Stacking is the most common storage method for warehouse cages, and also the most accident-prone stage in a warehouse. High stacking saves space, but once a cage collapses from height, the consequences usually involve people and goods being struck. Safety must be tackled on three fronts: floor conditions, cage condition and operating rules.
Start with the floor. The stacking-area floor must be flat, hardened and evenly load-bearing, with no potholes, standing water or oil. A standard warehouse cage weighs about 40~60kg empty, and 500~1000kg loaded; stacked three high, the bottom cage carries over 2 tons, and even slight floor unevenness shifts the center of gravity.
Next, cage condition. Before stacking, check whether the cage is deformed, welds are cracked, and stacking feet are intact. On a deformed cage the feet cannot seat accurately into the receiving holes, forcing them in is itself a hazard. Cages with bent posts or twisted base frames must be set aside or repaired—never stacked.
On operating rules: never exceed the design stacking limit—standard cages generally max out at 4 levels, heavy-duty cages at 3. Upper and lower levels must align, and stacking feet must seat fully into the lower level's receiving holes, never off-center. Mixing cages of different specs or heights is strictly forbidden, and temporary extra shimming on top of a finished stack is not allowed.
Last point: leave a sufficient safety gap between the stacking area and the aisles—at least 1 meter—and the stack edge must not cross the floor marking. Nanjing Tongnuo Warehouse Equipment Manufacturing Co., Ltd. recommends that stacking be done jointly by the forklift driver and a spotter; dropping cages from height by a lone worker is forbidden. Do a visual check of the stacking area on the morning shift every day, and straighten any leaning cage at once.