CAS CAS Automation Specialist Safety & Standards 1 — Questions and Answers
Question 1: Which IEC standard defines functional safety requirements for electrical/electronic/programmable electronic safety-related systems?
- IEC 61131-3
- IEC 61508 (Correct answer)
- IEC 62443
- IEC 60870
Correct answer: IEC 61508
IEC 61508 is the foundational international standard for functional safety of E/E/PE safety-related systems.
Question 2: What does SIL stand for in the context of industrial automation safety?
- System Integration Level
- Safety Integrity Level (Correct answer)
- Sequential Interlock Logic
- Signal Interface Layer
Correct answer: Safety Integrity Level
SIL (Safety Integrity Level) is a measure of risk reduction provided by a safety function, defined in IEC 61508.
Question 3: Which OSHA regulation applies most directly to lockout/tagout procedures for energy control in automated machinery?
- 29 CFR 1910.119
- 29 CFR 1910.147 (Correct answer)
- 29 CFR 1926.417
- 29 CFR 1910.303
Correct answer: 29 CFR 1910.147
29 CFR 1910.147 governs the control of hazardous energy (lockout/tagout) for general industry.
Question 4: In a Safety Instrumented System (SIS), what is the purpose of the final element?
- To detect a hazardous condition
- To process the safety logic
- To take action to bring the process to a safe state (Correct answer)
- To provide operator alerts only
Correct answer: To take action to bring the process to a safe state
The final element (e.g., a valve or motor contactor) executes the corrective action prescribed by the safety logic.
Question 5: What is the primary purpose of a Safety Integrity Level (SIL) verification study?
- To select the least expensive safety device
- To confirm that a safety function meets its required risk reduction (Correct answer)
- To certify operator training programs
- To validate network cybersecurity
Correct answer: To confirm that a safety function meets its required risk reduction
SIL verification confirms that the designed safety function achieves the required probability of failure on demand (PFD) target.
Question 6: Which document defines the process hazard analysis (PHA) lifecycle stage in the ISA 84 / IEC 61511 standard for process industry SIS?
- Layer of Protection Analysis (LOPA)
- Hazard and Operability Study (HAZOP)
- The Safety Requirements Specification (SRS) (Correct answer)
- Functional Safety Assessment (FSA)
Correct answer: The Safety Requirements Specification (SRS)
The Safety Requirements Specification (SRS) documents what a Safety Instrumented Function must achieve, derived from the PHA results.
CAS CAS Automation Specialist Safety & Standards 1
Which IEC standard defines functional safety requirements for electrical/electronic/programmable electronic safety-related systems?