CAS Automation Specialist Safety & Standards Flashcards
6 cards from real CAS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CAS Automation Specialist Safety & Standards flashcards as text
What is the purpose of a Layers of Protection Analysis (LOPA)?
Answer: To quantify risk reduction from independent protection layers to determine SIL requirements
LOPA is a semi-quantitative risk assessment method that evaluates the risk reduction provided by each independent protection layer.
Which of the following best describes a 'spurious trip' in an automated safety system?
Answer: An unplanned shutdown triggered by a false demand or component failure
A spurious trip is an unintended activation of a safety function not caused by a real process hazard, reducing plant availability.
According to ISA-18.2, what is the correct term for an alarm that is continuously in the alarm state for more than a defined period?
Answer: Standing alarm
ISA-18.2 defines a 'standing alarm' as one that remains active (unacknowledged or acknowledged but not resolved) for an extended period.
Which safety concept describes a system that moves to a known safe state upon detection of a fault?
Answer: Fail-safe design
Fail-safe design ensures that when a component or system fails, it defaults to a predetermined safe condition.
In the context of IEC 61511, what is a 'safety instrumented function' (SIF)?
Answer: A function implemented by a SIS to achieve or maintain a safe state for a process
A SIF is a specific safety function with a defined SIL, implemented by sensors, logic solvers, and final elements within a SIS.
What is the role of a 'logic solver' in a Safety Instrumented System?
Answer: To process sensor inputs and determine whether a safety action is required
The logic solver (e.g., a Safety PLC) receives inputs from sensors and executes the programmed safety logic to command final elements.