Rackable plastic pallets: racking, shelving and the right load capacity

In briefIn pallet racking the pallet is suspended between two beams and the racking load applies, the lowest of the three ratings: typically 800 to 1,400 kg for a pallet with runners, up to about 1,750 kg with steel profiles. On a solid shelf or on the floor the pallet rests on a surface, and the static and dynamic load ratings apply.

In a warehouse a plastic pallet can sit in two very different ways. On the beams of pallet racking it is suspended between two supports, with nothing underneath. On a solid shelf or on the floor its whole base rests on a surface. For rackable plastic pallets this changes which load capacity you read on the data sheet ^[1][3].

Racking or shelf: two different supports

In racking the pallet is suspended

In pallet racking the pallet rests only on two beams, the front one and the rear one. There is nothing in between: the deck works as a bridge and sags in the middle. ISO 8611 calls this condition "racking", meaning storage on beams or in drive-in racking with an unsupported clear span ^[13]. The figure to look at is the racking load, generally the lowest of the three ^[2].

On a shelf or the floor the pallet rests on a surface

On a solid shelf, steel or timber, or on the floor, the whole base of the pallet is supported. Here the static load applies with the pallet at rest, and the dynamic load when you lift and move it with a forklift or pallet truck ^[1]. Mesh decking is an in-between case, covered in the table below.

Where the pallet rests and which load to read

When in doubt, follow the safe rule: if there is no solid surface under the pallet, use the racking load. The three ratings and the tests that measure them are explained in the guide to plastic pallet load capacity.

What the racking load is

The racking load is the maximum load with the pallet resting only on the beams, without a shelf, and with the load spread over the deck ^[1]. Only pallets designed for beam racking state it ^[2]. On data sheets you will find it as racking load, edge rack, Regallast, charge en rack or "portata su scaffalatura". If a data sheet gives static and dynamic loads but no racking load, that pallet does not go on bare beams.

Deflection and creep: the time factor

Under load the deck sags in the middle: this is deflection. In the ISO 8611 racking test the supports sit 75 mm in from the edges of the pallet, so on a 1200 pallet tested along its long side the span is 1,050 mm ^[13]. The allowed deflection is 2% of the span under load, about 21 mm, and 0.7% after unloading ^[14]. The American ASTM D1185 allows 1.9% ^[3].

Plastic also gives way over time under constant load: this is creep. That is why ISO 8611 specifies 24 or 48 hour tests for plastic pallets, against 2 hours in ASTM D1185 ^[3]. Heat speeds up creep, and the maximum working load of plastic pallets is tested at 40 °C ^[14]. One maker of plastic products gives an operating range of about −45/+77 °C for HDPE and about −23/+82 °C for PP ^[10]. A pallet that holds overnight can exceed the allowed deflection after weeks of summer under an uninsulated roof.

Orientation: runners at 90° to the beams

For a 1200×800 pallet in pallet racking, the usual European configuration is ^[15][16]:

• 800 side facing the aisle, 1200 side running into the depth of the rack;
• the bottom runners, which run along the 1200 side, cross the beams at 90°;
• the corner blocks, or the runner ends, rest on the beams;
• the pallet overhangs by about 50 mm front and back, centred between the two beams; EN 15620 allows a tolerance of ±10 mm;
• the typical frame depth for this layout is 1,100 mm.

If you turn the pallet so the 1200 side faces the aisle, the runners run parallel to the beams and none of them crosses a beam. A racking manufacturers' association regards this as a problem. It is acceptable only if the pallet manufacturer states the racking load in that direction; otherwise you need two support bars per location under the runners, or a shelf ^[15]. A pallet that is not centred, resting at the back only on the edge of a runner, is also a risk ^[16]. The INAIL guide on pallet racking (INAIL is the Italian workplace safety institute) requires the pallet to overhang the beams by an adequate amount ^[17].

ISO 8611 tests the pallet in both directions and states the weaker result, unless the two values are within 15% of each other ^[13]. Data sheets rarely give the test direction, though. Ask the supplier and put it in your supply specification.

Nine-leg pallets: on shelves only

A nestable pallet has hollow, tapered legs, usually nine, and no runners. On bare beams it rests on only some of its legs, which can slip off the beam, and the thin deck flexes between supports ^[18]. Data sheets for these pallets generally state no racking load ^[4].

If you use nine-leg pallets and need to store them at height, put a solid shelf on the beams: the pallet then rests on a surface and the static and dynamic loads apply. Otherwise keep them on the floor, or choose a pallet with runners. The differences between legs and runners are in the guide to types of plastic pallet.

