The process of selecting a maintenance task to manage each failure mode begins by assigning it to a consequence category.
Why does the consequence category matter? Because there is no point in carrying out a maintenance task if it doesn't deal with the failure consequences. Any proposed task must achieve the target for that category before it can be selected.
| Consequence Category | What it Means | Target |
|---|---|---|
| Safety | One or more individuals could be injured or killed | Maintenance must reduce the risk of a safety incident to a tolerable level |
| Environmental | An environmental regulation that applies to the process could be breached | Maintenance must reduce the risk of an environmental breach to a tolerable level |
| Operational | The failure would stop production, including effects on product quality | Maintenance is only worth doing if the cost of maintenance is less than the cost of lost production and any secondary damage |
| Non-operational | The failure has no effect on safety, the environment or on production | Maintenance is only worth doing if it costs less than the cost of repairing any secondary damage |
| Hidden | The failure on its own has no effects at all in normal circumstances. The failure only has effects during abnormal circumstances, typically when a second failure has occurred | Maintenance reduce the risk of a multiple failure to a tolerable level |