Stackable pallets in plastic

What the style is for

Stackable is the style for pallets that ride loaded and wait loaded. A warehouse that block-stacks product three or four high, with no rack beams, is leaning on the pallet at the bottom of the stack. That pallet needs a high static rating and a deck that does not bow, and it rarely needs to nest.

The trade is plain. A stackable gives you rating and rigidity and takes back the empty-return saving. A used 48 x 40 x 6.3 in one-piece HDPE pallet one maker lists weighs 49 lb and is rated 30,000 lb static, 5,000 lb dynamic and 2,200 lb racking. Another maker's multi-use model weighs 18.0 lb. Both are fine pallets; they are fine for different days.

Where the static number runs out

Static is a rating at rest, with the load evenly spread. The sheet does not say how long. Plastic can deform slowly under a heavy load held for weeks, a behaviour called creep, so a stack that waits all winter is a different test from a stack that moves in a day. The creep guide puts it in numbers you can ask the maker for.

Pages for stackable buyers

A stack worked out

Take a stackable rated 8,000 lb static. The bottom pallet carries the pallets above it, so with each loaded pallet weighing 3,697 lb it can hold 2 above, a stack of 3. With 7,739 lb per pallet it can hold 1 above. This is a ceiling on a flat floor for a still stack, not a promise for a stack that moves or waits.

Questions to put to the maker

• What is the pallet's empty weight, so the load on the bottom pallet can be added up?
• Does the stack rating assume a closed deck on the pallet above?
• Is the dynamic rating printed next to the static one, and for which handling method?
• What stack height does the maker print for the loaded stack, and what is the tilt limit?
• Is the rating the same on a slick floor, a conveyor and a rack?
• Which deck pattern gives the best grip for the load, and what does it do to the rating?
• Is the rating taken on a rigid load or a flexible one?
• Does the sheet give a rating at the cold end of the temperature range you work in?
• How long does the static rating hold before creep sets in, and at what temperature?
• Does the pallet have a lip or a raised edge to hold the load in a stack?

From the dock

• Warehouse floors are rarely flat; a slight slope turns a safe stack into a tall lever.
• Creep is slow. A stack that looks fine on Monday may have sagged by the next month in a warm store.
• Weigh a sample loaded pallet before trusting any estimate; stacked weight grows faster than people expect.
• Label every stack with its pallet model so the rating being relied on is the one on the sheet.
• Stacking frames and corner boards spread load; they cost a few cents and save a collapsed pile.
• Mixed loads stack worst: a heavy case on one corner can cost more than a light load on the whole deck.
• Slick film wrap and a smooth deck make a skating surface; a gripping deck pattern holds cartons still.
• A stack leans before it fails: watch the bottom pallet's corners for bowing under a full load.
• Forklift tines catch deck edges; closed decks with chamfered edges suffer less from rough entry.

Words on this page

Racking load

The weight a pallet holds when it rests on two rack beams with an open gap between them. It is usually the lowest rating and only exists for pallets built for racks.

Open deck

A deck with slots or a grid, which drains water, sheds dust and weighs less than a solid one.

Closed deck

A solid deck that keeps small items and torn bags from falling through and wipes clean on top.

UL

Underwriters Laboratories, a safety testing body that publishes fire test standards, including one for storage pallets.

HDPE

High-density polyethylene, a tough resin used in many plastic pallets, valued for strength against its weight.

Footprint

The length and width of a pallet deck. It is chosen to fit the container, the drum, the bag or the receiving rack.

Bulk bag

A large woven bag, often sold as a Super Sack, that holds a ton or so of powder or granules and sits on a square pallet.

Static load

The weight a pallet holds while standing still on a flat floor, spread evenly across the deck. It is the highest of the three ratings.