Shelving usually are artificial access to goods assembled structure, the interlayer spacing is uniform and adjustable, goods often for parts or heavy packaged goods (easy manual access), the shelf height is usually less than 2.5motherwise artificially difficult to reach (eg, combined with high car can be set at about 3m). Shelf unit span (length) should not be too long, shelf unit depth (or width) should not be too deep, according to the load capacity of the shelf unit on each floor can be divided into light, heavy shelf to shelf, shelf mainly steel laminate , wood laminates two.