DPEE key terms

The ratio of a material's or structure's failure strength to the maximum stress it is expected to carry in service. A value above one indicates spare capacity against the design load.

A plot of applied stress against resulting strain for a material under load. Its slope gives elastic modulus, and key points identify yield, ultimate strength, and fracture behaviour.

The stress at which a material begins to deform permanently, so that strain is no longer fully recoverable when load is removed. It marks the practical limit for many design calculations.

The ratio of tensile stress to tensile strain within a material's linear elastic region, describing its stiffness. A higher value means the material deflects less under the same load.

Sudden lateral failure of a slender member under compressive load, occurring at a critical load that depends on length, end conditions, and bending stiffness rather than material strength alone.

Progressive cracking and fracture caused by repeated or fluctuating stress, even when each cycle is below the static strength. It typically starts at stress concentrations such as notches or weld toes.

A local increase in stress caused by abrupt changes in geometry, holes, notches, or inclusions. The peak stress can far exceed nominal stress and often initiates fatigue or brittle fracture.

The ratio of useful work or energy output to total energy input for a process or cycle. The remainder is lost, usually as low-grade heat, and cannot be fully recovered.

A dimensionless measure comparing actual heat transfer in an exchanger to the maximum theoretically possible for the given inlet conditions and flow rates. It supports sizing and performance comparison.

A design method that checks a structure against defined conditions of failure or unserviceability, such as ultimate strength, deflection, or fatigue, using factored loads and resistances.

A multiplier applied to nominal loads to account for uncertainty, variability, and consequence of failure in design calculations. It is paired with resistance factors in limit state methods.

A structured team technique that lists how a component or process could fail, rates severity, occurrence, and detection, and prioritises actions using a risk priority number.

A systematic investigation to identify the underlying reasons an incident or defect occurred, rather than the immediate symptom, so that recurrence is prevented. Common tools include the five whys and fishbone diagrams.

A quality process for eliminating the cause of a detected nonconformity and preventing similar problems from arising elsewhere. Actions are tracked to closure and verified for effectiveness.

A formal record describing a product, process, or service that does not meet a specified requirement, including the disposition decision such as rework, concession, or rejection.

Using control charts and statistical limits to monitor whether a process is stable and capable, distinguishing common-cause variation from special-cause signals that require investigation.

A ratio comparing the spread of a stable process to its specification limits, showing how well the process can meet requirements. Higher values indicate fewer expected defects.

A data-driven improvement methodology using define, measure, analyse, improve, and control phases to reduce variation and defects. Its name refers to a very low defect rate target.

An approach that applies lean principles such as waste elimination, flow, and pull planning to design and construction. It emphasises reliable work release and collaborative planning.

A project control technique integrating scope, schedule, and cost by comparing budgeted value of work performed with planned value and actual cost, yielding schedule and cost performance indices.

A scheduling technique that models activity dependencies, calculates earliest and latest dates, and identifies the sequence of activities with zero float that determines project duration.

The amount of time an activity can be delayed without delaying a dependent activity or the project completion date. Activities on the critical path have zero total float.

The sum of a project's future cash flows discounted to today at a chosen rate, minus the initial investment. A positive value suggests the project adds value.

The discount rate at which a project's net present value equals zero. Projects are often accepted when this rate exceeds the organisation's required hurdle rate.

The rate used to convert future cash amounts into present value, reflecting the time value of money and project risk. A higher rate reduces the present worth of distant cash flows.

A living project document listing identified risks with their likelihood, impact, owner, and planned response. It is reviewed regularly and updated as conditions change.

The legal and ethical obligation of a professional to act with reasonable skill and care so that foreseeable harm to clients, the public, and the environment is avoided.

A situation where personal, financial, or other interests could improperly influence professional judgement. It must be disclosed and managed, even when no wrongdoing has occurred.

Reporting suspected wrongdoing, danger, or illegality to an appropriate internal or external authority. Professional codes typically protect good-faith disclosures made through proper channels.

Failure to exercise the skill and care reasonably expected of a competent professional in similar circumstances, causing loss. It is judged against accepted practice, not perfection.

The degree of prudence and competence a professional is expected to apply, usually benchmarked against what a reasonable peer would do in comparable circumstances.

A ranked order of risk treatments, from eliminating the hazard and substituting it, through engineering and administrative controls, to personal protective equipment as the last resort.

A method that breaks a task into steps, identifies hazards at each step, and defines controls before work begins. It is often used to brief the crew at the worksite.

A formal written authorisation controlling high-risk activities such as hot work, confined space entry, or isolation. It confirms hazards are assessed and controls are in place before work starts.

As low as reasonably practicable: the principle that risks should be reduced until further reduction would be grossly disproportionate to the benefit gained.

A digital process for creating and sharing coordinated three-dimensional models of a facility, enriched with data for design, construction, operation, and asset management.

A virtual replica of a physical asset or process, kept updated with real data, used to monitor performance, simulate scenarios, and support maintenance decisions.

A single agreed source of project information where models and documents are stored, version-controlled, and shared between parties to avoid duplication and conflicting data.

A network of sensors and connected devices that collect and exchange data automatically. In engineering it supports condition monitoring, metering, and automated control.

A leadership approach that adapts the amount of direction and support given to a team member according to their competence and commitment for a specific task.

Specific, timely, behaviour-focused information given to help someone improve performance, delivered in a way that protects dignity and invites a response.

Planning and carrying out communication with individuals or groups affected by or able to influence a project, to understand concerns and build support for decisions.