Glossary - O

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The diminution in the usefulness or economic life of an asset at a greater rate than its physical deterioration. Source: G1

Obsolescence (Technical)

Impairment of the functionality, level of service, maintainability or usefulness of an asset resulting from economic, environmental, physical or technological changes. Source: D1


The manner in which a building is occupied by its users or residents. Source: S3


Occurrence is an assessment of the likelihood that a particular cause will happen and result in the Failure Mode during the intended life and use of the product. This term is particularly applicable to the FMECA process. Source: A4

Open Competitive Bid

An invitation to bid for the construction of a project or part of a project, issued to all interested parties through a public advertisement. It is also called a public bid. Source: G3

Principals invite by public advertisement without restriction on the number of bids sought. Principals would normally require biders to prove that they have the necessary competence, resources, industrial relations, quality and safety management and financial capacity to carry out the work. Source: D1

Operating Cost

That part of support costs associated with the day-to-day operation of a facility or part thereof, such as those arising from energy and other utility needs, cleaning, security and management, but not including maintenance and rehabilitation costs. The costs also include labor, materials and overhead costs. Source: S3

Operating Lease

A lease under which the lessor effectively retains substantially all the risks and benefits incidental to ownership of the leased asset. Source: D1


Active process utilizing an asset. It will consume resources including manpower, energy, chemicals and materials. Costs are part of life cycle costs of an asset. Source: G1

Opportunity Cost

The costs to an individual or enterprise of the alternatives foregone as the result of a decision to carry out a specific action. It is also considered to be the cost of resources in their next best alternative use. For example, the opportunity cost of "free" government owned land used for a project is the price at which the land could be sold in its existing state. Source: G3


Impacts of effects on the community as a result of producing outputs. Source: A4


Services or products produced and delivered by an organization for customers generally outside that organization. Outputs lead to outcomes. Source: A4


Works completed to upgrade facilities significantly from the existing asset. Source: G1