V O L U M E 2 6 , NO. 4, A P R I L 1 9 5 4
641
ROUTINE OPERATION
Upon receipt of the sample to be assayed in the control laboratory record office, the clerk removes from the file the punched card and work sheets which had been previously Ditto printed a t the time the manufacturing card was made. Since the lot number, job-identifying information, and complete manufacturing formula are already on the punched card, the only additional data requiring entry on the punched card are the label statements of the constituents to be assayed and the date of receipt of sample. The stage of production involved is merely circled on the punched card. The work sheets also contain the job-identifying data and formula and only require encirclement of the stage of production and entry of date. The component to be assayed is circled on the formula side of the work sheet. One work sheet is prepared for each constituent requiring analysis, and the sheets and sample are delivered to the analysts. The punched card is then numerically filed in the clerk’s “in process” file. Upon completion of the assay the analyst enters the analytical data, results, analytical notes, initials, and date on the work sheet
and in the permanent laboratory notebook, and returns the work sheet to the supervisor. The supervisor indicates disposition of the assay, his initials and date, and, if complete, returns the work sheet to the clerk. The assay results, analyst’s initials and pertinent comments are then entered on the punched card by the clerk. When all of the assay work is completed the job is released for further processing or shipment, and the date of release entered on the punched card. When the laboratory’s analytical work on a particular job is completely finished the punched card is filed serially by lot number in a standard metal file. The work sheets are retained for a short while before being discarded. LITERATURE CITED
(1) Casey, R. S., and Perry, J. W., “Punched Cards,” Yew York, Reinhold Pulilishing Corp., 1951. (2) Hale, -4. H., and Stillman, J. W., ANAL.CHEM.,24, 143 (1952).
RECBIVED for review J u l y 13, 1953. Accepted November 18, 1953.
Visual Control of Analytical Test Scheduling B. G. POST, M. 0. BAKER,T. A. HIETT, and J. Research Laboratory, Houston Refinery,
L. MURPHY
Shell Oil Co.,
Houston,
A visual system has been developed for use in the scheduling of routine analytical tests and for maintaining a daily status report of each sample in process. This system is based upon an application of a Produc-Trol visual order control board. By means of a series of colored plastic pegs which may be placed on the board, i t is possible to visualize the number and type of tests that have been submitted for analysis. Through the use of a color code it is possible to distinguish priority samples, samples which require special techniques or modification of an existing standard procedure, and samples on which the testing is complete but the results have not been reported. combination of a number code with the color code enables the scheduling supervisor to control the relative order in which the requested analyses on a given sample are to be made. Thus, the supervisor has a complete “picture” of the entire work load requested of his section available at all times for planning and assignment of personnel to the various required tasks. The two outstanding advantages of this scheduling system are its presentation in visual form of a summary of the entire work load of the test section and elimination of the necessity of written test assignments to the testers.
I
N R E C E N T years the scope of analytical chemistry in petroleum refinery laboratories has greatly increased both in variety of analytical functions performed and in the number of analyses required. These increasing demands upon the analytical groups have resulted in a proportionately larger number of routine-type analyses which require detailed technical supervision. Consequently, this trend has increased the amount of time that must be spent in nontechnical work such as sample scheduling, storing, and test reporting. Such housekeeping overhead, while a very necessary function, results in routine, nonskilled use of trained analytical chemists. Further, the inability to visualize readily the exact number and type of tests requested, their relative priorities, and any deviations from speci-
rex.
fied routine analytical procedures have made the problem of test status and scheduling a complex one. Continued studies of these problems during the past three years have been made in an effort to develop a more economical and more efficient procedure for the scheduling of routine analyBes. A review of the chemical literature since 1907 reveals that only three papers discuss this important phase of laboratory operation (a, 4, 5 ) , although a few references to analytical laboratory organization and methods of operation may be found (1, 3). A punch card system similar to that described by Hale and Stillman (4, 5) was developed several years ago, but has been replaced by the system described herein. REQUIREMENTS O F A CONTROL SYSTEM
Economical utilization of the available manpower and facilities of an organization must be based upon a well-planned program. This plan may be a long-range detailed plan of action or it may be a daily program whose details will be filled in as their need arises. Depending upon the scope of the laboratory program and the degree of supervision desired, the supervisor may be required to maintain a daily status report of each sample in process. The maintenance of a daily status report for each sample requires: 1. A means of showing each sample for which an analysis is requested. 2. A method of indicating the exact tests required for each sample. 3. A procedure which indicates priority tests, tests requiring special instructions, and testa that must be run in a predetermined order. 4. A method which indicates when a given test has been satisfactorily completed. I n addition to these basic requirements, the control system selected should: 1. Be simple in operation, easy to maintain and available to all interested personnel during normal working hours. 2. Automatically indicate to each individual his daily work assignment.
