Ergonomic basics of safety of life activity

CHAPTER 1.

ERGONOMIC AND PSYCHOLOGICAL BASICS OF SAFETY OF LIFE ACTIVITY

Ergonomic basics of safety of life activity

Safety of life activity (SLA) is a complex discipline, which grounds on knowledge of related sciences. One of such sciences is ergonomics.

Ergonomics studies functional possibilities of a person during activity and pursues the purpose of creation of such conditions, which make activity effective and ensure comfort for the person. In other words the question is about determination of compatibility of a person and medium characteristics. Ergonomics tries to apply technique to the person. But it's not always a solvable problem. SLA considers also problems of the person adaptation to the technique.

The experts in ergonomics specify five types of compatibility maintenance of which guarantees successful operation of systems «person-medium» and «person-manufacturing»: informational, biophysical, power, space- anthropometrical and technical-aesthetic.

In complicated systems an operator almost always doesn't manage physical processes directly. Frequently he is remote from the place of their fulfillment at a distance. The objects of management can be invisible, imperceptible. Operator sees indication of devices, screens, schemes, hears signals testifying process developing. All those devices are called as methods of information display (MID). If necessary operator uses handles, buttons, switches and other parts of management, what all together forms sensory-motor space. MID and sensory-motor devices make the information model of the machine (complex) though which operator manages the most complicated systems. The aim of ergonomics is to provide creation of such an information model, which would display all the necessary characteristics of machine at any moment and at the same time allow an operator to receive and process the information correctly, without overloading his attention and memory. This problem is very complicated. The safety, accuracy, quality and productivity of an operator depend on its solution. In other words, the information model should correspond psychophysiological capabilities of the person. This requires information compatibility.

Biophysical compatibility means creation of such environment, which would ensure sufficient work capacity and normal physiological condition of an operator. This problem connects with requirements of labor protection. The acceptable limits of safety factor of environment are set by the legislation, but they are not always coordinated to functional problems and possibilities of an operator. Therefore developing machines makes necessary special research of parameters of noise, vibration, illumination, air medium, etc.

The physical strength and power parameters of the person have the certain limits. Actuating sensory-motor systems (buttons, switches, etc) may take great or slight effort. Both cases are not good enough. In the first case the person will get tired, that can entail undesirable consequences in managing system. In the second case decreasing of system operation accuracy is possible, as the operator doesn't feel a resistance of handles. The power compatibility provides the coordination of machine operating control with optimum capabilities of an operator concerning the applied efforts, power, speed and accuracy of movement.

Space-anthropometrical compatibility takes into account sizes of the person's body, operator's external objective, position of an operator during work. Working out this problem includes determining of workplace space, zones of operator's reaching, distance from an operator to device console etc. Some difficulties of maintenance this compatibility lies in the variety of anthropometrical parameters. A seat which satisfies the person of medium size can turn out to be extremely uncomfortable for the short person or very tall. What to do about it? The answer is given by ergonomics.

The technical-aesthetic compatibility is to bring to person a satisfaction from the dialogue with the machine and working process. We all know very well a positive feeling while using elegantly made device or arrangement. For solution of numerous and extremely important technical-aesthetic problems ergonomics uses art-designers.