Downtime is the time that an asset is unavailable for its normal use due to servicing or maintenance requirements.

Why is downtime important?

Downtime is often called the hidden cost of fleet management. In many cases, downtime costs are substantial and fleet managers need to be aware of how machine downtime can affect business unit productivity.

Downtime is a significant factor when considering the overall cost of an item. Repairs and maintenance, lack of parts, insufficient operator skill, accidents, and incorrect design can all significantly impact on costs.

How is downtime calculated?

Downtime costs have two major components and both need to be taken into account when calculating the total cost of any downtime:

• Hire of a replacement, including holding onto other machines to compensate, and additional on-site and off-site charges involved in dry-hiring a replacement.
• Fixed costs related to the loss of an operational machine on a specific task. The fixed costs are as a result of ownership and include licence, insurance, finance and depreciation costs. They should also include costs related to the operator during the downtime.
• Other items and staff associated with the plant item that is unavailable. Where vehicles break down, the downtime cost associated with the breakdown should also take into account other items that are associated with this unit. For example if a Grader is working on a program of re-sheeting a gravel road it may have a water truck, three gravel trucks, a traffic control crew, and associated operators. By losing the operation of the Grader, the whole crew needs to be relocated or stood down while a replacement grader is moved to site.