Specifications and functions
Once the intended objectives of the implementation of RCM3 are established, detailing the scope, clarifying and determining the hierarchy tree of assets, is the time to start what really is the first stage of RCM3 methodology: determinate the functions of the assets included in the scoping study of RCM3.
There are two types of functions: the specific functions, which are related with the specification of the item subject of study (plant, area, system, subsystems or equipment) and the general functions, a set of functions that, in general, every item must achieve with secureness, visual aspect, etc. and which normally are not based in an specification.
In order to be able to define general functions, the specifications or standards which an analysed item must achieve must be analysed previously, either an equipment, subsystem, system, area or plant in a whole. Normally, these specification can be found in the equipment’s instructions, in acceptance tests, in engineering projects or there are reference values of transaction. Occasionally, detailed documentation is not provided, thus one has to either look for that information, reckon it or even skip this step. It has to be bear in mind that specifications are require for certain the functions, but it is possible to detail them with more or less precision without needing to indicate the specifications. It is a good solution to skip this step in some or in most of the items to analyse. This solution will eliminate precision and rigour to the study, but however, it will help to gain time and avoid stuck at the beginning of the process, when a little more speed is needed.
In general, specifications are into four different categories: related to resources that the item requires, related to functioning conditions, to internal operations that the item carries out or to the products or “outputs” of the analysed item.
Functions arise from specifications. For each one of the specifications, there is only one function associated. In such a case of appearing to be two functions associated with one specification, in fact it is two different specifications led to those two different functions, and both will have to be detailed.