Abnormal, undesirable state of a system element induced by the presence of an improper command or absence of a proper one, or by a failure
- Note 1 to entry: All failures cause faults; not all faults are caused by failure.
- Note 2 to entry: System elements can include, for example, an entire subsystem, an assembly, or a component.
Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global Standards
State of an item characterized by inability to perform a required function, excluding such inability during preventive maintenance or other planned actions, or due to lack of external resources.
Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandards
State of an item characterized by inability to perform a required function, excluding the inability during preventive maintenance or other planned actions, or due to lack of external resources. NOTE A fault is often a result of a failure of the item itself but the state can exist without a failure.
Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global Standards
inability to perform as required
- Note 1 to entry: A fault of an item is a state, as distinct from a failure of an item which is an event (see Figure 8).
- Note 2 to entry: A fault of an item may result from a failure of the item or from a deficiency in an earlier stage of
- the life cycle, such as specification, design, manufacture or maintenance.
- Note 3 to entry: Qualifying terms may be used to indicate the cause of a fault, such as specification, design,
- manufacture, maintenance or misuse.
- Note 4 to entry: Inability to perform due to preventive maintenance, other planned actions, or lack of external
- resources does not constitute a fault.
- Note 5 to entry: Figure 8 illustrate the relationship between the concepts of failure and fault:
— The Failure x occurs at stage 1 and leads to the state Fault x which is not detected.
— from stage 2 point of view Fault x is a pre-existing fault.
— The Failure y occurs at stage 2 and lead to the state Faults x,y which is not detected.
— From stage 3 point of view Fault x,y is a pre-existing fault.
— and so on.
[SOURCE: IEC 60050 −191]
Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global Standards