Material Handling and Storage Welcome to Material Handling and Storage training.

This material was produced under grant number 46B4-HT15 from the Occupational Safety and Health Administration, U.S. Department of Labor. It does not necessarily reflect the views or policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.  

Material Handling and Storage Warehouse facilities are exposed to many hazards due to the inherent nature of materials shipped, stored, and distributed. Warehouse operations perform three main functions: receiving bulk goods from suppliers; order picking to select desired goods from within the warehouse; and shipping goods to the customers. Information in this module describes example ergonomic hazards and solutions related to order picking, which accounts for a large number of musculoskeletal disorders (MSDs). The areas addressed are Transport, Storage, Packaging, and Work Practice.

Objectives Discuss the basics of ergonomics and functions of the spine Describe the various types of order picking systems Describe proper lifting techniques Identify material handling hazards associated with various warehouse operations Transport techniques Storage Packaging Work practices

Basic Functions of the Spine Supports the body’s weight Structure for body Flexibility to bend and rotate Maintains natural S curve for maximum strength The back is a very complex mix of muscles, ligaments, bones, discs, and nerves. It carries most of your body's weight and maintains the structure of the torso, acts as a shock absorber, protects the spinal cord and nervous system, and allows body flexibility. The spinal column has natural curves that act like arches of a bridge and allow us to load the spine 10 times more that if it were straight. The key to preventing back injuries is trying to maintain these natural curves in our daily activity. The spine is an "S" curve that in its natural state provides strength and balance to our daily activities and evenly distributes our body weight throughout its length. By maintaining the spine's natural "S" curve, we keep our backs in alignment and minimize stress and trauma.

Proper Lifting Techniques No tripping or slipping hazards Plan rest stops Easiest route Avoid stairs If it is too heavy - GET HELP! Plan the Job Lifting no-no’s Lifting loads across obstacles Lifting with one hand Fighting to recover a dropping object

Proper Lifting Techniques (cont’d) A ddress the item B end at the knee G et a good grip R aise with the legs Address the item Firm footing Shoulder width apart Staggered stance Straddle the object Bend at the Knee Not your waist Get a Good Grip Use whole hand Use gloves if necessary Raise with the Legs One of the largest muscles in the body. Using this approach will keep you from using another of the largest muscle groups in the body: the diaphragm in a scream of pain.

Keep the Load Close Closer to your spine Less force on back 10 pound load at arms’ length is 100 pounds on the back Remember the lever principle. The longer the lever, the more force is applied.

Lifting Techniques Diagonal lift Power lift The Diagonal Lift is used when lifting moderately heavy objects. This lift is the most common and allows for full use of good body posture. Use the following steps when using this lift: Straddle the object by using a wide diagonal foot placement and assume a full squat position. Lift the object by standing straight up, keeping the back in a neutral "S" curve position throughout the lift. The head and shoulders are held upright and the legs actually provide the strength for the lift. People with knee problems may have difficulty using this lifting style. The key to this lift is keeping the back arched. Using an improper technique will generally allow the hips to rise first, thus bending (arching) the back forward. The Power Lift is used when lifting moderately heavy objects. This is the lift preferred by most employees. It's more efficient because it requires less time and energy. Since it requires only a partial squat, people with knee problems may find it useful. Use the following steps when using this lift: Begin with the same diagonal foot placement as before. This time, bend mostly at the hips rather than doing a full squat. Bend the knees partially, keep the head and shoulders up. Grasp the load and stand up by lifting the head and shoulders up, keeping the lower back in a neutral "S" curve position.

Pivot…Don’t Twist Pivot your feet Turn entire body

Materials Handling Hazards in Warehouses Consist of job features which have a potentially harmful effect on the body Work station layout/environment Improper work methods Improper tools Job design problems Poor housekeeping Material handling hazards in warehouse - consists of job features which have a potentially harmful effect. These hazards can be the result of: Faulty workstation layout/environment: poor lighting, excessive reaching for phone or mouse, sitting or standing continuously. Improper work methods: application of excessive force to get the job done, high repetition rate, improper lifting techniques. Improper tools: tool does not match task, extreme or awkward postures when using tool, tools that dig into the palm. Job design problems: inadequate work/rest regimens, pace of work is too fast.

