Asset Criticality
Not all assets are equally important. Learn how to assess asset criticality, prioritise maintenance effort, and allocate resources where they matter most.
What is Asset Criticality?
Asset criticality is a measure of how important an asset is to the business. It considers the consequences of failure: safety, environmental, production, cost, and reputational impacts. Critical assets receive more maintenance attention, more condition monitoring, and more spare parts investment than non-critical assets.
Not every asset deserves the same level of maintenance. Applying the same strategy to a critical boiler feed pump and a non-critical garden hose tap wastes resources. Criticality assessment directs maintenance effort where it has the most impact.
Criticality Rating
A common approach rates each asset on several factors, typically on a 1 to 5 scale. The overall criticality is the sum or product of these factors. Key factors include:
- Safety: Could failure injure people? (5 = high risk of injury, 1 = no safety risk)
- Environmental: Could failure cause environmental damage? (5 = major spill/emission, 1 = no environmental impact)
- Production: Would failure stop production? (5 = entire plant stops, 1 = no production impact)
- Cost of downtime: How expensive is the downtime? (5 = very expensive, 1 = minimal cost)
- Repair cost: How expensive is the repair? (5 = very expensive, 1 = cheap repair)
- Redundancy: Is there a backup? (5 = no backup, 1 = fully redundant)
Criticality Categories
| Category | Description | Maintenance Strategy |
|---|---|---|
| A - Critical | Failure stops production or creates safety risk | Predictive maintenance, condition monitoring, redundant spares, highest priority |
| B - Important | Failure degrades production but plant can continue | Preventive maintenance, condition monitoring where practical, spare parts stocked |
| C - Standard | Failure has minimal impact, backup available | Run-to-failure or basic preventive maintenance |
The 80/20 rule
Typically, 20% of assets account for 80% of risk. Focus your best maintenance effort, condition monitoring, and reliability engineering on the top 20%. The bottom 80% can be maintained with a simpler, less intensive strategy. This is the most efficient allocation of limited maintenance resources.
Using Criticality for Maintenance Planning
- Assess criticality for every asset. PlantLogica's asset records include a criticality field for this purpose.
- For A-critical assets: implement predictive maintenance (vibration, temperature, oil analysis), condition monitoring, regular inspection, and stock critical spare parts. Plan for redundancy.
- For B-important assets: implement preventive maintenance (time-based or condition-based), stock commonly needed spare parts, schedule regular inspections.
- For C-standard assets: run-to-failure is acceptable. Maintain a basic preventive schedule. Don't over-invest in monitoring or spares.
- Review criticality annually. Process changes, new equipment, or organisational changes may shift an asset's criticality.
Tip: Don't over-categorise. If everything is A-critical, nothing is. Be realistic: if a failure causes a 10-minute production delay with a $200 repair, it is not A-critical, regardless of how inconvenient it seems at the time. Reserve A-critical for assets where failure truly threatens safety, production, or the business.