Risk Mitigation Measures for the Winterisation of LNG Carriers and the Co-dependency with the Human Performance in Low Temperature Environments
Authors: Bridges Robert , Upcraft Desmond , Ridgewell Christopher 
Published: December 2012

Abstract
In recent years there has been substantial interest and growing demand forLNG Carriers to operate in cold regions. As a result there is a pressing needfor rules and standards to give clear requirements for shipbuilders to developsuitable designs for cold climate operations. In parallel to the systems andfeatures fitted for the safety of the LNG Carriers, is the preparedness andsupport of the crew for the challenges of operating in these harsh, cold-climate regions. Sources of hazard can include accidental immersion incold water, freezing and non-freezing cold injuries, unusual day or nightlengths, and weather conditions affecting visibility and the sea state. Thispaper provides an insight into the background and development of winterisationrules and an explanation of some of the key features fitted to existingwinterised LNG Carriers, whilst outlining many of the physical and cognitiverisks to seafarers in conditions of extreme cold, including their personalsafety and their ability to control the vessel and its systems. It introducessome of the systems redundancy features to mitigate the risks due to remotenessand methods for managing the resulting risks. These, include proceduraladaptations to manage exposure times and the operability of the ship, anddesign adaptations to reduce or remove hazards to the people on board and theways in which they can work.

Introduction
More voyages are taking place in cold climates, for longer periods of theyear, on more trade routes and with a wider range of ship types, than haspreviously been the case. More ships and seafarers are therefore being exposedto the associated hazards of these cold environments.
Most ships are designed to operate safely in temperatures down to an averageair temperature of −10°C, providing that the crew carry out basicprecautions to prevent freezing of critical items. When operating intemperatures below this, the ship will require a more focussed review of theequipment and systems fitted and materials selected, as well as the crew'ssafety, and their ability to operate the ship and carry out their taskseffectively and efficiently. Preparation for the challenges and what supportthey are given is a key factor for operating in this harsh environment.
The need to assure safety and effectiveness for the growing trade in coldregions has inspired a rise in technology and innovation for ships, such as theintroduction of winterisation rules [1]. However this needs to becoupled with an increased understanding and practical application of knowledgerelating to operations and crewing [2]. This paper is intended tosupport advancement in this area and draws on and highlights the learning fromthese papers with relevant extracts and comments. The focus of this paper is onwinterisation and the associated risks due to low temperatures and iceaccretion, rather than navigation in sea ice which poses different risks, anddescribes some of the hazards which may be encountered during these conditions, explains the risks that these present to the seafarers and their ship, andintroduces potential solutions for managing these risks.