Transport Techniques Placing boxes on pallets Maintenance During this session we will be discuss the various hazards and solutions related to Order Picking, which accounts for a large number of musculoskeletal disorders (MSDs) in a warehouse. The areas addressed are Transport, Storage, Packaging, and Work Practice. During this process, employees usually move materials through the warehouse on pallet jacks. A pallet is placed on a pallet jack, and merchandise is removed from a storage area called a slot or pick bin, then placed on the pallet. Many of these loads, especially in refrigerated or freezer warehouses, are extremely heavy. Weights upwards of 80 to 100 pounds are not uncommon. See: http://www.osha.gov/SLTC/etools/grocerywarehousing/transport_techniques_animation.html

Placing Boxes on Pallets Repeated bending at the waist to place boxes on the lowest level of pallets Heaviest units are placed on the bottom layer for stability Requires employees to lift the heaviest loads using their worst body postures

Solutions Raise height of the bottom level Provide height-adjustable picking equipment Educate employees about the hazards of bending while moving heavy loads Stack empty pallets on the pallet jack to elevate bottom of load Place palletizer on forks of pallet jack to keep product at waist height Utilize power equipment Raise the height of the bottom level. This allows employees to keep the load close to the body, and minimizes bending of the torso. Provide height-adjustable picking equipment. Enables loads can be maintained at a height that minimizes bending at the waist. Educate employees about the hazards of bending while moving heavy loads, and ensure the use of proper lifting techniques. Utilize power equipment to reduce ergonomic stresses. Back belts: The effectiveness of back belts in reducing the risk of back injury among healthy workers remains unproven. If workers falsely believe they are protected when wearing belts, they may attempt to lift more than they would without a belt. This poses a risk of injury to the worker (See Back belts: Do They Prevent Injury? (DHHS) (NIOSH) Publication No. 94-127). See: http://www.osha.gov/SLTC/etools/grocerywarehousing/transport_techniques_animation2.html

Storage Low locations High locations Double or triple slots Reaching Aisle width Most goods in a grocery warehouse are stored for a period of time. Racking is used to expand the amount of storage that is possible. Metal racks are used for storage and the area created within the racking is called a pick bin or slot. Slots range in size, depending on the products stored.

Low Locations Pallets are stored in pick bins a few inches from the floor Low racking requires employees to bend at waist Is a significant problem since the heaviest load is in shortest stack Storing pallets in taller slots still requires employees to bend at waist Palletized products in warehouses are often stored in pick bins that are typically placed on the floor. This requires employees to bend at the waist to access loads that come to the warehouse stacked only a few feet high, or may be unloaded to the point where they are only a few feet high. Even when these pallets are stored in taller slots, employees must bend at the waist to access product. This is a significant problem since the heaviest product is usually in the shortest stacks. Low racking can force employees to bend at the waist to access loads. Loads in the bottom bins, require forward torso bending to reach under the rack, even when the top levels of the stack are at waist height or higher.

Solutions Elevate pallets within slot bin Place empty pallets under load Raise bottom level of racking so loads are at heights where bending is not necessary Provide a forklift with built-in vacuum hoist Whenever possible, elevate the pallets within a slot bin. The best technique is to place a palletizer into a tall bin. A palletizer will lower in height under the weight of a full pallet, then will raise the load as items are removed. The use of a turntable allows employees to reposition the load. This keeps the load close to the body. Pallets that do not have product stacked above waist height may be elevated by placing these empty pallets under the load. Care must be taken so the top level of the heavy product is not raised higher than mid-chest height. Raise the bottom level of racking so loads are at heights where torso bending is not necessary. Provide a device such as a forklift with a built-in vacuum hoist . The strong suction can lift up to 150 lbs.

