Industrial maintenance and CMMS glossary.

Asset Criticality

A ranking of how much an asset's failure would impact safety, production, quality, or cost. Criticality drives PM frequency, spare-parts stocking, and work prioritization.

Availability

Availability (OEE factor)

The share of planned production time that equipment is actually running. It is the OEE factor most affected by breakdowns, changeovers, and slow repairs.

Formula Availability = Run time / Planned production time

Backlog

Maintenance Backlog

The body of identified, approved maintenance work that has not yet been completed, usually measured in crew-weeks. A healthy, visible backlog enables planning; an invisible one drives reactive firefighting.

Bad Actor

Bad Actor (Reliability)

An asset that repeatedly fails or consumes a disproportionate share of downtime and maintenance spend. Finding bad actors is the fastest route to downtime reduction.

Calibration

The documented comparison of an instrument's reading against a known standard, with tolerances, certificates, and due dates. Calibration records are core maintenance evidence in audited industries.

CCP

Critical Control Point

A step in a food process where a control is essential to prevent, eliminate, or reduce a food-safety hazard to an acceptable level. CCPs are monitored against critical limits, and an overdue or failed CCP check can lock an asset out of returning to production.

CMMS

Computerized Maintenance Management System

Software that centralizes maintenance work orders, preventive maintenance schedules, asset records, spare parts, and maintenance history so teams can plan, execute, and prove maintenance work instead of relying on spreadsheets and paper.

Condition Monitoring

Continuously tracking measured asset parameters such as temperature, vibration, or pressure against defined warning and critical limits. Readings can be logged manually or pushed from a PLC, SCADA, or IoT gateway, and a breached limit can alert users or automatically open a breakdown. Condition monitoring is the data backbone beneath predictive maintenance.

Condition-Based Maintenance (CBM)

Condition-Based Maintenance

Maintenance triggered when monitored asset condition crosses a defined threshold. CBM sits between fixed-interval PM and fully predictive analytics.

Deviation

A recorded departure from a specification, tolerance, or procedure, such as an out-of-tolerance reading, along with the corrective work that resolves it. Closing deviations visibly is essential audit evidence.

Downtime

Time an asset or line is not available to produce. Planned downtime is scheduled for maintenance or changeover; unplanned downtime comes from breakdowns. Accurate downtime coding by asset, cause, and shift is the foundation of reliability analytics.

EAM

Enterprise Asset Management

A broader discipline and software category that manages the full lifecycle of physical assets, from capital planning and procurement through operation, maintenance, and disposal. A CMMS is the maintenance-execution core of an EAM program.

FMEA

Failure Mode and Effects Analysis

A method for cataloging how an asset can fail, the effect of each failure, and its risk, used to design targeted PMs and inspections.

Lot Traceability

The ability to follow a production lot in both directions: trace-back from a finished product to every raw-material lot and process step that created it, and trace-forward from a raw-material lot to every finished product and customer it reached. Lot traceability is the core requirement behind an effective food recall.

Mass Balance

Mass Balance (Traceability)

A reconciliation check that the quantity of a raw-material lot consumed equals the quantity accounted for across finished products, waste, and remaining stock. Mass balance is a standard test auditors use to confirm a traceability system is complete and trustworthy.

Mock Recall

Mock Recall (Recall Drill)

A practiced exercise that simulates a real product recall to verify traceability works under pressure. A good drill produces a recall report, measures time-to-trace, and calculates a recall-effectiveness percentage, so gaps are found before a real incident does.

MRO

Maintenance, Repair, and Operations

The spare parts, consumables, and supplies used to keep equipment running. MRO inventory management balances stockout risk against carrying cost.

MTBF

Mean Time Between Failures

The average operating time between failures of a repairable asset. Higher MTBF means greater reliability.

Formula MTBF = Total operating time / Number of failures

MTTF

Mean Time To Failure

The average operating time until failure for a non-repairable asset or component, used to plan replacements.

Formula MTTF = Total operating time / Number of units

MTTR

Mean Time To Repair

The average time to restore a failed asset to working order, including diagnosis, repair, and testing. Lower MTTR means faster recovery and less downtime.

Formula MTTR = Total repair time / Number of repairs

OEE

Overall Equipment Effectiveness

A composite metric of manufacturing productivity that multiplies Availability, Performance, and Quality. Maintenance most directly influences the Availability factor through uptime and fast repairs.

Formula OEE = Availability x Performance x Quality

Planned vs Reactive Work

Planned vs Reactive Maintenance Ratio

The split between maintenance scheduled in advance and unplanned breakdown work. World-class programs target roughly 80% planned or higher, because planned work is safer, cheaper, and faster.

PM Compliance

Preventive Maintenance Compliance

The percentage of scheduled preventive maintenance completed on time within its grace window. It is a leading indicator of future reliability.

Formula PM Compliance = PMs completed on time / PMs scheduled

Predictive Maintenance (PdM)

Predictive Maintenance

Maintenance triggered by the measured condition of an asset, such as vibration, temperature, or oil analysis trends, so work happens just before failure rather than on a fixed interval. PdM is a form of condition-based maintenance.

Preventive Maintenance (PM)

Preventive Maintenance

Maintenance performed on a planned schedule, by calendar date, runtime, meter reading, or cycle count, to reduce the chance of failure. Effective PM programs make overdue work visible before a shift starts.

Reliability-Centered Maintenance (RCM)

Reliability-Centered Maintenance

A structured method for choosing the right maintenance strategy for each asset based on its failure modes and consequences, balancing run-to-failure, preventive, and predictive approaches.

Work Order

The record of a single maintenance job: what to do, on which asset, by whom, with which parts, and the proof of completion. It is the atomic unit of a CMMS.

Wrench Time

The share of a technician's paid time spent actively performing maintenance, as opposed to traveling, waiting for parts, or searching for information. Mobile CMMS and parts readiness raise wrench time.