IEC 61511 Consulting

Consulting for safety instrumented system (SIS) verification and validation
Support for systems integrators in selecting components for systems designed to perform one or more safety functions, and which combine to achieve a specific Safety Integrity Level (SIL).

Verification and validation of a system in accordance with IEC 61511

The construction and commissioning of a safety instrumented system (SIS) involves the use of various individual components that are designed to perform specific control functions in relation to safety. However, even if each individual component selected for the system can reach the required SIL (Safety Integrity Level) this does not automatically mean that the SIS as a whole will achieve the same level of compliance.

For this reason, it is advisable to use consultants for the process of SIL verification and validation in line with IEC 61511. They can help you build a complex system, starting by selecting the most suitable components available on the market, thus ensuring that the system as a whole is able to reach a specific SIL.

A typical IEC 61511 compliance project will see us directly involved in planning and support at the following stages:

  • Support in selecting components from the point of view of Functional Safety
  • Preparation of the safety plan with contents in accordance with paragraph 5.2.4 of IEC 61511
  • Preparation of the SRS document with contents in accordance with paragraph 10 of IEC 61511
  • Preparation of the Safety Manual with contents compliant with paragraph 11.2.1 of IEC 61511.
  • Preparation of functional test plans and reports
  • Preparation of a Safety Analysis Report (SAR) in accordance with NOG 070, for evaluating all the main aspects in relation to functional safety

The development of the necessary application software, and its validation, are equally important parts of this process. Many potential risks to Safety Instrumented Systems relate to the fault management tools, or to diagnostic functions inactivated during programming. Our consultancy service helps you implement the application software in the correct way: from the development phase, to the targeted tests, and finally the validation process.

The service we offer is applicable to any system, whatever its size and complexity: from small stand-alone electromechanical systems, to entire systems distributed throughout the field with multi-platform software (e.g. HIPPS, Turbomachinery, Fire & Gas Systems, etc.)


A Safety Instrumented System (SIS) is a complex system that incorporates Safety Instrumented Functions (SIFs) and is composed of at least three elements: i.e. sensors, safety logic solvers, and final elements such as stop valves or circuit breakers.

IEC 61508 provides the basic framework for functional safety, describing the minimum requirements that equipment and systems must possess in order to be used in different industrial sectors. IEC 61511 expands on these rules, setting out the specific minimum requirements for systems used in production plants and processes.

The conformity process involves the verification and validation of the SIL (Safety Integrity Level). The first step is to select those components that will allow the system as a whole to reach the desired SIL, followed by the development, testing and validation of the application software.

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Why Choose us

  • We offer a customized service, adaptable to any system whatever its size and complexity
  • This includes a single interface for the hardware and software used to integrate the hardware and to develop and validate the application software
  • We use certified software in global use for calculating the individual safety functions and for verifying the final SIL

For more information about this service or to request a quote