Sizing a pallet racking bay: how load, beam and upright actually relate
Why the same bay can be rated 1,000 kg or 2,500 kg, and which of the three numbers a buyer should never accept verbally.
A selective pallet racking bay is three components doing three different jobs: two upright frames carry the vertical load down to the floor, a pair of beams carries each level, and the beam-to-upright connector transfers the load between them. Change one and the rating of the bay changes, which is why "our racking holds 2 tonnes" is not a specification.
Load per level is a pair-of-beams figure
When a supplier states a capacity per level, that figure normally assumes a uniformly distributed load across the two beams of that level — goods spread evenly, not concentrated in the middle or on one corner. Two pallets placed at the outer ends of a beam behave differently from the same two pallets pushed together in the centre. If your operation concentrates load, say so: the beam section is selected for the worst case, not the average.
The upright is governed by height and impact
Upright frames are usually the first thing damaged in a working warehouse, and the damage is almost always mechanical — a truck leg, not an overload. That matters when specifying: a heavier upright section buys capacity, but a properly specified frame also needs an impact protector at the aisle face and a repair policy that pulls damaged uprights out of service.
- Ask for the frame capacity at your actual height, not at a reference height.
- Ask what happens to the rating if a level is added later.
- Ask for the load sign per bay — it should state the capacity per level and the bay configuration it applies to.
Where the design code enters
In Europe, steel static racking is commonly checked against EN 15512; in the United States, against the RMI specification (ANSI MH16.1). Both treat racking as a structure rather than furniture, with defined load combinations, imperfection allowances and deflection limits. A factory that designs against a code will ask for the same inputs a structural engineer would.
The practical shortcut
Give the factory the unit load, the footprint, the number of levels and the clear height. Everything else — beam section, upright section, connector, base plate — is the factory's job to select and to state on the drawing. If they ask you to choose the steel thickness, they are quoting a commodity, not a structure.
