Functional Safety 2014

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November 2014

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The IEC61508 safety lifecycle is the most systematic approach for any safety-related system. The

requirements of each phase as stated in IEC61508 should be met to demonstrate the systematic

capability of the design. The Human Factor Integration Plan is not a mandatory requirement within

IEC61508, however, it would be beneficial to include such a document to raise awareness of the

human factor issues at the beginning of the project lifecycle to avoid any over-estimation of human

reliability. The Management of Change Procedure is an essential document for all phases of the

project lifecycle. Any changes and modifications from the conceptual design to

commissioning/decommission should be structurally managed and maintained with full traceability.

All safety-related documents should be made available to all project members and operational

personnel. They should be uniquely identified.

Fig. 5 – Safety Lifecycle Activities

Safety Lifecycle Systematic Approach Example

The following is an example of the systematic approach applied to the design,

development and verification process of a Programmable Electronic (PE) system.

A Programmable Electronic system consists of three parts:

Hardware – the physical part of the system;

ii.

Embedded Software – the operating system for the application software;

iii.

Application Software – the software written specifically for the project application.

The random hardware integrity for the Hardware and the systematic capability for the Embedded

Software should be verified independently by a third party. They will not be discussed further in this

paper.