used to hold workpieces during manufacturing.

Facility Maintenance

Maintenance activities focused on keeping buildings and infrastructure in optimal working condition. This includes inspections, repairs, cleaning, and upkeep of physical spaces, both internal to the facility and external.

Facility Manager:

An individual responsible for ensuring the functionality, safety, and efficiency of a building or facility’s infrastructure. Their duties can range from overseeing maintenance, planning and budgeting, strategic space planning, as well as coaching and managing staff.

First Time Fix (Ftf):

A metric that indicates the percentage of issues resolved on the first visit by a technician. A high first-time fix rate suggests efficient maintenance practices, sufficient skills and training, and minimal disruptions to operations.

Fleet Tracking:

Monitoring the real-time location and movement of vehicles within the fleet.

Fleet Safety Program:

Comprehensive plan to ensure the safety of drivers, vehicles, and the public.

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Connecting electrical equipment to the ground to prevent electric shock and provide a safe path for fault currents.


The actual place where value is created – often used to emphasize the importance of observing work processes firsthand.

Grounds Maintenance:

Activities aimed at maintaining and enhancing the outdoor areas of a facility, such as landscaping, gardening, and upkeep of external structures.


The process of removing material from a workpiece using abrasive wheels.


Hybrid Vehicles:

Vehicles that use a combination of internal combustion engines and electric propulsion systems.

Hazardous Area Classification:

Identifying and classifying areas in the plant where explosive atmospheres may exist.

Hot Work Permit:

Authorization for performing work that involves open flames or produces heat.

HMI (Human-Machine Interface):

A user interface that connects a person to a machine, system, or device.

Hydraulic Systems:

Systems that use fluids to transmit power, often found in machinery and equipment.

Health Monitoring:

Continuous tracking of the health and performance of equipment.


ISO 55000/1:

International standard for asset management.

Idle Time Management:

Strategies to reduce unnecessary engine idling and conserve fuel.

Issuance System:

A method for tracking the distribution of tools to employees and recording their return.

Indirect Purchasing:

The procurement of goods and services that are not directly involved in the production process but are essential for the overall functioning of a business.


Material that restricts or prevents the flow of electric current.

Inventory Management:

The process of efficiently overseeing the ordering, storage, and use of tools and equipment.

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ISO 9001:

International standard for quality management systems.

Instrumentation Diagrams (P&ID):

Piping and Instrumentation Diagrams that show the process flow and control systems.

Infrared Thermography:

Using thermal imaging to identify overheating or abnormal temperatures in equipment.

Instrumentation and Control Systems:

Systems that monitor and control industrial processes, including sensors and controllers.


Just-In-Time (JIT) Manufacturing:

A production strategy that emphasizes producing items at the exact time they are needed in the manufacturing process.


Automation with a human touch – empowering machines to automatically stop when a defect is detected.

Jigs and Fixtures:

Devices used to hold and guide tools or workpieces during manufacturing processes.

Just-In-Time (JIT) Inventory:

Maintaining inventory levels to meet demand without excess stock.



Continuous improvement philosophy aimed at making incremental improvements in processes and systems.


Assembling sets of tools or materials needed for a specific job or project.

Key Performance Indicators (KPIs):

Quantifiable measures used to evaluate the success of an organization, employee, or process in meeting objectives. In maintenance and facilities engineering disciplines, common KPIs include downtime reduction, maintenance cost tracking, repair times, response times, and asset lifecycle tracking.

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Applying the right type and amount of lubricant to machinery to reduce friction and wear.

Lockout/Tagout (LOTO):

A safety procedure to ensure that machines are properly shut off and not able to be started up again prior to the completion of maintenance or repair work.

Life Cycle Cost Analysis:

Evaluating the total cost of owning, operating, and maintaining a system over its entire life.

Lead Time:

The time it takes to receive a tool order from the moment it is placed.

Lean Manufacturing:

A production method focused on minimizing waste and maximizing efficiency.

Loop Check:

The process of verifying the functionality of a control loop.


