RIMAP Terminology List

Document Name: Terminology list Document Date: 2001-06-07 Document Author/s: RIMAP Consortium Reference Number: 2-21-F-2004-01-1 Version: Final Contract Number: G1RD-CT-2001-03008

RIMAP Consortium Det Norske Veritas AS (DNV) ExxonMobil Chemical Ltd. (Exxon) Bureau Veritas (BV) Energie Baden-Württemberg AG (EnBW) Staatliche Materialprüfungsanstalt (MPA) Siemens AG (Siemens) VTT Industrial Systems (VTT) Joint Research Centre of the European Commission (JRC) TÜV Industrie Service, TÜV SÜD Group Electricity Supply Board (ESB) TNO Industrial Technology (TNO) Corus Ltd. yARA Sluiskil B.V. (Norsk Hydro) The Dow Chemical Company N.V. (DOW) Mitsui Babcock Energy Ltd. (MBEL) Solvay S.A.

No distribution outside RIMAP Consortium No distribution outside RIMAP Thematic Network No distribution without prior approval by RIMAP Consortium Unrestricted distribution

COPYRIGHT 2004 THE RIMAP Consortium This document may not be copied, reproduced, or modified in whole or in part for any purpose without written permission from the RIMAP Consortium. In addition, to such written permission to copy, acknowledgement of the authors of the document and all applicable portions of the copyright notice must be clearly referenced. All rights reserved

Risk Based Inspection and Maintenance procedures for European industry Risk based Inspection and MAintenance Procedures for European industry (RIMAP) is an EU funded initiative1. RIMAP consists of 3 projects: a research and technological development project (RTD), a demonstration project (DEMO) and a Thematic Network (TN). The background for the RIMAP project is that current practice to inspection and maintenance planning for most industries is based on tradition and prescriptive rules, rather than being an optimized process where risk measures for safety and economy are integrated. New technology for taking risk based decisions is emerging in a broad range of sectors, and they have proven to be a very efficient tool. There is a great need to define the technical content, links to local legislation and to integrate this approach with the day-to-day operation of the plants. The RIMAP project shall:

• Develop a unified approach to risk based inspection and maintenance planning. • Set requirements to the contents of an analysis, personnel qualifications, and tools. • Provide the basis for future standardisation within risk based inspection and

maintenance. The work in the RIMAP RTD project has been organised as follows:

• WP1: Current practice within the involved industries. • WP2: Development of a generic RBIM method, based on a multi-criteria decision

process. • WP3: Development of detailed risk assessment methods, damage models for

different industry sectors, the use of inspection data. • WP4: Development of RIMAP application workbooks: guidelines for development of

Risk Based Inspection and Maintenance plans. • WP5: Validation of the RIMAP methodology.

RIMAP RTD reporting structure is given in below: Exec. Summary & Introduction to RIMAP

RIMAP Procedure

RIMAP Validation / Benchmarking

Overview Document (D3.1)

Damage Mechanisms

Human factors

PoF CoF

Power Petrochemical Steel Chemical

D4.x

D3.1 and I3.x as Appendices to D3.1

D2.2

D2.1

Requirements

RIMAP Documentation Level - III

RIMAP Documentation Level - II

RIMAP Documentation Level - I

RIMAP Tools

RIMAP Application Workbooks

RIMAP Framework

NDT Efficiency

WP 5 RIMAP Validation/Benchmarking

Exec. Summary & Introduction to RIMAP

RIMAP Procedure

RIMAP Validation / Benchmarking

Overview Document (D3.1)

Damage Mechanisms

Human factors

PoF CoF

Power Petrochemical Steel Chemical

D4.x

D3.1 and I3.x as Appendices to D3.1

D2.2

D2.1

Requirements

RIMAP Documentation Level - III

RIMAP Documentation Level - II

RIMAP Documentation Level - I

RIMAP Tools

RIMAP Application Workbooks

RIMAP Framework

NDT Efficiency

WP 5 RIMAP Validation/Benchmarking

The RIMAP DEMO project consists of four demonstration cases, one for each of the involved industry sectors: petrochemical, power, steel, and chemical industry. The techniques can easily be extended to other industry sectors. The RIMAP TN accompanies the RTD and DEMO projects by disseminating the information, and results of the RTD and DEMO part to a wider community of companies that review results and generate an overall industry acceptance.

1 The RIMAP project would like to acknowledge the financial support by the European Commission for the "GROWTH Programme, Research Project RIMAP Risk Based Inspection and Maintenance Procedures for European Industry "; Contract Number G1RD-CT-2001-03008. Without this support it would not have been possible to complete this work.

GROWTH Project G1RD-CT-2001-03008 “RIMAP” Document title: Terminology list Document number: 2-21-F-2004-01-1

Table of contents

1. INTRODUCTION..............................................................................................................4

2. ABBREVIATIONS............................................................................................................4

3. GLOSSARY .....................................................................................................................4

4. REFERENCES...............................................................................................................24

5. OTHER RELEVANT STANDARDS AND DOCUMENTS ..............................................25

List of tables TABLE 1 ABBREVIATIONS...........................................................................................................4

Revision number: FINAL of 26 Restricted


1. Introduction The current document contains a list of terminology to be used in the RIMAP project. Most of terms have been taken from international standards. The standards are given in the reference list. NOTE: where several definitions are given, the first one is used in RIMAP.

2. Abbreviations ALARP As Low As Reasonably Practicable PLL Potential Loss of Life API American Petroleum Institute POD Probability of Detection ASME American Society for Mechanical Engineers PoF Probability of Failure ASNT American Society for Non-destructive Testing P&ID Process and Instrumentation Diagram CoF Consequence of Failure P&UD Piping and Utilities Diagram

DNV Det Norske Veritas RAM Reliability, Availability, Maintainability Analysis

ESD(V) Emergency Shut Down (Valve) RBI Risk Based Inspection FMEA Failure Modes and Effects Analysis RII Risk Informed Inspection FAR Fatal Accident Rate RCM Reliability Centred Maintenance FMECA Failure Modes Effects and Criticality Analysis SMTS Specified Minimum Tensile Stress GVI General Visual Inspection SMYS Specified Minimum Yield Stress MAOP Maximum Allowable Operating Pressure WTM Wall Thickness Measurement PFD Process Flow Diagram UFD Utilities Flow Diagram

Table 1 Abbreviations

3. Glossary

A Acceptance Criteria for Risk – Criteria that are used to express a risk level that is

considered acceptable for the activity in question, limited to the high level expressions of risk. See also Risk Acceptance and Risk Criteria.