ANALYTICAL CHEMISTRY
648 3. Require a minimum of clerical operations. 4. Indicate the relative age of each sample awaiting analysis. 5 . Provide a. record of all test results for the
It is the purpose of this paper to describe in detail a sample scheduling system which fulfills all of these requirements with a minimum of technical supervision and clerical man-hours. This system is hssed upon the application of one or more Produo-Trol visual control hoards (manufactured by Wassel Organization, h e . , Westport, Conn.) which present a complete picture of the status of each sample and each test a t d l times. It is believed that the control system described in this paper is original and t h a t it can be adapted to any type of laboratory operational control. DESCRIPTION OF EQUIPMENT
The Produc-Trol Board. I n general appearance, the Produo-Trol board (Figure 1)resembles a large punch board with a card file attached to one side. The board ie 43’/* inches wide by 39 inches high and has an index panel containing Figure 2. Upper Left Section of Produe-Trol Board 100 individual card pockets. T h e card pockets are numbered from 1 to 100 and are arranged 80 that the lower quarter. inch of each pocket is visible. The the board. T h e peg with the attached string when inserted in index panel is mounted in a slotted metal support which allows the desired position on its row forms a white bar which is usuallly i t to be removed and placed on x desk for necessary clerical calibrated to measure progress in terms of days, hence the na me operations. A double row of 200 peg holes extends horizontally “progress pegs.” across the hoard for each card pocket. Each double row of holes The D ~ section B of the hoard is divided into 40 vertical C O ~ U ins N , 01* .m , is numbered on both ends and in the middle to correspond to its ~y ngnx green Lines emnosseu, on m e Iace e Doaru. bach card pocket. Figure 2 is a photograph of the upper left section column is 5 peg holes wide, thus giving 10 peg positions in each of the board and shows in some detail the general arrangement of numbered row. Above these columns is a small section for a the column headings, card pockets, and various types of pegs column heading strip. Sevewl rows of holes above the heading used. (This photograph and Figure 1 were not taken a t the strip are used in conjunction with similar holes below the last mme time, so the location of the pegs in the two photographs is numbered row to divide the board vertically with colored strings not necessarily the same.) At the left edge of the peg hole secsupplied with the board. tion is a round white plastic peg for each of the double row8 of Signal Pegs. The manufacturer has a wide assortment of plastic pegs of different shapes and colors. The lmge variety of holes. These pegs are also numbered to correspond to their designated row and card pocket. Each peg, in turn, is connected pegs permits the encoding of many kinds of information on the by a white string to a concealed spring mounted in the interior of board. Pegs may be obtained with Letters, numbers, or specid characters imprinted on their tops. Plain sanded pegs suitable for marking with either ink or pencil may also be secured. In the system described in this report two types of codes m e used to place information on the hoard. For la-ge-volume routine tests solid color pegs are used to indicate the desired action; for low-volume, miscellanous tests, square pegs of a given color combination are used to indicate the request of a speeifio analysis. Typical examples of the peg designations used in this system are shown in Table I. Colored Strines. - Three white strinxs are used to divide several of the columns vertically near the right edge of the board, in order to increase the number of columns available. A vertical orange Rtring is used with 8 calendar strip (described in a subsequent paragraph) to indicate the current date. A horizontal pink string is used to indicate the row of the newest sample on the board. Column Heading Strip. The column heading strip is lettered on lightweight card stock. The 40 most frequently requested tests are indicated on the column heading by appropriate ahbreviations. I n addition, columns m e provided for inorganic analyses, microanalyses, and miscellaneous tests. Title Card. Each board is assigned a number to identify i t permanently. This same number is placed on the corresponding card file to avoid switching of these files when being replaced upon Figure 1. Produe-Trol Control Board
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V O L U M E 26, NO. 4, A P R I L 1 9 5 4 the board. The identifjing number appears on the title card which contains a master legend for rapid interpretation of the information presented on the board. Calendar Strip. .A three-month calendar strip is pinned to the lower right portion of the board below the peg section. This calendar strip (supplied by t’he manufacturer) is divided so that each peg hole represents one day. The current date is indicated hy pegging the vertical orange strip over the appropriate date. This provides a reference axis which is advanced daily. The significance of this reference axis is explained later in this paper. Record Cards. Each sample submitt,ed for analysis muPt h e svconipanied by a written request (in duplicate). This request form is a 5 X 8 inch lithographed white card (Figure 3) made of liqhtweight stock to permit making duplicate requests with ordinary carbon paper. The form contains blank spacea for such information as sample description, special instructions, drsired tests, desired t,est order (if necessary), sample source, budget number, and date of request,. Spaces are provided for pertinent analytical remarks, the final results, arid the location of the original experimental data by laboratory record book and pagr number. The request form is designed for one samplr. Whc.re more than eight teste are desired, the back of the card is used to provide additional space. The lower right c’orner of the card is reserved for the analytical tePt order numlm.
