Reliability & maintenance, in plain English

Asset Health Score

A single 0–100 score summarising an asset's condition, blending age, failure history, open faults and live sensor data.

Availability

The percentage of scheduled time an asset is actually capable of running, accounting for both breakdowns and planned stops.

MTBF (Mean Time Between Failures)

The average operating time between one failure and the next, for equipment that gets repaired rather than replaced.

MTTA (Mean Time to Acknowledge)

The average time between a fault being reported and someone actually acknowledging and taking ownership of it.

MTTF (Mean Time to Failure)

The average time a non-repairable asset or component runs before it fails and is replaced outright.

MTTR (Mean Time to Repair)

The average time it takes to fix a failed asset and return it to service, from the moment the fault is reported.

OEE (Overall Equipment Effectiveness)

A single score combining availability, performance and quality that shows how effectively an asset or line is actually running.

Planned Maintenance Percentage (PMP)

The share of total maintenance labour hours spent on planned work versus reacting to breakdowns.

Uptime & Downtime

The time an asset spends running (uptime) versus stopped (downtime) — split into planned downtime and unplanned downtime.

Bathtub Curve

The classic failure-rate curve showing three phases over an asset's life: early failures, a stable middle period, then rising wear-out failures.

Condition-Based Maintenance (CBM)

Maintenance triggered when a live measurement — vibration, temperature, current draw — actually crosses a defined threshold.

Criticality Analysis

Ranking assets by how much a failure would actually cost — in safety, downtime and repair — to decide where maintenance attention and budget go first.

Failure Mode and Effects Analysis (FMEA)

A systematic method for identifying every way an asset can fail, and ranking those failure modes by how severe, frequent and detectable each one is.

Predictive Maintenance (PdM)

Maintenance triggered by forecasting when an asset is likely to fail, using trends in condition data over time.

Preventive Maintenance (PM)

Scheduled maintenance performed at fixed intervals — by date or by usage — regardless of the asset's current condition.

Reactive Maintenance

Fixing equipment only after it has already failed — also called run-to-failure or breakdown maintenance.

Reliability-Centered Maintenance (RCM)

A structured process for deciding the right maintenance strategy for each asset, based on how it fails and what that failure actually costs.

Root Cause Analysis (RCA)

A structured investigation into why a failure actually happened, aimed at the underlying cause rather than the symptom.

Total Productive Maintenance (TPM)

A maintenance philosophy that puts basic upkeep — cleaning, inspecting, lubricating — in the hands of the operators running the equipment.

Asset Register

The master list of every physical asset a facility maintains, with identifying details, location, criticality and full maintenance history.

CMMS (Computerised Maintenance Management System)

Software that tracks assets, schedules preventive maintenance, and manages work orders, parts and maintenance history in one system.

EAM (Enterprise Asset Management)

Software that manages an asset's entire lifecycle — procurement, maintenance, depreciation and disposal — usually across multiple sites.

MRO Inventory (Spare Parts Inventory)

Maintenance, Repair and Operations inventory — the spare parts, consumables and tools kept on hand to support maintenance work.

Work Order

A formal record of a specific maintenance task — what needs doing, on what asset, by whom, with what parts and labour, tracked to completion.

AMR (Autonomous Mobile Robot)

A self-navigating robot that moves goods or performs tasks around a facility without fixed tracks or wires, using onboard sensors to route around obstacles.

AS/RS (Automated Storage and Retrieval System)

A computer-controlled system of cranes, shuttles or robots that automatically stores and retrieves pallets, cases or totes without manual picking.

Goods-to-Person (GTP)

An order-picking model where automation brings the product to a stationary picker, instead of the picker walking to the product.

Pallet Shuttle System

A motorised shuttle that moves inside a high-density racking lane to store and retrieve pallets automatically, without a forklift entering the lane.

PLC (Programmable Logic Controller)

An industrial computer that directly controls machinery — reading sensor inputs and driving motors, valves and actuators in real time.

WES & WCS (Warehouse Execution & Control Systems)

The software layers that translate WMS orders into real-time instructions for physical equipment — WES orchestrates the work, WCS drives the machines directly.

WMS (Warehouse Management System)

Software that manages inventory, orders and warehouse operations at a business-logic level — what to pick, where to put it, how to fulfil an order.

LOLER (Lifting Operations and Lifting Equipment Regulations)

UK regulations requiring lifting equipment — cranes, hoists, forklifts, lifting accessories — to be thoroughly examined at set statutory intervals.

LOTO (Lockout/Tagout)

A safety procedure for isolating equipment's energy sources before maintenance work, using physical locks and tags to prevent it being switched back on.

PUWER (Provision and Use of Work Equipment Regulations)

UK regulations requiring work equipment to be suitable for its purpose, properly maintained, and used only by trained, competent staff.

Statutory Inspection

Any inspection legally mandated by regulation — LOLER, PUWER and similar — rather than one a maintenance team scheduled voluntarily.