FIRE AND GAS MAPPING STUDY
Inherent within the very nature of the energy industry, the hazards associated in refining oil and gas present a number of risks. One of the prominent and well documented risks is the potential for fire or explosions as a result of a break in containment.
Fire and gas detector mapping studies provide an objective analysis of detector layouts to support the design process and optimize the number of detectors needed to meet coverage targets.
Significance of undertaking F& G Mapping?
Major oil companies rolled out ‘ISA TR84.00.07 Guidance on the Effectiveness of Fire and Gas Detection’ to address the logic question of “How many detectors is required in Hazardous facility & Where to place it all?”
- F&G Mapping allows the designer to position flame and gas detection devices within the facility and assess the coverage afforded by the system. This is automatically correlated against pre-specified targets that the system must achieve.
- F&G Mapping does not only provide benefits during the design phase. The benefits of F&G Mapping can also be observed in a number of ways throughout the operational phase.
- F&G Mapping provides designers with the methodology and tools to review detection coverage against pre-determined targets, and ensure a suitable and optimised system is commissioned.
- One of the primary deliverables of an adequate F&G Mapping study is detailed detector contributions and allows for that crucial maintenance optimisation function. Therefore, F&G Mapping also provides the significant benefit of maintenance optimisation, which can save money and potentially lives.
When it should be done?
F&G mapping study should be conducted in the design stage to assure that the detector coverage targets are met and the current F&G arrangement is effective to fulfill its intended designed function.
Moreover, during the normal operation, the F&G mapping study should be performed when major changes or modifications are applied to the facilities. As a result, the study shall confirm whether the current arrangement remained suitable for continuous operating. If it is not the case, a set of recommendations shall be provided and considered to improve the FGS performance.
Approach / Methodology
A typical F&G mapping study is conducted as per the following steps:
- Step 1: Identification of leak scenario;
- Step 2: HC dispersion modelling using in-house spreadsheet or software;
- Step 3: Evaluation of HC gas detector arrangement;
- Step 4: Optimization of HC gas detector quantity and arrangement (the coverage targets are achieved with the minimum number of detectors);
- Step 5: Modify the detector arrangement as per step 4.
A 3D simulation software (e.g Detect 3D) is usually used to perform this F&G mapping study take into account the obstruction of equipment, structure. A F&G mapping study is mainly based on the comparison of detector coverage versus the coverage target.
Detector Geographic Coverage – is generally defined as the fraction of the geometric area of a defined monitored process area that would be detected by the detector considering the defined voting arrangement (if a release were to occur) in a given geographic location.
Detector (Scenario) Coverage – For each defined release scenario, an area of gas dispersion is defined. Detector Scenario Coverage is defined as the fraction of the area that can be detected by the detector considering the defined voting arrangement in the area of gas dispersion.
F& G System Life-cycle
iFluids Engineering helps to provide our CLIENT, the competent experts & resources for the step by step approach for F&G Mapping study.…