Plastic Pallets for Automated Warehouses: What AS/RS, Shuttles and Conveyors Actually Need

In an automated warehouse, the pallet stops being packaging and becomes part of the machine. A stacker crane, pallet shuttle or conveyor does not "make it work" the way a forklift driver does. If a pallet sags too far, sits out of square, has a broken bottom board or reflects the wrong signal back to a sensor, the system stops. The pallet that suits an automated warehouse is the one with low deflection on the supports it will actually meet, a base designed for the conveyors it will ride on, and dimensions that are identical from the first unit to the ten-thousandth.

Why the pallet has become an automation question in the Gulf

Automated pallet storage is not new in the region. Almarai commissioned a 22-metre automated high-bay warehouse at its Al Kharj plant in the mid-2000s, with around 15,600 pallet positions served by five stacker cranes. What has changed is the scale and the spread. NUPCO's fully automated warehouse in King Abdullah Economic City covers 300,000 square metres with capacity for more than 50,000 pallets. In September 2026, Starlinks announced a Swisslog system for an aviation maintenance facility in Saudi Arabia that combines stacker cranes, pallet conveyors and a pallet shuttle.

These projects are specified in fine detail: crane speeds, rack tolerances, software interfaces. The pallet is often left until late, or assumed to be "standard". It is the one component that every load touches, and the one most likely to stop the system if it is wrong.

Where the automation meets the pallet

Each piece of equipment in an automated warehouse loads the pallet in a different way. Understanding this is the starting point for any specification.

Equipment	How it handles the pallet	What the pallet must do
Profile check station	Light curtains, photo-eyes and scales check height, overhang, squareness and weight at the entry point	Arrive within dimensional limits; non-conforming pallets are rejected before they reach storage
Chain conveyor	Two or three chains run under the pallet, usually across the bottom boards	Present solid, continuous bottom runners at the chain positions
Roller conveyor	Pallet travels over a bed of rollers	Have a flat, continuous base that will not drop between rollers or "surf"
Stacker crane and racking	Forks lift the pallet and place it on two rack beams, often for weeks	Stay within deflection limits on the beam span, over time and in heat
Pallet shuttle	A battery shuttle travels under the pallet in rail channels and lifts it	Not sag into the shuttle's path; withstand lifting on its base
AGV / AMR	Robot forks or lift decks engage the pallet without a driver adjusting	Have consistent fork openings and entry geometry

 

The six specifications that matter

1. Deflection on the real supports

Deflection is how far a pallet sags under load. For automated storage it is usually the deciding specification. Research from Virginia Tech's Center for Unit Load Design gives typical automated-warehouse limits of about 13 mm (0.5 in) for the whole pallet and about 6 mm (0.25 in) for individual components under load. Pallet shuttle systems are generally specified for less than about 25 mm. Each integrator sets its own figure, so ask for it in writing.

The deflection that counts is the deflection on the supports the pallet will actually meet. A pallet rated for heavy loads on the floor can still fail in a rack. For conveyors, ISO 8611 includes a separate bottom-deck bending test (Test 5) for exactly this reason. Our guide to reading a plastic pallet spec sheet explains static, dynamic and racking ratings in detail.

2. A base designed for the conveyor

Conveyors need something continuous to run on. That generally means a pallet with three parallel runners, or a full perimeter base, oriented to suit the conveyor direction. Nestable pallets with nine individual feet suit manual handling and one-way export, but most automated conveyors cannot carry them. Plastic pallets on roller conveyors also need enough contact area to avoid "surfing", where the base skids over the rollers instead of travelling smoothly.

This is a design decision, not a load-rating decision, and it rules out whole families of pallets. Our comparison of nestable and rackable pallets covers where each design belongs.

3. Identical dimensions, every time

Profile check stations reject pallets that are out of size or out of square, and cranes place loads to fixed coordinates. Injection-moulded plastic pallets are produced from the same tool every cycle, which gives them a structural advantage over wood here. Wood moves with moisture, and repaired wooden pallets vary from board to board.

Specify the tolerance, not only the nominal size: allowable variation in length, width, height, squareness and flatness. Ask the supplier how those tolerances are controlled in production, and whether every batch is checked.

4. Creep and heat

Plastic is stiff enough to carry a load, but under a sustained load it slowly continues to deflect. This is called creep, and it is why ISO 8611 holds plastic pallets under load for 24 or 48 hours in its stiffness tests, against two hours under the American ASTM standard. In a high-bay store, a pallet may sit on the same two beams for weeks.

Heat accelerates creep. Many automated stores in the Gulf are chilled or air-conditioned, but inbound buffers, mezzanines and docks often are not, and cooling can fail. Ask whether a pallet's racking deflection was measured over 24 to 48 hours, and at what temperature. Our article on what Gulf heat does to load ratings explains why a rating measured at 20°C does not tell the whole story.

