How to Properly Store a Stack of Empty Pallets

Stacking pallets can be a hazard - learn how to do it safely

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Most distribution and many manufacturing operations must deal with empty pallets – sometimes it’s a lot of pallets.

They take space you could use for something else. They clutter your receiving areas. Sometimes they’re splintery, with nails protruding from the sides ready to bite a passerby. People re-use their pallets, holding onto them for a period of time until they’re used for an outbound shipment. But while they’re in your facility, they can eat space, potentially injure people, and generally cause trouble.

Never stack pallets on their sides

never stack pallets on their sides

Why would you ever stack empty pallets vertically? They don’t take up any more space than pallets stacked the right way.

But people wedge a couple of vertical pallets between stacks of horizontally stacked ones to get them out of the way. Or they’ll lean them against a building column or the side of a rack upright. The problem? They’ve just set a trap that can injure someone. When the stacks start being pulled, those vertical pallets – sometimes with nails, sometimes with splinters, always heavy enough to injure – are in danger of tipping over.

This can result in serious injuries and the litigation that accompanies those injuries. In this case, it may have been truck drivers or other outsiders who stacked the pallets wrong – another thing you have to watch.

While there is no specific OSHA code pertaining directly to vertical pallet stacking, inspectors can and do cite companies who engage in it. It may fall under OHSA 1926.25(a), under housekeeping. If a practice creates a potential safety hazard the rule can be applied to any operation. It’s a generally acknowledged safety problem, and an easily rectified situation. You can’t depend on the common sense of your employees, truckers, or others who deal with pallets.

Make it a company policy that pallets must never stack on their sides, and never leaned against anything. The safe way is flat on the bottom, every time.

pallet stacking racks

Never stack pallets too high

According to OSHA standard 1917.14, “Cargo, pallets and other material stored in tiers shall be stacked in such a manner as to provide stability against sliding and collapse.”

This covers a lot of ground, including the way they are stacked (haphazardly, in mixed sizes, etc.). But the main focus here should be on height.  How high is too high? According to OSHA, for a freestanding stack, that comes to 15 feet. Even that can be too high in a busy traffic lane. When a standard GMA pallet is 48″ x 40″, and has a height (which varies) of 5″ to 7″ from floor to top of deck, this means 20-25 empty pallets in a stack. Each pallet can weigh 55 pounds, so by regulation, you could have an unsecured stack that weighs up to 1,375 pounds.

The insurance industry prefers a more modest six foot stack, which works better if you are handling the pallets manually. It’s also recommended that pallet stacks higher than six feet should be protected by automated sprinkler systems (per National Fire Protection Association (NFPA) 13, Standard for the Installation of Sprinkler Systems.).

Never stack pallets crookedly, or in varying sizes

over door empty pallet storage racks

Poor pallet stacking could be characterized as the world’s most dangerous Jenga game; if your pallets are in poor condition, if they aren’t uniform in size, and if they are stacked haphazardly, they can tumble or break. At 55 pounds a pallet, that’s an injury waiting to happen, even if the pallets are in great condition. If they aren’t, 55 pounds driving a bent nail or splintery edge can be even worse.

The point: stack them in very straight stacks, and stay at relatively low heights. It’s better to eat a bit of floor space than it is to create a safety hazard. You can also employ pallet stacking frames or stacking racks to help stabilize them.

Pallet stacks should be separated by at least eight feet, and should be separated from general inventory by 25 feet.

One way to deal with a mass of pallets without covering your staging areas in stacks is to use dead space. While you typically don’t have the rack space to store idle pallets, many facilities have had success with over-dock-door pallet storage racking. This is often unused space, and can be converted to pallet storage with specialized racks.

Never keep or re-use damaged pallets

Damaged pallets are inherently unsafe, They are also a factor in  product damage incidents. When a pallet is splintered on its ends, it has a good chance of cutting or scraping workers who handle it. When it has protruding nails or fasteners, it’s even more unsafe. If it’s missing boards, stringers, or other components, it can break under a load, or while being transported by forklift. It can tilt or lean while stored in racks.  That’s unsafe for workers, and can result in a spilled pallet and lots of inventory damage.