Drive-in and gravity roller racking

In drive-in racking and push-back on rails, the pallet does not rest on two front-to-back beams but on two side rails, along its edges only. This is the "edge rack" support: on two edges alone, plastic can flex until it fails, depending on weight and span ^[8].

Before you use plastic in drive-in racking:

• ask the manufacturer whether the model is tested on that support and at what span;
• use pallets that are all identical and undamaged, because the lane is designed for a single pallet type;
• set the pallet down on the rails, do not push it;
• involve the racking designer.

On gravity roller racking the runners must run in the direction of flow, at right angles to the rollers. The base must be continuous and not deformed: a damaged pallet stops halfway down the lane ^[19].

How much they carry in racking: data sheet values

In short: the lightweight nestable pallet does not go on beams, the medium pallet typically carries 800–1,250 kg in racking, the heavy one 1,000–1,400 kg and up to about 1,750 kg with steel. These are values for individual models, for an even load and in the tested position. What counts is the data sheet of the pallet you buy.

Steel reinforcement

Steel profiles, inserted in the deck or the runners, stiffen the pallet and reduce deflection between the beams. Above all they raise the racking load. In a heavy 1200×1000 pallet with runners, reinforcement takes it from 1,000 to 1,400 kg ^[5]; in a 1200×800 with three runners, from about 1,000 to about 1,750 kg ^[6].

The downside is weight: a heavy pallet with steel weighs 18–25 kg ^[5], as much as a wooden pallet (typically about 10-20 kg) or more. If each racking location carries only a light load, a medium pallet without steel may be enough.

The flat pallet ROLL offers for racking

Among the flat pallets ROLL offers, the one designed for pallet racking is the PP69: 800×1200×155 mm, 16 kg, three steel bars, 1,200 kg in racking according to the manufacturer's data sheet ^[7]. The other two flat pallets ROLL offers have other jobs. The PPH1, with closed runners and no bars, is for hygienic environments and made of recycled material, so it is not for direct food contact ^[11]. The PP08, with a closed deck and 4-way entry, is for floor handling with a pallet truck and does not go on beams ^[12].

Common mistakes

• Reading the static load and using it for racking: for the same pallet with runners, the data sheet can give 5,000 kg static and 1,000 kg in racking ^[5].
• Putting a nine-leg pallet on bare beams ^[18].
• Turning the pallet round: with the 1200 side on the aisle, the runners do not cross the beams ^[15].
• Not centring it: 50 mm overhang at the front, only the edge of the runner resting at the back ^[16].
• Placing a drum, a small crate or a reel in the middle: load ratings apply to an even load ^[1].
• Forgetting heat and duration: a rating tested at 23 °C says nothing about how the pallet behaves for months at 35-40 °C under the roof ^[14].
• Assuming mesh decking raises the racking capacity: the limit is still the racking load notice ^[20].
• Using damaged pallets in drive-in or on rollers: they jam or fail inside the racking ^[19].

Pallet and racking have two responsible parties

The pallet and the racking are two different products. The pallet's load capacity is stated by its manufacturer. The racking capacity, the loads per level and the inspections are the responsibility of whoever designs, installs and operates the racking.

For steel racking, the European standard on application and maintenance is EN 15635:2008, which covers inspections, damaged components and the handling of unit loads ^[9]. When you change pallets, from wood to plastic or from one model to another, have the person responsible for racking inspections check compatibility. If the warehouse is served by stacker cranes or shuttles, the deflection and tolerance limits are tighter: see the guide to pallets for automated warehouses. For sprinklers and fire load, see the guide to fire safety.

If the load is reels, a flat pallet in pallet racking is not enough to hold them still: see the guide to reel pallets.

The three flat pallets offered by ROLL

ROLL does not sell generic plastic pallets. Among flat pallets it offers only these three, each for a specific use.

For pallet racking ROLL PP69 1200×800 with 3 steel bars, 16 kg; 1,200 kg racking load according to the manufacturer’s datasheet. Designed for rack storage, with the pallet spanning two beams.

For hygienic environments ROLL PPH1 H1 type with closed runners, no steel bars, washable. Made from recycled material: not for direct food contact.

For floor handling ROLL PP08 Closed flat deck, 4-way entry, 9 feet: for moving pallets on the floor with a pallet truck. Not designed for racking.

Found a mistake or an outdated figure? Write to us at info@roll-packaging.com