(Ref. NORSOK Z-013)

Accidental Event – Event or chain of events that may cause loss of life, health, or damage to environment or assets.

(Ref. NORSOK Z-013)

Accreditation – Procedure by which an authoritative body gives formal recognition that a body is competent to carry out specific tasks.

(Ref. ISO/TC 11/SC)

Acutely Toxic Chemicals – Chemicals that can cause severe short- and long-term health effects after a single, brief exposure (short duration). 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.

(Ref. API580)



Affected Area – Represents the amount of surface area that experiences an effect (toxic

dose, thermal radiation, explosion overpressure, etc.) greater than a pre-defined limiting value

Associated document – A document that must be used with the Code or Standard to demonstrate compliance with an international standard.

(Ref. ISO/TC 11/SC)

As Low As Reasonably Practicable (ALARP) principle – The ALARP principle expresses that the risk level is reduced - through a documented and systematic process - so far that no further cost effective measure may be identified.

(Ref. NORSOK Z-013)

Two risk levels are defined to apply the ALARP-principle:

Intolerable risk level boundary

Negligible risk level boundary

In the intolerable risk region, risk reduction measures shall be incorporated. In the ALARP region, risk reduction measures should be incorporated if the improvements gained are reasonable compared to the costs involved.

Asset – Item or facility owned, leased or contracted by the company used in pursuit of its corporate objectives

Asset Register – a record of items, including information such as constructional and technical details about each. This may be combined with an inventory. List of all the plant, equipment and buildings owned or used by the organisation and which require maintenance of any sort.

Availability – The ability of an item to be in a state to perform a required function under given conditions at a given instant of time or over a given time interval, assuming that the required external resources are provided.

(IEC 60050-191, ISO 14224, DRAFT prEN 13306)

Average Individual Risk (AIR) – The average individual risk is usually estimated from historical data as:

AIR = Number of fatalities per year/ Number of people at risk.

Average Rate of Death – The average number of fatalities from all incidents that might be expected per unit time

B C Capital Cost/CAPital EXpenditures – Capital cost shall be calculated by adding the

following cost elements: Equipment purchase cost, Installation cost, Commissioning cost, Insurance spares cost, Reinvestment cost. (Where there is a deviation between when the investments will be made and the base year for the evaluation, capital cost shall be discounted back to the base year.)

(NORSOK O-CR-001)



CMS – Corrosion Management System.

Code/standard – Documented, established and approved by a recognised body, that provides for common and repeated use, rules, guidelines or characteristics for activities or their results. (recognised body – an organisation that promulgates a national, regional or international boiler or pressure vessel standard).

(Ref. ISO/TC 11/SC)

Cold Weather Operation – the additional risks imposed on plant operations by cold climates, as they inhibit maintenance and inspection activities and can result in reduced operator monitoring of outside equipment.

Components – Parts which make up a pressure boundary and some pressure attachments which are bolted or welded into assembles to make up equipment (elbows, heads, stiffening rings, skirts, supports, etc.).

Condition-Based Maintenance – Preventive maintenance consisting of performance and parameter monitoring and the subsequent actions. (NOTE: Performance and parameter monitoring may be scheduled, on request or continuously. )

(Ref. DRAFT prEN 13306 )

Condition Monitoring – The continuous or periodic measurement and interpretation of data to indicate the condition of an item to determine the need for maintenance. Techniques to detect potential failure mechanisms with the use of special instruments.

Consequence – A consequence is an outcome of an event.

NOTE 1: There may be one or more consequences from an event.

NOTE 2: Consequences may range from positive to negative.

NOTE 3: Consequences may be expressed qualitatively or quantitatively.

(Ref. ISO N33, API580)

Consequence Analysis – This is the analysis of consequence that can be either qualitative or quantitative.

Consequence of Failure – The outcomes of a failure. This may be expressed, for example, in terms of safety to personnel, economic loss, damage to the environment.

Continuous Release – One that occurs over an extended period of time.

Corrective Maintenance –The maintenance carried out after fault recognition and intended to put an item into a state in which it can perform a required function.

(Ref. IEC 60050-191, ISO 14224, DRAFT prEN 13306)

Cost – of activities, both direct and indirect, involving any negative impact, including money, time labour, disruption, goodwill, political and intangible losses.

D Degradation – An irreversible process in the characteristic of an item with either time or use.

NOTE 1: Degradation may lead to failure.

NOTE 2: Degradation is often referred to as wear-out, damage, or deterioration.

(Ref. DRAFT prEN 13306)



Degradation Rate – the development of degradation over time.

Dependability – The collective term used to describe the availability performance and its influencing factors: reliability performance, maintainability performance and maintainability support performance.

NOTE: Dependability is used only for general descriptions in non-quantitative terms.

(Ref. IEC 60050-191)2

Designer – An organisation or individual that performs design of a boiler or pressure vessel in compliance with a Code or Standard.

(Ref. ISO/TC 11/SC)

Dimensioning accidental event (DAE) – Accidental event which according to the defined acceptance criteria represents an unacceptable risk, and which consequently serves as a basis for design and operation of installations and otherwise for implementation of the activities.

(Ref. NPD)

Down state – State of an item characterised either by a fault, or by a possible inability to perform a required function during preventive maintenance.

NOTE 1: This state is related to reliability performance.

NOTE 2: In French, the adjective “indisponible” qualifies an item in a down state.


Down time – The time interval during which an item is in a down state.

