BASICS OF PLANT LAYOUT 11292020 4 09 AM

BASICS OF PLANT LAYOUT 11/29/2020 4: 09 AM 1

Plant layout has been defined as a plan of, or the act of planning an optimum arrangement of industrial facilities, including Ø personnel, Ø operating equipment, Ø storage space, Ø materials handling equipment and Ø all other supporting services along with the design of the best structure to contain these facilities 11/29/2020 4: 09 AM 2

11/29/2020 4: 09 AM 3

11/29/2020 4: 09 AM 4

11/29/2020 4: 09 AM 5

11/29/2020 4: 09 AM 6

11/29/2020 4: 10 AM 7

11/29/2020 4: 10 AM 8

Locate All Areas In and Around Buildings – Equipment – Work stations – Material storage – Rest/break areas – Utilities – Eating areas – Aisles – Offices 11/29/2020 4: 10 AM 9

Problems of layout develop when needed: • to start a new product, • to change the product design, • to reduce the cost; And when • the market demand changes, • the plant, the product, the building become obsolete, • accidents occur frequently, • the working environment is poor. 11/29/2020 4: 10 AM 10

The resulting problems involve • planning a completely new plant, • re-arranging a presently installed layout, • making adjustments to existing layout. 11/29/2020 4: 10 AM 11

The objectives of a good study of plant layout are: • ensure effective space utilization, • minimize the cost of material handling (internal transports), • foresee future developments of the plant according to a rational master plan, • improve workers convenience as well as safety and create job satisfaction, and • avoid unnecessary capital investment. 11/29/2020 4: 10 AM 12

Types of Layout • Product Layout: In this type of layout, only one product or one type of product is produced in a given area. • The product must be standardized and manufactured in large quantities in order to justify the product layout. 11/29/2020 4: 10 AM 13

11/29/2020 4: 10 AM 14

Some of the Advantages of Product Layout are: • lower total material handling cost, • lower total production time, • less work in process, • greater incentive for groups of workers to raise level of performance, • less floor area required per unit of production and • greater simplicity of production control, fewer control records needed and lower accounting cost. 11/29/2020 4: 10 AM 15

Product Layout is Used When: • one or few standard products are to be produced, • large volume of production of each item over a considerable time is needed, • minimum of inspection is required during sequence of operations, • minimum of very heavy equipment or equipment requiring special facilities are needed, • materials and products permit bulk or continuous handling of mechanical means and • one machine is always used for one purpose. 11/29/2020 4: 10 AM 16

Process Layout: Similar equipment and similar operations are grouped together in the process or functional layout. It is particularly useful where low volume is required. 11/29/2020 4: 10 AM 17

11/29/2020 4: 10 AM 18

Some of the Advantages of Process Layout are: • less duplication of equipment, hence lower investment cost, • greater flexibility of production, • better and more efficient supervision, • greater incentive for individual workers to raise level of performance, • better control of complicated or precision processes, • easier to handle breakdowns of equipment by transferring work to another machine or station. 11/29/2020 4: 10 AM 19

Process Layout is Used when • many types or styles of products are on special order , • relatively low volume of production on individual items is needed, • many inspections are required during a sequence of operations, • high proportion of very heavy equipment or equipment requiring special treatment exist, • materials or products become too large or too heavy to permit bulk or continuous flow and • one machine is used for different operations. 11/29/2020 4: 10 AM 20

Fixed-Position Layout • Fixed-Position Layout: In this type of layout, the material or major component remains in a fixed location, and tools, machinery, men as well as other pieces of material are brought to this location. Typical examples are ship building, construction industries, aircraft building and bench work exercises. This type of layout is not frequently used in industrial enterprises. For this reason we are not going to look into its advantage and disadvantages. 11/29/2020 4: 10 AM 21

Developing Simulating Layout Problems Product Design Change New product Build New Plant Market Demand Change Move to existing Plant Obsolete Facility Poor Worker Environment Rearrange Existing Plant Market Relocation Cost Reduction Minor changes Class of layout problems Relation between causes and classes of layout problems Cause and result occur very frequently Cause and result occur less frequently Cause and result occur occasionally 11/29/2020 4: 10 AM No line Cause and result occur very seldom 22

STUDY OF PLANT LAYOUT • The solution of any size and type of plant layout problems could be facilitated by using a systematic and logical approach. • An early pioneer in this area was Richard Muther, developer of the Systematic Layout Planning (SLP) methodology. 11/29/2020 4: 10 AM 23

