Terms and Definitions Flashcards
An ideal and accurate description and quantification of risk.
Absolute Risk
A level of risk that is acceptable to the owner-user.
Acceptable Risk
A concept of minimization that postulates that attributes (such as risk) can only be reduced to a certain minimum under current technology and with reasonable cost.
As Low as Reasonably Practical
ALARP
Parts that make up a piece of equipment or equipment item. For example a pressure boundary may consist of components (pipe, elbows, nipples, heads, shells, nozzles, stiffening rings, skirts, supports, etc.) that are bolted or welded into assembles to make up equipment items
Components
An outcome from an event. There may be one or more consequences from an event. Consequences may range from positive to negative. However, consequences are always negative for safety aspects. Consequences may be expressed qualitatively or quantitatively.
Consequence
A person who is knowledgeable and experienced in the specific process chemistries, corrosion degradation mechanisms, materials selection, corrosion mitigation methods, corrosion monitoring techniques, and their impact on pressure equipment.
Corrosion Specialist
An activity that is both effective in resolving an issue (e.g. some form of mitigation) and is a financially sound use of resources.
Cost-Effective
A process that induces micro and/or macro material changes over time that are harmful to the material condition or mechanical properties. Damage mechanisms are usually incremental, cumulative, and, in some instances, unrecoverable. Common damage mechanisms include corrosion, stress corrosion cracking, creep, erosion, fatigue, fracture, and thermal aging.
Damage (or Deterioration) Mechanism
The physical manifestation of damage (e.g. wall thinning, pitting, cracking, rupture).
Damage (or Deterioration) Mode
The amount of deterioration that a component can withstand without failing.
Damage Tolerance
Assumptions made during the design (e.g. design life and corrosion allowance needed).
Design Premise
The reduction in the ability of a component to provide its intended purpose of containment of fluids. This can be caused by various damage mechanisms (e.g. thinning, cracking, mechanical). Damage or degradation may be used in place of deterioration.
Deterioration
An individual item that is part of a system. Examples include pressure vessels, relief devices, piping, boilers, and heaters.
Equipment
Occurrence of a particular set of circumstances. The event may be certain or uncertain. The event can be singular or multiple. The probability of an event occurring within a given period of time can be estimated.
Event
An analytical tool that organizes and characterizes potential occurrences in a logical and graphical manner. The event tree begins with the identification of potential initiating events. Subsequent possible events (including activation of safety functions) resulting from the initiating events are then displayed as the second level of the event tree. This process is continued to develop pathways or scenarios from the initiating events to potential outcomes
Event Tree
Events resulting from forces of nature, acts of God, sabotage, or events such as neighboring fires or explosions, terrorism, neighboring hazardous material releases, electrical power failures, forces of nature, and intrusions of external transportation vehicles, such as aircraft, ships, trains, trucks, or automobiles. External events are usually beyond the direct or indirect control of persons employed at or by the facility.
External Event
Any location containing equipment and/or components to be addressed under this RP
Facility
Termination of the ability of a system, structure, equipment or component to perform its required function of containment of fluid (i.e. loss of containment). Failures may be unannounced and undetected at the instant of occurrence (unannounced failure). For example, a slow leak under insulation may not be detected until a pool of fluid forms on the ground or someone notices a drip or wisp of vapor. A small leak may not be noticed until the next inspection (unannounced failure), e.g. slow leakage from buried piping or small leak in a heat exchanger tube; or they may be announced and detected by any number of methods at the instance of occurrence (announced failure), e.g. rupture of a pipe in a process plant or sudden decrease in pressure in the system.
Failure
The manner of failure. For RBI, the failure of concern is loss of containment of pressurized equipment items. Examples of failure modes are small hole, crack, and rupture.
Failure Mode
A methodology whereby damage or flaws/imperfections contained within a component or equipment item are assessed in order to determine acceptability for continued service.
Fitness-For-Service Assessment
A physical condition or a release of a hazardous material that could result from component failure and result in human injury or death, loss or damage, or environmental degradation. Hazard is the source of harm. Components that are used to transport, store, or process a hazardous material can be a source of hazard. Human error and external events may also create a hazard.
Hazard
A HAZOP study is a form of failure modes and effects analysis (FMEA). HAZOP studies, which were originally developed for the process industry, use systematic techniques to identify hazards and operability issues throughout an entire facility. It is particularly useful in identifying unforeseen hazards designed into facilities due to lack of information, or introduced into existing facilities due to changes in process conditions or operating procedures. The basic objectives of the techniques are:
- to produce a full description of the facility or process, including the intended design conditions;
- to systematically review every part of the facility or process to discover how deviations from the intention of the design can occur;
- to decide whether these deviations can lead to hazards or operability issues;
- to assess effectiveness of safeguards.
Hazard and Operability Study
HAZOP Study
Activities performed to verify that materials, fabrication, erection, examinations, testing, repairs, etc., conform to applicable code, engineering, and/or owner’s written procedure requirements. It includes the planning, implementation, and evaluation of the results of inspection activities. The external, internal, or on-stream assessment (or any combination of the three) of the condition of pressure equipment.
Inspection
Established limits for process variables that can affect the integrity of the equipment if the process operation deviates from the established limits for a predetermined amount of time.
Integrity Operating Window
IOW
Probability.
Likelihood
A documented management system for review and approval of changes in process, equipment or piping systems prior to implementation of the change.