(Ref. IEC 60050-191, ISO 14224, DRAFT prEN 13306) Durability – The ability of an item to perform a required function under given conditions of

use and maintenance, until a limiting state is reached.

NOTE: A limiting state of an item may be characterised by the end of the useful life, unsuitability for any economical or technological reasons or other relevant factors.

(Ref. IEC 60050-191, DRAFT prEN 13306)

E Environment – the area outside or inside a facility’s jurisdiction that would require

substantial costs to remediate in the event of contamination. It can include groundwater tables that pass through the bounds of the facility and would allow contamination of water external to the facility.

Environmental Consequence – The long or short term effects of an event on the environment.

Equipment – An individual item that is part of a system. Examples include pressure vessels, relief devices, piping, boilers, paper machines and pumps.

2 The current definition is too narrow. The definition should include other types of equipment.



Equipment under control (EUC) – Equipment, machinery, apparatus or plant used for manufacturing, process, transportation, medical or other activities.

NOTE: The EUC control system is separate and distinct from the EUC.

(Ref. IEC 61508-4)

Escape – The movement of employees or members of the public from a hazardous area to a safe location.

Evacuation – Evacuation is the planned method of leaving the installation in an emergency.

Event – Occurrence of a particular set of circumstances.

NOTE 1: The event may be certain or uncertain.

NOTE 2: The event can be singular or multiple.

NOTE 3: The probability associated with the event can be estimated for a given period of time.

(Ref. ISO N33)

Event Tree – Visually depict the possible chain of events that lead to the probability of flammable outcomes; used to show how various individual event probabilities should be combined to calculate the probability for the chain of events.

Event Tree Analysis – A technique which describes the possible range and sequence of the outcomes which may arise from an initiating event.

Explosion – Occurs under certain conditions when a flame front travels very quickly.

External Event – Events resulting from forces of nature, acts of God or sabotage, or such events as neighbouring fires or explosions, neighbouring hazardous material releases, electrical power failures, tornadoes, earthquakes, 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.

(Ref. API580)

F Facility – Production plant or equipment; can be applied to units within larger plant.

Failure – The termination of the ability of an item to perform a required function.


The concept includes: Complete failure of the item, Failure of part of the item for corrective action, Failure discovered during inspection or testing, or preventive maintenance, that requires repair. Failure of safety devices or control/monitoring devices that necessitates shutdown, or causes reduction of the items capability below specified limits.

The following outages are not considered as failures: Downtime due to preventive or planned maintenance, shutdown of the item due to external conditions, or where no physical failure condition of the item is revealed.

Failure Finding – entails checking a hidden function (at regular intervals) to find out whether it has failed.



Failure Mechanism – Physical, chemical or other processes which lead or have lead to

failure.


Failure Mode – The observed manner of failure.

(Ref. ISO 14224 , API580)

The effect by which a failure is observed on the failed item/system. The failure mode describes the loss of required function(s) that result from failures.

(Ref. NORSOK Z-016)

Failure Mode and Effects Analysis (FMEA) – A qualitative method of reliability analysis which involves the study of the failure modes which can exist in every component part of the plant and the required function of the plant.

Failure Modes, Effects and Criticality Analysis (FMECA) – A qualitative method of reliability analysis which involves a failure modes and effects analysis together with a consideration of the probability of failure modes, their occurrence and of the ranking of effects and the seriousness of the failures.

Failure on Demand Probability – The probability of failure of an item per demand. Demand is a situation where the item is required in order to initiate and complete a typical operation (e.g. opening of a valve when required).

Failure Rate – Number of failures of an item in a given time interval divided by the time interval.

NOTE 1: This value is an approximation.

NOTE 2: In some cases unit of time can be replaced by units of use.


The limit, if this exists, of the ratio of the conditional probability that the instant of time, T, of a failure of an item falls within a given time interval, (t, t + ∆t) and the length of this interval, ∆t, when ∆t tends to zero, given that the item is in an up state at the beginning of the time interval.

NOTE: In this definition T may also denote the time to failure or the time to fist failure, as the case may be.

(Ref. IEC 60050-191)

Fatal Accident Rate (FAR) – Fatal accident rate (FAR) is the number of fatalities per 108 exposed hours. (Roughly 1000 employee working lifetimes)

The FAR measure was developed to describe onshore occupational risks, which only apply during working hours. Hence, in onshore studies, ‘exposed hours’ is taken to mean ‘hours at work’, and the onshore FAR is defined as: Onshore

FAR = Number of fatalities · 108 / Person hours at work.

In offshore studies, ‘exposed hours’ are usually taken to be `hours spent offshore', and the FAR is defined as: Offshore

FAR = Number of fatalities · 108 / Person hours offshore.

Fault Tree Analysis (FTA) – An analysis to determine which failure modes of the subitems or external events, or combinations thereof, may result in a stated failure mode of the item presented in the form of a fault tree.(Ref. IEC 60050-191)



Fireball – occurs when a large quantity of fuel ignites after it has undergone only limited

mixing with the surrounding air.

Fitness-for-Service Assessment – A methodology whereby degradation or flaws/imperfections contained within a component or equipment item are assessed in order to determine acceptability for continued service.

Flammable Effect – the physical behaviour of the hazardous material that is released. See Safe Dispersion, Jet Flame, Explosion, Flash Fire, Fireball, and Pool Fire.

Flash Fire – occurs when a cloud of material burns under conditions that do not generate significant overpressure.

Frequency – a measure of probability expressed as the number of occurrences of an event in a given time. See also Probability.

G

Generic Failure Frequency – a compilation of available records of equipment failure histories, developed for each type of equipment and each diameter of piping; built using records from all plants within a company or from various plants within an industry, from literature sources, past reports, and commercial data bases. The values represent an industry in general and do not reflect the true failure frequencies for a specific plant or unit.

H Harm – Physical injury or damage to the health of people, or damage to property or the

environment.

(Ref. ISO/IEC Guideline 51)

Hazard – Potential source of harm.


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.