MTBF (Mean Time Between Failures):

The average time between consecutive failures of a repairable system.

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MTTR (Mean Time To Repair):

The average time it takes to repair a failed system.

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The ease with which a system can be repaired or maintained.

Maintenance Schedule:

A planned timetable for conducting preventive maintenance on equipment.

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Manufacturing Execution System (MES):

Computerized systems used for managing and controlling manufacturing operations on the shop floor.


A tool used to measure electrical voltage, current, and resistance.

Mean Time To Acknowledge (MttA):

The average time taken for a maintenance request or alarm to be acknowledged by a technician or maintenance team. This metric helps assess response times and maintenance efficiency.

Manufacturing Maintenance Management:

Managing and scheduling maintenance activities in a manufacturing setting.


The process of shaping materials through various methods such as milling, turning, and grinding.

Minimum Stock Level:

The minimum quantity of a tool or item that should be maintained in the tool crib.

Maintenance Checklist:

A comprehensive list of tasks and checks to be performed during maintenance activities. These checklists ensure consistency, completeness, and compliance with standards.

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Machine Learning:

An artificial intelligence technique that enables systems to learn from data and make predictions, often used in predictive maintenance.

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Meter Based Maintenance:

A maintenance strategy that triggers service activities based on the usage or runtime meters of equipment, rather than on a fixed, date-based schedule. This approach can optimize maintenance intervals and reduce unnecessary interventions.

Mobile Maintenance:

Maintenance tasks performed using mobile devices, allowing technicians to access information, update work orders, and report issues in real-time from any location.

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Nested PM:

A scheduling approach where smaller or redundant scheduled maintenance work is suppressed and the associated tasks are embedded within larger scheduled work orders, to optimize the maintenance schedule and reduce equipment downtime.

Non-Destructive Testing:

Inspection methods that assess the condition or integrity of materials and components without causing damage. NDT is crucial for preventive maintenance and quality assurance.


OEE (Overall Equipment Effectiveness):

A metric that measures the efficiency of manufacturing equipment.

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Odometer Reading:

Recording the total distance a vehicle has traveled.

Ohm’s Law:

The mathematical relationship between voltage, current, and resistance: V = I * R.

Oil Analysis:

Monitoring the chemical and physical properties of lubricating oils to assess the condition of equipment.


The process of making something as effective or functional as possible, often applied to maintenance strategies.

Obsolete Inventory:

Tools or equipment that are no longer in use or have become outdated.


Day-to-day activities involved in running a facility or manufacturing process, including production, maintenance, and logistics.


A U.S. government agency responsible for enforcing safety and health legislation. OSHA standards are crucial for maintenance practices, especially in hazardous environments.

Original Equipment Manufacturer (OEM):

The company that manufactures and sells the original equipment or parts. OEM parts are often recommended for maintenance and repairs to ensure compatibility and reliability.


Predictive Maintenance (PdM):

Maintenance tasks performed based on predictions of when equipment failure might occur.

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PM Schedule (Preventive Maintenance Schedule):

Regularly scheduled, planned maintenance tasks performed on assets to prevent breakdowns.

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Pressure Transmitter:

A device that measures and transmits pressure readings in an industrial process.

Proximity Sensor:

A sensor that detects the presence or absence of an object without physical contact.

Personal Protective Equipment (PPE):

Safety gear worn to minimize exposure to workplace hazards.

PID Controller (Proportional-Integral-Derivative):

A control algorithm used in feedback systems to maintain a desired setpoint.

Process Safety Management (PSM):

A set of standards and procedures to prevent the release of hazardous materials during industrial processes.

PLC (Programmable Logic Controller):

A digital computer used for automation of electromechanical processes.

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Parts Inventory Management:

Efficiently managing stock of spare parts for quick repairs and maintenance.

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Process Reliability:

Ensuring the continuous and reliable operation of industrial processes.

Preservation Maintenance:

Maintenance activities focused on preserving the current condition of equipment, guided by CBM data.

