CCST Safety Standards & Regulatory Compliance in Control Systems 5 — Questions and Answers
Question 1: Which US federal regulation requires facilities with extremely hazardous substances (EHS) above threshold planning quantities to notify the State Emergency Response Commission (SERC)?
- OSHA 29 CFR 1910.119 (PSM)
- EPCRA Section 302 (SARA Title III) (Correct answer)
- EPA 40 CFR Part 68 (RMP)
- RCRA 40 CFR Part 262
Correct answer: EPCRA Section 302 (SARA Title III)
EPCRA Section 302 (Emergency Planning and Community Right-to-Know Act, part of SARA Title III) requires facilities with EHS above TPQs to notify the SERC and participate in local emergency planning.
Question 2: In functional safety management, what does the term 'systematic failure' refer to?
- A failure that occurs at a predictable rate modeled by exponential distribution
- A failure that is deterministically related to a specific cause such as a design error or incorrect specification (Correct answer)
- A failure caused by random hardware degradation over time
- A failure that affects all redundant channels simultaneously
Correct answer: A failure that is deterministically related to a specific cause such as a design error or incorrect specification
A systematic failure has a deterministic root cause (design error, specification mistake, procedural error) and will always recur under the same conditions.
Question 3: A technician is performing functional testing on a SIS final element (emergency isolation valve). Which test result indicates a dangerous undetected (DU) failure?
- The valve closes on demand as required
- The valve fails to close when a test demand signal is applied (Correct answer)
- The valve closes spuriously during normal operation
- The valve position indicator shows an incorrect reading
Correct answer: The valve fails to close when a test demand signal is applied
A dangerous undetected failure is revealed when the final element fails to perform its safety function (fail to close) when a test demand is applied.
Question 4: According to NFPA 70E, what is the primary purpose of an Energized Electrical Work Permit (EEWP) in an industrial control environment?
- Authorize the use of live circuit testing instruments
- Document justification and safety measures when deenergizing is not feasible and work must be performed energized (Correct answer)
- Replace the need for arc flash personal protective equipment
- Allow unqualified workers to perform testing under supervision
Correct answer: Document justification and safety measures when deenergizing is not feasible and work must be performed energized
An EEWP documents that deenergizing is infeasible or creates greater hazard, identifies the hazards, and requires approval for energized work with appropriate PPE and precautions.
Question 5: Which concept in process safety describes the minimum set of conditions that, if all present simultaneously, could lead to a major accident?
- Bow-Tie Analysis
- Safety Critical Element (SCE)
- Accident Sequence
- Minimum Cut Set (Correct answer)
Correct answer: Minimum Cut Set
A minimum cut set in fault tree analysis is the smallest combination of basic events (failures/conditions) that together are sufficient to cause the top event (major accident).
Question 6: Under ISA-84 (IEC 61511), during which lifecycle phase is the Safety Requirements Specification (SRS) developed?
- After the SIS design is complete and before installation begins
- During the hazard and risk assessment phase before SIS design (Correct answer)
- After the proof test procedures are finalized
- During commissioning to capture as-built conditions
Correct answer: During the hazard and risk assessment phase before SIS design
The SRS is developed after the hazard and risk assessment (which establishes SIL targets) and before SIS design, capturing all functional and integrity requirements the SIS must meet.
Question 7: What distinguishes an 'active' safeguard from a 'passive' safeguard in a Layer of Protection Analysis (LOPA)?
- Active safeguards require energy input or mechanical action to function; passive safeguards provide protection without any action required (Correct answer)
- Active safeguards are operator-initiated; passive safeguards are automatically initiated
- Active safeguards are credited at full PFD; passive safeguards receive only partial credit
- Active safeguards are SIS-based; passive safeguards are BPCS-based
Correct answer: Active safeguards require energy input or mechanical action to function; passive safeguards provide protection without any action required
Passive safeguards (dikes, blast walls, check valves) provide protection inherently without action; active safeguards (SIS, relief valves) must detect a condition and take action.
CCST Safety Standards & Regulatory Compliance in Control Systems 5
Which US federal regulation requires facilities with extremely hazardous substances (EHS) above threshold planning quantities to notify the State Emergency Response Commission (SERC)?