Functional Safety 2016

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Communication
The ability to answer the 3rd of the 3 questions, is enabled by the ease in which the information from
the various activities performed in the operation and maintenance phase and the current health of
relevant barriers can be communicated and related back to the answers from the first 2 questions.
To be able to achieve this goal, we need to ensure the information for the first 2 questions is recorded
in the correct context. As previously stated tools are available which enable a simplified flow of
information through the different phases of the lifecycle. These tools also enables information
associated with the individual hazardous events such as initiating causes, protection layers, SIF design
and implementation to remain related. This relationship can then be readily utilized within the
operation and maintenance phases.
‘Big Data’ and the ‘Industrial Internet of Things’ (IIoT), provides connectivity to more and more
devices and data sources, however to make use of this data, we need to be able to contextualize this
data and quickly access the ‘needles’ from the ‘haystack’. The recording tools enable digitalization of
the lifecycle information and connectivity to the relevant data, which can then provide up to date
barrier health information in the context of the hazardous events. This can then be used to provide the
necessary decision support for the operation and maintenance teams.
If we consider the previous LOPA example, the SIL determination exercise identified a BPCS
interlock and alarm as independent protection layers to the SIF.
If a proof test is due to be carried out on the SIF, while the process operation is to be continued and a
bypass is required, then an appropriate risk assessment is to be performed prior to the bypass being put
in place (IEC61511-1 16.2.4). As well as reviewing the suitability of the temporary compensating
measure, a review of the other related protection layers should under taken.
The illustration below shows how information which is available on the health of the barriers can be
represented to the user in the context of the hazardous event, to enable a quicker, more effective and
streamlined risk assessment to be made. In this example the BPCS Interlock is in a manual state and
the alarm is masked, both resulting in ineffective barriers. In addition, the Standard Operating
Procedure (SOP-001) is currently underway which was identified as an initiating cause that could lead
to a demand on the SIF.