Module 6 - SRS Documentation

Question 1

What is the purpose of SIS documentation?

Answer 1

Documentation of the SIS enables each of the lifecycle phases to be performed effectively, and enables verification, validation, and functional safety assessment

Question 2

What is the role of document management?

Answer 2

To prevent the use of out-of-date documents and ensure the current SIS configuration is being used during all lifecycle phases. This is important because the use of incorrect documents can have severe safety consequences, disrupt the functional safety lifecycle, and prevent traceability where required.

Question 3

What is the role of the SRS?

Answer 3

To provide a set of documents that underpin all subsequent lifecyle stages, usually presented as a master document with references to detail safety documents.

Question 4

What are the contents of the SRS?

Answer 4

1. General and common SIF requirements
2. Logic solver requirements
3. SIF requirements

The SRS would typically also link to other detailed documents such as HMI requirements and LOPA reports

Question 5

What are some common omissions from the SRS?

Answer 5

1. Process safety time
2. Modes of operation
3. Allowable spurious trip rates

Question 6

What is a common method of documenting a SIF?

Answer 6

Cause and effect diagrams