Empty pallets stacked to raise product to waist height Solutions (cont’d) Empty pallets stacked to raise product to waist height Raised shelving

Solutions (cont’d) Vacuum hoist

Reaching above shoulder height High Locations Reaching above shoulder to access products on upper shelves Results in stress to back and shoulders Requires awkward hand and wrist postures Lifts above shoulder height often require awkward hand and wrist postures. Reaching above shoulder height

Solutions Use elevated rack locations Provide "Pick Sticks" or "Bow Peep" hooks Use elevated rack locations as the overstock storage area. Pallets of product should be lowered to more appropriate heights prior to being selected. Selections should be  performed with arms close to the body. Provide employees with "Pick Sticks" or "Bow Peep" hooks to pull small, light-weight product closer to the edge prior to lifting “Bow Peep” hook

Triple slotting requires elevated reaches to access product Multi-slot Hazards Maximizes shelving space Increases ergonomic stressors Forces workers to bend to access product Workers must reach above shoulders to access materials Double slotting Double or triple slotting is used to maximize shelving space so the greatest amount of product can fit in the smallest amount of space may increase ergonomic stressors such as bending and elevated reaches. Workers may be forced to bend at the torso to reach under low racking to access product. Stacking product at more desirable heights which would not interfere with racking system would eliminate worker bending. Workers must reach above shoulder height to access materials placed on three-tier racking or to access tall, palletized loads placed on two-tiered shelving. In general bottom and top racking in three tiered systems creates significant access issues. Triple slotting requires elevated reaches to access product

Solutions Provide full slotting Use gravity feed flow rack for slow moving product Full slotting Provide full slotting, especially for product that is heavy or bulky, so employees can have better access without undue reaching or bending. Slower moving product that is fairly compact can be warehoused using gravity fed flow racks. These racks allow highly condensed usage of warehouse space. However, hazards are created by this type of racking since it must be loaded by hand from the back of the rack. This can require repeated elevated reaches, repeated bending of the torso, as well as using box openers to cut open shipping boxes. Also, Selectors must pull product over the stop lips that keep the product from sliding out onto the floor. Heavy product in the slot creates additional pressure when lifting boxes over the stop lips. Gravity fed flow racks

Reaching Product is often removed from the front of pallets first Leaves remaining product in the back of pallets Creates additional stress on the shoulders and back Reaching to the back of the pallet Hazards due to reaching are usually the result of product that has often been removed from the front of pallets first. This leaves the remaining product stacked in the back of pallets, where employees must reach to access and lift product. This creates additional stress on the shoulders and back.

For optimal access, place Solutions Develop product rotation process Place pallets on turntables Use roller and channel devices Provide wider slots for heavier products Train stockers to allow sufficient space to move pallet during selection Develop a product rotation process where pallets are regularly turned using a forklift or pallet truck after the majority of product has been removed. This involves pulling the pallet out of the slot, turning it 180 degrees and replacing it into the slot. Place pallets on turntables so the pallet can be turned and optimal access to the product can be maintained at all times. Use roller and channel devices These devices allow the load to be pulled out for better access. The addition of a turntable at the end of such device will allow the pallet to be turned and then replaced into the slot with the load closer to the front. Provide wider slots, especially for heavier product. This will allow selectors to walk into the slot and access all sides of the pallet. Stockers should be trained to leave at least 16 inches between pallets so there is enough space for Selectors to move around the pallet during selection. For optimal access, place product on turntable

Aisle Width Insufficient access to faster-moving product Creates congestion Forces selectors to stop farther from pick slot and carry product longer distances to pallet jack To save trips, selectors may be tempted to carry multiple parcels at the same time Congested aisle The width of aisles in many warehouses is often insufficient for access to fast-moving product. This may be due to the size of the aisles, or the congestion of products on skids that are being loaded or unloaded into supply bins.

Solutions Increase aisle width of aisles where fast-moving product is located Will allow pallet jacks to get closer and reduce distance loads must be carried Stagger the start times at beginning of day Results in fewer selectors hitting the same slots at the same time Increase the width of aisles where fast-moving product is located. This will allow more pallet jacks to get closer and will reduce the distance that loads must be carried. Stagger the start times for Selectors at the beginning of the day so that fewer selectors hit the same slots at the same time. Five to 10 minute start differentials should provide adequate spacing for sufficient disbursal of selector.

Packaging Heavy containers Inadequate handholds Plastic wrapping Wooden pallets Wrapping pallets Opening boxes Products vary in warehouse can vary in weight by up to 100 pounds — and are shipped to the warehouse in a variety of containers, including boxes, bags, and cans. The shape, weight, and/or material of these package can greatly affect the stress that a grocery warehouse employee experiences. 5-Gallon (40 lbs)

Heavy Containers Boxes are extremely heavy in cold or freezer warehouses Weigh as much as 100 lbs. Manually lifting places stress on employee’s muscles Repeated lifting can result in back injuries, muscle strains and disc injury In cold or freezer warehouses many boxes are excessively heavy; they may weigh as much as 100 pounds. Manually lifting loads in this weight range places great stress on the employee's muscles. Back injuries, such as muscle strains and disc injury, can occur when repeatedly lifting these heavy objects.

