Kenexis Effigy

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Kenexis Effigy 2017-06-25T19:58:07+00:00

Performance Based Fire & Gas Detector Design

Fire and gas system design has historically been a challenge. The design of systems was based on inconsistent rules of thumb that resulted in widely varying requirements for similar facilities. In an effort to formalize and standardize the process for designing fire and gas systems, industry experts, including the pioneers at Kenexis, developed the ISA 84.00.07 Technical Report. This built on the performance-based quantitative approaches of the IEC 61511 standard, including safety integrity level (SIL) and added requirements specific to fire and gas detection arrays, notably coverage requirements.

Since the release of this technical report, most sophisticated process industry companies have incorporated the concept of achieving quantitative coverage targets into their fire and gas design processes. With the advent of fire and gas mapping for coverage targets using sophisticated computerized tools, such as Kenexis Effigy™, process safety has taken a step forward.


As part of the original team of experts that developed the techniques described in the ISA 84.00.07 Technical Report, Kenexis was charged with developing the software that would be required to allow calculation of the metrics that the technical report defined. Through several years of research and extensive validation, Kenexis has been able to develop an unparalleled software solution that performs coverage calculations with a degree of sophistication and accuracy unrivaled by any other software or method.

Fire and Gas Coverage Calculation

At the heart of the Effigy fire and gas mapping application is an algorithm for the calculation of the coverage, both geographical and scenario, that considers the specific application, equipment, and instrumentation used in the facility under study. Consider the following features of the calculation engine:

  • Analyzes fully in three dimensions, including, detector cone-of-vision manipulation, obstruction location, and obstruction shadow orientation
  • Calculates results for any user selected elevation of interest – multiple elevations if required
  • Accurately and specifically models any brand of detector, and separately assesses all documented sensitivity settings of those detectors
  • Includes a database of most common fire and gas detection equipment and associated performance metrics
  • Accurately models cone-of-vision projections as detectors are moved away from the elevation of interest and rotated away from parallel
  • Accurately model different materials of interest for each detector as required (e.g., methane, hexane, methanol)
  • Analyzes modeling of multiple obstruction geometries, including cubes (cuboid), sphere, cylinders, cylindrical vessels (horizontal and vertical), in all rotations and orientations
  • Presents tabular results of areas where 1) no detectors are sighted, 2) one detector is sighted, and 3) two or more detectors are sighted
  • Presents color-coded graphical coverage maps indicating extent of the various coverage areas
  • Limits graphic and tabulated results to the areas of interest as defined in grading maps, in addition to the results of the overall zone
  • Presents multiple and independent results for each of the multiple graded areas of each zone

In addition to the more common geographic coverage, Effigy also presents scenario coverage maps. These maps provide a geographic risk profile the combines all of the thousands of scenarios that are possible in a zone, and also provides a mitigated risk profile that only maps the scenarios that are not detected by the fire and gas array – along with a tabulated calculation of the fraction of the scenarios that are detected. The results of scenario analysis are plotted as color-coded isopleths of constant release frequency.

Comprehensive Software Environment

powered by kenexisThe Kenexis Effigy™ Fire and Gas Mapping application is part of the Kenexis Instrumented Safeguard Suite™ (KISS). This suite of tools allows users to create and verify design basis calculations and specifications for the full range of instrumented safeguards including SIS, FGS, alarm systems and more. This suite of tools is available through Kenexis’ unique cloud based model and is accessed by any licensed user on any computer, tablet, PDA, or even smartphone through a standard browser. The unique architecture ensures that your software is always available and up to date with the latest performance metrics and equipment databases, removing the IT burden of hardware and software maintenance while allowing you to leverage Kenexis resources for project assistance, outsourcing, and verification and certification of your analyses. The software environment includes:

  • Compatibility with most browsers in most operating systems
  • Extensive standard and custom equipment databases
  • Detailed technical documentation and help
  • Dedicated help desk and support
  • Reports and graphical results output and export