What is SILStat?

A tool that captures key operational and maintenance data for review and analysis as required by the IEC 61511 / ISA 84.00.01-2004 standard and as part of compliance with an OSHA PSM Mechanical Integrity Program. Such data includes:

• Equipment failures
• Process demands
• Success or failure of protection layers
• Proof test results, etc.,

The IEC 61511 / ISA 84.00.01-2004 functional safety lifecycle consists of three main phases:

• Analysis
• Realization
• Operation & Maintenance

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SILStat Uses

To optimize the risk reduction of safety instrumented functions and other layers of protection, it is necessary to collect actual performance data so that it can be compared to the expected performance (determined during the Analysis and Realization phases.) Operation and Maintenance data (such as demands and failures) can be used to determine the actual risk posed by a hazardous situation and the effectiveness of the individual layers of protection. Comparing actual (achieved) risk reduction vs. expected risk reduction allows safety practitioners to evaluate the effectiveness of their risk reduction design and take appropriate action.

Level of Actual Risk Reduction Provided	Actions
✓ Protection is adequate	Continue data collection
(-) Protection is inadequate	The process hazard has higher risk than expected. Return to Analysis phase for redesign and implementation.
(+) Protection is more than adequate	System is overdesigned to prevent hazard. Allows modification of design practices for future applications and potential for costs savings.