(Ref. API580)

Hazard and Operability (HAZOP) Study – a HAZOP study is a form of failure modes and effects analysis. 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:

a. To produce a full description of the facility or process, including the intended

design conditions;



b. Systematically review every part of the facility or process to discover how

deviations from the intention of the design can occur; and c. To decide whether these deviations can lead to hazards or operability issues. (Ref. API580)

Human Error – A human action that produces an unintended result. (Ref. IEC 60050-191)

Human Reliability – The probability that a person: 1. Correctly performs some system-required activity in a required time period (if time is a limiting factor) and 2. Performs no extraneous activity that can degrade the system. Human unreliability is the opposite of this definition.

I Impairment – The term impairment is used when assessing the site or installations safety

functions’ capability to survive an accident. For example, an escape route can be impaired, if the radiation level exceeds a certain value.

Individual Risk (IR) – Individual risk is the frequency (usually per year) at which a single individual is expected to suffer a given level of harm (usually death) due to specific hazards.

Individual Risk Measures – consider the risk to an individual who might be located at any point in the effect zones of incidents

Inspection – Check or conformity by measuring, observing, testing or gauging the relevant characteristics of an item.

NOTE: Generally inspection is carried out on the item itself without dismantling.


Inspection Effectiveness – A description of the ability of the inspection method to detect the degradation inspected for.

Inspection Methods – the means by which inspection is carried out, covering the technique and a description of its application.

Inspection Programme – Detail of inspection activity giving the precise location, type and timing for each individual inspection action that is planned.

Inspection Techniques – A combination of inspection method and the means by which it is to be applied, concerning surface and equipment preparation, execution of inspection with a given method, and area of coverage.

Instantaneous Release – one that occurs so rapidly that the fluid disperses as a single large cloud or pool

Intangible Assets – assets for which the value, though real, cannot readily be measured and for which a company frequently incurs costs.

Inventory – the upper limit of the amount of fluid that can be released from an equipment item. (The term is frequently used in RBI.)

Inventory Group – the inventory of attached equipment that can realistically contribute fluid mass to a leaking equipment item.



Item – Any part component, device, subsystem, functional unit, equipment or system that can be individually considered. NOTE: A number of items e.g. a population of items, or a sample, may itself be considered as an item. (Ref. IEC 60050-191, ISO 14224, DRAFT prEN 13306)

J Jet Flame – results when a high-momentum gas, liquid, or two-phase release is ignited.

K

L Life Cycle Cost (LCC) – Cumulative cost of a product over its life cycle.

(Ref. IEC 60300-3-3)

All of the costs generated during the life cycle of an item.

NOTE: For a user or an owner, the total life cycle cost may include costs of acquisition, operations maintenance and disposal.

(Ref. DRAFT prEN 13306) Limit State – a mathematical description of the load on a component when failure is

expected to occur. This may include “safety factors”.

Limit State Design – limit state design identifies explicitly the different failure modes and provides a specific design check to ensure that failure does not occur. This implies that the component’s capacity is characterised by the actual capacity for each individual failure mode (i.e. limit state) and that the design check is more directly related to the actual failure mechanism.

Logistic delay – That accumulated time during which maintenance cannot be carried out due to the necessity to acquire maintenance resources, excluding any administrative delay.

NOTE: Logistic delays can be due to, for example, travelling to unattended installations, pending arrival of spare parts, specialists, test equipment, information and suitable environmental conditions.

(IEC 60050-191)

Loss – any negative consequence, financial or otherwise

Loss of Containment – occurs only when the pressure boundary is breached

Loss of Integrity – Loss of capacity to carry out the functions intended, e.g. structural support.



M Maintainability – The probability that a given active maintenance action, for an item under

given conditions of use can be carried out within a stated time interval, when the maintenance is performed under stated conditions and using stated procedures and resources. NOTE: The term “maintainability” is also used to denote the maintainability performance quantified by this probability.

(Ref. IEC 60050-191) The ability of an item, under given conditions of use, to be retained in, or restored to, a state in which it can perform a required function, when maintenance is performed under given conditions and using stated procedures and resources.

NOTE: Maintainability is also used as a measure of maintainability performance.

(DRAFT prEN 13306) Maintenance – The combination of all technical and administrative actions, including

supervision actions, intended to retain an item in, or restore it to, a state in which it perform a required function.


Maintenance Time – The time interval during which a maintenance action is performed on an item either manually or automatically, including technical delays and logistic delays. NOTE: Maintenance may be carried out while the item is performing a required function. (Ref. IEC 60050-191) Time during which a maintenance is carried out on an item either manually or automatically, including technical and logistic delays. NOTE: Maintenance may be carried out while the item is performing a required function. (Ref. DRAFT prEN 13306)

Maintenance Reference Plan (MRP) – plan detailing the scheduled maintenance activities to be carried out by whom, with what frequency and the recording systems related to that activity.

Management Systems Evaluation – an evaluation of all areas of a plant’s Process Safety Management’s system that impact directly or indirectly on the mechanical integrity of process equipment.

Manufacturer – An organisation or individual that performs or subcontracts all relevant requirements in accordance with a code or standard and is responsible for compliance.

(Ref. ISO/TC 11/SC)

Mean Failure Rate – The mean of the instantaneous failure rate over a given time interval (t1,t2).

(Ref. IEC 60050-191)

Mean Repair Rate – The mean of the instantaneous repair rate over a given time interval (t1,t2).

(Ref. IEC 60050-191)



Mean Repair Time (MRT) – The expectation of the repair time.


Mean Time Between Failures (MTBF) – Expectation of the time between failures.


NOTE: In English, the use of abbreviation MTBF in this sense is now deprecated.

Mean Time To Failure (MTTF) – The expectation of the time to failure.

(Ref. IEC 60050-191)

The mean time to failure is a predictor of the time to failure.

NOTE: The MTTF of an item could be longer or shorter than the design life of the system.

(Ref. NORSOK Z-016)

Mean Time To Repair (MTTR) – The expectation of the time to restoration.

