THE PRINCIPLES OF WORK STUDY 13 Dept. Unit Per, •.:.o Elapsed Time.•.*,.•. roduction - .File & Study Sheet No. ..................... Operation ........................ IRd' g Rat- Non- td' g Rat- Non- ing Prod ing Prod , B. • •o,,• F • 7 • •' F /• •/y• Figure 9. Typical Work Measurement observation sheet A 60 r is really the lowest rate of working acceptable to management. Since this rating is subjective, it is desirable to take as many readings and ratings by as many observers as possible. A simple illustration from the laboratory is titration. (1) The job is broken up into elements, and for ease of timing and rating these are normally between 5 and 20 seconds duration. These end with what are known as breakpoints--actions which are readily discernible.

14 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS (2) These elements are written down on the observation form on which Work Measurement is carried out. (3) The series of operations are timed and rated as previously indicated. When in "mental rhythm" with the operator's movements: T X R should equal a constant It should be noted that at this stage one is rating on a curve (Fig. 8), and this causes difficulties. (4) The times and ratings are recorded for each element and worked out as previously shown. A typical element, its summary and working up is detailed below: Element B Allow contents of 10 ml pipette (N NaOH) to run into conical flask. 21 1 80' 22 1111 80' ' ' ' 75 ' 23 1 80' 24 1 70' 25 1 75' Selected value: 22.0 sec at 80 rating. (5) The normal times for each operation are worked out similarly and listed as shown in Table $. Table 3. Element Summary sheet Element N.M's. C.R. S.W.M's. A. Suck up 10 ml NaOH into pipette 0.354 12% 0.397 B. Allow contents of pipette to drain into conical flask ...... 0.489 !2% 0.548 C. Drain pipette for 15 sec .... 0.333 12% 0.373 D. Pipette aside to rack .... 0.078 12% 0'087 E. Add 3 drops of phenolphthalein indicator to NaOH .... 0.117 12% 0.131 F. Read burette and record .... 0.253 12% 0.283 G. Titrate to end point ...... 0.775 12% 0.868 H. Read burette and record .... 0.!88 12% 0.210 2.897 Allowance for calculation of result 0-750 3.647 (6) The number of titrations possible in a working day of, say, 7 hours is then determined.