Yokogawa provides functional safety services to assist plant owners to meet their obligations to comply with the IEC 61511 Safety Lifecycle requirements, regardless of the lifecycle stages being examined. Whether it be from the preparation stage through to report finalisation, we work closely with our clients to ensure that all gaps are bridged and the activity is carried out as efficiently and smoothly as possible. The IEC 61511 Safety Lifecycle steps outlined in the detail tab provide an insight into the value that can be provided by partnering with an experienced, certified and established functional safety organization like Yokogawa. Browse through our comprehensive safety service offering to see how we can assist.
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Hazard and Risk Assessment (e.g. HAZOPs)
The first step in the safety lifecycle is to identify all potential hazards and analyse their risks. This first step is critical as studies have shown that plants are often inadequately protected due to gaps in the carrying out of this step.
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Allocation of Safety Function (SIL Classification)
Following the Hazards and Risk Assessment, the IEC 61511 safety lifecycle model requires to identify all safety functions (SF) for each middle or high risk HAZOP scenario, and to allocate target SIL for each hazard scenario. If further reduction is required, an SIF shall be allocated. This target SIL is determined by taking into account the initiating event likelihood (IEL) and independent protection layers (IPL) such as PSV, alarm, BPCS, etc.
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SIL Verification
After SIL classification, SIL verification is necessary to confirm if the SIF design and instrument model determination are safe enough to meet the target SIL.
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Safety Requirement Specification (SRS)
After the allocation of Safety Instrumented Functions (SIFs) with the target SIL, the next step is to specify the requirements of the SIS and the application program such as mode of operation, (de-)energize to trip, override, reset, process safety time, response time, diverse, separation, proof test, etc.
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SIS Safety Validation
One of the important functional safety requirements is to ensure that the design and engineering of the SIS and installation and commissioning of the SIS meets all Safety Requirement Specifications.
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Proof Testing
Proof Testing of safety critical components and elements is an obligatory and often onerous task that operators must carry out in maintaining their Safety Instrumented Systems (SIS).
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Functional Safety Management System/Framework
Most of the accidents and disasters within the process industry are caused by wrong management, including the management of Safety Instrumented Systems (SIS).
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Functional Safety Assessments
The IEC standards require Functional Safety Assessments (FSA) as part of the SIS Safety Lifecycle.
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Functional Safety Management & Audits
The IEC standards require Functional Safety Management as part of the Systematic Safety Integrity.
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Safety Training
Yokogawa provides a broad range of specialized Instructor led courses next to certified TÜV Rheinland trainings to help enhance your knowledge and awareness of functional safety.
Details
Plant owner’s responsibility
During 1970’s and 1980’s, serious incidents that occurred at petroleum and chemical plants initiated several countries to legislate that “owners of industrial plants where dangerous materials are handled must evaluate possible risks that may occur in the plants.” These legal regulations stipulate that the plant owners are socially responsible in the entire lifecycle, from planning to disposal, to minimize the risks of hazards to “human beings, physical assets and the environment.” In order to fulfil these social responsibilities, the plant owners are expected to identify risk factors of hazardous scenarios that cause incidents; to analyze and evaluate them; then to reduce the risks to a socially acceptable level. The international standards IEC 61508 and IEC 61511 define guidelines to identify, analyze and evaluate risks, then implement the risk reduction measures based on legal regulations of several countries.
Figure 1 Flow from incidents to standardization
What is Functional Safety
In the context of industry process plants, 'functional safety’ is defined as part of the overall safety relating to the process and the basic process control system (BPCS), which depends on the correct functioning of the Safety Instrumented System and other protection layers. International standard IEC 61511 “Functional Safety – Safety instrumented systems for the process industry” defines two important concepts, namely the safety lifecycle and safety integrity levels (SILs). All phases throughout the safety lifecycle (see diagram below), from Hazard & Risk Assessment (H&RA) to Operation and even Decommissioning require management of functional safety to ensure reliable safety systems free of design failures are realized and maintained to the targeted safety integrity levels. Yokogawa’s functional safety experts have extensive industry experience and are highly capable to assist plant owners understand and effectively meet their obligations to comply with the SIS requirements for each safety lifecycle phase. Yokogawa’s safety specialists have gathered many years of experience and offers practical solutions and services to meet requirements of IEC 61511, regardless of the safety lifecycle stage. In delivering our solutions and services, we work closely as partners with our clients, from the preparation stage through to report finalization, to ensure that all gaps are bridged, and the project is carried out to completion as efficiently and smoothly as possible. Check out our comprehensive safety service offering to see where we can help and feel free to contact one of our friendly relationship managers for more details.
Figure 2 quoted and derived from figure 7 IEC 61511-1 Ed.2 2016 Safety Lifecycle diagram
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