Document ypLo1Bxpx88BdvME7J9rKqO93

62 BOSS A. MC FABLAND First of all, the time and motion study analyst is handicapped because the results of his efforts are ordinarily gauged solely on the basis of increases in pro duction. While he will not knowingly substitute a less safe motion for a moro safe one, he nonetheless must devote his efforts toward increasing production, since that is his assigned task. The limited scope of activities forced upon him implies that full advantage is not being taken of his special training. Second, economy procedures are frequently confused with the "speed-up." While it is the purpose of time and motion economy to increase the amount of production, it is not the intent to do so simply by increasing the speed of the motions presently employed. Basically, time and motion economy seeks to eliminate slow movements and those that accomplish little work, and to substitute motions that are naturally more rapid and those that accomplish more work. Thus, while the speed at which items of work are completed is increased, this increase is not to be achieved through greater costs to the employee. Unfortunately, the principles of time and motion economy have not been developed with safety in mind, and, as a conse quence, it cannot be said that the employment of this technique will necessarily result in a decrease in accidents.3 b. Analysis of Errors and Near Accidents. The job description itself may or may not indicate which types of activities are likely to lead to accidents. In some instances, unsafe acts are very obvious. Thus, following closely behind a -vp.hi cl p--while-traveling at high speeds is clearly dangerous. In other cases, the danger might not be so obvious. The mangle, which requires the operator to sup port herself on one leg while operating a foot pedal with the other, would seem to have some elements of danger, yet one cannot be absolutely certain. Finally, some types of activities may be quite dangerous and yet go unsuspected. In cer tain situations, the application of the accepted principle in time and motion econ omy of opposite and symmetrical motions of both arms may be poo? because it does not permit the simultaneous lateral movements to be well guarded by>he eyes. As a consequence, some attempts have been made to analyse case reports of accidents in order to determine mistakes made by the worker which led to the p.ypnl..t-T.hf>-rH.nge-okpossib.le_mi3takes_that an individual can make tis,great and the opportunityiiylBieSSSrkedly-from one occupation to another^Thiiimeansthat there is littie pdsMBiliiiyrbf5 generalizing the findings with respect`tollilnsafe acts from one occupatiomto another. Furthermore, if unsafe acts are described in very general terms, as .in the American Standard Code for Compiling Accident Causes, important details wilfbe lost. While it is of some 'TkelpTSTlKA ebtoitrUiEitltflHn*" dustry to know that a significant number of accidents are due to poor or faulty use of tools, it would be of immeasurably greater help to know that more acci dents result when fixed or controlled movements are used in swinging a pick 'E. E. Ghiselli and C. W. Brown, Personnel and Industrial Psychology. McGraw-Hill, New York. 1948. R. P. Blake, ed., Industrial Safety. Prentice-Hall, New York, 1946. HUMAN ENGINEERING AND INDUSTRIAL SAFETY 63 than when ballistic movements are used. The value of an analysis of errors and unsafe acts will be in direct proportion to the specificity with which the error Sfr act is described. As an aid in a preliminary analysis of unsafe acts in accident *eports, and for the purposes of occupational and industrial comparisons, some /System like the American Standard Code will be helpful. ||* The study of near accidents is a part of the critical incident technique, p|escribed by Flanagan. In this approach, incidents having a special significance fqr relevance to accidents are recorded with the aim of permitting inferences and ^predictions to be made about the person performing the act. Such data can assist _ Slinsthe advance elimination of the accident-repeating individual, just as analyses pip near accidents can assist in the elimination of the accident-inducing situation "h to)-' i or work method.9 II. Equipment Design in Relation to Human Body Size Whenever the design engineer is concerned with the development of machin ery to be operated by man, he must make decisions as to the dimensions and jrangements of the operator's control area and all of its components. In some 1 istances, he is given general directions such as "all machine controls must be ^Sg^vtforking space about machines or equipment."10 He is rarely supplied with the "'"Tailed quantitative descriptions of man that will enable him to meet these |p|(Cifications. The design engineer, then, has been obliged to work out required J|||ensions on the basis of general familiarity and experience with the operation, llgdiicated guesses," measurements of trials with only a;;few subjects, and refer- nbfeto previous design (which, in all likelihood, was established upon an equally Jknjhous basis). It is probable that in the great majority of cases where design pgficiencies in fitting the machine to the man have occurred, the errors have limited not from lack of concern for the operator but rather from the lack of Ppgfibflte descriptions of his body measurements and other>physioal and physiologTCpijpracteristios upon which equipment design must be base!!. Such a situation i|j||esrIy unacceptable from the point of view of industrial safety, since the ex'^^|and the success of the provisions that are made for the satisfaction of human ^^tements in any design or work situation will determine,`Si* a considerable ^^^tlTthW8SfetyTSd the"BVef-all efficifency Of the operatiffi"pefs6nnel.3 obvious, then, that designers must have access to descriptive data on S,3y size of the populations who are to use their machines. These data can ^ -rA?' Flanagan, The critical incident technique in the study of individuals, Modern ^^monal Problems,. Report oj the 17th Educational Conference. American Council on Edu^ijmyWashington, 1952. jlfSafety subjects, Bull. No.. 67, Bur. Labor Standards, U. S. Dept, of Labqr, 1944. i