Changes in work accuracy in a noisy environment: a case of work accuracy in the marine engine room environment

It is a requirement that the noise level in the engine rooms of modern ships meet the International Maritime Organization (IMO) noise level code criteria. This standard comes as it had been revealed that, in noisy environments, ship engineers are uncomfortable and lack concentration, and as a result might experience a reduction in work accuracy. In a noisy environment, it has been found that engineers not only feel fatigued but also work with less precision. These facts have been empirically demonstrated. In the laboratory, a noisy environment was reconstructed by playing the machine operating sound, recorded in a ship engine room, and laying down metal floor plates similar to those found in a ship engine room. Speakers were installed under the metal floor plates, and the recorded machine operating sounds were played back from the speakers during the experiments. In the experiments, the participants were asked to perform work tasks in the noisy environment. The participants’ biological responses were measured during the experiment. The output from speakers during the experiment was measured by a precision sound level meter at a height corresponding to the ear level of the participant. In this study, we measured biological responses, such as heartbeat and brain waves (alpha band wave, beta band wave, etc.), as an evaluation index. From the biological responses, we estimated the participants’ mental workload in the noisy environment.