Layout of a warehouse depends on the proposed material handling systems and requires development of a floor plan to facilitate product flow. If pallets are to be utilized, the first step is to determine the pallet size.
Process of Layout Design
The layout of a warehouse may need to be changed to accommodate new product lines or to add greater flexibility to the warehouse operations. When a new warehouse layout is proposed a detailed planning process should be followed to ensure the success of the project. The planning process should include the following six steps.
- Define Objectives
- Collect Information
- Analysis
- Create Plan
- Implementation
- Post Implementation
Define Objectives – When deciding on the layout for a warehouse, the objectives should clearly be defined. The objectives should be aligned with the overall warehousing strategy of the company. Objectives can be defined at a high level such as to reduce warehousing costs or to provide maximum customer service.
Equally, the objectives can be more specific, such as maximizing warehousing space, providing maximum flexibility in the warehouse, or increasing warehousing efficiency without increasing resources.
Collect Information – The specific information of the proposed warehouse should be collected. This includes the specifications of the warehouse from the architectural drawings that can affect storage and material handling.
The details should include a physical map of the warehouse space to show columns, doors, height restrictions, docks and storage racks. External features that can affect the receiving, storage and shipment of materials should also be noted.
Analysis – After the specific information about the warehouse has been collected the analysis can commence with respect to the objectives that have been defined for the warehouse layout. The analysis should determine if the overall objectives can be met and if not how the objectives can be modified.
At this point in the planning process, decisions need to be made by warehouse management to determine what actions need to be taken if the overall objectives cannot be met or will need substantial changes.
If the objectives can be met based on the analysis of the information, the detailed implementation plan can be created.
Create Plan – The detailed implementation plan should show all the steps that are required to create the warehouse layout.
The objectives and the analysis of the information gathered should be used in creating the plan. The plan should first be at a high level showing the major tasks and then each of those should be sub-divided into the individual tasks that are required.
Each task should be reviewed and an allocated the appropriate resources, as the allocation of estimated time required to complete the task. The plan should indicate when a task is required to start and finish based on the availability of resources, either internal or outside contractors, or if it is dependent on another task.
The plan should be checked to ensure that all dependencies have been correctly linked. Once the plan has been created it should be checked to see if the timeline is attainable and if there are enough resources are available.
Implementation – Sometimes the warehouse layout that is implemented is not the one that is in the plan. This can occur due to unrealistic timelines in the plan, lack of resources, unavailability of outside contractors or poor analysis of the information that was gathered.
To ensure that the plan for the warehouse layout is achieved the implementation should be timed so that there is little or no movements of materials in the warehouse. An ideal time for this would be during a plant shutdown or at a weekend if the implementation was of a smaller size.
However in modern warehouses, this is not always possible so often additional warehouse resources are needed to keep shipping products during the implementation. If this is the case then this will need to be factored into the plan. The implementation should ensure that all changes made in the warehouse are replicated in the warehouse management system that is operated so that each item can be found.
A physical inventory of the products in the warehouse after implementation should be carried out to ensure that the system accurately reflects the warehouse.
Post Implementation – After the layout has been implemented, there should be a series of checks to ensure that the layout is exactly as defined by the approved drawings.
Every item should be stored according to the overall plan and this should be checked to ensure the layout is correct. If there are errors, this could lead to picking errors or lost material within the warehouse. Shipping could be disrupted if the warehouse systems have not been updated accurately with the correct layout information or if items have been stored in the wrong locations.
For a period of time after the new layout has been implemented, regular checks should be made to ensure that the layout is working and that there are no operational problems that have occurred due to the new layout. These checks should include cycle counts and regular physical inventories.
Factors affecting the design and layout of a warehouse
Product: What kind of goods will it hold?– Warehouses are used for storing goods, as part of the supply chain. It is essential that we clearly understand all the characteristics of these goods: the load unit used, its dimensions and minimum/maximum weights. The amounts, types and references of each one of them, their sensitivity to different temperatures, and so on, all determine issues as crucial as the storage system to be used, the required dimensions of the shelves and the installation work areas, among others.
Space: What physical characteristics does the building have? – The dimensions and characteristics of the warehouse infrastructure are essential and must be very accurate information. They are required for the design of shelves, to calculate the capacity of the installations and the distribution of the goods inside the warehouse. There are also limitations that must be taken into account: access, floors, windows, columns, boxes, lines and power lines are all examples of parts of an installation that influence its design. Furthermore, there are the building regulations that directly affect the calculations of metal storage structures.
Equipment: What means are available? – Contrary to what one might think, in many cases the design of a warehouse does not begin with an empty space. Any such elements as racks, lifts or transport equipment must be taken into account and their characteristics analysed. These components influence the design proposal. They make it possible to evaluate which design best adapts to project needs, any limitations present and/or the need to integrate new equipment.
