Glossary - D

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Damage is the severity of injury or the physical, functional, or monetary loss that could result if control of a hazard is lost. Source: S1


Expresses a relative exposure to a hazard. A hazard may be present, but there may be little danger because of the precautions taken. Source: S1


A collection of data arranged in an ordered manner; it can be used for many applications and by many programs. It is independent of the programs that use it. Meaningful information is extracted from the data to facilitate informed decision-making. Source: G1

Data Capture

The encoding of data including map digitizing, direct recording by electronic surveying instruments, and the encoding of text and attributes by whatever means. Source: G1

Data Management

The management of data that is held within the computer system to ensure its structure complies with the requirements and specifications of the system. Source: G1

Decision Tree

A method of representing a series of events in terms of a combination of smaller, simpler, more manageable, independent segments, with the smaller segments arranged as the branches of a tree and with each event given a probability with respect to the decision alternatives for each event. Source: T4


Activities required to take an asset out of service. Source: P1

Defects Liability Period

The specified period of time within which the contractor is required, at the contractor's cost, to rectify any defects in the completed works due to faulty materials or workmanship, and notified in writing by the Principal. The period commences from the date of issue of the "Certificate of Practical Completion" and lasts for the period stated in the contract. Source: P1

Deferred Maintenance

Maintenance that is due to be carried out in the current financial year but which will not be carried out because of shortage of funds or unavailability of parts. Deferred maintenance should be added to the backlog of maintenance items awaiting attention. Source: P1

Demand and Customer Expectations

The demand for services and expectations of level of service expected by the users of the service. Source: G1

Demand Management

The active intervention by a service provider, at any stage of the service delivery cycle, for the purposes of influencing the demand for the service within financial, social and political constraints. Source: P1

Demand Side Management (DSM)

The activities involved in managing the demand for our assets both strategically and operationally (e.g. load shedding).

Depreciation (Economic)

Depreciation in an economic sense, is the same as the asset consumption. In effect it relates to the decrease in the value of a capital asset due to use, wear and tear, physical degradation, obsolescence through technological or market changes, ageing or any other cause that reduces its useful economic life, or due to obsolescence through technological or market changes. The notional amount of money involved in the decrease in value is regarded as a cost. Sources: G1 & A4

Depreciation (Financial)

An accounting practice that aims to distribute the cost or other basic value of tangible assets, less salvage value if any, over the estimated useful life of the assets in a systematic manner. Source: G1

Deprival Value

The cost to an entity if it were deprived of an asset and was required to continue to provide services and/or goods, or deliver programs without the use of that asset. Assets are valued at an amount that represents the entire loss that might be expected to be incurred if the entity were deprived of the service potential or future economic benefits of these assets at the reporting date. Deprival value may also represent an opportunity value, i.e. the cost avoided as a result of having control of an asset. Sources: G1 & A4

Design Life

The proposed life of the asset determined as part of the design process. It becomes an input into the design criteria. Source: G1


In an FMECA process, detection is an assessment of the likelihood that the current controls (design and process) will detect the cause of the Failure Mode or the Failure Mode itself, thus preventing it from reaching the customer. Source: A4

Deterioration Rate

The rate at which an asset approaches failure. Source: A4

Digital Mapping

The process of acquisition (capture), transformation, and presentation of spatial data held in digital form. Source: G1


The process of converting analogue (graphic) maps and other sources to a computer readable format. Source: G1

Direct Cost

A cost item that can be traced specifically to an output in an economically feasible way. Source: G1

Discounted Cash Flow

The current value (in today's $ value) of all future cash flows to be generated by a development project. Source: T4

Discount Factor

A percentage rate used to convert monetary values occurring at different times in the future, to values at a common point in time, generally the current year. Source: A4

Discount Rate

An interest rate at which costs and benefits in future years are discounted to represent them in present day values - to convert the value of all future dollars to the value of dollars at a common point in time, usually the present. It is wise to check with Finance to obtain the current discount rate. This also facilitates sensitivity testing. For instance, if the current discount rate was advised to be 7%, then sensitivity testing at 4% and 10% could be conducted. Source: A4

Discount Year

The base year to which costs and benefits are discounted to arrive at a present value. It is most usually the current year. Source: T2

Discounted Payback Period (DPP)

The elapsed time between the point of initial investment and the point at which the sum of the present values of benefits to date equals the sum of the present values of costs to date. Source: T1


The process of converting money values that occur over different years to a common year (discount year), to enable comparison between options. Source: A4

Disposal Cost

Certain activities are often necessary to dispose of a decommissioned asset. The costs associated with such asset disposal are recognized as part of the life cycle costs of the asset. Source: A4

Disposal Planning

The development of plans that prioritize and optimize the disposal of assets identified as surplus in the "asset review and analysis" process. Source: L1

Dispute Resolution Procedure

The methods and actions involved in mediating and settling disputes. An alternative technique for the resolution of a contract dispute by way of independent third parties rather than court proceedings. Source: N1

An alternative technique for the resolution of contract disputes other than by arbitration or litigation. It need not involve an independent third party. Source: S2

Distributed Database

A database with unique components in geographically dispersed locations linked through a communications network. Source: G1


Pertaining to the variety of species within a given association of organisms. Areas with low diversity are characterized by a few species; often relatively large numbers of individuals represent each species. Source: S2


That element of time during which a facility, part of a facility, or an item is not in a condition to perform its intended functions. Source: N1

Due Diligence

The process of reviewing and analyzing in detail the physical, legal and financial activities, work processes, agreements, etc. of an existing service which are relevant to the performance of a future contract for this service, qualifying risks and establishing strategies to minimize these risks. Source: T2

Can be demonstrated if a responsible person can show that all reasonable measures were taken to identify and manage a risk to health and safety and financial considerations. It requires full documentation of all steps undertaken. Source: S1