Standards And Definitions Of Terms; Standard Iec 61508 (2010), Part 1 And 2; Dangerous Failure; Safety-Related System - ABB Endura AZ20 Manual

4 E N D U R A A Z 2 0 & A Z 3 0 | OX YG E N A N A LY Z E R | S I/A Z 2 0/A Z 3 0 - E N R E V. A
...2 Acronyms and abbreviations
...Safety Integrity Level (SIL)
Table 1 Safety Integrity Levels
Safety Integrity Level
4
3
2
1
Low demand mode of operation
≥ 10 to 10
-5 -4
≥ 10 -4 to 10 -3
≥ 10 to 10
-3 -2
≥ 10 to 10
-2 -1
3

Standards and definitions of terms

Standard IEC 61508 (2010), Part 1 and 2

Functional safety of electrical/electronic/programmable
electronic safety-related systems (target group: manufacturers
and suppliers of devices).

Dangerous failure

A failure that has the potential to place the safety-related
system in a dangerous state or render the system inoperative.

Safety-related system

A safety-related system performs the safety functions that are
required to achieve or maintain a safe condition, e.g., in a plant.
Example:
Pressure meter, logics unit (e.g., limit signal generator) and
valve form a safety-related system.

Safety function

A specified function that is performed by a safety-related
system with the goal, under consideration of a defined
hazardous incident, of achieving or maintaining a safe
condition for the plant.
Example:
Limit pressure monitoring.