The SLP procedure leads the planner through • Abstraction (Analysis): Gathering appropriate information and analyzing the flow of materials and the activity relationships to form a relationship diagram. Space considerations when combined with the relationship diagram develop the space relationship diagram. 11/29/2020 4: 10 AM 24

Search (for possible solution): • The overall layout is designed by combining space consideration with the relationship diagram. • The search phase is the phase in which alternative layouts are developed by examining the space relationship diagram under modifying consideration such as materials handling, storage facilities, site conditions and surroundings, building types, personnel convenience, etc. , and practical limitations. 11/29/2020 4: 10 AM 25

Selection: • The most efficient general method of evaluating layout alternatives is termed factor analysis. It follows the engineering concept of breaking down the problem into its elements and analyzing each one. 11/29/2020 4: 10 AM 26

Activity Relationship Diagram Space Required Space Available Space Relationship Diagram Computerized Layout Planning Practical limitation Modifying Consideration Layout X SEARCH Flow of Material ABSTRACTION (ANALYSIS) INPUT ACTIVITIES AND DATA Layout Z Layout Selected Detail a 11/29/2020 4: 10 AM Systematic layout Planning Procedure Detail b Detail c EVALUATION Layout Y 27

Abstraction (Analysis) • There are two basic elements on which every layout problem rests • Product (or material) • Quantity (or volume) • These two elements underline all other features or conditions directly or indirectly in layout work. 11/29/2020 4: 10 AM 28

S. Support services P. Product-Material What is to be produced R. Routing-Process With what support will production be backed How will it (they) be produced T. Time Q. Quantity-Volume How much of each Item will be produced When will it be produced W H Y Key PQRST to unlock layout problems 11/29/2020 4: 10 AM 29

This phase will require the assembly of different data. In general, information about the following is needed: • the list of items to produce and store, and the relative quantity; • successive operations needed for every product; • the volume, the weight and the characteristics of materials to transport along the production line; 11/29/2020 4: 10 AM 30

• the number, type and technical data of machines and plants necessary; • the manpower needed; • the necessary electric energy, steam, water, compressed air, fuel, oil, etc. • the necessary general service (offices, labs, cafeteria etc. ); • the necessary auxiliary services like maintenance department, tool store, etc; • the possible variation of the product in the future. 11/29/2020 4: 10 AM 31

• If the study is on an existing plant, it is necessary to have drawings of the plant layout and the building with all the technical data. 11/29/2020 4: 10 AM 32

Search for Possible Solution • The systematic approach of generating possible alternatives of plant layout is conducted by taking in to consideration: 1. type of layout, 2. the possible internal transport systems and 3. the working condition. 11/29/2020 4: 10 AM 33

• Type of Layout: It is necessary to determine which type of layout to select, product (line) or process (functional) layout. • In addition to the selection of type of layout it is also important to fix the arrangement of machines 11/29/2020 4: 10 AM 34

Q Q A Product α P= Product β B Q=Quantity Product y C P P P-Q Diagram 11/29/2020 4: 10 AM 35

• In region A there are few types of products but in a great quantity. For these products it is advisable to have product layout. • In region C there are very many products in small quantity. Hence, preferred to have process layout. • For products in region B (medium types of products and medium quantity) the case has to be studied closely so as to be able which layout to select. 11/29/2020 4: 10 AM 36

• There are different types of machine arrangements. The form of an industrial building is mainly dependent on machine arrangements and the advancement of a workpiece. The usual forms are shown 11/29/2020 4: 10 AM 37

a) IN PARALLEL a) IN SERIES a) COMBINED 11/29/2020 4: 11 AM Examples of Machine Arrangements 38

11/29/2020 4: 11 AM 39

The Possible Internal Transport System: • After considering the type of workpiece advancement, the production capacity and the machineries required, it is necessary to examine the volume and weight of materials that has to be transported from one machine to the other, or from one department to the other 11/29/2020 4: 11 AM 40

Cont’d… • The type of material handling equipment influences directly the plant layout and also the building. The working position, the form of the layout, the height, width and length of the building, the loading and unloading of materials, the positions and dimensions of accessibility depends in general, on the type of internal transport system adopted. 11/29/2020 4: 11 AM 41

• A good study of internal transport system may boil down to the following major benefits: Reduce costs by - utilizing space to better advantage, - increasing productivity and - making few number of effective movements. Reduce waste by - eliminating damage to material during the handling process and - maintaining proper control over in-and-out of stock handling process. 11/29/2020 4: 11 AM 42