Purchasing Manager:

An individual responsible for overseeing the procurement of goods and services, including MRO items.

Proactive Maintenance:

Maintenance activities initiated based on predictive insights to prevent equipment failure.

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Prescriptive Maintenance:

Recommendations for specific actions to be taken based on predictive maintenance insights.

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PM Optimization:

Continuous improvement of preventive maintenance processes for efficiency and effectiveness.


The field of study that involves predicting the future performance of equipment and estimating the remaining useful life.

PM Task List:

A comprehensive list of tasks to be performed during preventive maintenance.

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PM Inspection:

Thorough examination of equipment during preventive maintenance to identify potential issues.

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Procurement Software:

Technology used to streamline and automate the procurement process, often including features for order management and vendor collaboration.


Quality Maintenance (QM):

Integrating quality control practices into the maintenance process to ensure the production of high-quality products.

Quick Changeover (SMED):

Single-Minute Exchange of Die – a set of techniques to reduce the time it takes to change from one production job to another.


Reliability Centered Maintenance (RCM):

A systematic approach to developing maintenance strategies based on the reliability of equipment.

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Root Cause Analysis (RCA):

A methodical process used to identify and address the underlying cause of equipment failures.

RAM Analysis (Reliability, Availability, and Maintainability):

A comprehensive evaluation of system performance considering reliability, availability, and maintainability.

Remote Monitoring:

Monitoring equipment conditions from a distance, often using sensors and communication technology.

RTD (Resistance Temperature Detector):

A temperature sensor that measures temperature based on the resistance of a metal.

Reliability Block Diagram (RBD):

A graphical representation of the reliability of a system using blocks to represent components and their interconnections.

Reliability Engineer:

A professional responsible for ensuring the reliability and performance of equipment.


Opposition to the flow of electric current, measured in ohms.

Risk-Based Maintenance (RBM):

A maintenance strategy that prioritizes actions based on the level of risk associated with equipment failures.

Reorder Point:

The inventory level at which a new order should be placed to avoid running out of stock.

RFID (Radio-Frequency Identification):

Technology using wireless communication to identify and track tools and equipment.

RFQ (Request for Quotation):

A document used to solicit price quotes from potential suppliers for specific MRO items.

Return On Asset Investment (ROA):

ROA is a financial metric that measures the profitability returned or realized in relation to the cost of the assets employed to generate that return. It is calculated by dividing the net income generated by the total assets invested. ROA indicates how efficiently assets are being utilized to generate profits.

Reactive Maintenance:

Maintenance performed in response to equipment failure or breakdown. While sometimes necessary, excessive reliance on reactive maintenance can lead to higher costs and downtime.


A maintenance strategy where equipment is deliberately allowed to operate until it fails. This approach may be used for non-critical assets where the cost of preventive maintenance exceeds the cost of replacement.


Spare Parts Inventory:

Stock of replacement parts kept on-site for quick equipment repairs.

Safety Data Sheet (SDS):

Document containing information about the properties and hazards of chemical products.

5S Methodology:

Sort, Set in order, Shine, Standardize, Sustain – a system for organizing the workplace.

SCADA (Supervisory Control and Data Acquisition):

A system for monitoring and controlling industrial processes.

Sustainability Practices:

Implementing environmentally friendly and resource-efficient maintenance practices.

Six Sigma:

A set of techniques and tools for process improvement to achieve near-perfect results.


Total Productive Maintenance (TPM):

A holistic approach that involves the entire workforce in maintaining and improving equipment reliability.

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Technology that combines telecommunications and informatics to monitor and track vehicle performance and location.

Time-Based Maintenance:

TBM is a maintenance strategy that involves scheduling maintenance activities at regular, predetermined intervals based on the equipment’s estimated lifespan.

Tool Identification:

Labeling tools with unique identifiers for easy tracking and management.

Total Cost of Ownership (TCO):

The overall cost associated with owning and using an MRO item, including acquisition, operation, and maintenance costs.

