Reliability, Availability and Maintainability (RAM) Models
A Reliability, Availability and Maintainability (RAM) model can be a key strategic tool.
RAM models can be developed for brownfield sites and at any stage during the operate phase of the life cycle. If there is the opportunity though to develop it during the design process it can be used to maximise reliability and availability in the design. The information can also be used to develop life cycle costs for the plant. This type of information is critical when comparing alternative design options or equipment choices. The cheapest to purchase may have significantly increased operate and maintain costs.
If the RAM model is developed during the design phase, the manufacturers data for equipment reliability and maintenance schedules should be used. When decisions are to be made on design options for equipment choices the RAM model will be invaluable tool to trial the options and be able to be used as justification for the decision made.
When moving into the operate phase the model will be able to demonstrate the inherent reliability of the plant and the availability that can be achieved. The model should be updated on a regular basis as the actual operation, reliability and maintenance data becomes available. This will allow the gaps between the actual and theoretical to be identified as areas requiring improvements. It will also enable a predication to be made for the coming production period which may be quarterly or annually for example.
Any plant improvements or new projects should also be modelled with the existing plant. This can highlight the bottleneck areas or where the proposed new project will reduce the overall availability and reliability of the plant. Again design options or equipment choices can be modelled to determine which is most cost effective and help the asset achieves it production and reliability goals.
If the model is developed during the operate phase the process is the same, the theoretical model will be developed with either the manufacturers data if it is still available or from a reputable source such as the Oreda data. The actual model will be able to be developed at the same time from the production loss accounts, the maintenance records and interviews with staff. At this stage there is little that can be done to influence the design of the plant unless it can be demonstrated that a proposed change would be cost effective. The model would help with predicting and quantifying the production and reliability improvements that would be achieved.
Any new projects, modifications or tie ins should still be modelled and simulations run with the existing model to ensure the plant performance is not negatively impacted with the new addition.