Factory Layout Design

Contributed By

Guntapudi Udayravichandra

Factory layout design is the process of arranging and organizing elements of a manufacturing facility. Physical spaces, equipment, machinery, workstation, materials, and people are some of the elements of a manufacturing facility.

Following points is to be considered while designing the factory layout design;

• Smooth and efficient movement of man and materials
• Safety and security
• Production flow
• Allocation of actually what is needed as per the requirement

In this article we are going to discuss following points related to factory layout design. Our focus will be on how to design, how much dimensions to give, how many no of exits, what should be the aisle width, etc. Let’s get started.

When to design a factory layout

Following are the situations when you need to design a factory layout;

New Manufacturing Facility : When anyone starts business. The business owner will buy empty land. Here we should know how to start flow of the factory, if the production is planned in a huge quantity, #of buildings should be constructed for Warehouse, Production and FG separately or combinedly in 1 building. The flow of the factory should be designed.

Here the work will be done by civil engineers, but the plan should be done by IE, CI or Lean. Here lean management team should have excellent knowledge on product to provide these insights while starting of Factory. This is when you need to design the layout.

Facility Expansion : With the increase of production capacity, business tends to increase the production buildings to meet Customer requirements.

Introduction of new products : Whenever a new product is introduced, it needs an additional space and work station. For this the existing layout to be edited or optimized to accommodate this new product. Initially, its better to check the possibility of combining new product line with existing ones, to save resources and hence cost.

Process Improvements : Whenever there is a change in the process there may be a change in the layout. But, all process improvements do not require layout change.

Changes include addition of an operation or work station, its elimination or change in location.

Safety Improvements : In the same way, we will rearrange the layout if there is any improvements in the safety perspective. Some of the changes may include, addition of an emergency exit, change in fire extinguisher location, addition of fire extinguisher, addition of an emergency exit, etc.

Ergonomics improvements : Ergonomics considers the comfort of the operator. Any improvements in ergonomics shall also be reflected in the layout. This include change in the location of storage of raw materials for assembly or providing additional storage facility for an item which improves the ergonomics

Changes in demand : Suppose demand for a item in your factory is doubled. You may not be able to fulfil the requirement with your existing assembly lines. You need to provide additional line. Hence the layout change.

Changes in Equipment : Ange changes in the equipment due to Upgradation or replacement, shall be reflected in the layout.

What all to be considered while designing a layout

Following points to be considered while designing a factory layout. Let’s discuss one by one.

No of Workstations or Equipment/Machineries

Only provide optimum no of workstations or equipment according to the requirement. Optimum numbers can be calculated from process cycle time and demand.

Facility Details

Facility details ( Dimension, Exits). Define the layout whether it is for production or not. If Production, what product we produce in the building. How many floors we design, Total Building Dimensions, distance between pillar to pillar and length and width of each pillar.

Based on the building plan and number of manpower need to plan for no of of Exits. Based on production type and capacity and then design the Layout.

Safety Standards

Other important requirements for Layout Design is to know what are the safety standards to be followed. It may vary depending on Customer requirements and also which country your working with.

Now we will discuss few points which are need to be considered in most of the factories.

Pathways

Pathways are the key elements in designing a layout.

Basically there are following types of Pathways.

1. Main Pathways – This is the pathway which connects different sections of the factory. It should be capable for the movement of materials, people, trolley, forklift if any, etc. Every man, material, equipment, trolley, forklift, etc. move through this pathway. In general the width of pathway can be considered as 1.2 meters to 1.8 meters. If we are using forklift width need to increase further. Main pathways are directly connected to Main gates of the facility. While selecting pathway width no of occupants also need to be considered. The width should be proportional to the no of occupants.
2. Production Line/Inline Pathways – These are the pathways between the production lines. These will not be as busy as main pathways. The width of production line pathways can be given between 0.9 meters to 1.2 meters. If you have large equipment to be moved through this pathway, consider its width while designing.

Guidance in deciding the width of pathway : Approximately 3 feet is required for a person to move freely. A normal trolley width will be 60 cm. A trolley can also move through 3 feet slowly. A normal pallet width is 80 cm. A pallet can move through 120 cm width passage. But its better to choose 150 cm width is there is frequent movement of pallets. No of persons in a factory has significant role in deciding the width of pathway. We should provide sufficient width to avoid congestion. These are only a guidance you may select appropriate width according to your requirement.

Construction

Construction and Layout design are directly proportional. Layout design can be done based on the Construction and Construction can be done on Layout design.

If Layout design is based on the Construction, then the re-sources are limited and we need to design based on the Main exits and pillars will be major concern while designing.

If construction is based on layout design, then resources can be maximized. Since the design is based on the product requirements, Safety requirements, Electrical requirements and Pathway requirements. If the construction is based on Layout design can be made only when concern IE, Lean having more knowledge on Product layout.

Warehouse or Non-Production related

If your designing non-production like storage or outsourcing. Then need to consider height of the storage and security concerns need to be considered.

Fire Extinguisher

This is another key aspect while designing layout, Fire extinguisher should be accessible to everyone. It should be placed near to a pathway and nearer to the areas where the chances for getting fire is high. While designing layout, designer should co-ordinate with Safety officers for the location.

No of fire extinguishers : No of fire extinguisher is decided in such a way that, a person should be able to access a fire extinguisher within walking a distance of 75 feet. This is a general guideline, you may finalize this by discussing with experts in the same field, for your situation.

Height of fire extinguishers : Fire extinguishers shall mounted at a height by which, a person shall easily take the fire extinguisher in case of emergency. Easily means, without bending or stretching.