Table 1. Color Pink Pink Orange Yellow
Designation of Colored Signal Pegs
Shape Round Round numbered Round Round
Purpose Nornral routine test (high volume test) Xornial routine test where order of test is desired in a given sequence Priority or rush Test reouiring special instructions which are either o n reauest card or must be obtained from sunervisor orior t o runninn analysis Saturate frac:tion for refractivity intercept measurement Conipleted test Assigns peraonnel to specified test
White
Square
Green Yellow
Round Rectangular imprinted with name Scluare
Emission sriectrosconic analysis reauested
Square
Octane niiruber requested
Black-tan triangle Black-ariiia blue triangle Black-orange triangle White
Square
Resin content requested
Roundnumbered
D a t e sample received f o r out-of-sequence sample
Analytical Test Order Number. Every request for analytical services is assigned a serial number. This number is stamped on the request form and on a gummed label which in turn is placed on the ?ample container. Each sample in the service section is placed on designated shelving in numerical sequence. F;\perience has shon n that this system reduces the number of lost and misplaced samples to a minimum and the resulting saving of time more than compensates for thr time required to place the number on the sample. The test order number also permits keeping all requests in the same sequence in rhich thev are received and provides a convenient method of filing for future rpfercnrr. In addition, the test order numbcr eliminates confusion rnused by original deqignations of samplrs. OPERATION O F T H E SYSTEtI
Upon receipt of a request for testing, together with the designated sample, an analytical test order number is stamped on the request and on the sample. (The duplicate copy of the request, after being stamped with an order number, is retained by the person submitting the sample.) All requests received prior t o 3 P.U. each day are posted daily on the Produc-Trol board by plac-ing the request cards in numerical order in the card pockets beginning with the next vacant pocket. Opposite the request (which now has a numbered line on the board reserved for it) the
649
appropriate types of signal pegs are inserted in the columns corresponding to the requested services. This completes the posting of the sample. Occasionally, a n insufficient number of blank envelopes are available to post all new requests in successive envelopes. In such instances, the envelopes already occupied by a request are bypassed and the next vacant envelope is used to post the next sample request. The bypassed sample, which is now considered an old sample, is distinguished by placing the appropriate progress peg over the calendar strip so that the peg indicates the date of receipt of the sample. The length of white string thus exposed is a function of sample age, with the shortest string representing the oldest sample on the board. Conversely. the number of peg holes between the current datelineandtheprogrrss peg represents the age of the sample. Comparison of the various lengths of white string evposed quickly identifies the old samples for remedial action. By proper combination of the signal pegs it is possible to indicate several different instructions about a test. For instance, a red. yellon, and pink numbered peg may be used to shorv that the test is a priority test, that it requires special handling or instructions from the supervisor, and that it is to be run in a certain srquencr n ith reference to the other tests requested on the sample. X yellov peg alone would shou that special instructions are on the request card or that the supervisor wishes to give oral instructions regarding the test before i t is run. After the posting of new samples has been completed, the next d a j ’s FT ork program is planned by the supervisor and individual personnel assignments are made by plaring the individual name pegs above the test columns. This completes the scheduling of the next day’s work. Figure 1 illustrates the appearance of the board a t this phase of the operation. The outstanding advantages of this phase of the system are that the entire test inventory is visually available to the supervisor a t the time the succeeding da>’s program is being planned and no uriting of instructions is required.
Sampie Description -Special Instructions:
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I
Test Dssired
Order
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Send Results To
]Bu@4t Na
Figure 3.
IAcaIylicaI Rormrkrl Rsrults
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\Date
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]Acalytml Sample
I Book Ryle I
No.