5. Sensor-friendly surfaces

Automated systems "see" pallets through photo-eyes and laser sensors. Shuttle-system guidance notes that some colours, red among them, can absorb a sensor signal instead of reflecting it. Confirm pallet colour with your integrator before ordering a fleet. Top-deck friction matters too: too smooth and the load shifts under crane acceleration, too rough and it can catch on slide plates. Stretch-wrap must stay above the bottom deck so loose film cannot catch on chains or shuttles.

6. Identification built in

Automated warehouses track every load unit. Pallets with moulded recesses for barcode labels or RFID tags let the identity sit in the same place on every unit, protected from conveyor wear, without adding fixtures afterwards.

The slave pallet question

Most automated warehouses cannot control the pallets suppliers ship in on. Inbound loads arrive on wooden pallets in mixed condition, different sizes and different designs. Many facilities therefore transfer incoming goods onto their own in-house pallets, known as slave or system pallets, before the loads enter automated storage.

A slave pallet fleet is a closed loop: the pallets never leave the building. That changes the economics. A high-specification plastic pallet that lasts many years costs very little per movement, and its consistency protects equipment worth many times the pallet fleet. For a new automated warehouse in the GCC, deciding early whether to use slave pallets is one of the most important packaging decisions in the project.

Wood or plastic in an automated store?

Wooden pallets do run in automated systems, but they bring specific risks. Protruding nails, missing boards, damaged stringers and misaligned blocks are the defects automated inspection systems are built to catch. Splinters and loose nails can fall into conveyor tracks. Wood also absorbs moisture, which changes both its dimensions and its weight. Plastic avoids these failure modes. Its trade-off is creep and heat sensitivity, which are managed by choosing the right design and checking deflection data rather than relying on a single headline load rating.

Common mistakes on Gulf automation projects

•      Choosing the pallet after the system is designed. Rack beam spacing, conveyor chain positions and shuttle clearances are fixed early. Bring the pallet into the design conversation from the start.

•      Specifying "1200 × 1000, heavy duty". That describes a size and a sales category, not deflection on the rack span, base design or tolerances.

•      Relying on test data at room temperature only. Ask how the pallet behaves in an unconditioned buffer zone in August.

•      Mixing pallet suppliers. Two pallets of the same nominal size from different moulds may differ enough to trip a profile check. Standardise the fleet. Our guide to comparing pallet suppliers explains how to put quotations on the same basis.

•      Buying on unit price. The pallet fleet is a small share of an automation budget. A single jam in a high-bay aisle can stop a crane and require manual recovery.

Checklist: what to ask before ordering

Ask your integrator:

1.    What is the maximum allowable pallet deflection, and on what support span?

2.    Which conveyor types will the pallet ride on, and in which orientation?

3.    What dimensional and squareness tolerances will the profile check enforce?

4.    Are there any restrictions on pallet colour or surface finish for sensors?

5.    Will the system use slave pallets, or accept suppliers' inbound pallets?

Ask your pallet supplier:

1.    What is the racking deflection on our beam span, measured over 24 to 48 hours?

2.    At what temperature was it tested?

3.    Is the base suitable for chain and roller conveyors in our orientation?

4.    What tolerances are held in production, and how are they checked?

5.    Can you supply sample pallets for a trial on the integrator's equipment?

Frequently asked questions

What is the best pallet for an AS/RS?

A rackable pallet with a three-runner or perimeter base, low deflection on the rack beam span, consistent dimensions and a surface that suits the system's sensors. The exact choice depends on the integrator's limits and the loads being stored.

How much can a pallet deflect in an automated warehouse?

Typical limits are around 13 mm for the whole pallet and 6 mm for individual components, with pallet shuttle systems generally requiring less than about 25 mm. Each integrator sets its own figure, so confirm it for your system.

Can nestable plastic pallets be used in automated systems?

Usually not on conveyors or in shuttle systems, because their individual feet do not give conveyors a continuous surface to run on. They are better suited to manual handling and one-way shipping.

What is a slave pallet?

A pallet owned and kept inside an automated facility. Incoming goods are transferred onto it so that only known, consistent pallets enter automated storage.

Are plastic pallets suitable for automated cold stores?

Yes, provided the material and design are suited to the temperature. Cold makes plastic stiffer but can reduce impact strength, so confirm the pallet has been tested for the store's operating range.

Planning an automated warehouse? Talk to IPLAST

IPLAST manufactures rackable plastic pallets in Mussaffah, Abu Dhabi and Al Jubail, Saudi Arabia. If you are planning or expanding an automated warehouse in the UAE or Saudi Arabia, our team can work with you and your integrator on pallet design, deflection data and trials before the fleet is ordered. Contact us or explore our plastic pallet range