(Ref. IEC 60050-191)

The mean time to repair is a predictor of the active repair time.

Mean time to repair denotes the downtime (or repair time) or repair time after a failure of an item.

MTTR is also sometimes called the mean downtime (MDT) of the item. In some situations MTTR is used to denote the mean active repair time instead of the mean down time of the item.

Mitigation – is the implementation of activities that will result in a reduction in either the probability or consequence of an event.

(See also API580)

Monitoring – Activity, performed either manually or automatically, intended to observe the actual state of an item.

NOTE: Automatic supervision may b e performed internally or externally to the item.

(Ref. IEC 60050-191)

NOTE 1: Monitoring is distinguished from inspection in that it is used to evaluate any changes in the parameters of the item with time. Monitoring may be continuous or over time interval or number of operations.

NOTE 2: Monitoring is usually carried out during up state.




N NDT – Non-Destructive Testing (NDT) is a procedure which covers the inspection and/or

testing of any material, component or assembly by means which do not affect its ultimate serviceability. NDT methods are aimed to assess:

• Deficiencies in material and products.

• Determination of physical and geometric properties of materials and products.

• Structural behaviour of materials, products and installations.

Net Present Value, NPV – A method for assessing the value of investment proposals.

The net present value (NPV) is obtained by calculating the discounted value of the future cash returns and subtracting the discounted value of the investments (or cash outflows) required to produce the positive cash flow.

O Operate to Failure – a maintenance option that entails items running until they break down

with no preventive maintenance work being undertaken and no attempt to detect failure in advance.

Operating Cost/OPerational EXpenditures (OPEX) – Operating cost shall be calculated by adding the following cost elements: Man-hour cost, spare parts consumption cost, logistic support cost, and energy consumption cost. For costs that will be constant through the lifetime, multiply the annual cost with a discount factor to get the cost over the lifetime. (Ref. NORSOK O-CR-001)

Operating Time – The time interval during which an item is in an operating state.

(Ref. IEC 60050-191, ISO 14224)

Time interval during which an item is performing its required function.


Operational Boundaries – both the normal operation and periods of non-routine operation (startups, shutdowns, process upsets, etc.) of the system being studied.

Operations Reference Plan – the plan that demonstrates that all activities, resources, threats and opportunities for improvement to a facility’s technical integrity have been fully evaluated and the impact on cash flow quantified over the life cycle.

Operator – The organisation responsible for operation of an installation. P Physical Boundaries – all equipment items that make up the pressure envelope of the

system being studied

Planned Maintenance – the maintenance organised and carried out with forethought, control and the use of records to a predetermined plan.



Plant Condition – the current condition of the facility being evaluated, based on general

appearance of the plant, effectiveness of the plant’s maintenance program and the plant layout and construction.

Pool Fire – is caused when liquid pools of flammable materials ignite.

Potential Loss of Life (PLL) – Potential loss of life (PLL) is the predicted long-term average number of fatalities in a given time period. "PLL per year" is another term for annual fatality rate.

Preventive Maintenance – The maintenance carried out at predetermined intervals or according to prescribed criteria and intended to reduce the probability of failure or the degradation of the functioning of an item.


(Preventive maintenance actions include lubrication, cleaning, modification, sparing and periodic inspection.)

Probability – Extent to which an event is likely to occur. 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 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”.

(Ref. API580)

Probability of Detection (PoD) – probability that a given damage in a component will be detected using a given inspection method. PoD usually varies with the size or extent of damage and inspection method.

Probability of Failure (PoF) – The probability that failure of a component will occur within a defined time period.

Process monitoring – Monitoring of process conditions which may give rise to given failure mechanisms. Examples are monitoring of dew point in a gas line, monitoring temperature, sand monitoring.

Process Unit – A group of equipment arranged in a specific fashion to produce a product.

Production availability – The ratio of production to planned production, or any other reference level, over a specified period of time.

NOTE 1: This measure is used in connection with analysis of delimited systems without compensating elements such as substitution from other producers and downstream buffer storage. Battery limits need to be defined in each case.

NOTE 2: The term injection availability may be used meaning the ratio of injection volume to planned injection volume.

(Ref. NORSOK Z-016)



Q Qualification – Proof of suitability of an individual, process, procedure, or service to fulfil

specified requirements.

(Ref. ISO/TC 11/SC)

Qualification can also denote individual competence.

R Redundancy – In an item, the existence of more than one means for performing a required

function.

(Ref. IEC 60050-191, ISO 14224)

In an item, the existence of more than one means at a given instant of time for performing a required function.

Active redundancy

Redundancy wherein all means for performing are intended to operate simultaneously.

Standby redundancy

That redundancy wherein a part of the means for performing a required function is intended to operate, while the remaining part(s) of means are inoperating until needed.


Provision of additional equipment, usually a duplicate that is ready but normally out of operation until needed

Regularity – term used to describe how a system is capable of meeting demand for deliveries or performance. Production availability, deliverability or other appropriate measures can be used to express regularity.

NOTE: The use of regularity terms must specify whether it represents a predicted or historic regularity performance.

(Ref. NORSOK Z-016) Regulation – a standard issued by a government body or regulatory agency with which an

Operating company must comply.

Release Duration – the length of time the release occurred.

Release Rate – rate expressed as units of mass of volume per unit of time of a substance.

Reliability – The probability that an item can perform a required function under given conditions for a given time interval (t1, t2).

NOTE 1: It is generally assumed that the item is in a sate to perform this required function at the beginning of the time interval.

NOTE 2: The term “reliability” is also used to denote the reliability performance qualified by this probability.




Reliability Block Diagram (RBD) – Block diagram showing, for one or more functional modes of a complex item, how failures of the sub-items represented by the blocks, or combinations thereof, result of a failures of the item.

(Ref. IEC 60050-191)

Reliability Centred Maintenance (RCM) – a systematic approach for identifying effective and efficient preventive maintenance tasks for equipment and items in accordance with a specific set of procedures and for establishing intervals between maintenance tasks.

