A rack is an unforgiving place for a pallet. On the floor, a pallet carries compression. In a rack, it becomes a bridge — and bridges fail in bending. Plastic pallets perform excellently in racking, but only when specified to the racking rating and matched to the beam layout. This guide covers the compatibility rules.
The support conditions
| Support | Description | Relative capacity |
|---|---|---|
| Full floor support | Flat ground, whole underside bearing | Highest (static rating) |
| Two-edge (beam) support | Two beams under the pallet edges | Lowest rack rating |
| Three-edge support | Two beams + centre rail | Higher, often 1.5–2× two-edge |
The trap: datasheets do not always state which condition the racking figure assumes. Ask the supplier directly: “Is this rack rating two-edge or three-edge, at what span?” The difference can be a factor of two.
Deck type and deflection
- Closed decks resist bending across the span and deflect less — the safe default for rack-heavy operations.
- Open/ventilated decks depend on rib alignment with beams; if the ribs miss the beams, the deck carries the load alone. Ratings reflect this and are lower.
- Edge skids/rails concentrate load into the beams — good for capacity, but the skids must sit squarely on the beam surface.
Deflection matters beyond capacity: a sagging pallet lets cartons settle out of square, jams pallet extraction, and slowly walks toward the beam edge. Set a visible deflection limit (20 mm at rated load is a common working figure) and measure it with a straightedge during inspection rounds.
Size matching with the beam layout
- Pallet depth must match beam depth — a pallet overhanging the front beam loses edge bearing; a pallet short of the beams has no bearing at all.
- Standard footprints (1200×1000, 1200×800 Euro, 1100×1100) exist so beams can be set once. Mixed fleets force compromise beam spacing — avoid it.
- Entry orientation matters for four-way pallets only if the rack is accessed from both sides; check our 2-way vs 4-way entry guide before standardising.
Load distribution on the rack pallet
Racking ratings are usually quoted for uniformly distributed loads. Point loads (a single heavy machine part on an otherwise empty pallet) concentrate bending stress at the centre of the span and can exceed the rating at a fraction of the rated weight. For point-load duty, either spread the load with a load board or step up a pallet class — the static vs dynamic load guide explains the rating logic that applies here.
Inspection and retirement rules
| Check | Action |
|---|---|
| Deflection > 20 mm at load | Remove from rack duty |
| Cracked ribs at beam contact lines | Remove immediately |
| Creep sag visible when empty | Downgrade to floor duty |
| Missing/deformed edge skids | Remove from rack duty |
| Wear at fork entry points | Monitor; replace on cracking |
Retire rack pallets on margin loss, not collapse. A pallet that survives until it breaks in a rack has already spent months quietly bending toward a failure that happens at head height — which is the single worst place for a pallet to fail.