SIL certification process

The BYHON certification roadmap is based on a Functional Safety Assessment (FSA) process that consists in assessing the adequacy of the functional safety obtained from the analyzed equipment, compared to the clauses established by IEC 61508.

The certification scheme can be divided into three parallel phases:

Detailed review of hardware and software design, where auditors review the product design against functional safety requirements together with the manufacturer’s designers;

Revision of the development of the Functional Safety Management System, which aims to verify the presence and applicability of a management system for the fulfilment of functional safety requirements;

Quality constraint audit, which aims to verify the implementation of the quality requirements of IEC 61508 in the manufacturer’s quality management system.

The certification scheme, the Certification Agreement and more information about the certificates issued by BYHON are available on request by filling out our contact form, under the heading Request documentation and by specifying the type of document desired.

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The above flow chart is based on the following working criteria:
  • Activity flow is top-down. All steps are shown chronologically (from top to bottom);
  • The activities shown in parallel branches can be developed independently and simultaneously because the implementation of each phase is not closely related to the others;
  • The documents listed to the left or right of each phase (blank) represent the input of a phase;
  • The documents issued by BYHON along the workflow are highlighted in orange;
  • Audits carried out at the client are highlighted in blue:

Detailed analysis and review of hardware and software, i.e. the review by product design auditors of functional safety requirements, working alongside the manufacturer’s designers. This audit may take several days depending on the complexity of the product.

Review of the development of the functional safety management system, which aims to verify the presence and applicability of a management system for the fulfilment of functional safety requirements.

The quality constraint audit, which aims to verify the implementation of the quality requirements of IEC 61508 in the manufacturer’s QS.

The SIL certificate will be issued following positive testing of the equipment at the customer’s premises based on the dedicated test procedure and the successful completion of all previous phases.

Steps in the SIL certification process

The detailed analysis of hardware and software design is based on relevant product design documentation (detailed hardware schematics, device data sheet, software code, etc.). During the hardware review, BYHON auditors study the product design to identify safety-relevant subsystems and components and define their functional architecture (presence of any redundant elements.

If gaps are identified during the design review with respect to the requirements of IEC 61508, they are documented through an analysis (GAP Analysis), in which the indications for the correction of these gaps in terms of design, documentation, etc. are reported.

FMEDA analysis (analysis of the effects and diagnostics of product failure modes) is based on a systematic analysis and breakdown of the product into its safety-relevant components, in order to identify the failure rates (safe/dangerous and detected/undetected) and potential failure modes of each component, analyzing them and classifying them according to their effects on the expected safety function of the product. The result of FMEDA analysis is an estimation of product reliability and diagnostic capability through quantification and distribution of failure rates.

The systematic capability provides a quantitative estimate of the robustness of the system with respect to systematic failures resulting from project management, documentation quality, control requirements, structured design, etc., managed through all phases of the system life cycle, in order to avoid systematic failure.

BYHON supervises the functional safety validation tests performed at the customer’s premises following the detailed protocol in the FS Test Procedure developed by BYHON and provided to the manufacturer. The objective is to demonstrate that the product meets the specifications for the general requirements of the safety functions and the general integrity requirements.

The Functional Safety Assessment (FSA) report is included in the SIL Certificate and contains the results of the assessment according to IEC 61508 requirements, together with the results of each step of the certification process.

The SIL certificate confirms compliance with IEC 61508 requirements and contains references to the FSA report and safety manual of the article.

The functional safety label (FS) accompanied by the unique identification code (ID) of the product is the label that must be affixed on the product to allow the identification and tracking of SIL certified items.

In this phase, BYHON analyses the relevant documentation for the implementation of the customer’s functional safety management system (FSMS) as policies and procedures that specify the organizational policy and strategy to achieve functional safety.

During this phase the presence of a quality management system is verified to ensure the manufacturer’s ability to maintain functional safety certification in all products manufactured with the validity of the certificate. The quality constraint audit carried out by BYHON focuses on the review of all relevant quality documents and procedures, production and test documentation relevant to effective functional safety management.

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