Remaining Life Assessment (RLA) – remaining life is the estimated time to failure for a component. In this case, failure is usually defined as the non-compliance with the design code for that component.

Repair – The part of corrective maintenance in which manual actions are performed on the item.

(Ref. IEC 60050-191)

That part of corrective maintenance in which physical actions are carried out to restore the required function of the item.


Repair Time – That part of active corrective maintenance time during which repair actions are performed on an item.

(Ref. IEC 60050-191)

That part of active corrective maintenance time during which repair is carried out on an item.


Residual Risk – the risk remaining after risk treatment.

(Ref. API580)

Risk – Combination of the probability of an event and its consequence.

NOTE 1: In some situations, risk is a deviation from the expected.

NOTE 2: See ISO/IEC Guide 51:1999 for issues related to safety.

(Ref. API580, ISO N33)

Risk Acceptance – A decision to accept a risk.

NOTE 1: The verb “to accept” is chosen to convey the idea that acceptance has its basic dictionary meaning.

NOTE 2: Risk acceptance depends on risk criteria.


Risk Analysis – Systematic use of available information to identify hazards and to estimate the risk.

(ISO/IEC Guideline 51, ISO N33)

Systematic use of information to identify sources and to estimate the risk. Risk analysis provides a basis for risk evaluation, risk treatment and risk acceptance. Information can include historical data, theoretical analysis, informed opinions and concerns stakeholders.

(Ref. API580)



Comment: In a risk analysis the probability and the consequence of an event may be determined using engineering judgement and/or based on mathematical models, where the result is expressed in dimensioned numerical terms. The terms qualitative and quantitative are sometimes used to distinguish these methods. (See, e.g., API580)

Risk Assessment – Overall process comprising a risk analysis and a risk evaluation.

(Ref. API580, ISO/IEC Guideline 51, ISO N33)

Risk Avoidance – 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.

(Ref. API580)

Risk Based Inspection – risk is used to prioritise inspection activities.

A risk assessment and management process that is focused on loss of containment of pressurised equipment in processing facilities, due to material degradation. These risks are managed primarily through equipment inspection.

(Ref. API580)

Risk Based Life Management – A concept used in the area of industrial plant asset management which extends the idea of risk-based inspection (RBI) and maintenance (RBMI) by introducing more of the overall life and life-cycle considerations into the RBI/RBMI decisions, and by performing, where appropriate, e.g. for safety/mission critical components and systems, more detailed life assessment.

Risk Based Management – the process of using risk assessment results (including understanding uncertainties) to determine the “best” means of risk reduction

Risk Communication – 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, treatment or other aspects of risk.

(Ref. API580)

Risk Control – Actions implementing risk management decisions. Risk control may involve monitoring, re-evaluation, and compliance with decisions.

(Ref. API580)

Risk Criteria – Terms of reference by which the significance of risk is assessed. NOTE: 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.

(Ref. API580, ISO N33) Risk Evaluation – Procedure based on the risk analysis to determine whether the tolerable

risk has been achieved.


Process of comparing the estimated risk against given risk criteria to determine the significance of the risk.

NOTE 1: Risk evaluation may be used to assist the acceptance of treatment decision.

NOTE 2: See ISO/IEC Guideline 51:1999 for risk evaluation in the safety context.




RISK EXpenditures, RISKEX(n) – Risk exposure is determined by calculation of the

probability of an event happening and multiplying it by the consequence of the event. The total RISKEX are determined by summing the cost for all these events.

[Risk exposure can (and commonly does) evaluate aspects throughout a project lifecycle such as: project overruns, new technology concerns, delays and quality issues, personnel safety, asset damage, environmental concerns, loss, production and decommissioning concerns.]

Risk Indices – a single number measure of risk.

Risk Informed Inspection (RII) – inspection planning based on a qualitative “information” on the risk involved but not fully utilising the results from the calculated risk.

Risk Management – Co-ordinated activities to direct and control an organisation with regard to risk. Risk management typically includes risk assessment, risk treatment, risk acceptance and risk communication.

(Ref. API580)3

Risk Matrix – This is a pictorial representation of risk, on an n*n matrix of probability and consequence.

Risk Reduction – Actions taken to lessen the probability, negative consequences, or both associated with a particular risk.

(Ref. API580)

Risk Treatment – Process of selection and implementation of measures to modify risk. The term risk treatment is sometimes used for measures themselves.

(Ref. API580)

S Safe Dispersion – occurs when flammable fluid is released and then disperses without

ignition.

Safety – Freedom from unacceptable risk.

NOTE: Adapted from ISO/IEC Guide 2:1996 definition 2.5.


Safety Functions – Safety functions are key components necessary to allow evacuation in major accidents.

Safety Integrity Level (SIL) – Discrete level (one out of a possible four) for specifying the safety integrity requirements of the safety functions to be allocated to the electric/electronic/programmable electronic safety-related systems, where safety integrity level 4 has the highest level of safety integrity and safety integrity level 1 has the lowest.

(Ref. IEC 61508-4)

Scenario – The set of events that can result in an undesirable outcome.

Scheduled Maintenance – the preventive maintenance carried out to a predetermined interval of time, number of operations, mileage, etc.

3 Risk management also includes other activities, e.g. to define the scope of work and risk mitigation.



Segment4 – A number of components forming part of the same pressure system, consisting

of pipes, valves, vessels, etc, which can be automatically closed-in by emergency shut-down valves. The segment defines the maximum volume of fluid or gas that can released from that system in the event of a failure in any of the components. Some segments contain both liquid and gas which may be considered differently regarding consequence effects. Note that it is normal to assume that the ESD isolation functions on demand, but this may not be applicable to all cases.

Severity class – A measure of how a failure effects on an item.

Severity Class Types: Critical failure: A failure which causes immediate and complete loss of an item’s capability of providing its output. Degraded failure: A failure which is not critical, but which prevents the item from providing its output within specifications. Such a failure would usually, but not necessarily, be gradual or partial, and may develop into a critical failure in time. Incipient failure: A failure which does not immediately cause loss of an item’s capability of providing its output, but which, if not attended to, could result in a critical or degraded failure in the near future. Unknown: Failure severity was not recorded or could not be deduced.