Improve working conditions by • providing safer working conditions and • reducing worker fatigue. Improve the efficiency of the plant by • improving location of storage facilities, • improving routing and • increasing productivity. 11/29/2020 4: 11 AM 43

Raw Material Finished Good Store Working Dep’t Future Expansion 11/29/2020 4: 11 AM Typical One Floor Industrial Building 44

• In some plants, the cost of repeated handling constitutes a very high proportion of the total cost of the end product, and in some others, the distance, materials have to move is not the sole criterion, and often is not even the primary concern for locating an area or an operation. Hence, more realistic value assessment of the factors that truly affect total cost in different kinds of layout planning situations is needed. • The available computer aided layout algorithms fall into, either improvement, or construction routine categories. 11/29/2020 4: 11 AM 45

IMPROVEMENT ROUTINE: • The basic approach is to find a suboptimum design by making improvements in sequential fashion. First, a given layout has to be evaluated to determine what the effect will be if department locations are interchanged. • If improvements can be made by making pairwise exchanges, the exchange producing the greatest improvement can be adopted. • The process continues until no improvement is possible by pairwise exchanges. 11/29/2020 4: 11 AM 46

The objective function to be evaluated is: TC = Total internal transport cost Ø Cij = Cost of internal transport, per unit distance per unit weight, for material movement between department i and j Ø Wij =Weight of material transported, per unit time, from department i to j Ø Dij = Distance from department i to j 11/29/2020 4: 11 AM 47

• The routine accepts input data of Wij and Cij in the form of a FROM - TO chart. It may also accept Dij in the form of a FROM - TO charter, or it may accept the co-ordinates of the work centers. • A FROM - TO chart is a square matrix whose elements represent flow or distance between departments. • The chart is constructed by listing the departments down the left hand column and then across the top in the same order. • The departments on the left are the originating (FROM) departments and the ones at the top are the receiving (TO) ones. 11/29/2020 4: 11 AM 48

11/29/2020 4: 11 AM 49

• A relationship chart is a triangular matrix whose elements represent the relationships among plant layout departments. Letter codes are also used to represent desirable or undesirable levels of closeness between departments. 11/29/2020 4: 11 AM 50

• Six standard letter codes are used to show closeness relationships. • "A" indicates an absolutely necessary closeness relationship; • "E" indicates especially important; • "I" important; • "O" ordinary; • "U" unimportant; • "X" indicates a not desirable closeness relationship. Although the letter codes are standard, the ratings reflect the user's own reasons for assigning the letter codes. 11/29/2020 4: 11 AM 51

CONSTRUCTION ROUTINE: • This routine constructs layouts without the need for an existing (preliminary) layout. • Basically find the starting point or initial activity placement and then add the remaining activity areas in accordance with logical rule. Thus, the routine accepts qualitative information from the relationship chart with closeness value numerically rated. 11/29/2020 4: 11 AM 52

• The relationship chart and the numerically weighted ratings, assigned to the closeness values, are the basis for the order and placement in which departments enter the layout. The ratings assigned for A, E, I, O, U and X are used to calculate the Total Closeness Rating (TCR) for each department. 11/29/2020 4: 11 AM 53

where • TCRj =Total Closeness Rating for department; • V(rij) =Numerical value assigned to the closeness value for department i and j. • n = Total number of departments. 11/29/2020 4: 11 AM 54

11/29/2020 4: 11 AM 55

• The first department to be placed in the layout is assigned by taking the department with the greatest TCR. Next, the relationship chart is scanned to see if there is any department that has an A value with the department already placed. If no A value exists, a check is made for E value, and if no E value appears, a check is made for I value, followed by O value. If ties develop, the department having the greatest TCR is chosen. This process is continually used until finally all departments are placed in the layout. 11/29/2020 4: 11 AM 56

Working Condition • Proper working conditions are considered important by management because they increase production effectiveness. Employee working conditions are influenced by many factors, over which the employee has very little or no control. • A good layout considers the factors influencing working conditions. 11/29/2020 4: 11 AM 57

LIGHTING • Good lighting facilitates accuracy and ease of seeing. A lighting system that aids these two demands means that the worker is able to see the critical details required in his job without excessive visual strain. • The lighting fixtures are described according to the way they distribute light. Ø Direct lighting 0 -10% of flux directed to the roof Ø Semi direct 10 -40% " " " Ø General diffuse 40 -60% " " “ Ø Semi indirect 60 -90% " " “ Ø Indirect 90 -110% " " " 11/29/2020 4: 12 AM 58

• In most European countries, the law requires for a minimum level of illumination. The following ranges are accepted internationally 11/29/2020 4: 12 AM 59

