Quantifying human performance for simulation of passenger ship evacuation in polar climate

Abstract

The evacuation of passenger ships is always a difficult process, and the availability of time to evacuate is the most critical factor for a safe evacuation of the passengers. Indeed, the cold environment of the polar regions introduces additional hazards and challenges in maritime emergencies where it is necessary to abandon a vessel or an offshore platform. By introducing Polar Code, the International Maritime Organization (IMO) requires that all passenger vessels operating in polar waters shall provide thermal protective immersion suits (TPIS) for all passengers in case of an evacuation and possibility of immersion of passengers in polar waters. While IMO requires that the maximum time allowed for passenger ship assembly and abandonment should be evaluated using advanced computerised simulation of evacuation, the impact of adverse environmental factors such as different vessel angles of orientation, the presence of smoke and heat are not required to be modelled. Hence, IMO recommends using an arbitrary safety factor of 25% in the modelling to account for the impact of all factors that are ignored in the simulation. In the event of a ship evacuation in polar waters, it is critical to determine how much the ship's assembly and abandonment are influenced by the deployment of TPIS and whether the employed arbitrary safety factor (25 %) can accommodate the impact of TPIS deployment on assembly time. Answering this question requires an understanding of how long it takes to put on a TPIS and how a TPIS can influence individuals' walking speeds at different angles of orientation of floor.

This thesis has two main goals. The first goal is to quantify the time required to don a TPIS and measuring the effect of wearing TPIS on individuals' walking speeds. The second goal is to use the acquired data on human performance in a maritime evacuation model to evaluate the impact of donning and walking with the TPIS on passenger vessel assembly and abandonment. The required time for donning a TPIS (Suit-2) was measured in this thesis by collecting donning data from 108 participants who were instructed to don the TPIS as fast and correct as they could. The data analysis revealed that the total donning time ranged between 75 and 431 seconds. Furthermore, the effect of TPIS on individual walking speeds was investigated by collecting data from 210 participants wearing two different types of survival suit (Suit-1 and Suit-2) and walking through a 36-meter-long corridor at different angles of heel (0°, 10°, 15°, and 20°). The findings indicated that the effect of a survival suit on walking speeds is dependent on the type of survival suit and the angle of the heel. In extreme cases (i.e., 20°of heel, Suit-2, 65-years-old female), wearing a survival suit can reduce individual's walking speed by 38%.

Following the second goal, a maritime evacuation simulation model (maritimeEXODUS) was modified to incorporate the impact of donning and walking with the TPIS during the assembly and abandonment of a passenger vessel. The evacuation of a hypothetical passenger ship was simulated in day and night case scenarios. The simulation results revealed that by deploying the TPIS (Suit-2) during the evacuation, at 0° of heel, the assembly time of the ship was increased by 65% and 38% respectively in day and night case scenarios. The simulation revealed that the arbitrary 25% safety factor is insufficient to accommodate the impact of donning the TPIS within assembly time of a passenger vessel operating in polar waters. Furthermore, results indicated that walking with TPIS increases the travel time during the abandonment leaving less time available for embarkation and launching of the lifeboats.

The findings of this thesis demonstrated that the requirements of the current guideline for evacuation analysis of passenger ships (MSC.1/Circ.1533) may not be adequate to ensure the safety of evacuation for passenger ships operating in polar waters. As a result, this thesis recommends that the IMO guideline for evacuation analysis may require including the time it takes to don the TPIS in the calculation of assembly time for certification analysis of passenger ships operating in polar waters. This thesis suggests several approaches in which this can be achieved. Furthermore, several areas for future research in quantifying human performance during evacuation in polar waters are suggested.