Desktop version

Home arrow Health arrow Case Studies in Maintenance and Reliability: A Wealth of Best Practices


Approaches to Staffing Numbers

Companies and consultants use a number of methodologies and algorithms to calculate numbers. The main approaches are: [1]

time is multiplied by the frequency to give an annual man-hour requirement. The method is hugely time consuming. It also tends to inflate work requirements and the man-hours because conservatism adds in lots of low-value activities and because of a tendency to always round up fractions of hours or workers. It does sell well to the workforce though, as they can understand how the answer has been arrived at. This is almost a work-study process.

  • • At a slightly higher level is a synthesis of the work hours needed to operate and maintain specific building blocks of a plant. This data is industry specific.
  • • At an even higher level, we can work out an equivalent "plant com plexity" Using a proprietary multiplier, we can derive the staff re sources needed for the whole operation. More complex or bigger plants need more people than smaller, less complex plants. You will see numbers per complexity unit or per unit of production.
  • • Specific, easily-counted elements of the business are a way to esti mate the resources using a set of standardized ratios. For example, for an Instrument group, we can use the number of control valves; for electricians the number of motors, etc.

The validity of all of these methods is always open to challenge and hangs to a large extent on the quantity and quality of relevant data available. A consultant's detailed knowledge of large groups of similar plants is much more convincing than snapshots of a few different plants across a number of industries. As discussed in Chapter 8, arguments will rage about the divisor used to normalize complexity and size of an operation. Does it really take that much longer to maintain a big pump than a small one?

What we are really doing is working out the resources needed to maintain your plant professionally. We need to count all the human resources used. You are fooling only yourself if you hide work and the effort to do it. It is important to include not only normal hours, but also overtime, and effort expended by contractors either on site or performing activities in their premises. For instance, if you send a pump out to a repair workshop, the hours spent on the repairs should be counted in these calculations.

To get the number of heads, you need now to work out the attendance hours of our workforce. By the time you have knocked off holidays, sickness, training, etc., of the working weeks, you may well be down to something like 1700 hours per year. Note: That does not mean hands-on-tools time (or wrench time as it is sometimes called) which can be as low as 30% of this number.

Production facilities may, or may not, carry out a wide range of secondary activities such as refurbishment, gardening, purchasing, and sales. These are usually excluded from the norms, but treated and calculated separately. A focus is put on the standard types of activity, i.e., production (operations), maintenance, inspection, and technical support.

84 Chapter 9

  • [1] Activity/work volume based where each element of supposedlynecessary work is identified, the time to do it is calculated, and that
Found a mistake? Please highlight the word and press Shift + Enter  
< Prev   CONTENTS   Next >

Related topics