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J
Anal)-tical Test Request Form
Upon reporting for work, each individual assigned to the section proceeds t o the boards, determines his xork assignment, and notes the order numbers of the samples he will test. In the absence of priority samples or other instructions, the testers are expected to run the tests in numerical sequence. If the assigned samples are pegged with a yellow peg, the tester reads the special instructions on the request card. If these instructions are missing or are not clearly understood, instructions are obtained from the supervisor. If the requested test is pegged with a numbered pink peg the lowest numbered test is run first. For example, the assigned test is pegged with a number 4 peg. The tester checks the status of the other tests requested on the sample to determine whether the tests numbered 1, 2, and 3 are completed. If the latter tests are finished, then the number 4 test is run. However, if any of the lower numbered tests are not complete, the number
ANALYTICAL CHEMISTRY
650 4 test is left to be run later. (Posting by numbered pegs thus permits the supervisor t o control the test operations where limited sample quantities are available. Also, these pegs can be used in those cases where i t is necessary to obtain certain data before another test can be run.) Upon completion of the assigned tests, including the preparation of a report sheet (Figure 4), the tester places a green peg in the appropriate row and column to indicate that the test has been completed. The report of the test is given the supervisor a t the end of the day.
REPORT OF ANALYTICAL TEST DATE:
ANALYST : SAMPLE NO.:
BOOK AND PAGE NO:
II
TEST :
1
RESULTS:
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I
.1
REQUESTED B Y :
Figure 4.
Form for Report of Analytical Test
The supervisor checks the test results and, if they are satisfactory, he has them entered on the corresponding request card. The pegs representing the reported tests are removed from the board daily. If the test results are unsatisfactory, the superviqor removes the green peg, thus rescheduling the test. Satisfactory test results are distributed daily to the persons requesting the tests. When all of the tests requested on a sample have been satisfactorily completed, the request card is removed for filing as a permanent record. The remainder of the sample (or the empty container, if the sample is consumed) is returned to the submitter. This action relieves the supervisor from any further responsibility for storage of the sample and ensures that only current samples are in the service section’s storage spaces. The lower section of one board has been reserved for samples requiring considerable testing time. This arrangement keeps such samples segregated and reduces to a minimum the number of out-of-sequence samples in the remaining areas of the board. Personnel on special assignments-e.g., control testing for pilot plants, precision distillation, etc.-or absent are shown in the lower left corner of one board. I n this way, the supervisor may determine a t a glance the location of all personnel in the service section.
DISCUSSION
The sample scheduling system described in this paper ha.: been tested over a period of two years. I t has proved to be a valuable aid in maintaining a daily status report of each request test. The name peg scheduling has been found to be particularlir advantageous in reducing the time lag before the section personnel caan receive their daily assiznments and begin their nork. I t is riniple to maintain and easy to understand, and requires a minimum of clerical time and paper work on the part of the service srrtion. The visual features of the board enable the superviqors to see which tests are requested, the number to be run, and the position of any sample relative to other samples awaiting anal\.&. Testing bottlenecks are quickly observed in time to reasbign personnel to prevent any one test from holding up completion of a given sample. Priority and old samples are easily located and can be expedited if necessary. This sample scheduling system is based upon the use of three Produc-Trol boards and was designed for an average sample inventory of about 225 samples. Experience in this laboratory has indicated that the maximum posting time for average samples ( q i l tests per sample) is about 40 to 50 samples per hour and that 95% of the posting can be done by nontechnical personnel after a short training period. With modification this system could be used for the processing of several hundred samples per day but in its present state of development an average daily increase of 100 samples appears to be the maximum economical load. The use of these boards has reduced considerably the amount of paper work required to maintain a daily status record and hac;, in effect, made a minimum of 3 technical man-hours per da\ a\:iilahle for other work in the section. ACKNOWLEDGMEVT
The authors wish to acknodedge the many helpful suggestions v hich were made by F. D. Mary and R. C. Tyson of the Houston
Refinery Industrial Engineering Department during thr initial development of this system. LITERATURE CITED
(1) (2) (3) (4) (5)
Chapman, R. P., C h e m l n d . , 65,718 (1949). Chem. Eng. Sews,31,1919 (1953).
Clarke, B. L., Ind. Eng. Chem., 23, 1301 (1931). Hale, -4. H., and Stillman, J. W., ANAL.CHEM.,23, 678 (1951). Ibid., 24, 143 (1952).
RECEIVED for review May 25, 1953. Accepted January 4, 1954. Presented before the Fifth Annual Symposium, Southeastern Texas Section, .4\lERICAN CHEMICAL SOCIETY, Houston, Tex., May 15, 1953.