NOTE: As with all safety advice on this website and in our literature, this is general in nature, and is derived from what are believed to be reliable sources. Please consult a safety engineer for specifics regarding safe storage of pallets or any other material in your facility. This is an article for informational purposes and may not cover other issues relating to safe pallet storage.

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Scott Stone Cisco-Eagle's Director of Marketing. He has over 25 years of experience in the industry.

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  • Twinsburg worker

    As warehouses are getting larger with more people working in them, do you suggest a recommended procedure for pallets? The warehouse I work has two sets of racks above the dock. The first set above the dock door holds 17 normal pallets and the set above is practiced at 20 pallets per stack, which can be taller. There is also several types of skids at the warehouse: Blue euro type pallets, plastic black pallets, small size pallets, plastic blue pallets, wood pallet bases (a particle board on top pallets), cardboard slip-sheets, and black plastic slip-sheets.

    There are several people who separate and put skids up in the rack. Sometimes just stacks of normal pallets look really unstable and I would hate to think of what would happen if someone were to bump a rack.

    • Thanks so much for the question. In this situation, since the pallets are being stored in racks (rather than on the floor) you have two factors: Stability and capacity.

      Typically, capacity shouldn’t be much of an issue for most racks designed to hold palletized loads. But it’s best to understand your rack’s capacity ratings. You can find this by identifying the rack manufacturer and model. Most of the time, rack manufacturers will have online documentation for that.

      Stability sounds like the biggest factor here. Since pallets are single piece loads in a stack, they may be less stable as the stack gets taller. If the stack is too tall, you may have issues with adding or removing pallets as well. You should not mix different sizes or types of pallets (or skids), as that can only contribute to instability. Stacking neatly is also important. If the pallets are going to stay in the rack for a reasonable length of time, consider shrink wrapping them together before they’re loaded. Obviously you cannot always do that.

      Let us know if you have any questions. Thanks!

      • Neilo

        I would like to express that care should be taken with plastic pallets, after conducting a thorough fire investigation for an incident involving a warehouse, it was discovered that the plastic pallets burn more fiercely and more readily than the wooden pallets, once alight the fire spread is aggressive. In the same test, clear plastic wrapping was also used to test the burning droplets and the relationship with fire spread, surprisingly the wooden pallets did not ignite unlike the plastic pallets.

  • Twinsburg worker

    Here are some real world pictures taken before I suggested that more care should be given to stacks in the tallest (completely open) racks. Now the stacks look better but some workers are suggesting that all the bad pallets should go in the top rack until the truck can take them away. The reason given is that workers on machines that can only reach the lower rack are incorporating bad skids back into the warehouse. How should I approach this bad practice? Workers get upset when you “go above their head” and talk to bosses, yet are unwilling to listen directly. I have asked (6 months ago) for labels given to sections for “bad skids” on the lower rack and the bosses have not responded.

  • I like the idea of putting the damaged pallets in a high bay rack spot, as you’d have to go to some effort to access them. Could you perhaps band them or shrink wrap them, then put a sign on as bad/don’t use?

    • Twinsburg worker

      We have settled on good skids in the middle and mixed skids on the top. As it takes an hour or so to stack them, there is no time to wrap but some good skids in the pile help. The stacks are a bit unsteady and I refuse to put the most damaged skids up there. Those I leave on the ground. People wont take the most damaged skids to work with, although a bit of training on what is good/bad to use is in order (in my opinion).

  • KAM

    What is the rule for having pallets on, let’s say, a production floor? For instance, we have a lot of large boxes that get packed in production and then need to be stacked directly onto the pallet. Is there a standard rule for this. I’ve been told empty pallets cannot be flat on the floor and need to be place vertically against a wall until use. Reading this piece I am not quite sure what is appropriate. Thank you

    • KAM,

      My take is that pallets that are stacked flat are less likely to fall and break – or potentially injure someone. You can also forklift the entire stack if they are flat (and stable), so there is a convenience factor. You can make the argument that if stacked on their sides, it’s impossible for someone to stack them too high, and thus make them unsafe due to vertical over-stacking. But in terms of functionality, I can’t think of any other reason to do it that way. Let me know if you discover something different.


