Equipment Maintenance Glossary
The definitions are written for maintenance and facilities teams. It is centred on keeping equipment safe, functional and fit for purpose: maintenance approaches and planning, work management and records, and the systems, assurance and related disciplines that support them.
Core equipment maintenance concepts
Asset
A physical item of value that an organisation owns, leases or is responsible for. In equipment maintenance, it is the item being maintained, such as a pump, vehicle, machine or piece of clinical equipment.
Asset hierarchy
A structured parent-and-child view of equipment and its parts, for example site, building, plant room, system, asset and component. It helps maintenance teams locate equipment and understand dependencies.
Asset register
The controlled record of equipment, including its identity, location, ownership, condition and key dates. A maintenance register usually holds operational and service information alongside core asset details.
Asset lifecycle
The stages an item passes through from specification and acquisition to operation, maintenance, renewal and disposal. Maintenance planning should reflect the asset’s age, condition, criticality and remaining useful life.
Asset management
The coordinated management of assets to deliver value, performance, cost control and risk reduction throughout their lifecycle. Equipment maintenance is one operational part of wider asset management.
Availability
The proportion of time that equipment is able to perform its required function when needed. It is affected by reliability, maintainability, planned downtime and response to faults.
Breakdown
An equipment failure that prevents the item from performing its intended function or makes continued operation unsafe. A breakdown normally triggers corrective maintenance.
Condition
The assessed physical or functional state of an asset at a point in time. Condition may be established through inspection, testing, monitoring or engineering judgement.
Condition assessment
A documented evaluation of an asset’s condition against agreed criteria. It supports maintenance priorities, replacement planning and capital decisions.
Condition monitoring
The routine or continuous observation of an asset’s condition using inspections, readings or sensors. It helps identify deterioration before it becomes a failure.
Critical asset
Equipment whose failure would create a significant safety, operational, financial, environmental or compliance risk. Criticality should influence maintenance frequency, escalation and spare-parts planning.
Criticality
A rating of the consequence of an asset failing. A criticality assessment considers factors such as safety, service disruption, statutory obligations, cost and available redundancy.
Damage
Physical deterioration or harm that affects the condition or performance of equipment.
Disposal
The controlled removal of equipment or materials that are no longer required or suitable for use.
Downtime
The period during which equipment is unavailable for its intended use because of failure, maintenance, inspection or another planned outage.
Equipment maintenance
The activities used to keep equipment safe, functional and fit for purpose, including inspection, servicing, repair, testing and replacement of parts.
Equipment management
The broader process of controlling equipment information, location, use, maintenance, cost and lifecycle decisions. It combines operational maintenance with management oversight.
Failure
The loss of an asset’s ability to perform a required function. Failures may be complete, partial, intermittent, hidden or identified through testing.
Failure mode
The way in which an asset or component fails, such as overheating, leakage, excessive vibration or loss of electrical power. Knowing the failure mode helps select effective maintenance tasks.
Functional failure
A failure in which an asset can no longer meet the required performance standard, even if it is still running. For example, a pump may operate but no longer achieve the required flow rate.
Maintainability
The ease and speed with which equipment can be inspected, serviced or repaired. Good maintainability reduces downtime and makes planned work more efficient.
Reliability
The probability that equipment will perform its required function without failure for a specified period under stated conditions. 2. Maintenance approaches and planning Term Definition
Maintenance approaches and planning
Breakdown maintenance
Maintenance carried out after equipment has failed. It can be appropriate for low-risk, non-critical assets but is usually costly or disruptive when used as the main approach for important equipment.
Corrective maintenance
Work carried out to restore equipment after a fault, defect or failure has been identified. It may be urgent or scheduled, depending on risk and operational impact.
Condition-based maintenance (CBM)
Maintenance triggered by evidence of an asset’s actual condition rather than a fixed calendar interval. Readings, inspections and sensor data can be used to determine when work is needed.
Deferred maintenance
Necessary maintenance that has been postponed, usually because of budget, resource or access constraints. It should be recorded and risk-assessed rather than simply left outstanding.
Emergency maintenance
Unplanned work required immediately to address a serious safety, security, environmental or operational risk. It normally follows an accelerated authorisation and escalation process.
Inspection
A planned visual, functional or technical examination to check an asset’s condition, safety or compliance. An inspection may result in a work order, defect record or pass/fail outcome.
Maintenance plan
The agreed set of maintenance tasks, frequencies, responsibilities, standards and resources for an asset or asset class. It provides the basis for planned work orders.
Maintenance schedule
The timetable showing when planned maintenance tasks are due or allocated. A schedule may be calendar-based, meter-based, condition-based or linked to regulatory requirements.
