Features of ladders during evacuation from oil and LNG plants

Ladders are an escape option in case of emergencies in oil and LNG plants, and are commonly used due to easy implementation outdoors. Evacuations accompanying the use of ladders in oil and LNG plants have been studied as little as evacuations in normal building. The design of a plant must include at least two routes to move downstairs using ladders or stairs. Compared to stairs, ladders offer advantages of cost and space. However, research on ladders such as speed of movement on ladders, is not enough. This study first conducted experiments to measure the speed of descending ladders. The speed of movement on ladders was found to be slower than that on flat planes and stairs, with ladders serving as bottlenecks. Thereafter, a simulator was developed based on the extended Floor field model, which was capable of simultaneously handling flat planes and stairs and ladders dynamically to find advantage of ladders. Parameters of simulator such as the speed of movement on ladders were set based on the result of the experiment. The simulator was used for case study. The critical density to begin congestion for the simulated part of plant was determined by gradually increasing the human density. The results of the simulation indicated that faster escape was possible using only stairs even if the total travel distance became longer. However, simulation with scenario which is situation was changed dynamically indicated that it is better to evacuate by using ladders or stairs closer to the current position. The tendency also depends on the location of stairs and ladders. This extended model and developed simulator can help to analyze evacuation from oil and LNG plants.& COPY; 2023 Elsevier B.V. All rights reserved.