Ergonomics for the Lean Supply Chain

Feb. 18, 2004
At every stage of the supply chain, ergonomics can be used to protect workers and streamline the movement of materials.

Welcome to the world of ergonomics, logistics and retailing. Ergonomics can play a vital role in supporting materials management and the retail aspect of the business world. Ergonomics allows an employee to function at their highest level of productivity, quality and efficiency. This is accomplished without the occupational risks of workers' compensation claims, disability claims, lost work time, production problems, quality issues and labor relations issues.

Ergonomics can be viewed as the principal engineering discipline involved in the physical planning for materials transportation: from the suppliers to points of storage or use; for the materials handling in receiving and shipping and between processing operations; and for material storage (purchased, work in progress and finished goods). The engineering ergonomist may have to work with suppliers, providing specifications to minimize injuries, lost work time and inefficiencies to the human system, as well as specifications related to the materials management. Other objectives for the procurement, transportation, production planning and control, warehousing and information systems must also be included in the ergonomics process.

In the 1970s, materials management referred to the group of functions that manage the complete cycle of material flow. Today, the trend in materials management is to keep inventories low, while still providing very high levels of product and material availability, and a very fast response to changing or unexpected demands.

Flexible and Fluid

The thought of rigid, fixed, linear supply chains is rapidly being replaced by more flexible and fluid networking alliances and economic webs. There is more volume concentrated with fewer select suppliers. Manufacturing dictates that products be produced more frequently and in smaller lots, within cells dedicated to particular parts or products. In repetitive assembly, inbound parts may be sequenced and kitted by a logistics service company to match planned assembly sequences. More components and parts are being delivered to the point of use.

In distribution, more incoming goods are being shared on multiple docks, moving directly to outgoing orders or lanes without any storage stops. In retail distribution, retailers expect goods to be delivered in "floor-ready" condition. Finished goods are being reduced as more products are made to order and shipped directly to the customer.

A new model, called Connective Technologies, is built around new elements:

  • People
  • Information
  • Smart products

There is a crucial need to connect the people, information and smart products along the supply chain. For companies using "old" business methodologies, their ability to compete on a worldwide basis will be greatly impacted. An AMR Research study provides insight into why companies are still actively pursuing B2B e-commerce activities. The financial benefits range up to $465 billion annually.

With new challenges on the horizon, employees will be expected to work faster, harder and with more quality to meet the production schedules for the "just in time" manufacturing, assembly and delivery requirements. Companies are laying off employees in order to maintain their viability while still attempting to compete on the same level. The reduction of MUDA (Japanese for waste) or waste within facilities will be crucial, as it will cut costs and allow for greater useable space. Ergonomic specifications and assessments can be developed and communicated via the Internet for all of the crucial elements for successful logistics management.

Ergonomics in the Process

Ergonomics supports a variety of the issues that impact suppliers' production schedules, especially in a just-in-time production environment. For example, how efficient is the setup or changeover process? Ergonomic assessments of time and motion should consider the capabilities and limitations of the workers that have to perform these jobs. Ergonomic risk assessments allow facilities to identify the jobs with the greatest injury potential before problems occur, which reduces costs and improves productivity.

Computer simulation programs can be used to model jobs based on movement. While you want employees to move, you don't want them to move excessively because it is not efficient. Why make a person move 100 or 200 yards to pick up a component or part?

While these short runs have been reduced, it is also important to make sure the correct equipment is being used. You do not want to produce a secondary or tertiary risk to the employee by not having the appropriate tools or equipment for the job.

Cellular manufacturing can allow a person or a few people to operate in an area and perform a multitude of jobs, which is very efficient. However, an ergonomic assessment should be conducted to make sure new stresses are not introduced and that the cell operates in an effective manner.

Ergonomic product assessments can be used to ensure that containers are the proper size for the operation. Sometimes, OEMs bring to the workplace products or components in containers that aren't proper for the operation, which causes the employees to have to jerry rig something or tear it down completely and start anew. Make sure you understand the ergonomic specifications for your suppliers and your vendors so it doesn't interfere with your production and create the possibility of injury to your employees.

Web-based data sharing offers an important advance in the management of information. By making ergonomic specifications available on the Web, suppliers and OEMs can bid according to them and the company cuts down on waste and time.

Transportation Planning

Is your company paying the price of poor utilization and unnecessary transport costs that may be the result of workers' compensation claims, employee dissatisfaction and lost work time? These problems are all reflected in end-product pricing and constitute an indirect cost that you are paying.

Ergonomics can play a role in reducing these transportation costs. For example, poor pallet and container selection may be a problem. Wooden pallets may be less expensive to purchase initially than plastic pallets, but they are not as durable and they are a source of worker injuries. Moreover, pallets often are repaired in the plant and that takes time from other activities.

The right ergonomic specifications can also help avoid the loading and unloading problems that can result in late deliveries and waste. For example, tires may be literally jammed into a delivery truck to minimize costs, but then workers unloading the truck are forced to pry them out, taking unnecessary time and setting up the potential for injury.

