Industry Regulations & Compliance Flashcards

The concept of 'Independence' in ISA-84/IEC 61511 requires that the Safety Instrumented System be separate from the Basic Process Control System (BPCS) because:

Answer: Common cause failures could defeat both control and safety functions simultaneously

Independence is required so that a common cause failure cannot simultaneously defeat the BPCS and the SIS, ensuring the safety layer provides genuine risk reduction.

Under the NFPA 72 National Fire Alarm and Signaling Code, initiating devices in a fire alarm system must be:

Answer: Tested annually at minimum with records retained for three years

NFPA 72 requires initiating devices such as smoke detectors and pull stations to be tested annually, with records of inspections and tests retained for at least three years.

In nuclear power plant instrumentation and control, which standard establishes criteria for safety systems?

Answer: IEEE 603

IEEE 603 establishes the standard criteria for safety systems of nuclear power generating stations, covering design, qualification, and independence requirements.

When applying the hierarchy of controls to process safety, which control measure is considered most effective at reducing risk?

Answer: Elimination or substitution of the hazardous material or condition

The hierarchy of controls ranks elimination and substitution as the most effective measures because they remove the hazard rather than managing exposure to it.

The ISA-18.2 standard addresses management of the alarm system lifecycle, including a recommended maximum steady-state alarm rate for an operator of:

Answer: No more than 144 alarms per day or approximately 1 per 10 minutes

ISA-18.2 recommends that the acceptable steady-state alarm rate not exceed approximately 1 alarm per 10 minutes (144 per day) to prevent operator overload.

Under OSHA 29 CFR 1910.119, an 'incident investigation' must be initiated within 48 hours of:

Answer: An incident that resulted in or could have resulted in a catastrophic release

OSHA PSM requires incident investigation to begin within 48 hours of an incident that resulted in, or could have reasonably resulted in, a catastrophic release of a highly hazardous chemical.

In the context of IEC 61508, what does the term 'hardware fault tolerance' (HFT) refer to?

Answer: The number of random hardware faults a system can withstand while still performing its safety function

Hardware fault tolerance (HFT) is defined as N, where N+1 faults are required to cause loss of the safety function, indicating the system can tolerate N simultaneous hardware faults.