ABB Endura AZ20 - Standards and definitions of terms; Standard IEC 61508 (2010), Part 1 and 2; Dangerous failure; Safety-related system

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ENDURA AZ20 & AZ30 | OXYGEN ANALYZER | SI/AZ20/AZ30-EN REV. A
…2 Acronyms and abbreviations
…Safety Integrity Level (SIL)
Table 1 Safety Integrity Levels
Safety Integrity Level Low demand mode of operation
4 ≥ 10
-5
to 10
-4
3 ≥ 10
-4
to 10
-3
2 ≥ 10
-3
to 10
-2
1 ≥ 10
-2
to 10
-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.