Flammable and Toxic Gas Risk Reduction by 3D Gas Detection Mapping Study

Abstract Gas detection systems are crucial for alerting and mitigating the risks associated with flammable or toxic gas leaks. Detecting gas releases early is key to preventing potential explosions or toxic hazards either by isolating the source promptly or manual intervention. Properly placed detectors are essential for effective gas detection. To achieve this, determining the optimal quantity and location of gas detectors is critical. Traditional methods of detector placement have often relied on past experiences, engineering judgement, common practices, and standards. Whilst these approaches are not incorrect, they may lead to unnecessary costs and limited effectiveness in mitigating specific risks due to overlooking various factors such as different gas release scenarios, wind conditions, and obstructions. This limitation hinders users from fully optimizing their gas detection assets and accurately assessing the effectiveness of their current detection systems. To address these challenges, a risk-based methodology for gas mapping, based on industry best practices like ISA-TR84.00.07, has been established. This methodology aims to enhance the evaluation of gas risks within a process facility and reduce these risks to an acceptable level by considering the facility's unique characteristics. A detailed case study is presented in this paper to demonstrate how this risk-based approach can assist in evaluating gas risks and optimizing detector placement. By utilizing Influx CFD 3D Mapping Software, this methodology can help verify the preliminary locations and quantities of gas detectors proposed during the early stages of Front-End Engineering Design (FEED). The graphical results generated in 3D by the software can showcase residual risks, recommend detector placements, and provide numerical estimates of detection coverage within each fire zone, ensuring effective gas detection within each fire zone and throughout the facility.