The sixth and seventh steps on the path to safety lead us to the crucial topic of material handling. Last month we discussed strategies for safe manual material handling. This month we will focus on the use of mechanical assistance in material handling as well as other strategies to consider to reduce injuries. Material handling equipment is used for the movement and storage of material within a facility or site. It falls into four categories: transport, positioning, unit load formation and storage.
When transporting material from one location to another, mechanical devices such as conveyors, cranes and industrial trucks can be used. Conveyors move materials over a fixed path. Commonly used conveyors are roller tables which allow the material to be pushed along its length rather than lifted and carried or a flat belt conveyor which moves the product along mechanically. Other specialized conveyors exist to meet manufacturing needs. Cranes are used to move materials over horizontal and vertical variable paths within a restricted area.
They are able to handle varied loads with respect to their shape and weight. Commonly used cranes include jib cranes which can be mounted on delivery vehicles and used to unload heavy materials at a delivery site. Bridge and gantry cranes are used especially to move pipe within a distribution center. Industrial trucks are used to move materials or employees over variable paths, with no restrictions on the area covered by the movement.
This category includes such commonly used items as hand trucks, pallet jacks, lift trucks, and order pickers. It is important to note that even a device as simple as a hand truck has many variations. Care must be taken to identify the specifications of the item to be moved and the best hand truck model to perform the task. For example, if 55 gallon drums are to be transported, choose a hand truck designed specifically to handle drums. If water heaters and boilers need to be taken up and down stairs, choose a mechanized hand truck that can “walk” them up or down the stairs.
Positioning equipment is used to handle material at a single location so that it is in the correct position for subsequent handling, machining, transport, or storage. Use of this equipment will raise the productivity of each worker when the frequency of handling is high, improve product quality, limit damage to materials, and reduce fatigue and injuries. Commonly used equipment in this category includes dock levelers and lift/tilt/turn tables. Dock levelers are used at loading docks to compensate for height differences between a truck bed and the dock.
Lift/tilt/turn tables are used when positioning involves the lifting, tilting, or turning of a load. Pallet load levelers are lift and turn tables used in manual palletizing to reduce the amount of bending and stooping involved with manually loading or unloading a pallet. It combines a lifting and turning mechanism with a device that raises or lowers the table as each layer is completed so that loading always takes place at the optimal height of 30 inches. It turns the pallet so items located in the back can be easily reached after the pallet is turned. If such tables are not economically feasible, the pallet to be loaded can be placed on a pallet jack that is manually raised or lowered to the desired height. If necessary, empty pallets can be placed under the pallet to be loaded to further elevate it.
Unit load formation equipment is used to restrict materials so that they maintain their integrity when handled as a single load during transport or storage. This category includes pallets, skids, totes, bags, boxes, strapping, shrink wrap, bins/baskets/racks, cartons and palletizers. Palletizers are automatic wrapping machines where the pallet sits on a turn table and the shrink wrap is applied by the machine. If shrink wrap has to be manually applied, use the lightest roll possible and apply using a handle to prevent cuts to the fingers. Raise the pallet up on empty pallets to avoid the bending and twisting that is required to apply shrink wrap to a pallet sitting on the floor.
Storage equipment to hold product is found in all of our workplaces in the form of racking, shelves, and bins. Racking presents several ergonomic challenges that are worth mentioning. It is common to use multitier racking with material placed on the floor underneath the lowest tier. The material may or may not be on a pallet. Placement of material in such a position requires employees to assume the high risk posture of bending at the waist, leaning forward and reaching under the rack to access and lift product.
Strategies to minimize the risk of injuries include:
(1)make the bin slot taller to allow more upright access to the material;
(2) use a load leveler palletizer with turn table so the load is at an ideal height of 31 inches and product is within an easy 24-inch reach;
(3) elevate the load on empty pallets if the top of the load is not higher than mid-chest height;
(4) have a regular rotation schedule so the pallets are turned using a pallet jack or forklift to ensure materials remain within easy reach;
(5) instead of using the floor, install the lowest tier of racking 12-15 inches off the floor;
(6) provide a minimum width of 16 inches between pallets so employees can move around the pallet to more easily access the material on it.
Material handling is a fact of life in the workplace. Developing and implementing a compliant material handling program will lead your company on the path to an effective safety program and positively impact your productivity, the health and well-being of your employees, and a better bottom line.
This article was written in conjunction with participants in the OSHA and ASA Alliance. It does not necessarily reflect the official views of OSHA or the U.S. Department of Labor.
