Fire and Gas Systems (FGS) are important tools for safeguarding process plants and production facilities that handle flammable and toxic materials. All such facilities have inherent risk that can not be fully mitigated by preventative instrumented functions, in some cases these facilities require the installation of fire and gas systems to mitigate these hazards. Kenexis assists our clients in performance-based design and independent validation of fire and gas systems, commonly referred to as fire and gas mapping.
Kenexis Fire and Gas Mapping services include assistance in all phases of the fire and gas system lifecycle. These services are based around our unparalleled expertise in not only fire and gas system design, but also process knowledge and risk analysis capabilities. This expertise is then deployed using best-in-class tools such as the Effigy™ Fire and Gas Mapping engineering software. This combination provides the most rigorous analysis against performance targets, which results in the optimal coverage at the best cost.
A well designed fire and gas system is intended to detect and in some cases automatically mitigate fire, combustible gas, and toxic gas hazards. Although national standards such as NFPA 72 address numerous aspects of good engineer practice for fire and gas systems, the standard does not prescribe how to site fire and gas detectors in industrial process facilities, nor does it address the selection of appropriate detection technologies. Consequently, the ISA TR84.00.07 Guidance On The Evaluation Of Fire And Gas System Effectiveness was developed to provide guidance.
Proper placement of detectors is critical in the design of a fire and gas system to ensure that coverage is adequate to detect hazards at their incipient stage, before escalation makes mitigation actions ineffective on impractical. Kenexis engineers are experienced in the siting of fire and gas detectors in a variety of applications, including enclosed processes, plants and refineries, and offshore oil & gas platforms. In addition, our advanced fire and gas detector mapping software, Effigy™, allows Kenexis to verify that the fire and gas detector layout meets your performance targets to protect people, assets, and the environment.
Selection of the improper detection technology can often lead to problems in the operation and maintenance of a fire and gas system. In many cases detectors are selected which are not suitable for the application, resulting in spurious alarms, excessive maintenance requirements, or ineffective detection of hazards. Kenexis ensures that the selected technology will meet performance requirements and is appropriate for the application resulting in a safer design with reduced maintenance costs.
Optimizing Gas Detector Placement
Using Kenexis work practices, we are able to mathematically validate the proper detector locations to maximize coverage with the minimal number of detectors. In a recent study, the prescriptive model of 27 detectors was reduced to 14 detectors using performance-based modeling techniques, while only reducing the actual coverage from 91% to 86%. The eliminated the 13 detectors that were only providing 5% of the total coverage.
This result is a substantial reduction in capital expense, installation cost, reduced conduit and space burden, and the reduction of the maintenance cost of the life of the platform.
While these results were very good, not every scenario produces the same results. In fact, the quantity of detectors can actually increase to provide the level of protection required. Regardless, our clients appreciate knowing why every detector is at its location.
Activities in Fire and Gas Mapping Services:
Development of Fire and Gas System Philosophy
Performance Target Selection
Detector Placement and Technology Assessment
Detector Mapping (Coverage) Assessment
Fire and Gas Functional Safety Assessment
Fire and Gas Requirements Specifications Development
Maintenance and Testing (Validation) Support
Performance Target Selection
Kenexis uses a performance-based target and assessment strategy in fire and gas system mapping to ensure that the system is adequately designed to meet our clients’ needs. Performance-based design of fire and gas systems has proven to result in a cost-effective and reliable design at lower overall installed and maintenance costs from systems designed using other methods.
Proper design of fire and gas systems begins with the selection of a performance target for functions employed by the fire and gas system. Performance of a fire and gas system is primarily characterized by the system’s ability to detect a hazard (detector coverage) and the system’s ability to mitigate the hazard (mitigation effectiveness).
Determination of the necessary coverage is done by zones typically and is based on your company’s risk matrix. It is common to have four zones typically classified like Zone A minimal coverage will be 90%, Zone B… 80% and Zone C… 60% coverage, and no coverage (ungraded). However, the number of zones and coverage percentage for each zone, is completely dependent on your company.
Detector Mapping Coverage Assessment
A fire and gas detector mapping assessment seeks to determine the degree of fire and gas detector coverage with respect to a given area (zone) or specific hazard. For new fire and gas system designs, a mapping assessment is used to ensure that the proposed detector layout is capable of achieving the performance targets with respect to detection of fire and gas hazards. For existing fire and gas systems, a mapping assessment will ensure the adequacy of the system or validate assumptions made about its performance in previous risk assessments (e.g. QRA’s, Safety Cases, PHA/HAZOP).
For years, fire and gas detector mapping was either not feasible (due to technology limitations) or considered unwarranted. Recent incidents, in which fire and gas systems failed to sense or operate as intended, have proven that fire and gas mapping assessments are not only warranted but have resulted in a shift to performance-based design with fire and gas detector mapping as the best-practice.
Our advanced fire and gas detector mapping software, Effigy™, allows Kenexis to provide cost-effective studies into fire and gas detector coverage.
FGS Functional Safety Assessment
Adequacy of system architecture and reliability of hardware in fire and gas systems is not always scrutinize in the same detail and other safety critical systems such as Safety Instrumented Systems (SIS). Since the introduction of performance-based standards for SIS design, statistics indicate that there has been a significant decrease in the number of dangerous failures of such systems. At Kenexis we believe that fire and gas systems should be subject to the same level of functional safety assessment as the SIS.
Fire and Gas Mapping Tools
Kenexis has developed advanced software tools which enable or engineers to execute reliability calculations accurately and efficiently, providing our clients with superior results at a fraction of the price. Our proprietary equipment performance statistics database contains reliability statistics from numerous well known and industry specific sources.
Kenexis also developed Effigy, an industry leading technological platform for performing fire and gas analysis to determine coverage accurately.
These tools are utilized in a variety of risk and reliability analysis, ensuring that our calculations are accurate, providing our clients with confidence in the design and performance of their fire and gas systems.
Click here for more information about our Fire & Gas Mapping Software, Effigy.
Fire and Gas Requirement Specification
All of the requirements developed during the risk analysis and conceptual design phases, and other safety critical requirements, need to be collected and presented in a consolidated document, commonly called system requirements specification (SRS), that can be used for subsequent detailed design engineering. Kenexis assists in the preparation of fire and gas SRS packages that ensure a sound design basis and provide a guideline for subsequent acceptance testing activities.
Our strong engineering experience in the authoring of SRS in multiple industries including fire and gas engineering, ensure that the systems integrator is provided with an easy to follow detailed design document for implementation of the fire and gas system while providing the end user with complete documentation of the design of basis.
Maintenance and Testing (Validation) Support
Ensuring the ongoing integrity of a fire and gas system throughout its lifecycle requires vigilant maintenance and testing practices that are in alignment with the risk analysis assumptions and requirements specifications. Kenexis helps its customers to meet their mechanical integrity requirements by developing test procedures for fire and gas systems, and assisting in the implementation of those tests.
Kenexis also helps to ensure good lifecycle performance by monitoring and tracking actual equipment performance against assumptions, and auditing system activity and changes to reconcile system performance and equipment changes against initial assumptions and specifications.