New Developments in Detector and Bund Wall Standards to Mitigate the Risk of Hazardous Liquid Leaks

Abstract

Ensuring early leak detection and implementing effective secondary containment systems are critical for preventing the dispersion of hazardous liquids and minimizing the casualties of a chemical accident. This study reviews the standards for leak detectors and their placement in various regions, as well as the key parameters involved in bund design such as bund capacity, bund wall height, and separation distance from the bund wall. In this study, Computational Fluid Dynamics (CFD) simulations are conducted considering storage tanks with heights (H) of 1.75 m, 3.5 m, and 7.0 m. The detection times using a level transmitter (LT) and a leak sensor are compared at eight monitoring points. Exclusively employing the leak sensor led to a significant detection time delay of up to 16 times, ranging from 0.5 s to 8.1 s depending on the placement of the leak sensors. However, the average rate of liquid level change was 3.0 mm/s, which demonstrates that the LT consistently detects leaks faster than the leak sensor at all monitoring points. Hence, the integration of an LT alongside a leak detector offers a valuable approach to expedite leak detection, regardless of the direction or location of the leak. Furthermore, the optimized separation distance between the storage tank and the bund wall is suggested. The analytical solution and numerical solution for a separation distance matches up to 95% for H=1.75 m. The separation distance increases as both the tank height and the height of the leak source increase. The relationship between the separation distance and the tank height exhibits a square root dependence on the liquid level from the leak point. The proposed detection method and optimized separation distance hold the potential to facilitate a revision of liquid storage and handling standards grounded in robust scientific and quantitative evidence.