  • KAM, thank you for the comment. There are definitely times when vertical stacking will save space. The issue with vertical stacking is that it can pose a safety hazard, since it’s easy for them to shift when being accessed, and thus easier for them to fall and potentially hit someone. Absolutely, they can take more space up when they’re horizontal, and they are slightly more difficult for one person to grab and initially move. But they are also fork accessible when stacked horizontal, and they won’t shift and potentially fall.

    In some circumstances you may have to stack them vertically, but it isn’t recommended for these reasons.

    • Twinsburg worker

      There seems to be rumor and unclear rules on this. Different companies seem to have different views. I have been told by companies in the past that OSHA requires skids to be flat on the floor. This seems to change according to the particular company. The companies that stress non-vertical skids say they have been fined in the past.

      Storing skids vertically takes less room until the amount of skids exceed the floor space of one flat skid (about 6 or so). After that, it becomes a problem. If the skids are four or less, it isn’t that big a deal. Although OSHA may say different.

      • I do think OSHA would prefer them stacked flat, since they are inherently more stable that way, but like I mentioned, the enforcement is spotty. You save a little room, but create a safety and stability issue.

  • Mn Worker

    What would a recommended height for storing plastic Nestable mail skids/pallets on a concrete warehouse floor? Generally ive seen them come off a truck in stacks of 45 about 12 feet high. Was wondering if they could be stacked 90 or 24 feet high safely?

  • Mn Worker, thank you for your question!

    I didn’t have a specific answer, so we consulted with a manufacturer of nesting plastic pallets to help get it right. As a rule of thumb, you can stack the pallets higher than 12 feet. But, the how high you can stack them depends on the design of the pallet you are using. Consider how tightly the pallets fit together when stacked. If they fit too tightly, they may be difficult to remove from the stack with a forklift. This is because, once stacked, there is typically a very limited amount of space for forks to fit beneath the pallets when stacked.

    This can make unstacking them with a forklift a problem. And when the forklift has issues separating the pallets, this may increase the possibility of a stack tipping over at higher stack
    heights. One last factor to consider is this: Will your forklift reach high enough to remove a pallet from the top of a 24-foot stack?

    I can’t specifically advise you on that, but check your lift truck reach. You should consult with your pallet supplier as well. They may have stacking height specifications and answers particular to your pallet type.

    Thanks again!

  • Tim

    My Loss Prevention Insurance carrier gives me a hard time for storing, stacks of empty pallets in our racking. Each time I dispute the claim. Is there specific NFPA codes regarding the storage of stacks of pallets in the racking? Id like to research this topic so I have accurate information

    • Hi Tim,

      The concern with wood pallets is that they are considered a combustible material. In bulk, the concerns are only multiplied. Over time and with persistent use, they can become dry and frayed and more easily ignited. This is why many companies do not store them in their general inventory racks—in bulk they could accelerate due to their relatively large surface area. If you store quantities of empty pallets, it’s best that they are segmented away and are covered by fire prevention measures.

      According to the Denver Fire Department’s guidelines, “a wood pallet fire can have heat release rates more consistent with a plastics or flammable liquids fire than a typical fire involving paper or wood.”

      If you can segment those pallets out of that rack, and into a safer area, it’s recommended. According to Nationwide insurance, stacked pallets) “should be separated by at least eight feet, or 25 feet from commodity storage.” This tends to align with what your agent is telling you.

      Also, no matter what standards are in play, your insurance agent is often the bottom line. Their company is the policy provider, and has to pay in case of an incident.

      Please consult with safety professionals or your insurance agent to come up with a safer way to store these pallets. Best of luck!

  • Jeff Bridges

    My brother works in a large warehouse and accidents do happen. Its important to be extra cautious when dealing with pallets. One thing that can be dangerous is racking them crooked. You always want to make sure they are straight and the same size before you stack them.