Functional Safety 2016

Institute of Measurement and Control. Functional Safety 2016

Page 2

Figure 1 Failure types

Systematic Capability

IEC 61508:2010 Edition 2 introduced the term “systematic capability” back in 2010 to be used to

quantify the capability of a SIF Element (such as a sensor, logic solver or actuator) in terms of its

systematic safety integrity.

Systematic Capability is defined as "...a measure (expressed on a scale of SC 1 to SC 4) of the

confidence that the systematic safety integrity of an element meets the requirements of the specified

SIL, in respect of the specified element safety function..."

The term “SIL Capability” has long been used as a way of referring to the systematic safety integrity of

specific devices within a safety instrumented function. SIL capability, however, is not a term

specifically defined by IEC 61508 & IEC 61511 and its specific meaning is often misunderstood or

misused. The introduction of the term “systematic capability” gives a better, more specific way of

expressing how well a SIF element will perform in terms of systematic failures.

Developing a Product to Achieve a Specific Systematic Capability

Meeting the general requirements of IEC 61508

To claim a level of systematic capability the broader requirements of the IEC 61508 standard must be

addressed. Such as:-

Lifecycle approach and functional safety management

Competence and Competency Management

Processes, Procedures, Planning

Roles, Responsibilities

Verification , Validation, Testing

Auditing, Assessment,

Planning, Documentation,

The ‘V’ model.

Safety Requirement Specifications

Application software Safety requirement specifications etc , etc

IEC 61508-4 IEC:2010 Para 3.5.9