PUBLICATIONS AND VIDEOS

SUMMARY

Flame detection is a critical part of process safety. However, with an individual detector costing thousands of pound plus installation and maintenance costs, it is crucial that each detector added to a system provide 'good' coverage. This is not always the case. There is significant scope to improve the fire mapping approaches used in the energy industry to determine the number of flame detectors required for a process facility. Most studies do not demonstrate ALARP, do not adequately explain assumptions, completely omit some assumptions, or do not consider the fundamental physics of fires or detector operation. However, such issues are not black and white and there is significant uncertainty in any fire detection mapping exercise. This is not acknowledged in typical studies, which are not conservative enough to encompass all reasonable uncertainties. Essentially, studies may follow a defined methodology, but they cannot be shown to drive the risk of non-detection to be ALARP. To reduce the uncertainty in fire mapping studies and be confident that flame detector layouts demonstrate ALARP, DNV has developed an enhanced approach built upon existing 3D mapping techniques. This approach considers all deficiencies observed during three years of critical evaluation of multiple fire mapping studies for onshore and offshore facilities, reference documents and standards. The DNV enhanced approach considers and addresses the inherent uncertainty in the common assumptions made within typical fire mapping studies and the impact these have on the final detector layout/count. To address this uncertainty, DNV has developed three criteria that ensures that flame detectors add meaningful value to a layout, with conditions that must be satisfied for a detector to be included within a flame detector system. The approach:

• Demonstrates that only detectors that are providing coverage greater than the inherent uncertainty within the modelling are added to a facility;
• Typically leads to a reduction in flame detector count when compared to more traditional approaches, offering significant cost savings while simultaneously demonstrating that the produced system is ALARP; and critically
• Gives the operator and designer better understanding of their fire detection system.

To demonstrate that the risk of non-detection is ALARP, the enhanced approach does not rely on arbitrary coverage targets often cited in company documents or international standards. Although, it is noted the coverage achieved using the enhanced approach broadly aligns with those in existing standards and, to DNV’s knowledge, the enhanced approach is the only approach that can robustly demonstrate a fire detector layout achieves ALARP. The enhanced approach is applicable to all liquid and gas fire types (including hydrogen). The approach can be used for new build systems and revalidation of existing flame detector layouts both onshore and offshore, many of which may have a historical basis or have been based on a rule of thumb approach. To ensure accessibility to a wide range of users, the enhanced approach is currently being developed into a DNV recommended practice (RP) due to be published in January 2026. The RP includes step-by-step instructions on how to use the enhanced methodology and includes a fully worked example.