AAOM Handbook

SS.09 Identify Cost of Strategies

Context

There are six basic strategy options that may be applicable to manage a risk. These are; 1. Modification of the process – remove or reduce the risk and the need for service work. 2. Monitor process condition and/or performance to identify the best time and type of service action. 3. Initiate service actions based on a pre-defined interval or life. 4. Install back-up or containment systems to circumvent or mitigate the consequences of the threat. 5. Operate the process to the point of failure. 6. Closure of the process.

The strategies that are appropriate for a particular failure mode will depend upon a few basic factors;

• The technical feasibility of each of the strategy options. • Whether the early development of the threat is detectable. • The warning time for detectable threats. • Whether the threat has an Age Related characteristic. • The interval to occurrence for Age Related threats.

• The consequence of the threat (the HSE threat, the direct cost of dealing with the consequences of the threat, and the lost opportunity cost arising from the threat). • The direct and lost opportunity cost to implement the strategy option. Every strategy option will require at least one action to implement it. A condition/performance monitoring strategy will require at least two actions for implementation. For example: The vibration level for a gearbox bearing may be monitored on a regular basis in order to predict the failure of the bearing – this action may occur hundreds of times over the life of the gearbox. When the vibration indicates an imminent failure of the bearing the bearing will be changed – this action may occur several times over the life of the gearbox. These actions are generally referred to as the primary and secondary actions of the strategy.

In evaluating the cost to implement a strategy the direct and opportunity cost of all actions associated with the strategy must be included.

The most cost effective strategy can only be determined after all the relevant consequences and costs to implement each of the viable strategy options have been estimated.

Purpose

To estimate the cost for implementation of each potential Service Strategy option for a threat.