ISO 16708:2006 石油および天然ガス産業—パイプライン輸送システム—信頼性に基づく限界状態法 | ページ 6

3.1

basic variable

load or resistance variable entering the limit state function including the variable accounting for model uncertainty in the limit state function itself

3.2

characteristic load

nominal value of a load to be used in determination of load effects

Note 1 to entry: Characteristic load is normally based upon a defined fractile in the upper end of the distribution function of the load.

3.3

characteristic resistance

nominal value of a strength parameter to be used in determination of capacities

Note 1 to entry: Characteristic resistance is normally based on a defined fractile in the lower end of the distribution function of the resistance.

3.4

characteristic value

nominal value to characterize the magnitude of a stochastic variable

Note 1 to entry: Characteristic value is normally defined as a fractile of the probability distribution of the variable.

3.5

commissioning

activities associated with the initial filling of a pipeline with the fluid to be transported

[SOURCE:ISO 13623]

3.6

construction

phase comprising installation, pressure testing and commissioning

3.7

design life

period of time selected for the purpose of verifying that a replaceable or permanent component is suitable for the anticipated period of service

[SOURCE:ISO 13623]

3.8

design point

most probable outcome of the basic variables when failure occurs

3.9

design value

value to be used in the deterministic design procedure, i.e., characteristic value multiplied by the safety factor

3.10

failure

loss of ability of a component or a system to perform its required function

3.11

fluid category

categorization of the transported fluid according to hazard potential

3.12

importance factor

dimensionless number between zero and one describing the contribution of a random variable to the overall uncertainty

3.13

inspection

processes for determining the status of items of the pipeline system or installation and comparing it with the applicable requirements

3.14

limit state

state beyond which the pipeline no longer satisfies the design requirements

Note 1 to entry: Categories of limit states for pipelines include serviceability limit state (SLS) and ultimate limit state (ULS).

3.15

limit-state design

structural design where specific limit states relevant for the actual case are explicitly addressed

Note 1 to entry: A limit-state design check can be made both using the deterministic approach or using the probabilistic approach where uncertainties are modelled.

3.16

limit state function

function of the basic variables, which has negative values when the structure fails and positive values when the structure is safe

3.17

load

any action causing deformation, displacement, motion, etc. of the pipeline

3.18

load combination

set of loads acting simultaneously

3.19

load effect

effect of a single load or load combination on the pipeline

3.20

location class

geographic area classified according to criteria based on population density and human activity

[SOURCE:ISO 13623]

3.21

maintenance

all activities designed to retain the pipeline in a state in which it can perform its required functions

[SOURCE:ISO 13623]

Note 1 to entry: These activities include inspections, surveys, testing, servicing, replacement, remedial works and repairs.

3.22

maximum allowable incidental pressure

MAIP

maximum allowable internal pressure due to incidental operation of the pipeline or pipeline section

3.23

maximum allowable operating pressure

MAOP

maximum allowable pressure at which a pipeline, or parts thereof, is allowed to be operated

[SOURCE:ISO 13623]

3.24

mean value

first order statistical moment of the probability distribution function of the considered variable

3.25

mill test pressure

test pressure applied to pipe joints and pipe components upon completion of manufacture and fabrication at the mill

3.26

model uncertainty

uncertainty in the predictions of a selected calculation model that remains when the exact values of all input parameters are known

3.27

nominal wall thickness

specified wall thickness of a pipe, which is equal to the minimum design wall thickness plus the negative manufacturing tolerance and the corrosion allowance

3.28

normal operation

conditions that arise from the intended use and application of the pipeline, including associated condition and integrity monitoring, maintenance and repair

Note 1 to entry: Normal operations includes steady flow conditions over the full range of design flow rates, as well as possible packing and shut-in conditions.

3.29

ovality

deviation of the pipeline perimeter from a circle, having the form of an elliptical cross-section

3.30

pipeline

those facilities through which fluids are conveyed, including pipe, pig traps, components and appurtenances, up to and including the isolating valves

[SOURCE:ISO 13623]

3.31

offshore pipeline

pipeline laid in maritime waters and estuaries seaward of the ordinary high water mark

[SOURCE:ISO 13623]

3.32

on-land pipeline

pipeline laid on or in land, including lines laid under inland water courses

[SOURCE:ISO 13623]

3.33

reliability

ability of a component or a system to perform its required function without failure during a specified time interval

Note 1 to entry: Reliability equals 1 minus the failure rate, P_f.

3.34

risk

combination of the probability of an event and the consequences of the event

[SOURCE:ISO 17776]

Note 1 to entry: Individual risk is related to the risk of a single person injury/death and societal risk is the risk of human safety in the entire society affected by the pipeline.

3.35

safety class

concept to classify the criticality of pipelines

3.36

safety factor

γ

factor by which the characteristic value of a variable is multiplied to give the design value

3.37

specified minimum tensile strength

SMTS

minimum ultimate tensile strength required by the specification or standard under which the material is purchased

3.38

specified minimum yield strength

SMYS

minimum yield strength required by the specification or standard under which the material is purchased

[SOURCE:ISO 13623]

3.39

system reliability

reliability of a system of more than one element, or the reliability of an element which has more than one relevant failure mode

3.40

target safety level

maximum acceptable failure probability level for a particular pipeline and limit state condition