INTRODUCTION

SIL Calculations & Design provides the ability to manage all steps in the field of functional safety, as described in the standard IEC61511, in one place and to validate them.

Dymenzions SIL Calculations & Design helps you in setting up a Safety Requirement Specification (SRS).

In the next step, you can interactively design SIFs (Safety Instrumented Functions). Dymenzions contains an extensive database with up-to-date information of process equipment, such as failure rates, SIL certificates and safety manuals. Dymenzions SIL Calculations & Design automatically calculates and determines the SIF associated parameters such as test frequencies, MTTR and spurious trip rate. Dymenzions provides a verification of your SIF loops based on your SRS and calculates whether it meets the required SIL level. In this way, you can obtain an on-line design verification.

DESCRIPTION

SRS

SRS is a specification of the safety function. Dymenzions accompanies you in an interactive way to gather all the necessary information needed to make an SRS and will support you in making design choices. Dymenzions combines data from the HAZOP and LOPA in an efficient manner, such as:

  • Required SIL level and required response time
  • Function and location of the sensors and final elements
  • For the safety functions you make a number of choices such as:
  • Preferred minimum SFF (“Safe Failure Fraction”) for all components in the complete SIL loop
  • Configuration and wishes concerning redundancy and voting (1oo2, 1oo3, 2oo3 etc.)
  • Required availability

A user specification for a safety system may also contain:

  • Maintenance Override functions
  • Communication with other systems
  • Any preferred brands and models of the components, such as PLC, transmitters, barriers andvalves
  • Hardware requirements: ATEX classification and materials
  • Description of alarm handling and required staff action.

At any time you can print an up-to-date SRS document.

SIL / SIF Design

With Dymenzions SIL Calculations & Design you can easily design SIF loops. The system has a database with failure rates, SIL certificates and safety manuals for the most common components in the process technology. You select the equipment and the system will calculate parameters such as the PFD Average per component, a PFD average for the whole loop, test frequencies, MTTR (Mean Time To Repair), Spurious Trip Rate, etc. Dymenzions also verifies compliance with all requirements specified by you in the SRS, and whether the desired SIL level is achieved by using the chosen instrumentation.

BENEFITS

  • Complete documentation and registration of the functional safety Lifecycle
  • Assisting with the compilation of an SRS
  • Designing of SIL and SIF loops based on average PFD and SIL calculation
  • Use an up-to-date manufacturers database with failure rates, SIL certificates and safety manuals
  • Run the on-line design verification
  • Assessments of the safety lifecycle
  • Check for completeness of data
  • Check the compliance status according to current safety laws and regulations

CONCLUSION

With SIL Calculations & Design you can manage the complete design phase of the functional safety lifecycle and run on-line verifications and calculations.