Maintenance strategy
The overall approach used to manage an asset’s maintenance, balancing risk, cost, performance and compliance. It may combine preventive, predictive, corrective and run-to-failure approaches.
Mean time between failures (MTBF)
The average operating time between failures of repairable equipment. It is a reliability measure used to identify recurring issues and assess maintenance performance.
Mean time to repair (MTTR)
The average time taken to restore failed equipment to service. It usually includes diagnosis, repair, testing and return to operation.
Meter-based maintenance
Maintenance triggered after a defined amount of use, such as operating hours, mileage, cycles or starts. It is common for vehicles, generators and production equipment.
Planned maintenance
Maintenance that is identified, prepared and scheduled before work starts. It includes preventive tasks and non-urgent corrective work that can be organised safely and efficiently.
Planned preventive maintenance (PPM)
A programme of recurring planned tasks designed to reduce the likelihood of failure and maintain safe operation. The term is widely used in UK facilities and equipment management.
Predictive maintenance
A data-led maintenance approach that uses condition trends, diagnostic techniques or analytics to predict when a failure is likely and intervene at an appropriate time.
Preventive maintenance
Maintenance carried out at planned intervals or according to set criteria to reduce the probability of failure. It can include servicing, lubrication, adjustment, cleaning and replacement of wear parts.
Project Allocation
Assigning equipment, work, or resources to a specific project.
Reactive maintenance
Unplanned work performed in response to a reported fault, breakdown or defect. Reactive maintenance includes both urgent corrective work and emergency repair.
Run-to-failure
A deliberate strategy of allowing a non-critical item to operate until it fails, then repairing or replacing it. It should be used only where the risks and costs are acceptable.
Service level agreement (SLA)
An agreed standard for service delivery, such as response time, repair time, availability or completion targets. SLAs are commonly used to manage internal teams and maintenance contractors.
Statutory maintenance
Inspection, testing or servicing required by law, regulation or an applicable safety regime. Evidence of completion and results must be retained for audit and compliance purposes. 3. Work management, records and resources Term Definition
Work management, records and resources
Backlog
Approved maintenance work that remains outstanding. A managed backlog is prioritised by risk, due date, asset criticality and available resources.
Call-out
A request for a technician or contractor to attend a fault or incident, often outside normal planned work. Call-outs may be chargeable under a maintenance contract.
Completion date
The date on which a maintenance task was finished and recorded as complete. It may differ from the date the equipment was formally returned to service.
Consumables
Items that are used up during maintenance activities and need regular replacement.
Defect
A recorded condition, fault or non-conformance that requires assessment or corrective action. Defects may be found during inspection, testing, operation or maintenance.
Escalation
The process of raising an overdue, high-risk or unresolved issue to a higher authority or specialist team. Escalation rules help ensure that critical work receives prompt attention.
Fault Logging
Recording details of an equipment fault or issue so it can be investigated and resolved.
Fault log assignment
Allocating a reported fault to the person or team responsible for investigating or resolving it.
Job plan
A reusable description of how to complete a maintenance task, including steps, safety requirements, expected labour, parts and acceptance criteria. It improves consistency and supports planning.
Labour time
The recorded time spent by staff or contractors carrying out maintenance work. It supports job costing, productivity analysis and resource planning.
Maintenance history
The chronological record of inspections, faults, work orders, parts, readings and costs associated with equipment. It is used to identify trends and support auditability.
Maintenance log
A record of maintenance events for an individual asset or item of equipment. It may include dates, tasks performed, findings, technician details and supporting documents.
Maintenance Notifications
Messages, emails or alerts used to communicate maintenance-related information or updates.
Permit to work
A formal authorisation used to control hazardous work, confirming precautions, isolation and responsibilities before work begins. It is often required for high-risk maintenance activities.
Priority
A ranking used to determine the order in which maintenance work should be addressed. Priority should reflect risk, safety, operational impact, compliance and asset criticality.
Repair
Work carried out to restore equipment to a required condition or performance standard. A repair can be temporary, permanent, minor or major.
Response time
The elapsed time between reporting a fault and the initial attendance, acknowledgement or action by the maintenance provider. It is often measured against an SLA.
Root cause analysis (RCA)
A structured investigation into the underlying reason for a failure or recurring problem. RCA aims to prevent recurrence rather than only correcting the immediate symptom.
Spare parts
Replacement components and consumables held or obtained to support maintenance and repairs. Effective spare-parts control balances equipment availability against inventory cost and obsolescence.
Stock control
The process of recording, storing, issuing and replenishing maintenance materials and spare parts. It provides traceability and helps avoid delays caused by unavailable components.
Technician
A suitably trained person who carries out inspection, servicing, repair or testing work. Competence requirements should match the equipment and task involved.
