Time and Motion Study in the Chemical Process Industries HOWARD ROSSMOORE, Consulting Industrial Engineer, New York, Ν. Υ., AND

ROBERT S. ARIES, Polytechnic Institute of Brooklyn, Brooklyn, Ν . Υ.

Λ per manhour productivity increase o f 3,000% i n one case and a 34% saving of t ime in another instance are reported as resulting from simple applications of t i m e and mot ion study methods

K E C E N T developments in the chemical process industries indicate increasing interest in time and motion economy methods which have hitherto been adopted by various industries with marked success.

As is well known, the earliest pioneer in motion and time study, or work simplifica­tion, was Frederick W. Taylor, who formu­lated its basic theories in his "Principles of Scientific Management/' first published in 1911. Mr. Taylor is chiefly remembered for the remarkable results he achieved in the application of his principles to the met­als industry where motion and tine stud­ies have been accepted practice for many years.

In view of the success in other fields, i t may logically be asked why the chemical process industries have not, to a large ex­tent, utilized time and motion economy methods which could doubtless give results comparable to those attained in many in­dustries throughout the country.

One reason, possibly valid, is that me­chanical industries, contrasted with those in the chemical process field, may be more adaptable to time and motion study analy­ses. Another fact which may explain the infrequent use of motion and time studies is that less than 20% of the cost of produc­ing chemicals goes toward wages and sal­aries, as compared to the more than 50% of labor costs apportioned to industry as a whole.

There are, however, several reasons why the chemical process industries could bene­fit greatly if they would become more time and motion study conscious. Ajnong these reasons are· the following:

1. As an independent expense item, labor costs have an important and some­times deciding effect on plant location and product economics.

2. Many of the operations in chemical process plants are by their very nature mechanical, although they are related to, or are a part of, inherent chemical proc­esses, a fact which would indicate that the percentage of labor costs may be much more than the 20% previously mentioned.

3. On the basis of successful perform­ance in other fields, there seems to be little doubt that "unit operations" in chemical process industries could be sim­

plified so that their supervision and execu­tion would require less time and effort.

4. If engineers and management had a greater awareness of motion economies and how they ultimately effect increased ef­ficiencies, the entire concept of chemical plant design and layout would be stimu­lated in the direction of higher standards and greater achievement.

5. As a result of the foregoing benefits accruing from the adoption of widespread time and motion economics, various types of equipment would be evolved reflecting improved design and greater productive­ness.

Motion and time study has a twofold ob­jective: the first is to improve the job being studied; the second, to measure the amount of work there is in a job. This is accomplished by first making a detailed record of the job. The record is then ana­lyzed. The application of the principles of work simplification follows. The amount of work in the job is measured by means of a stop watch and effort rating by the time study engineer.

Space limitations preclude further dis­cussion of the principles of motion and time studies. However, the authors

Hotvard Rossmoore

would refer the interested reader to the suggested list of titles at the end of this ar­ticle.

The'authors' main thesis in relation to time and motion studies is exemplified in the accompanying three case histories of methods improvements in the chemical process industries.

The histories are purposely drawn from three phases of these operations—labora­tory, production, and shipping—as indica­tive of the application of time and motion study principles.

Time Saving in the Laboratory

Case 1 took place in the control labora­tory of a plastics plant (see Figs. 1 and 2). The operation charted is testing a sample of the product which must undergo three processes—namely, titration, pH test, and specific gravity measurement. With the introduction of the improved method a time decrease of 34% resulted without the addition of new equipment or even the re­location of old equipment. Moreover, a further saving would be possible if the equipment location were rearranged in accordance with work simplification prin­ciples.

The implications inherent in the results achieved in the case history just described are worthy of consideration by any person or company interested in economical op-

Robert S, Aries

3142 C H E M I C A L A N D E N G I N E E R I N G N E W S

OPÉRATION: Control laboratory teetine of «ample of product I ENGINEER: E. Holdgraf

OLD METHOD

Pipet 5-cc. sample to beaker Walk to buret

Titrate sample

Take sample for pH test Walk to ρ Η meter Take pH Return to sample Put sample in water bath to cool Wait for sample to cool to tem­

perature Take temperature of sample Remove sample Walk to hydrometer Put sample in graduate Insert hydrometer Read specific gravity Test completed. Give results to operator orally Totals

T I M E I N SECONDS

15 6

20 e 4 3 5 3 2

34 5 2 1 3 2 β

117

15 0 2 β

20 3 δ 3 δ 2 1 δ 2 β

7β

N e w METHOD I

Pipet 5-cc. sample to beaker 1 (Add sample for pH N.o beaker

while pipet drains) Put remainder of sample in bath Walk to buret, dropping off pH

sample on way Titrate sample Walk to pH meter Take pH Return to sample Take temperature of sample Remove sample Walk to hydrometer Put sample in graduate Insert hydrometer Read specific gravity Test completed. Give résulte to operator orally

