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|