Work order assignment
Allocating a work order to the person or team responsible for completing it.
Work order
A controlled instruction to carry out a defined maintenance task. A work order typically records the asset, task, priority, dates, labour, parts, findings and completion status.
Work order parts
Parts or components required to complete maintenance or repair work.
Work request
An initial report or request for maintenance work, raised by a user, operator or automated alert. It is normally assessed and converted into a work order where action is required.
Work-in-progress (WIP)
Maintenance work that has started but is not yet complete, including work awaiting parts, access, approval or further diagnosis.
Workload
The total volume of maintenance work requiring attention over a period. Monitoring workload supports resourcing, scheduling and contractor management. 4. Systems, assurance and related disciplines Term Definition
Systems, assurance and related disciplines
Audit trail
A time-stamped record of changes, approvals and completed activity. In maintenance management, it supports accountability by showing who changed a record, what changed and when.
Barcode
A machine-readable code attached to an item or location. Scanning a barcode can identify equipment quickly and support inspections, work updates and stock movements.
Calibration
The comparison of a measuring instrument against a recognised standard to confirm its accuracy. Calibration records are important where measurements affect safety, quality or compliance.
CAFM
Computer-aided facilities management software used to manage buildings, space, facilities services and related maintenance. CAFM may overlap with equipment maintenance but has a broader facilities focus.
Checklists
A structured list of checks or tasks used to ensure required actions are completed.
CMMS
Computerised maintenance management system: software that manages maintenance work, asset records, schedules, labour, parts and history. It is the common term for an equipment maintenance system.
Compliance
Meeting applicable legal, regulatory, contractual, manufacturer and organisational requirements. Maintenance records provide evidence that required tasks have been planned and completed.
EAM
Enterprise asset management: a broader discipline and software category covering the lifecycle, performance, cost and risk of physical assets across an organisation. CMMS functionality is often part of an EAM approach.
Equipment register
A controlled list of maintained equipment, normally including a unique reference, description, location, status, criticality and relevant service information.
Fleet management
The management of vehicles and mobile equipment, including use, maintenance, compliance, fuel, drivers and costs. It overlaps with equipment maintenance but includes transport-specific responsibilities.
Health and safety
The processes and controls used to prevent injury, illness and harm arising from work or equipment. Maintenance teams must manage hazards such as energy isolation, access, lifting and hazardous substances.
Inspection checklist
A structured list of checks used during an inspection or routine maintenance task. It provides consistency and creates evidence of what was examined and the result.
Internet of Things (IoT)
Connected sensors and devices that collect and transmit operational or condition data. In maintenance, IoT can support remote monitoring, alerts and condition-based maintenance.
Key performance indicator (KPI)
A measurable indicator used to assess maintenance performance, such as planned-maintenance completion, downtime, backlog, response time or repeat failures.
Lifecycle cost
The total cost of owning and operating equipment over its life, including acquisition, maintenance, energy, downtime, refurbishment and disposal. It helps inform repair-versus-replace decisions.
Lockout/tagout (LOTO)
A safety procedure for isolating hazardous energy sources before maintenance. Locks and tags make clear that equipment must not be energised or operated until work is complete.
Mobile maintenance
The use of mobile devices to access asset records, receive work orders, scan equipment, complete checklists and update maintenance activity while on site.
Planned maintenance compliance
The percentage of planned maintenance tasks completed by their required due dates. It is a useful measure of delivery discipline, but results should be considered alongside quality and risk.
Radio-frequency identification (RFID)
A tagging technology that identifies items through radio signals rather than line-of-sight scanning. RFID can support equipment tracking and inventory verification.
Risk assessment
A systematic assessment of hazards, likelihood and consequences used to determine appropriate controls. Risk assessments inform maintenance priorities, methods and authorisations.
Safety-critical equipment
Equipment whose failure or incorrect maintenance could create an immediate or serious risk to people, the environment or essential operations. It requires enhanced controls and reliable evidence of maintenance.
Service record
The record of servicing, inspection and repair completed for an item of equipment. It may include certificates, test results, readings, technician notes and supporting attachments.
Total productive maintenance (TPM)
A maintenance philosophy that involves operators and maintenance teams in improving equipment reliability, performance and care. It emphasises prevention, ownership and continuous improvement.
Warranty
A supplier or manufacturer commitment covering repair, replacement or performance for a defined period and under stated conditions. Maintenance records may be needed to support a warranty claim.
Put these terms into practice
FMIS Equipment and Maintenance software helps UK teams plan preventive and statutory work, manage work orders, defects and spare parts, and keep a complete maintenance history against every asset.
About this glossary. These definitions describe equipment maintenance concepts in plain English for operational use. This glossary is general guidance and is not engineering, legal or technical advice.