Fig. I. Process Chart

Window Thro·* Wkid»

Ο pH Meter

Bath

W o * Bench

ο Graduate

10' 1 · · — Return for pH Staple Walk to pH Meter 1 10'

j» J * _ Return for S.G. Simple

Simple in W«ter B«th 1 6' 2* I · To Hydrometer

Titrate Simple — . J

D.sunce Walked Old Method 7 Î Feet New Method 46 Feet —

M · ^ - Piece pH Sample ^-Simple in Beth I J , ,

20' + 3' - 23 '

^-Talce •iclc Up Semple from B*A—-*>

Reed S.G.

CONTROL LABORATORY

Fig. 2. Diagram of step-saving procedure effected in Case 1

erations and increased efficiency. Time and motion studies, when applied by trained industrial engineers to any phase of the chemical process industries, inevit­ably result in increased worker efficiency and also greater utilization of equipment— factors adding to the growth and well-being of individual companies and the industry as a whole.

In Fig. 1, the operation chart describes, step by step, the original method, together with the improved method. A complete picture of the operation may be had by ex-amining the chart in Fig. 1 in conjunction with Fig. 2. It may be noted that the im­proved method—and it is a big improve­ment—is obtained with the utmost sim­plicity. That is, the saving is accom­plished by eliminating some walking and doing away with the time spent in waiting for the sample to cool.

The original method handled each step of the complete sample test as a separate

operation. By approaching each sepa­rate test as just part of one complete opera­tion, substantial savings are effected. Thus, instead of walking to the buret, then back to the table and over to the pH meter, the sample for the pH test is deposited near the pH meter on the way to the buret. The pH test is made on the way back to the point on the work bench where the sample is received.

With the original method, the sample to be tested for specific gravity would be placed in the cooling bath to cool after the titration and the pH test were completed, involving waiting time on the part of the laboratory operator. However, putting the sample in the water to cool when it is received eliminates this wait in the new method.

A further improvement is possible by locating both the buret and pH meter within the working area of the operator at the receiving window. This eliminates

the walking plus the pickups and places of the samples.

Method Improvement in Production

Case 2 is an operation that involves fill­ing a mixer with pigments from bags and with oil or other liquids from tanks (see Fig. 3). At present the oil is poured into portable tanks on wheels, weighed, and then wheeled over to the mixer. The pig­ments need not be weighed except in cases when only part of a bag is utilized.

The setup, comprising four tanks, is shown in Fig. 3. Actually there are 30 additional tanks to the left of the mixer not shown in the diagram. The tanks shown are those most frequently used. The operation involves these steps:

1. Take the pigment bags from the stock pile and load the mixer. This is re­peated about four times, the exact number depending on the batch size.

2. Move the portable tank to the position shown in Fig. 3.

3. Move the scale to the portable tank. 4. Fill «the required weight of oil in the

portable tank. 5. Wheel the portable tank to the

mixer. 6. Using a small stationary pump,

transfer the oil from the tank to the mixer. 7. Return the scale. The proposed method of loading the oil

is to run a one-inch pipe along the row of tanks. The stopcock or discharge opening is connected with a gate valve to this line, terminating at the mixer. Air pressure that is controlled at the mixer is at the op­posite end of the line.

In the new method, one man is at the valve at the tank and another controls the air pressure—which acts as an air-liquid injector—and watches the scale. The scale, as well as the portable tank, re-

Fig. 3. Diagram of loading method suggested in Case 2

Mi»

1 ι 1 Pump · Tank on I

' I Scale I

Oi l Tank I tx; Oil Tank II tx:

Port­able Tank

Oi l Tank III ixd Oil Tank IV &

Scale

LJ

1 Compressed Air Controlled

' A t Miner

Pigment Storage

Barrel Storage

V O L U M E 2 5, N O . 4 3 . . O C T O B E R 2 7, 1 9 4 7 3143

mains stationary and need not be moved. The small pump unit transfers the oil to the mixer. I n this way, no movement of transportation is required. When the other 30 tanks must be used, the saving in movements i s even greater.

Contamination was found to be unim­portant because of the very small amounts remaining in the p ;oe, the similar nature of the oils, and the purity of the final prod­uct did not dictate eliminating this factor.

The only cost i n assembling such a unit is that of the pipe since all other accesso­ries are available.

