CMMS Software Terms & Definitions: Complete Maintenance Glossary

Preventive Maintenance (PM)

Preventive maintenance is maintenance performed on a regular schedule to reduce the likelihood of equipment failure before it occurs. CMMS software automates PM scheduling by generating work orders based on calendar intervals, meter readings, or runtime hours, ensuring tasks never fall through the cracks.

Example: A manufacturing plant schedules quarterly lubrication and inspection of conveyor motors, triggered automatically by the CMMS every 90 days or 2,000 operating hours, whichever comes first.

Predictive Maintenance (PdM)

Predictive maintenance uses real-time sensor data and analytics to forecast when equipment will fail, triggering maintenance only when conditions indicate deterioration is likely. Unlike PM, PdM avoids unnecessary tasks by acting on evidence rather than fixed schedules.

Example: Vibration sensors on an industrial pump detect increasing frequency anomalies. The CMMS flags the asset for inspection two weeks before the predicted bearing failure, allowing the team to replace the component during a planned window.

Work Order

A work order is a formal, authorized request to perform a specific maintenance task. In a CMMS, work orders capture the task description, assigned technician, priority level, required parts, estimated labor, and completion status, creating a traceable record from request to closure.

Example: A technician submits a work order through the CMMS mobile app after noticing unusual heat from a compressor. The system auto-assigns it to a specialist, reserves the needed replacement valve from inventory, and tracks progress through completion.

Asset Management

Asset management in a CMMS context refers to tracking every physical asset, its location, specifications, maintenance history, warranty information, and lifecycle costs within a centralized registry. It provides the foundation for all maintenance planning and decision-making.

Example: A hospital CMMS stores complete records for every HVAC unit, from installation date and warranty terms to every inspection, repair, and part replacement, enabling facilities managers to identify units approaching end of life.

Reactive Maintenance

Reactive maintenance (also called corrective or breakdown maintenance) is performed after equipment has already failed. While not ideal as a primary strategy, reactive maintenance is appropriate for non-critical assets where the cost of prevention exceeds the cost of repair.

Example: A facilities team does not schedule preventive care for office printers since failures are infrequent and replacements are inexpensive. When a printer jams, a reactive work order is created to address it on the spot.

Downtime

Downtime is any period during which an asset or production line is non-operational. CMMS software categorizes downtime as planned (scheduled maintenance outages) or unplanned (unexpected breakdowns), helping teams quantify losses and prioritize improvements.

Example: A food processing plant tracks 14 hours of unplanned downtime in a single month due to conveyor belt failures. The CMMS report identifies the root cause and recommends a preventive maintenance schedule to reduce future losses.

Mean Time Between Failures (MTBF)

MTBF measures the average operating time between consecutive failures of a repairable asset. A higher MTBF indicates greater reliability. CMMS platforms calculate MTBF automatically from work order history, enabling teams to benchmark performance and identify assets that need attention.

Example: If a generator fails three times over 3,000 operating hours, the MTBF is 1,000 hours. Maintenance teams use this metric to compare assets, set replacement timelines, and justify preventive maintenance investments.

Mean Time to Repair (MTTR)

MTTR measures the average time required to repair a failed asset and return it to operation. Lower MTTR signals faster response and more efficient repair processes. CMMS software calculates MTTR from work order timestamps, including diagnosis, repair, and testing phases.

Example: A fleet maintenance team tracks an average repair time of 4.2 hours per vehicle. After implementing standardized checklists in the CMMS, MTTR drops to 2.8 hours, representing a significant gain in fleet availability.

Spare Parts Inventory

Spare parts inventory in a CMMS is the digital record of all replacement components in stock, including quantities, storage locations, reorder points, and vendor details. Effective parts management prevents stockouts that delay repairs and overstocking that ties up capital.

Example: A CMMS tracks 12,000 spare parts across three warehouses. When a critical pump seal drops below its reorder point, the system automatically generates a purchase order to the approved vendor, ensuring the part is available before the next scheduled replacement.

Root Cause Analysis (RCA)

Root cause analysis is a systematic investigation process used to identify the underlying reason a failure occurred rather than just treating the symptom. CMMS platforms support RCA by linking failure codes, work order histories, and asset data, making it easier to spot recurring patterns.

Example: After a motor fails twice in one quarter, the maintenance team uses CMMS data to discover that both failures were caused by misalignment from a common installation procedure. They update the standard operating procedure and add a verification step to the PM checklist.

Manufacturing: Reducing Unplanned Downtime

A automotive parts manufacturer implements CMMS to schedule preventive maintenance on 200 CNC machines. Within six months, unplanned downtime drops by 34 percent as the system automatically generates PM work orders, tracks completion, and escalates overdue tasks.

Healthcare: Managing Regulatory Compliance

A hospital network uses CMMS to document every inspection, calibration, and repair on critical medical equipment. The system maintains audit-ready records for Joint Commission compliance and sends automated reminders when certifications are due for renewal.

Facilities: Coordinating Multi-Site Maintenance

A property management company oversees 50 commercial buildings through a single CMMS. Maintenance requests flow in from tenant portals, are auto-assigned based on trade and availability, and tracked to completion, giving leadership real-time visibility across all locations.