TS-120
A Study on Human Factors in Engine Room
Hiromi SHIIHARA*, Naotoshi SUMI*
Abstract
A study for characterizing the human factors that affect machinery failure in engine room has been carried out using damage data reported periodically and occasionally by surveyors of Nippon Kaiji Kyokai. The results of this study shows that major failures, after which a ship is towed by tug or operates at reduced navigation speed, are mostly attributable to human factors for ships less than about ten years of age. On the other hand, constructive defects such as degradation in system performance due to wear and tear, corrosion, among other factors may have a greater impact than human factors on the occurrence of major failures in the case of ships over about ten years of age. It may be recognized that human errors occur as the result that these constructive defects disturb to break the chain of mistakes caused by human factors.
Key Words: Human Error, Human Factors, Chain of mistakes caused by human factors, Human Error Mode, Omission Error, Commission Error. Imperfection Error,
1. Introduction
Recently many discussions have been held on human factors and man-machine system at various meetings at all levels throughout the world aimed at decreasing the number of ship casualties and incidents of environmental pollution caused by ships. On the other hand, several high-profile environmental and human disasters caused by oil leakage from tankers or the sinking of passenger vessels in recent years have resulted in introduction of new regulations as well as amendments to existing regulations following detailed investigation and discussions. Since a number of these major disasters were found to be the consequence of human errors considerable research and discussion on measures for preventing of human error has already been carried out around the world.
It has been generally recognized that 60〜80% of accidents or problems are directly or indirectly attributable to human errors. There are still, however, only a limited number of reports which have examined machinery and electrical systems related failures or accidents onboard ships from the viewpoint of human error. For these reasons almost all related discussion continue to be carried out more on the basis of theoretical perceptions rather than on actual circumstances onboard ship at sea.
In order to address this needs, a study for characterizing the human factors that affect machinery failure in engine room has been carried out using damage data reported periodically and occasionally by surveyors of Nippon Kaiji Kyokai (hereinafter, referred as classNK). The results were compared with data compiled on ninety-six cases of failures and associated problems which occurred to machinery on board the ships provided by shipowners in Japan in response to a questionnaire.
2. Definition and occurrence process of human error
Before starting any study or analysis of human error, it might be helpful to review the process of how human error occurs based on a theory by Mr. A. Shoda, described briefly below [1], and the definition of human error shown in Fig.1.
(1) Defect in a system, plant, industrial process, industrial method, or work procedure will become a source of the occurrence of human error from the perspective of machinery and hardware. This source may normally not be recognized and is often only determined during the investigation process after trouble has occurred.
(2) Trouble occurs after a worker has a chain of mistakes due to human factors under conditions in which several sources of human error are present.
*Nippon Kaiji Kyokai
4-7 Kioicho. Chiyodaku. Tokyo 102-8567 JAPAN
FAX: +81-3-5226-2030, E-mail: pld@classnk.or.jp