Flow and rotation: How do goods circulate? – By flow we mean the movements performed in logistical operations, such as dispatch, receipt and order preparation processes. By product rotation we mean how often the goods are renewed; that is, a high-rotation product is one that has a high rate of inputs and outputs. Moving loads involves costs, and therefore movements must be minimised, provided that the company operational procedure admits it. Detecting these flows is very important as they contribute to defining the needs of the project and to designing the most efficient installations.
Personnel: What staff is available? – The staff is one of the most important assets of any company. Knowing the number of employees, their level of training, how they are organized, the shifts they work, and other factors, can help refine the proposed design of the warehouse. The introduction of automated components, warehouse management software and health and safety standards mean that nowadays operators are much more specialised than before.
Management and company policy: How is the warehouse organised? – Good warehouse management means that the necessary stock is available, the warehouse provides the best possible service, has a high level of occupancy and optimises internal operation times, among many other things. It is therefore a basic factor.
Understanding how installations are managed allows us to assess their effectiveness and define which processes can be optimised during their design and planning. For example, a change in the way the shelves are distributed can simplify the picking processes.
Today, the trend is increasingly geared towards professional facilities using warehouse management software (WMS) to ensure the control of all these processes. Each of these factors influences the design to a greater or lesser extent, in accordance with the needs and characteristics of each business.
Guidelines for Warehouse Layout
Understand the Design Objectives and Constraints – The first step in your review should be to determine and prioritise the objectives for your warehouse facility and operation. It’s also important to document any constraints that will impact your plans to meet those objectives.
For example, your company’s objective might be to achieve maximum operational productivity, to improve customer service, or perhaps to minimise capital expenditure. If you don’t plan to commission a new warehouse on a greenfield site, your plans might be constrained by the characteristics of an existing facility.
A clear understanding of objectives and constraints will provide you with the starting point for your design review, so it’s important to get them documented and to make sure all stakeholders are aware of them.
Know Your Operational Profile and Requirements – In order to maximise the benefits of your warehouse review, you should be completely familiar with the characteristics of all products that are to be stored. The most important SKU characteristics to understand are as follows:
- Dimensions, weight, number of units per pack, pack dimensions, pack weight
- Pallet size, height, and weight
- Special handling needs and environmental/temperature control requirements
Order and picking profiles should be examined too. For example, is an SKU typically ordered by the pallet, carton, split carton, or individual unit?
In addition to profiling individual SKUs, you should try to look at the relationships between them. For instance, do you have two or more SKUs that are commonly ordered together? If so, you should plan to slot them close together to improve picking efficiency.
Another key factor in warehouse-design planning is the quantity of inventory you intend to hold, either in an existing or new facility. This means taking into account stock currently on hand, along with any plans for expansion. Stock-on-hand snapshots should be taken during peak, normal, and low seasonal periods.
When planning, remember also to consider requirements for specialised storage and processing areas, such as a production room or caged-off quarantine areas.
Storage & Layout Design – Having evaluated your operational profile, you should be able start thinking about warehouse storage media and the number/capacity of storage locations.
Will you fit your warehouse with standard racking, or do you see a need for more specialised apparatus such as carousels, or an automated storage and retrieval system (ASRS)?
Whether you bring in some external help or go it alone, keep the following tips in mind when planning your new warehouse layout:
- Optimise flow by minimising the number of touches as SKUs pass through the warehouse
- Prioritise workforce safety when designing your solutions
- Model a few design options and determine the best solution through quantitative/qualitative comparisons
- Involve all stakeholders in the planning and design process to attain their buy-in
It will pay to make use of digital design and modeling software to help you arrive at an optimal warehouse layout and strategy. There are a number of very good applications on the market. These tools will help you design different solution-options to compare and evaluate. You might try any of the following three examples, or hire external specialists that work with them:
- CLASS (Cirrus Logistics Ltd): Commonly used by 3PLs, the CLASS software license is expensive but the application is user-friendly and provides 2D/3D views of your layout designs, including elevation views of storage media. CLASS allows users to design the layout of their warehouses ahead of commissioning projects and without disrupting current operations. CLASS delivers scale models and drawings that are clear and easy to understand.
- AutoCAD : An AutoCAD software license is less expensive than CLASS. However, the application is less user-friendly and is typically used by engineers and racking vendors for design and specifications.
- Google Sketchup : Sketchup is not specifically intended to be a warehouse layout design tool, but has the capabilities necessary for warehouse modeling and can generate perfectly good design visualisations. The biggest benefit of this tool though is cost, as the license is less expensive than either AutoCad or CLASS.
Document All Results and Assumptions – Throughout the warehouse planning and design process, you will gather a lot of facts and probably make a fair number of assumptions. It’s good practice to document all facts and assumptions, because this will help you recall how designs were derived. Your records will also prove useful for future layout reviews, which should ideally be conducted every couple of years.