Were it n o t for the fact that this opera­tion is performed on the top floor of the building, the pigment could be stored on the floor above and loaded to the mixer by-gravity.

Μα η hour Economy-Case 3 is a shipping operation, the pur­

pose of which is the loading of casks con­taining chromic acid onto customers' trucks (see Fig. 4 ) . Originally the casks were loaded on the customers' tracks by an ordinary hand truck. The weight of the casks necessitated a three-man team. Only one cask could be handled at a time. The first improvement made in this oper­ation was t h e installation of the fork-type lift truck and pallet. The customers' trucks have room for 48 casks, 32 standing up and 16 lying o n their sides on top of the upright ones (see Fig. 4). The upright

3144

casks are loaded four to a pallet. The pal­let is then transferred onto the truck by the fork truck. B y using the lift truck it became possible to load a second layer of casks lying on their sides. This was done by rolling one cask on the two fingers of the fork truck, transporting t o the custom­er's truck, and roiling it off onto the top of the upright casks. The introduction of the lift truck not only more than quad­rupled the production of the three-man team, but also made the second layer pos­sible, thus increasing the customer truck capacity.

The necessity of loading the second layer as described was the only reason for the presence of the two men in addition to the fork truck operator. These men were not essential in the loading of the first up­right layer, so they were released to work in other parts of the plant when the hori­zontal casks were loaded on pallets. As a result of this second change the one-man team loaded the second layer faster than the old three-man team. Since the fork truck operator can load only when custom­ers' trucks are waiting, there are usually periods of enforced idleness. These pe­riods can be utilized to preload a pallet of horizontal casks on top of a pallet of up­right casks.

This operation cuts in half the number of trips the fork truck must make into the customers' trucks, and thus greatly expe­dites the departure of filled, customers'

trucks. The net result is that one man does the work of three in about one tenth the time, a per manliour productivity in­crease of 3,000% over the original method. A further improvement could be effected if the customer truck body were height­ened to allow room for two layers of up­right casks.

Expanding Use It may be assumed that the trend to­

ward the use of scientific motion and time studies in the chemical process industries, which began a few years ago, is destined to expand in conjunction with important new developments.

If the chemical engineer is Jto keep abreast of the steady changes that will take place within the near future, he should study, learn, and apply his experience to the new conditions a s they confront him.

The science of t ime and motion study, as practiced by industrial engineers, has helped to increase the productive capacity of a bricklayer from 125 to 350 bricks a day. Hence it is n o t unreasonable to ex­pect that a filter-press operator, guided by similar motion and time studies, might increase his productive efficiency consid­erably.

Work simplification is not limited to any one or two phases in the chemical process industry. O n the contrary, it may be applied in the offices, research labora­tories, and in the receiving, production, and shipping departments with equally successful results.

I t behooves the chemical engineer to supplement his knowledge with factual data and other essential information on motion economy if he is to take full ad­vantage of the opportunities that lie ahead for successful achievement in the chemical process industries.

Suggested List of Titles (1) American Management Association.

periodicals. (2) Barnes, R. M.., "Motion and Time

Study," New York, John Wiley é Sons, 1946.

(3) Bjorksten, J., CHEM. ENG. NB"WS. "Time and Motion Studies for Chem­ists/' 21 , 1324 (1943).

(4) Carroll, P., "Time Study for Cost Con­trol," New York, McGraw-Hill Book Co., 1943.

(5) Lowry, S. M.» Maynard, H. B., and Stegemarten» G. J., "Time and Motion Study/ ' New York, McGraw-Hill Book Co., 1940.

(6) Maynard, H. B . , and Stegemarten, G. J., "Guide to Methods Improve­ment/ ' N e w York, McGraw-Hill Book Co., 1944.

(7) Mogensen, A. H.t "How* to Set U p a Program for Motion. Economy/' Factory Management and Mainte­nance Plant Operation Library.

(8) Morrow, R. U„ "Time and Motion Economy," New York, Ronald Press. 1946.

(9) Presgrave, R., "The Dynamics of Time Study," N e w York, McGraw-Hill Book Co., 1945.

(10) Society for the Advancement of Man­agement, periodicals.

A N D E N G I N E E R I N G N E W S

Fig. 4, Diagram of chromic acid cask handling method tvhich increased manhour productivity 3,000% over original method as explained in Case 3

Uprlfht Horizontal Preloaded

ŒBSBSaffi Side View End Vitw

Arrangement of Pallets in Truck

ask handling method tvhich increased original method as explained in Case 3

ttizontal Preloaded

ÛÛ, rm mi mm End Vitw

of Pellets in Truck

C H E M I C A L