Tool Tracking System:

Software or technology used to monitor the location and usage of tools within the tool crib.

Tool Reconditioning:

The process of restoring tools to their original condition to extend their lifespan.

Tool Wear:

Gradual deterioration of a tool’s cutting edge or surface due to use.

Tool Crib:

A centralized area or storage facility where tools, equipment, and supplies are kept for use by employees.


The allowable limit of variation in a dimension or physical property of a manufactured part.

Tool Life:

The duration for which a tool remains in good condition and produces satisfactory results.

Tool Room:

A facility or department dedicated to the design, manufacturing, maintenance, and repair of tools, dies, and molds.

Tool and Die:

Precision tools used in manufacturing processes, including dies for shaping materials and molds for forming parts.

Time to Failure (TTF):

The estimated time remaining before a piece of equipment is expected to fail.

Total Quality Management (TQM):

A management approach that focuses on quality in all processes, complementing TPM.

Three-Phase Power:

A type of electrical power supply that uses three alternating currents.

Thermography Inspection:

Using thermal imaging to identify overheating or abnormal temperatures in equipment during preventive maintenance.


A temperature sensor that generates a voltage proportional to the temperature difference between two junctions.


Devices that change the voltage of an electrical circuit.


A device that converts one form of energy into another, such as a sensor converting a physical quantity into an electrical signal.

Temperature Sensor:

A device that measures and transmits temperature readings in an industrial process.

Tire Tread Depth:

Measurement of the depth of the tread on vehicle tires, critical for safety and performance.

Torque Wrench:

A tool used to apply a specific torque to a fastener, ensuring proper tightening.



The opposite of downtime, representing the time when Assets or a facility is operational.

Ultrasonic Testing:

Using ultrasound to detect anomalies or issues in machinery.

Unplanned Downtime:

Unexpected interruptions in operations due to equipment failure, lack of materials, or other unforeseen issues. Reducing unplanned downtime is a key objective of effective maintenance management.


Vehicle Routing and Scheduling Optimization:

Efficiently planning routes and schedules to minimize fuel consumption and maximize productivity.

Vehicle Inspections and Compliance:

Ensuring that vehicles meet safety and regulatory requirements.

Vendor Management:

The process of managing relationships with suppliers and vendors to ensure timely and cost-effective procurement.

Vibration Analysis:

Monitoring and analyzing vibrations in machinery to detect potential issues.


The electric potential difference between two points, measured in volts.


Work Order:

A formal request for maintenance or repair work.

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Work Permit System:

Formal documentation and authorization for performing maintenance tasks in a controlled manner.

Work Order System:

A system for initiating, tracking, and managing preventive maintenance work.

Workplace Organization:

Creating a well-organized and efficient work environment to support TPM goals.

Wiring Diagram:

A visual representation of an electrical circuit, showing how components are connected.

Weibull Analysis:

A statistical technique used for analyzing reliability data and predicting failure rates over time.

Warranty Tracking:

The process of monitoring the warranty status of assets and components to ensure repairs and replacements are claimed under warranty when applicable, reducing maintenance costs.

Work Request

A formal, documented request for maintenance, repair, or improvement work on an asset, a piece of equipment, or an area within a facility. A sound work request process helps prioritize and track maintenance activities, and speeds time to completion.

Wrench Time:

The actual time maintenance technicians spend working on equipment, as opposed to administrative tasks or waiting for parts. Increasing the wrench time as a percentage of overall work week or work period is paramount to lowering overall cost of asset ownership.




Zero Breakdowns:

A goal of achieving and maintaining zero equipment breakdowns through effective TPM practices.

Zero-Based Maintenance (ZBM):

A maintenance strategy that questions the necessity of current maintenance routines and seeks to implement maintenance tasks and schedules purely on need and justification.

Getting Started With LLumin

LLumin develops innovative CMMS software for healthcare & hospitals. To get started, we encourage you to schedule a free demo or contact the experts at LLumin to see how our software can help you reach your maintenance and asset management goals.