How to define and implement the right Key Performance Indicators (KPIs)
Industrial maintenance is essential in plants to ensure continuity of operations and optimise operating costs. Relevant key performance indicators (KPIs) are important for effective monitoring. These indicators can be used to identify faults, establish benchmarks, and implement strategies to reduce downtime and improve equipment reliability.
Some of the most effective KPIs in maintenance include:
- Mean Time Between Failures
- MTBF (Mean Time Between Failures)
- Overall Equipment Effectiveness (OEE)
- Preventive maintenance
- Planned vs. unplanned maintenance
- Root cause analysis
- Maintenance backlog
- Scheduled critical maintenance percentage (SMCP)
But how do you choose and implement the right KPIs to optimize decision-making? This article proposes a practical approach to identifying, selecting and using KPIs effectively in industrial maintenance.
Key Performance Indicators (KPIs)
Key Performance Indicators (KPIs) are specific parameters used to assess the effectiveness and efficiency of maintenance activities within an organisation. Monitoring them helps to achieve the objectives of industrial maintenance, which include in particular
- Optimising the availability of critical equipment (crushers, mills, conveyors, etc.);
- Reducing unplanned downtime.
- Improving safety and reducing the risk of incidents.
- Reducing preventive and corrective maintenance costs.
KPIs must be clearly defined and targeted at a specific aspect of performance. They must be:
- Quantifiable, with precise data for objective evaluation.
- Achievable, considering available resources.
- Aligned with the company's strategic objectives and reflecting its priorities.
- Impactful, having a direct influence on the company's success.
- Measurable over a given period, with transparent monitoring shared with key stakeholders.
Lean tools for defining and monitoring maintenance KPIs
Implementing Lean tools enables maintenance problems to be identified and actionable KPIs to be extracted. Each Lean tool provides a specific methodology for analysing, structuring and improving plant maintenance processes.
Identify the main maintenance problems in the plant
Lean tool: Pareto chart (80/20)
The Pareto chart is based on the principle that 80% of breakdowns come from 20% of the causes. By classifying breakdowns in order of frequency or impact, this tool enables maintenance teams to focus their efforts on the most critical problems.
Implementation:
Collect data on breakdowns and incidents.
Classify breakdowns by frequency or cost.
Draw up a Pareto chart to visualise the major causes of breakdowns.
Associated KPIs:
Number of breakdowns per equipment.
Maintenance cost per type of breakdown.
MTBF (Mean Time Between Failures).
FMEA - Failure Modes and Effects Analysis of equipment for production
Il existe une très grande variété d’outils et de méthode pour évaluer la criticité . La méthode FMECA classe les équipements en fonction de leur impact sur la production et de leur probabilité de défaillance. Elle permet de prioriser les actions de maintenance en fonction du risque. Cette méthode évalue les modes de défaillance d’un équipement en fonction de trois critères :
Gravité (S) : Impact de la défaillance
Occurrence (O) : Fréquence d’apparition
Détectabilité (D) : Probabilité de détection avant l’impact
On peut calculer le Risque Prioritaire (RPN) par :
RPN=S×O×DRPN = S \times O \times DRPN=S×O×D
Implementation:
Identify production-critical equipment.
Assess the frequency and severity of potential failures.
Assign a criticality index based on the impact and probability of failure.
Related KPIs:
Equipment criticality index.
Availability rate of critical equipment.
MTTR (mean time to repair) for critical equipment.
Identify the main cause of unplanned downtime
Lean tool: 5 Whys and Ishikawa Diagram (Cause-Effect)
The 5 Whys helps to get to the root cause of repetitive breakdowns by successively questioning the ‘Why’ of the problem. The Ishikawa diagram structures possible causes into five categories: Human Factors, Methods, Machines, Materials, and Environment.
Implementation:
Select a frequent breakdown and ask the question ‘Why?’ 5 times to get to the root cause.
Construct an Ishikawa diagram to visualise the various contributing causes.
Related KPIs:
Rate of unplanned breakdowns (%).
Average response time after a breakdown.
Total downtime for critical equipment.
Performance evaluation
Lean tool: OEE (Overall Equipment Effectiveness)
OEE is a key indicator that measures equipment efficiency by combining three parameters: availability, performance and quality.
Implementation:
Monitor equipment availability (actual production time compared with total available time).
Calculate equipment performance (actual speed compared with theoretical speed).
Analyse quality (number of compliant products compared to total number of products manufactured).
Related KPIs:
Availability (%) = (Operating time / Total available time) x 100.
Performance (%) = (Actual production / Theoretical production) x 100.
Quality (%) = (Compliant products / Manufactured products) x 100.
OEE (%) = Availability × Performance × Quality.
Conclusion
The adoption of key performance indicators (KPIs) in industrial maintenance improves equipment reliability, reduces costs and optimises production. Lean tools make it easier to identify the causes of breakdowns, assess the criticality of equipment and monitor performance.
The Pareto diagram prioritises critical problems, the FMECA identifies strategic equipment, while the 5 Whys and the Ishikawa diagram analyse the root causes of breakdowns. Gemba Walk and TPM improve data collection in the field, and OEE measures overall equipment performance.
Rigorous implementation and a culture of continuous improvement maximise the impact of these approaches, enabling companies to reduce downtime, increase productivity and strengthen their competitiveness.
💡 What KPIs do you use to optimise maintenance in your plant?