Management of Change
MOC
Limitation of any negative consequence or reduction in probability of a particular event.
Mitigation
Extent to which an event is likely to occur within the time frame under consideration. The mathematical definition of probability is “a real number in the scale 0 to 1 attached to a random event.” Probability can be related to a long-run relative frequency of occurrence or to a degree of belief that an event will occur. For a high degree of belief, the probability is near one (1). Frequency rather than probability may be used in describing risk. Degrees of belief about probability can be chosen as classes or ranks like “rare/unlikely/moderate/likely/almost certain” or “incredible / Improbable / remote / occasional / probable / frequent.”
Probability
A group of systems arranged in a specific fashion to produce a product or service. Examples of processes include power generation, acid production, fuel oil production, and ethylene production.
Process Unit
An analysis that uses broad categorizations for probabilities and consequences of failure. Methods that use primarily engineering judgment and experience as the basis for the determination of probabilities and consequences of failure. The results of qualitative risk analyses are dependent on the background and expertise of the analysts and the objectives of the analysis. FMEA and HAZOPs are examples of qualitative risk analysis techniques that become QRA methods when consequence and failure probability values are estimated along with the respective descriptive input.
Qualitative Risk Analysis
An analysis that quantifies the probabilities and consequences of the probable damage mechanisms and that:
• identifies and delineates the combinations of events that, if they occur, may lead to a severe event or any other undesired consequence;
• estimates the probability of occurrence for each combination;
• estimates the consequences.
QRA generally:
• integrates information about facility design, operating practices, operating history, component reliability, human actions, the physical progression of incidents, and potential environmental and health effects;
• uses logic and probabilistic models depicting combinations of events and the progression of incidents to provide both qualitative and quantitative insights into the level of risks;
• analysis logic models consisting of event trees and fault trees to estimate the frequency of each incident sequence.
Quantitative Risk Analysis
QRA
The process of integrating inspection data or other changes into the risk analysis.
Re-Assessment
The comparative risk of a facility, process unit, system, equipment item or component to other facilities, process units, systems, equipment items, or components, respectively
Relative Risk
The risk remaining after risk mitigation.
Residual Risk
Combination of the probability of an event and its consequence. In some situations, risk is a deviation from the expected. When probability and consequence are expressed numerically, risk is the product.
Risk
A decision to accept a risk. Risk acceptance depends on risk criteria.
Risk Acceptance
Systematic use of information to identify sources and to estimate the risk. Risk analysis provides a basis for risk evaluation, risk mitigation and risk acceptance. Information can include historical data, theoretical analysis, informed opinions, and concerns of stakeholders.
Risk Analysis
Overall process of risk analysis and risk evaluation.
Risk Assessment
Decision not to become involved in, or action to withdraw from a risk situation. The decision may be taken based on the result of risk evaluation.
Risk Avoidance
A risk assessment and management process that is focused on loss of containment of pressurized equipment in processing facilities, due to material deterioration. These risks are managed primarily through equipment inspection.
Risk-Based Inspection
RBI
Exchange or sharing of information about risk between the decision maker and other stakeholders. The information may relate to the existence, nature, form, probability, severity, acceptability, mitigation, or other aspects of risk.
Risk Communication
Terms of reference by which the significance of risk is assessed. Risk criteria may include associated cost and benefits, legal and statutory requirements, socio-economic and environmental aspects, concerns of stakeholders, priorities and other inputs to the assessment.
Risk Criteria
An item affecting either the probability, consequence, or both such that it constitutes a significant portion of the risk.
Risk Driver
Process used to assign values to the probability and consequence of a risk. Risk estimation may consider cost, benefits, stakeholder concerns, and other variables, as appropriate for risk evaluation.
Risk Estimation
Process used to compare the estimated risk against given risk criteria to determine the significance of the risk. Risk evaluation may be used to assist in the acceptance or mitigation decision.
Risk Evaluation
Process to find, list, and characterize elements of risk. Elements may include: source, event, consequence, probability. Risk identification may also identify stakeholder concerns.
Risk Identification
Coordinated activities to direct and control an organization with regard to risk. Risk management typically includes risk assessment, risk mitigation, risk acceptance, and risk communication.
Risk Management
Process of selection and implementation of measures to modify risk. The term risk mitigation is sometimes used for measures themselves.
Risk Mitigation
Actions taken to lessen the probability, negative consequences, or both associated with a particular risk.
Risk Reduction
A semi-quantitative analysis includes aspects of both qualitative and quantitative analyses.
Semi-Quantitative Analysis
Thing or activity with a potential for consequence. Source in a safety context is a hazard.
Source
Any individual, group or organization that may affect, be affected by, or perceive itself to be affected by the risk.
Stakeholder
A collection of equipment assembled for a specific function within a process unit. Examples of systems include service water system, distillation systems, and separation systems.
System
A period of down time to perform inspection, maintenance, or modifications and prepare process equipment for the next operating cycle.
Turnaround TA
Any chemical that presents a physical or health hazard or an environmental hazard according to the appropriate material safety datasheet. These chemicals (when ingested, inhaled, or absorbed through the skin) can cause damage to living tissue, impairment of the central nervous system, severe illness, or in extreme cases, death. These chemicals may also result in adverse effects to the environment (measured as ecotoxicity and related to persistence and bioaccumulation potential).
Toxic Chemical
The risk prior to mitigation activities.
Unmitigated Risk
