CCST Safety Standards & Regulatory Compliance in Control Systems 4

Question 1

Which standard provides cybersecurity guidance specifically for industrial automation and control systems (IACS)?

Accepted Answer

Both IEC 62443 and ISA-99 (they are the same standard series)

Answer

IEC 62443 and ISA-99 are the same standard series—ISA-99 was the original designation, later adopted and renumbered as IEC 62443.

Question 2

What is the difference between a SIL Capability and a SIL Claim Limit in IEC 61508?

Accepted Answer

Capability is the maximum SIL a subsystem can support; Claim Limit is the maximum credit claimable for risk reduction

Answer

SIL Capability is the maximum SIL a subsystem's hardware can support, while SIL Claim Limit is the maximum risk reduction credit that can be claimed for a single protection layer.

Question 3

A control systems technician discovers that a pressure transmitter feeding a SIS has drifted beyond its calibration tolerance. What is the correct immediate action?

Accepted Answer

Initiate a bypass of the affected SIF, apply compensating measures, and follow the site bypass management procedure

Answer

A failed SIS sensor requires initiating a formal bypass, implementing compensating measures (such as increased operator monitoring), and following the site's bypass management procedure.

Question 4

In the context of the OSHA PSM Hot Work Permit element, which location always requires a hot work permit?

Accepted Answer

Any location within the process area covered by PSM

Answer

OSHA PSM requires a hot work permit for any hot work operation conducted on or near a covered process to prevent ignition of flammable releases.

Question 5

Which architectural constraint in IEC 61508 defines the minimum hardware fault tolerance (HFT) based on the safe failure fraction (SFF)?

Accepted Answer

Architecture Constraints Table

Answer

The Architecture Constraints Table in IEC 61508 specifies the minimum HFT required to achieve a given SIL based on the subsystem's SFF.

(CCST) Certified Control Systems Technician Practice Test

(CCST) Certified Control Systems Technician Practice Test

CCST Safety Standards & Regulatory Compliance in Control Systems 4