SIL/SIS CONSULTING SERVICES

Our facilitators are highly skilled in safety integrity level (SIL) engineering, ensuring compliance with the international IEC 61511/61508 standards.  Using advanced safeguarding expertise, in many cases we can guide the team to solutions that  avoid the need for a safety instrumented function (SIF).  When a SIF is determined to be the best available safeguarding option, we can help to provide solutions that are reliable, practical and maintainable.  The efficiencies gained by using our facilitators for both HAZOP and LOPA will save both time and money on your projects.

Many industrial facilities have some equipment that presents significant risk to personnel or the public.  LOPA may not be the best risk assessment technique for high complexity or very high risk scenarios. Rather than accepting unreasonably high SIL targets, consider a Quantitative Risk Analysis (QRA) as an option for some of the highest risk and complexity scenarios.  This analysis requires a higher level of engineering effort but enables the analyst to remove some of the conservatism inherent to less quantitative techniques such as LOPA.

SIL verification calculations are performed to verify a proposed design meets the safety integrity target identified in a SIL assessment.  Watchmen can perform these calculations quickly and accurately presenting options that can minimize the need for additional hardware or redundancy and maximizing proof test interval.  A strong understanding of this technique can often save money stemming from over designing.  Under designing can leave you lacking protection.

A comprehensive Safety Requirement Specification (SRS) is a key document used to ensure all SIF's are designed, installed, maintained and tested properly to ensure they provide the needed safety integrity.  Watchmen can provide detailed and comprehensive SRS packages quickly and effectively using our proprietary SRS tools.

Performing an effective proof test is critical to maximizing SIL performance and extending the test interval.  Watchmen can develop comprehensive test procedures that will maximize proof test coverage.  Our easy to use checklists and procedures will help you to document the regular testing being performed and take action if there are any failures.

A functional safety assessment is an audit performed at various stages of the lifecycle to assess the capability of the SIS to provide the required safety integrity.  There are many activities required to ensure proper implementation of a safety system, and many ways this can go wrong.  

Audits and assessments are a good way to identify gaps in processes and performance with an eye on improvement.  The IEC 61511 standard requires that this be performed by a competent party that is independent from the SIS design and maintenance/operations.  During our audits and assessments, Watchmen offers coaching for the personnel that we work with to help get them up to speed with best practices and standards required to support an effective SIS implementation.

 SIS audits and assessments typically include a detailed review of engineering and test documents, plans and procedures including an inspection of installed SIF(s) and interviews with key personnel. 

A Stage 3 FSA is a mandatory part of the SIS lifecycle performed prior to placing SIS in active service where hazards may be present.  At this stage Watchmen will verify that all engineering, installation and commissioning activities have been performed as required and that the operations team has been properly prepared for safe operation of the SIS.  

A Stage 4 FSA is a mandatory part of the SIS lifecycle performed regularly during the operations and maintenance lifecycle.  The Stage 4 FSA will review operating and maintenance history to confirm assumptions used in the SIL analysis are correct and that maintenance and testing has been performed as specified to meet the target SIL.  In the event of changes to the SIS application or updated assumptions, it may be necessary to move back into an earlier phase of the lifecycle and make the necessary adjustments.  Performance gaps or updated information will result in recommendations for update or improvements as needed.  

Regular SIS audits are necessary for compliance with IEC 61511 and are performed during the operating phase of the lifecycle to validate that a SIS Functional Safety Management System is in place, up to date and being followed.  Where gaps in the process are revealed by the audit, recommendations are provided to improve upon the process to ensure the SIS and associated SIF(s) provide the reliability intended.   The SIS Audit may be performed together with the Stage 4 FSA.   

Watchmen recommends that the SIS Audit be performed annually for the first few years of installation and then potentially extended out once it can be seen audits are no longer identifying gaps in the process.  Performing an audit within the first year following placing SIF(s) in service is very important, since this often reveals serious issues that may impair SIF integrity.