TYPE OF WORK ILLUMINATION VALUE IN FLUX • Store and rarely accessible working places • Rough work (Brewery) • Medium work (automobile assembly) • Precise work (wool work) 100 - 200 - 500 - 1000 500 – 1000 • Fine work (Radio and TV assembly) 1000 - 2000 • Very fine work (controlling wool work) 1000 - 2000 • Working on a very small pieces (watch assembly) 11/29/2020 4: 12 AM 2000 - 7500 60

AIR CONDITIONING • Air conditioning is used for many plants to control contamination by dust, bacteria and toxic gases in addition to air temperature and humidity. • Air conditioning is a system which provides an atmosphere comfortable to the human being and maintain an atmospheric environment demanded by a manufacturing process or storage of products. 11/29/2020 4: 12 AM 61

NOISE • A wide variety of sound exists in industry. Continuous exposure to high noise levels frequently results in temporary or even permanent loss of hearing. • But there is no clear cut line to indicate how much noise results in hearing loss. • The following are standard measurements for different sound sources in decibels: 11/29/2020 4: 12 AM 62

SOURCE - Hydraulic process at one meter d. B 140 - Automobile horn push at one meter 120 - Automatic lathe at one meter 100 - Conversation at one meter 70 - Workshop (mechanical) 11/29/2020 4: 12 AM 80 63

The reduction of noise may be brought about by a variety of methods. Some of these methods are: ü Control of the noise at the source. ü Isolation of the noise. ü Use of baffles and sound absorbers. ü Acoustical treatment. ü Use of ear protection devices. 11/29/2020 4: 12 AM 64

USE OF COLOR • The objective of utilizing scientifically selected colors is to bring about a clear three dimensional vision. • Color codes have been developed for particular uses. The red, yellow and green of traffic lights is a well known example of color coding. Red - danger; stop Yellow - caution Green - safety equipment • It is advisable to paint the roof of the industrial building with a minimum reflection index of 0. 7, the walls 0. 5, and the floor 0. 25. 11/29/2020 4: 12 AM 65

Different colors have different psychological effects. • Red - Hot and heavy, exciting, stimulating. • Orange - Hot, exciting and stimulating less than red. • Yellow - Hot, exciting lovely. • Green - Fresh and light, pacific. • Blue - Light, pacific. • Violet - Light, loneliness. • White - Cold, brilliant (seems to increase volume). • Black - Hot (seems to decrease volume) depressing. 11/29/2020 4: 12 AM 66

SPACE REQUIREMENTS • The layout man often finds himself involved in work space arrangement; at any rate, he must determine the floor space that will be required by an operator. The study of floor space needed considers the following points: • While at work, the operator's arms and hands should move as easily as possible and he ought to reduce, to the minimum the movement of his shoulders, his body and his person from one position to another. 11/29/2020 4: 12 AM 67

11/29/2020 4: 12 AM 68

• Fixed posts for utensils and materials should be assured. • The disposition of utensils, materials and organs of maneuver near and infront of the operator. • Avoidance of the standing operator wherever possible. The study of the working area should consider a proper and comfortable position for the legs of the operator in an armchair or on a stool. • When the operator is transporting material, or when he is in a position to push, or pull he should do it in such a way that: • he is in an equilibrium position and • he applies the possible minimum force to produce the effect. 11/29/2020 4: 12 AM 69

11/29/2020 4: 12 AM 70

PASSAGE IN AN INDUSTRIAL BUILDING • From the very beginning of the study one has to determine the corridors within the building. Their width is determined according to the internal transport system selected and according to the clearance needed for passages. • Principal corridors which normally start from one end of the building and end at the other end are 3 to 5 meters wide. • Corridors within the department: 1. passage for one person 60 cm, 2. passage for two persons 120 cm, 3. passage for three persons 170 cm. 11/29/2020 4: 12 AM 71

SAFETY • A good plant layout should consider the safety of all personnel. • Lack of adequate storage space which is beyond the control of the foreman, can lead to unsafe practices in the storage of materials. Some of the safety hazards to be watched for in plant layout are: 11/29/2020 4: 12 AM 72

• inadequate passage, • insufficient storage space allowance for safe handling procedures, • insufficient handling equipment capacity, • floor load capacity, • floor obstructions, • slippery finish floors, • inadequate exits, • inadequate stairs, ramps and ladders, • inaccessible fire extinguisher and first aid boxes • unguarded moving parts of equipment , • workers located under the above hazards and • improper ventilation for removal of dangerous or toxic gases. 11/29/2020 4: 12 AM 73

