SIL Functional Safety Principles & Standards 2

Question 1

Which IEC 61511 clause specifically addresses the competency requirements for personnel involved in functional safety activities?

Accepted Answer

Clause 5

Answer

IEC 61511 Clause 5 defines organizational and functional safety management requirements including competency of personnel.

Question 2

In the context of IEC 61508, what does the term 'proven-in-use' (also called prior-use justification) allow an engineer to do?

Accepted Answer

Use existing components without full V&V if sufficient field history demonstrates reliability

Answer

Proven-in-use allows components with sufficient documented field history to be credited without full V&V, provided failure data supports the required failure rate.

Question 3

Which of the following best describes the relationship between IEC 61508 and IEC 61511?

Accepted Answer

IEC 61511 is a sector-specific standard derived from IEC 61508 for the process industry

Answer

IEC 61511 is the process-sector application standard derived from the generic IEC 61508 framework.

Question 4

A safety function is classified as SIL 2. What is the required probability of failure on demand per hour (PFH) range for a high-demand mode SIS?

Accepted Answer

≥10⁻⁶ to <10⁻⁵

Answer

For high-demand (continuous) mode, SIL 2 requires PFH ≥10⁻⁶ to <10⁻⁵ dangerous failures per hour.

Question 5

What is the primary purpose of a Functional Safety Audit (FSA) as defined in IEC 61511?

Accepted Answer

To verify that functional safety activities are being carried out in accordance with plans and procedures

Answer

An FSA is an independent review to confirm that functional safety management activities conform to established plans, procedures, and the standard.

(SIL) Safety Integrity Level Certified Practice Test

(SIL) Safety Integrity Level Certified Practice Test

SIL Functional Safety Principles & Standards 2