fault-related-terms-and-definitions.md

Fault-related terms and definitions

Fault

abnormal condition that can cause an element (3.41) or an item (3.84) to fail

Note 1 to entry: permanent, intermittent, and transient faults (3.173) (especially soft errors) are considered.

Note 2 to entry: when a subsystem is in an error (3.46) state it could result in a fault for the system (3.163).

Note 3 to entry: an intermittent fault occurs from time to time and then disappears again. This type of fault can occur when a component (3.21) is on the verge of breaking down or, for example, due to an internal malfunction in a switch. Some systematic faults (3.165) (e.g., timing irregularities ) could lead to intermittent faults.

Detected fault

Dual-point fault

3.57 Fault injection

3.58 Fault model

3.60 Fault tolerance

3.85 Latent fault

3.97 Multiple-point fault

3.108 Perceived fault

3.109 Permanent fault

3.119 Random hardware fault

3.125 Residual fault

3.130 Safe fault

fault (3.54) whose occurrence will not significantly increase the probability of violation of a safety goal (3.139)

Note 1 to entry: As shown in ISO 26262-5:2018, Annex B, both non-safety and safety-related elements (3.144) can have safe faults.

Note 2 to entry: Single-point faults (3.156), residual faults (3.125) and dual-point faults (3.39) do not constitute safe faults.

Note 3 to entry: Unless shown relevant in the safety (3.132) concept, multiple-point faults (3.97) with higher order than 2 can be considered as safe faults.

References

1. ISO 26262-3:2018 Road vehicles — Functional safety