By Ross Moody
Most people would expect mechanical workshop staffing requirements to relate to the number of items in the fleet, but it isn’t that easy to define what an appropriate level of staff is.
The old method of using vehicle equivalents (ratio of mechanics to particular vehicle types) is less relevant today. Diagnostic and electronic technology has advanced to a point where the time it takes to find a problem has been significantly reduced and this must be taken into account in determining staffing levels.
The complexity of equipment, usage patterns and other local conditions also play a role in determining optimum staff size. Regular vehicle replacement will lead to a fleet of a lower average age and this will impact on the number of mechanical staff required for maintenance tasks. The amount of outsourcing utilised for specialised works can increase or decrease the number of positions needed to meet the requirements of the workshop.
Other determining factors include climate and geographic location, location of the suppliers’ workshops, the usage of the plant/vehicle/equipment and the workshop equipment available to undertake the mechanical work.
Applying First Principles
Rather than using vehicle equivalents, it is sounder to use first principles for estimating labour requirements. First principles involve estimating both scheduled and unscheduled maintenance requirements and making allowances for administrative tasks.
To start, you need a comprehensive list of all the manufacturers scheduled maintenance tasks and the recommended labour times. Scheduled service hours are based on the usage of each item and the manufacturers’ recommended service intervals. An allowance may need to be made for safety checks in between scheduled services and for additional service tasks based on local conditions.
An estimate of unscheduled maintenance is applied as a ratio to scheduled maintenance, based on a combination of historical records, local conditions and experience. It will be greatly affected by the age of the fleet. A new fleet will have much less repair time than an old fleet nearing optimum replacement. The ratio should be discussed with mechanical maintenance staff. The ratio will vary for different items in the fleet. For example, a street sweeper will have a much higher allowance for unscheduled maintenance than a motor car.
Finally a percentage should be applied to the total estimated labour hours for administrative non-productive tasks.
Tips
Don’t try to use anyone else’s mechanic to plant/vehicle ratios. As has been explained, ratios are built on a number of factors, including utilisation, which determines the frequency of scheduled services. A high-use item will need to be serviced more often than a low-use item.
The recently released third edition of the IPWEA best practice Plant & Vehicle Management Manual provides a step-by-step approach to calculating workshop labour requirements.