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SIL Certification – Value or Vanity?

Author : Paulo Oliveira, Associate Director, ESC

15 October 2019

Is the well-presented stamped paper certificate an indulgent bureaucratic way to feel good about using equipment in a safety critical application, or does it actually carry value with regards to evidencing an adequate level of compliance with IEC61508?

IEC61508 requirements for a traceable and systematic approach to the capability of safety related systems has given rise to certification activities which aim at quantifying the SIL capability of elements and systems. The IEC61508 standard does not mandate certification as a necessary activity to demonstrate compliance with the requirements explicit therein. So why is certification needed?

The risk of poorly structured analyses and vague capability statements could result in an application with non-competent safety-related system equipment with significant integration issues which could result in flawed claims of compliance and capability against IEC61508 and subsequent inability to provide the necessary risk reduction. Conversely, the need for a certificate does not assure the items covered under the certificate are better developed to provide the risk reduction than other non-certified equipment.

This paper aims at providing a view based on the application of a compliance assessment process to IEC61508 and highlight some of the benefits and downfalls of typical certification process for equipment or systems. The presentation will also provide examples of good certification processes, expected deliverables, required activities and look at typical inflated claims of SIL capability which could potentially compromise risk reduction requirements associated with your application.

Paulo Oliveira

Paulo Oliveira is a Chartered Engineer (CEng) with more than 10 years’ experience in asset management and safety applications. Paulo has split his experience in project, maintenance and safety roles in hazardous and non-hazardous industries, such as chemical, steel and FMCG. Paulo was the Functional Safety Leader for a COMAH top tier site where he was accountable for the development and implementation of IEC61511 compliant systems, covering the whole lifecycle including competence and with links to broader Process Safety areas like process hazard analysis, human factors, alarm management and compliance auditing under OSHA 1910.

Paulo Oliveira, ESC Associate Director
Paulo Oliveira, ESC Associate Director

As part of ESC’s team, Paulo specialises in IEC61508/61511 compliance, certification and broader reliability analysis, including experience in chairing SIL Determination studies (UK and ME), SIL verification and reliability modelling, IEC61511/IEC61508 compliance gap analysis, Functional Safety Assessments, competence reviews and product certification including FMEA studies.

Paulo is a certified TÜV Rheinland Functional Safety Expert and Trainer in Safety Instrumented Systems (SIS - #301/19) within the TÜV Rheinland Functional Safety Training Program for courses accredited on the scheme. Paulo is also an CMSE - Certified Machinery Safety Expert (TÜV Nord).

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