Conveyors can be one of the biggest contributors to improved productivity or one of the biggest problems in a warehouse. It all depends on...
Hand Stack Rack
Hand stack rack is intended for large bulky and/or unusually shaped products that are too large for bin shelving or are stocked in too large a quantity to conveniently fit in bin shelving. Typically this type of rack is furnished in 30", 36" or 48" depth and from 60" to 120" wide with a per shelf capacity of 2,000 to 2,500 pounds. The actual shelf surface is either wire decking or wood particle board, depending on depth. This deck material usually sets in the step or depression on the inside of the beam.
Frame capacity is normally 14,000 pounds and the beams are rated at 2,000 to 2,500 pounds per pair. This type of hand stack rack will readily support a mezzanine or catwalk system as desired.
Each beam that supports a shelf level will be 3" or 4" in height thereby reducing the usable storage space in the rack by 3" or 4". Usually there is not a beam level at the floor so that product is set on the floor or on a piece of particle board on the floor.
Racks must be set 2" or so away from any fixed object such as a wall or beam or other racks. If this is not done, the back beams cannot be inserted or removed or adjusted without moving the entire rack row. Row spacers which connect to the rear of each frame in a back to back arrangement are used to set and maintain this clearance. Usually there are two (2) row spacers between each pair of frames. Row spacers can be any length you want.
Pallet Storage Rack
Selective Pallet Rack is the most common type of rack used for the storage of pallet loads of merchandise. This style of rack provides individual and unobstructed access to each and every pallet that is stored in every rack.
The aisle in front of the selective pallet racks should be wide enough for your powered fork truck to make a right angle stack into the rack.
How to design Pallet Rack
- Height: Measure the vertical dimensions of the pallet, pallet load and beam (usually 4"; or so). Add 4" to 6" for clearance between the top of the pallet load and the beam above. The top beam needs to be at least 6" less than the lifting height of the fork truck.
- Depth: Measure the depth of the pallet. The pallet should overhang the frame by 3" in the front and the back. The frame depth should be 6" less than the depth of the deepest pallet.
- Width: Measure the width of the pallet and pallet load; use the greater of these two dimensions. Add 3" to 4" between the loads and between the loads and the rack frames. This total is the minimum beam length you should use. Select beams with a capacity at least equal to the weight of the pallets to be supported.
- Frame Capacity: Add the total weight of the loads to be supported in each unit (exclude the weight of the pallet loads on the floor)
- Common Frame: Adjoining sections will share frames for supporting the load beams. Frame width is 3". Center to center of frames is beam width plus 3".
Note: For varying depth pallets, wire decks or pallet supports will be required between the front and rear load beams.
In a back to back configuration, row spacers are used to maintain the spacing between the rack rows. 12" row spacers are usual to allow a 6" flue space between pallet loads. Usually there are two (2) row spacers between each pair of frames. Row spacers can be any length you want.
Double Deep Rack
Double Deep Rack is a method of increasing the pallet capacity in a given storage area. Double deep rack is simply one row of pallet rack in front of another row of rack. This results in one pallet being behind another pallet which can create problems unless the pallet loads are all the same product. Double deep rack requires a straddle truck with a reach mechanism to reach the rear load. Generally the bottom level of pallet loads is placed on a beam level approximately 8" or 10" above the floor. This allows room for the straddles on a straddle truck to enter the rack under the lower loads. Typically a 6" spacer is used between the front and rear frames of double deep rack. Double deep rack can be used in single faced or back to back configurations similar to selective pallet rack. With the exception of the lower beam level, the design and specifications for double deep rack are the same as for selective rack.
Push Back Rack
Push Back Rack is another type of high density storage commonly in use. In this type of storage unit you may have up to three (3) pallet loads in the same lane or face, one behind the other. Each pallet face or opening is its own lane and is independent of the loads in other lanes. As a load is placed into a lane in the push back rack it pushes the load already in the lane back into the rack and leaves the last load put in front. When a pallet load is removed from a lane, the load behind it flows forward and becomes the front load. Push back rack provides a Last In, First Out (LIFO) inventory rotation. This is a similar application to double deep rack but with greater depth and without the need for a straddle or reach truck. Push back rack can have as many levels of storage as selective pallet rack.
Drive-in/Drive-thru (DI/DT) Racks are yet two other types of high density storage rack configurations commonly in use. These types of storage are generally employed when a large quantity of pallets of the same commodity need to be stored and they cannot be self stacked more than one or two high. Generally, 9 pallets of the same commodity is considered a minimum to make this type of storage effective. A standardized pallet size and configuration is a must to allow these types of racks to be efficient.
Cantilever Rack is commonly used to accommodate odd sized or large loads of merchandise such as carpets, furniture, conduit, and pipe and bar or flat stock. Unlike all the above racks, cantilever rack does not have vertical members or columns in the front of the rack to limit the width of the loads to be stored. As the name implies, the storage levels are cantilevered from a rear vertical support only. This is a specialized type of storage media and should be discussed with your rack supplier for proper application and design.
Contact Us to learn more about our Pallet Rack solutions.