Fire Hydrants

While designing a overall Factory layout, Fire hydrants also require but it is not much needed for Designing.

Aisles

Aisles are another most important aspect of layout design. While designing Aisles shouldn’t be obstructed with anything and as well Aisles should be marked with Yellow Paint or Yellow sticker.

Table

The dimensions of the table is highly customizable and it depends upon the specific requirement.

In highly optimized condition minimum table length required for a person is 2 feet. But in this condition the operator will not be able to move his hands freely, if another operator is sitting next to him.

But 75 cm table length will be comfortable one. But this depends on the tools and equipment operator is using while working.

Trolleys

Generally the length and width of trolley is 60 cm and 100 cm respectively. You can customize this as per your requirement.

Chair

Chair design should be Ergonomically designed for the operator. So that operator can work more time in production and provides production effectively.

Another key is since operators may take small breaks for water; we can arrange a water bottle holder for the Chairs so that they won’t get frequent breaks for the water.

Chair designs can be made based on the management requirements, but for more time life we can use iron and wooden and make sure to have water bottle.  

Length and width of a chair is normally 20 inches. You can give a clearance of 70 cm from table for chair.

Emergency Assembly Area

An emergency assemble area should be placed in the factory, if any fire accident and any emergency. People should be gathered at an area where no emergency occurs. This is known as emergency assembly area.

The Area can be specified based on the factory head count.

Exits

Exits are another key for designing layout, it may based on the Manpower strength in a factory. The Exits length may vary based on the machinery width as well. But number of exits will be based on the Manpower count and it should be based on the safety standards of Customer and Business as well.

No of exits for Small factories : For manpower strength up to 50 numbers, we can consider minimum no of exits as two.

No of exits for Medium factories : For employee strength from 51 to 200 employees its better to have 3 exits.

No of exits for Large factories : For factories above 200 employees, its suggested to have additional 1 exit for every 150 to 250 employees.

Exit width : Normal width of exits are 3 feet and 6 feet. If it is more busy exit (more peoples move frequently) it can be increased further and may go up to 4.5 meters.. Consider the dimensions of equipment while deciding this width. Internal exits or doors shall have the width of 3 feet and 6 feet.

Another point to be considered is its better to have exits within 30 meters distance from each worker at any position in the facility.

Latrine

As a general guideline no of latrine required is one per 25-30 employees. But, consider the near future expansion plans also in calculating the numbers.

Urinal

As a general guideline, no of urinal required for male employees is one per 50 male employees. But its better to consider the near future expansion plans also in calculating the numbers.

Steps in factory layout design

For Layout design we need to follow 9 steps.

Step 1 : Calculate Standard time for each process of the product. This can be done by direct stopwatch time study. If this is an entirely new product you may need to do PMTS to calculate the cycle time.

Step 2: Determine Takt time:  Takt time is defined as Target time of the product to complete which determined by customer and Takt time formulated as below. TT Provides for which the line/Factory need to set up. You may refer our article on takt time to know more.

5th Step: Now calculate the no of workstation, equipment and operators based on takt time. You may refer below articles for this.

1. Manpower calculation
2. Workstation calculation

Step 3 : Need to Prepare “Value Stream Mapping” of the product which is going to be produced in the facility. Consider top model for this Value stream mapping. This VSM should be from Warehouse to Finished goods. For knowing more about Value stream mapping, read this article from us.

Step 4 : Based on the VSM, No of work station, people and equipment, design the layout in such a way that all resources are optimized. Also consider safety and ergonomics while designing.

You may check out following assembly line models. 

How to get Layout Approval

Since the designing of layout is one part and getting approval for layout another key. Following process will get approval.

• After layout design team should review with all concerned persons (Civil, Maintenance, Safety, HR and Management team, etc.) to get feedback.
• If not ok, need to consider the inputs and redesign the layout.
• You may also need to discuss with your customer as well.
• Here Safety, Capacity, Manpower required, Construction and how much power required should be focused.
• If you are designing a entire new factory government approval may be needed.

Software for Design

Many of the Companies use AUTO CAD for this. Check our article on other CAD software.

These are the major points to consider in layout design. Please comment if any.

Conclusion

Whatever values or dimensions or requirement we provided here are in general. Those will highly vary according to your real situation, geographical area, etc.

You can also refer below guidelines also, which bests suits you. But there is only one rule allocate resources considering optimum cost and safety, to satisfy your customer.

Here are some examples of factory rules or regulations from popular countries around the world:

United States:

• Occupational Safety and Health Act (OSHA) regulations
• Fair Labor Standards Act (FLSA) provisions
• National Fire Protection Association (NFPA) codes and standards
• Environmental Protection Agency (EPA) regulations

United Kingdom:

• Health and Safety at Work etc. Act 1974
• The Factory (Safety Management and Administration) Regulations 1992
• Control of Substances Hazardous to Health (COSHH) regulations
• The Electricity at Work Regulations 1989

Germany:

• Arbeitsschutzgesetz (Occupational Safety and Health Act)
• Betriebssicherheitsverordnung (Ordinance on Industrial Safety and Health)
• Gefahrstoffverordnung (Hazardous Substances Ordinance)
• Arbeitssicherheitsgesetz (Workplace Safety Act)

China:

• Labor Law of the People’s Republic of China
• Regulations on Safety Management of Dangerous Chemicals
• Occupational Disease Prevention and Control Law
• Fire Prevention Law

India:

• The Factories Act, 1948
• The Building and Other Construction Workers Act, 1996
• The Environment (Protection) Act, 1986
• The Mines Act, 1952

Guntapudi Udayravichandra @guntapudi

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