Societal Risk Measures – consider the risk to groups of people that may be effected by incidents.

Source – Thing or activity with a potential for consequence. Source in a safety context is a hazard.

(Ref. API580)

Source Identification – Process to find, list, and characterise sources. In the safety area, source identification is called hazard identification.

(Ref. API580)

Spurious Trip Rate – The Spurious Trip Rate is the frequency of false alarms which result in system shutdown. The spurious signal can be caused by abnormal stimulation of protection or control instrumentation or by component failure. The rate will generally be quoted in spurious trips/year.

Stakeholder – any individual, group or organisation that may affect, be affected by, or perceive itself to be affected by the risk.

(Ref. API580)

Sub-unit –Assembly of items that provides a specific function that is required for the equipment unit within the main boundary to achieve its intended performance.

(Ref. ISO 14224)

System – a collection of equipment assembled for a specific function within a process unit.

T Tag, Tagnumber – The unique identification of a part, component, pipe or equipment.

4 The term Segment is frequently used in the chemical/petrochemical industry.



Technical Module5 – the systematic methods used to assess the effect of specific failure mechanisms on the probability of failure. It evaluates two categories of information: degradation rate of the equipment items material of construction, resulting from its operating environment; and the effectiveness of the facility’s inspection program to identify and monitor the operative failure mechanisms prior to failure.

Testing – An activity carried out to determine by specific procedures that one or more characteristics of a product, process or service meets one or more specified requirements.

(Ref. ISO/TC 11/SC)

Time Between Failures – The time duration between two consecutive failures of a repaired item. (Ref. IEC 60050-191, DRAFT prEN 13306)

Time to Failure – Total time duration of operating time of an item, from the instant it is first put in an up state, until failure or, from the instant of restoration until next failure.

(Ref. EC 60050-191, DRAFT prEN 13306)

Third party inspection body – An organisation independent from the manufacturer or user that perform inspections on boilers and pressure vessels as provided for by Codes and Standards.

(ISO/TC 11/SC)

Tolerable Risk – Risk which is accepted in a given context based on the current values of society.


Trip –Unexpected shutdown of equipment. Trips are either spurious or real, i.e. either caused by human or instrument failure, or actual process upsets. See Spurious Trip Rate.

U Unplanned Maintenance – the maintenance carried out to no pre-determined plan.

Up state – A state of an item characterised by the fact that it can perform a required function, assuming that the external resources, if required, are provided.

NOTE: This state relates to availability performance.


Up time – The time interval during which an item is in an up state.


User – An organisation or individual using or operating the asset under consideration.

5 A concept used in API.



V Vibration Monitoring Element – a sensor for monitoring equipment such as pumps and

compressors to detect developing problems before equipment failure occurs.

W X Y Z



4. References 1. API RP 580 “Risk Based Inspection”, 4th draft. 2. IEC 60050(191) “International Electrotechnical Vocabulary (IEV), Chapter 191:

Dependability and quality of service”, 1990. 3. IEC 61508-4 “Functional safety electrical/programmable electronic safety related systems

– Part 4: Definition and abbreviations of terms”, 1998. 4. IEC 60300-3-3 “Dependability management – Part 3: Application guide – Section 3: Life

cycle costing”, 1996. 5. ISO/IEC “Guide 51 – Safety aspects – Guidelines for their inclusion in standards”,

Second edition 1999. 6. ISO/TC 11/SC “Boilers and pressure vessels”. The National board of boiler and pressure

vessels. 7. ISO N 33 “The Third Working Draft of Risk Management Terminology”, 199-12-24. 8. ISO 14224 “Petroleum and natural gas industries – Collection and exchange of reliability

and maintenance data equipment” First edition, 1999-07-15. 9. DRAFT prEN 13306 “Maintenance terminology”, June 1998. 10. NORSOK O-CR-001 “Life cycle cost for systems and equipment”, Rev. 1, April 1996. 11. NORSOK Z-CR-008 “Criticality classification method”, Rev.1, May 1996. 12. NORSOK Z-013 “Risk and emergency preparedness analysis”. Rev. 1, March 1998. 13. NORSOK Z-016 “Regularity management & reliability technology”, Rev. 1, Dec. 1998. 14. MIL-STD-1629A “Military standard procedures for failure mode, effects and criticality

analysis” November 1980)



5. Other relevant standards and documents 1. API 510 Pressure Vessel Inspection Code; Maintenance Inspection rating, Repair and

Alternation 8th edition, Dec. 1998. 2. API 570 Piping Inspection Code; Maintenance Inspection Rating, Repair and Alternation

2nd edition, October 1998. 3. API 574 Inspection Practices for Piping System Components, 2nd Edition, June 1998. 4. API 579 code or fitness-for-service evaluation. 5. API RP 580 “Risk Based Inspection”, 4th draft. 6. API 581, Base Resource Document – Risk Based Inspection, Preliminary Draft, 1st

Edition, June 1996. 7. ASME RBI code 8. DNV RP-F 101 “Corroded pipelines” 9. DNV RP-G 101 “Recommended practice for risk based inspection of topsides static

mechanical equipment”, DNV 2001. 10. DOW Fire and Explosion Index. Hazard Classification Guide, 6th edition, 1987. 11. IEC 60050(191) “International Electrotechnical Vocabulary (IEV), Chapter 191:

Dependability and quality of service”, 1990. 12. IEC 61508-4 “Functional safety electrical/programmable electronic safety related systems

– Part 4: Definition and abbreviations of terms”, 1998. 13. IEC 60300-3-3 “Dependability management – Part 3: Application guide – Section 3: Life

cycle costing”, 1996. 14. IEC 60300-3-11 “RCM” 15. ISO/IEC “Guide 51 – Safety aspects – Guidelines for their inclusion in standards”,

