One of the last remaining hurdles to be overcome in the design of safe, reliable systems is the human being. For some time now safety and reliability engineers have recognised that they not only need to be able to assess the likelihood and impact of human unreliability but would benefit from a working knowledge of how to apply human factors engineering technology to optimise overall systems design. Most safety and reliability engineers also appreciate that beyond the immediate superficial level human engineering principles are not only difficult to enunciate, understand or evaluate, but are occasionally costly to apply. Often sub-systems which are manifestly well-engineered from a human factors standpoint fail to achieve the sort of total reliability expected when integrated with other sub-systems, to the consternation of the process and system designer. When this happens the operator finds it hard to believe that such a mismatch could have occurred because of a high level failure of human engineering, and will often resort to remedies from the management "tool-kit", rather than the human factors design database. This paper attempts to minimise the likelihood of such outcomes by identifying the relevant factors, which from the author's experience, are considered likely to facilitate the achievement of high man-machine system reliability. It demystifies human factors technology by assigning relative weights to the factors, identifying impacts and suggests a set of human error data which should assist assessors and designers in working towards the achievement of high systems reliability. (A)
Abstract