Some suppliers are willing to modify weight of packages Solutions Work with suppliers to provide product in smaller, lighter containers Improve access to heaviest items Provide handhold cutouts or handles on all heavy products Work with suppliers to ensure container integrity is adequate Load pallets with lighter product in center and heavier on outer edges Work with suppliers to provide product in smaller, lighter containers. Improve access to heaviest items. Employees should be able to access these items without bending at the waist, pulling the elbows away from body while reaching, or twisting. Redesigning storage racks and transport devices can greatly improve the employee's ability to maintain these neutral postures. Provide handhold cutouts or handles on all heavy products. Work with suppliers to ensure that container integrity will be adequate so the box, bag, or bucket will not accidentally break, rip, or pull apart during lifting operations. Load pallets with lighter product in the center and heavier on the outer edges to ensure easier access and lifting of the heavier items. Some suppliers are willing to modify weight of packages

Heavier packages on the outside Solutions (cont’d) Heavier packages on the outside

Inadequate Handholds Many packages do not have handles or handle cut-outs Makes heavy cases difficult to grasp Forces employees to use awkward posture Many packages that come into warehouses do not have adequate handles or handle cut-outs. This makes heavy cases difficult to grasp and/or retrieve, which forces employees to use awkward postures when lifting these packages. Without hand cut-outs or handles, employees must press on the sides of boxes, slip fingers under the lips of products, or grasp the loose material of bags to gain control. These techniques place strain on the hands and shoulders. Boxes without handles are difficult to grasp

Solutions Encourage suppliers to provide product in stable boxes with hand hold cut-outs or handles Is especially important for product that is extremely heavy Examples of handhold devices

Workers bend to lift pallets several times during a shift Wooden Pallets Weigh between 40 and 70 pounds Lifted several times during work shift Repeated lifting causes stress to lower back Splinters from handling wood is also a hazard to worker Workers bend to lift pallets several times during a shift

Solutions Request lighter, plastic pallets Easily nest together to reduce space of stacking Eliminates splinters and uneven surfaces Provide a pallet dispenser to reduce handling of pallets Pallets weigh 20 to 30 lbs. Request that suppliers provide product on lighter, plastic pallets. The employees of both the warehouse company and supplier will benefit from the reduced weight. Plastic pallets easily nest together to reduce the space of stacking. They also eliminate splinters and uneven surfaces that employees may step on when walking over pallets. Provide a pallet dispenser to reduce handling of pallets. This device allows Selectors to drive their pallet jack to the dispenser. An empty pallet is then automatically loaded onto the forks without manual lifting. Pallet dispenser

Training New Employees New employees may not recognize ergonomic hazards or understand effective techniques used to minimize these hazards

Solutions Provide general ergonomics and work-task specific training at time of orientation Explain risk factors and proper work techniques to minimize hazards Provide video tapes of proper work practice for employee review Retrain injured employees regarding ergonomic risks pertinent to their injuries Mentor new employees with experienced workers Explain the medical management system Provide general ergonomics training and work-task specific training at the time of new-hire orientation. Explain the risk factors and proper work techniques to minimize these hazards. Provide appropriate video tapes of proper work practice for employees to review on a regular basis. In addition to regularly scheduled refresher training, injured employees should be retrained regarding ergonomic risks pertinent to their injuries. Provide Post Incident Refresher Training after injuries. Mentor new employees with an experienced worker who can provide insights on the proper and most efficient methods to perform their tasks. Explain the medical management system to new-hires. This will let employees understand how to report an injury and how the company prefers its employees to seek medical attention. This can expedite assistance, reduce costs, and improve lines of communication.

Summary Discussed the science of ergonomics and functions of the spine Described the various types of order picking systems Described proper lifting techniques Identified various material handling hazards associated with warehouse operations Transport techniques Storage Packaging Work practices