Abstract
	Working environment in engineering operations are often characterised by a complex of negative factors, which at every moment load  human body during the active work with various intensity. Determination of intensity of work load is important for creation of working comfort, which closely connects to worker’s contentment. 
	The analysis of current working load evaluation of employees shows that in practice the approach of partial working load evaluation predominates. This means that the impact of each influencing factor on the employee’s body is evaluated individually during his working activity, independently from other environmental factors present.  The current way of evaluation is unable to consider the mutual synergism, i.e. the confluence of all present negative factors of the working process. 
	This contribution submits a new and human method of evaluation of working load through ascertainment of immediate  complex  of man’s work-load. The original mathematical model of determination of total effect of present factors on worker during working activity was successfully applied in praxis. The developed model engaged the attention of the international jury on 3-rd year of international competition EKO 2000 in Košice, where it obtained silver medal and a special prize. Output effect of new evaluation are graphs of time development of complex worker´s load, which are important for optimalization of working conditions. New trends in approach to evaluation of work-charge are especially important by assuring of working comfort, working safety or protection of worker´s health in hot engineering operations, where is always present high degree of work-charge. 
	At the evaluation of physical and then complex human body load there are some secondary SI units used in the contribution. These units are usually used in scientific fields as the working hygiene and working medicine, especially at determination of energy expenditure during working activity.