11/29/2020 4: 12 AM 74

• The layout man should give due consideration to the problem of safety. Overlooking the problem will lead to Ø lower morale of the workers, Ø lower productivity and Ø heavy accident liability costs. 11/29/2020 4: 13 AM 75

Selection • Every layout plan has intangible costs which to all intents and purposes cannot be measured in terms of birr and cents. • Moreover, a comparative cost analysis of alternative layouts is sometimes a standoff, no one plan has a clear-cut financial advantage over the other. Essentially, however, there are three: 1. balancing advantages against disadvantages; 2. cost comparison and justification; and 3. factor analysis rating. 11/29/2020 4: 13 AM 76

Advantages versus Disadvantages • Probably the easiest of the three evaluation methods mentioned above is the listing of advantages and disadvantages. • It is also the least accurate; therefore, it is used more for preliminary screening out of rough alternatives. • This pros and cons system involves merely listing in columns or on sheets placed adjacent to each other all the advantages of each alternative, below them are listed the disadvantages. • This simple comparison is surprisingly effective and certainly is not a time consuming procedure 11/29/2020 4: 13 AM 77

Cost Comparisons • A more economical approach to the evaluation problem is cost comparison, by establishing the total factory cost of a product and added investment for machine tools, a comparison between alternatives is possible. 11/29/2020 4: 13 AM 78

• In preparing a cost analysis, there are basically two approaches we can follow. – We may either consider total cost involved or – We may consider only those costs that will be affected by the project under considerations. 11/29/2020 4: 13 AM 79

• A systematic way of classifying cost elements and accumulating cost figures are required. For this the following procedures are recommended. – prepare a worksheet(s) that picks up investment requirements for each alternatives; – prepare a worksheet that establishes operating cost estimates, and – make calculations to compare and justify expenditures for alternative layout plans. 11/29/2020 4: 13 AM 80

Factor Analysis • The overall desires of what is wanted in layout being planned are broken down into so-called factors or considerations. They may also be termed criteria or objectives. Follows a list of the most commonly involved factors or considerations; not in order of importance. 11/29/2020 4: 13 AM 81

• ease of future expansion, • adaptability and versatility, • flexibility of layout, • flow of materials effectiveness, • materials handling effectiveness, • storage effectiveness, • space utilization, • effectiveness of supporting service integration, • safety and housekeeping, 11/29/2020 4: 13 AM 82

• working conditions and employee satisfaction, • ease of supervision and control, • appearance, promotions value, public or community relations, • quality of products, • maintenance problems, • fit with company organization structure, • equipment utilization, • utilization of natural conditions or surroundings , • ability to meet capacity or requirements, • investment or capital required and • savings, payout, returns, profitability. 11/29/2020 4: 13 AM 83

PROCEDURE FOR EVALUATING ALTERNATIVES BY FACTOR ANALYSIS A. Identify the plan to be evaluated. – Select the alternatives that are to be evaluated. – Have a visual plan, or sketch of each layout infront of each rater clearly understood by him, during the evaluation process. – Identify each visual plans by letters A, B, C, etc. Also give it a brief three-to-five word description. 11/29/2020 4: 13 AM 84

B. Establish the factors or considerations. – Establish what factors, consideration criteria or objectives are involved, or wanted from the layout. – Define the factors so that they are clearly understood. Avoid duplication of terms and congestion as to meaning. 11/29/2020 4: 13 AM 85

C. Arrange a rating sheet. – List the factors or considerations vertically on the lines of a sheet of paper. – Arrange the identification letter for each alternative plant horizontally in columns across the same sheet. – Leave room for adequate reference notes. 11/29/2020 4: 13 AM 86

D. Determine the relative importance of each factor. – Determine the weight or importance value of each factor relative to the other factors. – Record by whom the weight values are determined. 11/29/2020 4: 13 AM 87

E. Rate each factor for alternative plans. – Establish a rating code or system. – Rate each element on the extent to which it achieves, or affords the ends represented by the factor in question - - - rating each layout exactly as it is planned. – Rate all the plans for one factor; then take the next factor. – Record by whom the rating(s) was (were) made. 11/29/2020 4: 13 AM 88

F. Calculate weighted value and total. – Translate the rating symbols into numerical values and multiply the weight value by each rating number. – Total the weighted rating values for each alternative plan by adding the respective columns. – Record by whom the extension and tally were made. – Take actions as appropriate, based on the totals. 11/29/2020 4: 13 AM 89

11/29/2020 4: 13 AM 90