#PARETO CHART MINITAB SERIES#

The two principal maintenance control systems are those which deal with effectiveness and organizational efficiency, respectively (see Figure 4.3). In other words, control systems are integral to the operation of organizations. For example, if an overtime limit is set then the actual overtime needs to be monitored and reported to the supervisor for necessary corrective action. Indeed, it could be argued that a control system is needed for each objective that is set. It will be appreciated from Figure 4.3 that it needs to be complemented by control systems operating at a lower level (and on a shorter time scale). In addition, only rarely do such systems have the facility of comparing maintenance costs against the various parameters of output.Įven if properly designed, a maintenance costing system has to be a high level, longerterm one, providing a means of controlling the overall maintenance performance. cost centers may not be plant-specific and, even when they are, each one may encompass too large an area of plant to be of any use in maintenance management.

Most company budgeting and costing systems are designed by accountants for corporate financial control and are not sufficiently equipment-oriented to shed light on the problems of maintenance control, e.g. The diagnosis of deviations from intent and the prescription of appropriate remedial action. The monitoring of output parameters (such as availability) and of inputs (such as resource cost relative to budget) which can influence the levels achieved The setting of objectives/PIs (or key performance indices, KPIs *) The above, although not ideal, should satisfy most of the requirements of an overall maintenance performance control system, facilitating: (v)Īctual cost of major overhauls – again for comparison with budget (a part of the major overhaul procedure, see Chapter 7). (iv)Īctual maintenance costs per cost center per trade group or per supervisor – for comparison with budget (a part of company budgetary control). Plots of output performance vs maintenance costs, per unit or per plant.

Identified areas (plants or units) of high maintenance cost or low availability, perhaps presented via Pareto plots or ‘top ten’ ranking lists). The main outputs and their possible uses are as follows: (i)Īctual maintenance costs (separated into labor and material costs and, if required, divided according to work type and trade) and recorded levels of relevant output parameters (availability, product quality losses) – which can be compared against budgeted costs and targeted levels of performance (per period, per unit and per plant). The system could be designed to provide a variety of outputs, either automatically or on demand – especially if the processing is computerized.

#PARETO CHART MINITAB SERIES#

This explains a series of 'jumps” in the freshwater cost shown in Figure 2. Comparison between Figure 2 and 3 highlights that a change to the network structure would lead to significant repercussion in the freshwater demand. In both cases, the selected treatment technologies are TU1 2 and TU2 1 - this is in line with the results of Karuppiah and Grossmann (2006). The former corresponds to freshwater flowrate of 40 ton/h while freshwater flowrate in the later is 75.16 ton/h. Figure 3 compares two different water networks involving minimum freshwater and treatment costs. The figure also shows a minimum total operating cost of $655,110 which corresponds to minimum freshwater case. Consequently, this leads to higher treatment cost.

It shows that for a network with less freshwater flow, it needs to be compensated with more flow of reused water. The Pareto plot in Figure 2 shows a trade-off between freshwater and treatment costs. Table 3 shows the distances between PUs and TUs. The freshwater cost is $1/ton and the annualized factor for investment is taken to be 0.1/yr. The discharge limits for both contaminants are 10 ppm. It involves two contaminants A and B, for which the PU and TU data are shown in Table 1 and 2, respectively. We have solved the case study of Karuppiah and Grossmann (2006) shown in Figure 1.

Pareto chart minitab