Travel time may be impacted by driver discomfort or injury. Companies should carefully examine truck cab design and seats to make sure they are comfortable and don't result in unnecessary driver fatigue. And by choosing trucks with automatic transmissions, companies prevent the cumulative stress placed on drivers, particularly in urban areas, who must constantly shift and use the clutch.

Material Handling and Storage

Ergonomic assessments can determine if the material handling methods employed in a facility are appropriate. The lifting, lowering, pushing and pulling that go on in material handling have great potential for costly injuries.

The manual material handling equipment should be the most suitable for the tasks. Often, solutions are inexpensive. A $150 scissors lift table may prevent a $100,000 back injury. You can stack pallets and allow them to serve as a lift off the floor. You can set up a work rule that an employee cannot lift material from the floor and that the minimum lift is maybe two or three pallets high.

While lift trucks are usually replaced only when they wear out, new designs can provide important ergonomic and safety benefits. In selecting lift trucks, make sure that they offer good driver visibility. Lift trucks with center-line steering are available that do not force the employee wearing a seat belt to twist and look back over their shoulder when tasks call for reversing the lift truck. Also, maintain plant flooring in good condition so that vibration does not create health issues.

Companies should ensure that conveyors are appropriate for the tasks, and are safe and efficient. Make sure materials, parts or packages can't fall off the conveyors; avoid sharp angles in the conveyor setup. Good maintenance is necessary to avoid breakdowns and resultant hazardous situations such as employees pushing product down the conveyor.

In warehousing, space is king. Shelving is set up to maximize storage space, but it important to make sure that employees can retrieve items in a safe manner. For example, avoid storing material so high that lighting interferes with pickers or so low that employees are crawling on the floor to pull things out.

In storing material, weight is an important issue. The heavier an item, the closer it should be to the employee and the less they should have to lift over the shoulder or bend from the floor. Be sure to maintain adequate working height with heavier articles. Lightweight parts or packages don't have as much impact on the body unless there is a lot of repetition.

Cases, cartons and totes have to be easily carried, which means they should have handles or cutouts. Handles and cutouts should be sized for a 95th-percentile male hand wearing a glove.

Be on the lookout for process and methods improvements. By changing a processing method, a company can simplify or reduce the cost of handling and storage and reduce setup. Examine whether implementing manufacturing cells and using teams of employees cross-trained on various tasks will improve production. Ergonomic audits provide a roadmap for what issues must be addressed and what budget will be needed for improvements. Employers should establish the criteria for this audit, whether it be reductions in lost worktime or improvements in quality or production.

When changes are made and employees are properly trained, go back after a period of time, such as three months, and determine what improvements have occurred. That assessment will provide a cost-justification for the ergonomic changes.

A system or process for work measurement in your operation allows you to develop a clear, complete job definition for every job. This job definition is broken down into the task requirements, the tools or equipment needed, and what type of human capacity is needed to perform the job, not just once but over the long haul.

At the retail end of the supply chain, companies need to reduce ergonomic hazards from an efficiency as well as a safety perspective. For example, a good hand-held scanner that can read bar codes without repeat swipes or the necessity to keep turning items not only reduces stress on employees but makes checkout faster for consumers who have no desire to stand in long, slow lines.

The aisles have to be free of obstruction so that customers can make their selections. The checkout area must be set up so they can unload their goods. The facility has to be clean. Signage has to be easy to read. Loading docks have to kept clean, especially in the winter. Dock doors should be well-maintained so that employees can easily lift them up and pull them down.

Information systems integration provides a company with the proper information so it can direct and control the physical movement of goods and make sure that customers don't have to wait for goods or, much worse, come back for unstocked items.


Ergonomics plays a critical role in translating the physical capabilities of workers, the task requirements, the equipment/tool requirements and the policies and procedures in a working system. From moving the goods from manufacturer to warehouse to point of sale, the consumer must have the availability and the best price to have the choices necessary to make buying decisions. Electronic commerce (e-commerce) has already reshaped the retail world, and the pace of this transformation continues to accelerate. It is not easy to predict what principles and skills will be essential to retail survival and which will fade.

How can today's retailer translate yesterday's achievement into tomorrow's success? How can the manufacturer and the warehouse meet the needs of the retailer? Discussions will center on docks, maintenance, signage, checkout stands, inventory control, types of manufacturing and e-commerce solutions. Through the Internet, the development of intelligent solutions, the correct methodologies, management and control of costs and nearly instantaneous distribution of the information for inventory as well as storage will provide the ability to react immediately to changes in demand. All of the cost-effective, practical answers to the questions asked can be answered through the application of ergonomics. This translates into greater profits for the logistics and retail industries.

Cynthia L. Roth is president and CEO of Ergonomic Technologies Corp. (ETC), an ergonomics consulting and training firm based in Syosset, N.Y. She can be reached at (516) 682-8558 or via e-mail at [email protected].

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