Second edition 1999. 16. ISO/TC 11/SC “Boilers and pressure vessels”. The National board of boiler and pressure

vessels. 17. ISO N 33 “The Third Working Draft of Risk Management Terminology”, 199-12-24. 18. ISO 14224 “Petroleum and natural gas industries – Collection and exchange of reliability

and maintenance data equipment” First edition, 1999-07-15. 19. DRAFT prEN 13306 “Maintenance terminology”, June 1998. 20. NORSOK O-CR-001 “Life cycle cost for systems and equipment”, Rev. 1, April 1996. 21. NORSOK Z-CR-008 “Criticality classification method”, Rev.1, May 1996. 22. NORSOK Z-013 “Risk and emergency preparedness analysis”. Rev. 1, March 1998. 23. NORSOK Z-016 “Regularity management & reliability technology”, Rev. 1, Dec. 1998. 24. MIL-STD-1629A “Military standard procedures for failure mode, effects and criticality

analysis” November 1980) 25. OREDA: Offshore Reliability Data Handbook, DNV, 1999.




Contact information

Det Norske Veritas AS (DNV) Mr. Sture Angelsen Veritasveien 1 N-1322 Høvik Norway Tel: +47 67 57 99 00 E-mail: Sture.Anglesen@ dnv.com URL: www.dnv.com

Bureau Veritas (BV) Mr. Rémy Giribone Place des Reflets 17 BIS Place La Defense 92400 Courbevoie, CDEX 44 France Tel: +33 1 42 91 54 27 E-mail: remy.giribone@ bureauveritas.com URL: www.bureauveritas.com

Staatliche Materialprüfungsanstalt (MPA Stuttgart) Dr. Aleksandar Jovanovic Pfaffenwaldring 32 D-70569 Stuttgart Germany Tel: +49 711 685 3007 E-mail: jovanovic@ mpa.uni-stuttgart.de URL: www.mpa.uni-stuttgart.de

Technical Research Centre of Findland (VTT) Mr. Pertti Auerkari Kemistintie 3 Postbox 1704 FIN-02044 VTT, Espoo Finland Tel: +358 9 456 6850 E-mail: Pertti.Auerkari@ vtt.fi URL: www.vtt.fi

TÜV Industrie Service TÜV SÜD Group Dr.Ing. Robert Kauer Westendstrasse 199 D-80686 München Germany Tel: +49 (89) 57 91 12 77 E-mail: robert.kauer@ tuev-sued.de URL: www.tuev-sued.de

TNO Industrial Technology Metals Technology (TNO) Mr. Jan Heerings Rondom 1 P.O.Box 6235 5600 HE Eindhoven Netherlands Tel: (+31) 40 265 0275 E-mail: [email protected] URL: www.tno.nl

yARA Sluiskil B.V. (YARA) Mr. Arie deBruyne Industrieweg, Postbox 10 4541 HJ Sluiskil Netherlands Tel: +31 (0) 115 47 41 16 E-mail: arie.de.bruyne@ yara.com URL: www.yara.com

Mitsui Babcock Energy Limited (MBEL) Dr. Barrie Shepherd Technology and Engineering Porterfield Road Renfrew, Renfrewshire PA4 8DJ UK Tel: +44 (0) 141 885 3977 E-mail: bshepherd@ mitsuibabcock.com URL: www.mitsuibabcock.com

ExxonMobil Chemical Ltd. (EXXONMOBIL) Mr. Andrew Herring Beverkae House, Mossmorran KY4 BEP Cowdenbeath Fife Scotland Tel: +44 (0) 1383 846142 E-mail: andrew.herring@ exxonmobil.com URL: www.exxonmobil.com

Energie Baden-Württemberg Ingenieure GmbH AG (EnBW) Dipl.-Ing Jörg Bareiβ Postbox 10 13 11 D-70012 Stuttgart Germany Tel: +49 (0711) 128 21 24 E-mail: j.m.bareiss@ enbw.com URL: www.enbw.com

Siemens Aktiengesellschaft (SIEM) Dr. Artur Ulbrich Wiesenstraβe 25 D-45466 Mülheim a.d. Ruhr Germany Tel: +49(208) 456 2853 E-mail: artur.ulbrich@ kwu.siemens.de URL: www.siemens.de

European Commission, Directorate General Joint Research Centre, Petten (JRC) Dr. Luca Gandossi Postbox 2 1755 ZG, Petton Netherlands Tel: +31 224 565250 E-mail: [email protected] URL: www.jrc.nl

Electricity Supply Board (ESB) Dr. Alan Bissell 27 Lower Fitzwilliam Street Dublin 2 Ireland Tel: +353 (1) 702 6467 E-mail: [email protected] URL: www.esb.ie

CORUS UK Ltd. (CORUS) Mr. Colin Davies Moorgate Rotherham South Yorkshire S60 3AR UK Tel: +44 (0) 1709 823105 E-mail: colin.davies@ corusgroup.com URL: www.corusgroup.com

Dow Benelux N.V. (DOW) Mr. Antoine Baecke H. Dowweg Postbox 48 430AA Terneuzen Netherlands Tel: +31 115 67 2667 E-mail: [email protected] URL: www.dow.com

SOLVAY S.A. (SOLVAY) Mr. Alain Fobelets Rue de Ransbeek Postbox 310 B-1120 Bruxelles Belgium Tel: +32 2 264 3655 E-mail: Alain.Fobelets@ solvay.com URL: www.solvay.com

DNV Report No.: 2004-0307 DNV Library Services, Veritasveien 1, N-1322 Høvik, Norway Contacts Judit Berthelsen tel (+47) 67 57 81 29 Mette Nore tel (+47) 67 57 93 96 Ingunn Lindvik tel (+47) 67 57 82 38 Sigrun Rosholt tel (+47) 67 57 94 47

mailto:Sture.Anglesen@�dnv.com

mailto:Sture.Anglesen@�dnv.com

http://www.dnv.com/

mailto:[email protected]


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http://www.vtt.fi/



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http://www.tno.nl/



http://www.hydro.com/



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