Reference 08 · The numbers behind the quotation
Pallet rack load capacity: what the number means before you sign.
Almost every racking dispute starts with a capacity figure that two parties understood differently. A beam rated for two tonnes is rated for a specific load pattern over a specific span, and a bay rated for eight tonnes is not four levels of two tonnes just because the arithmetic works. This page sets out how capacity is derived, what limits it, and how to write it into a tender so it is enforceable at delivery.
In brief
Pallet rack load capacity is rated as a uniformly distributed load per beam pair, at a stated clear span, with deflection limited to L/200. Total bay load is a separate figure limited by the upright frame, not by multiplying level capacity by the number of levels.
- Capacity applies to the beam pair together, spread across the span — it is not a per-beam or point-load rating.
- A capacity quoted without a clear span is not a specification; the same beam carries less as the bay widens.
- Bay capacity is limited by the upright and its unbraced lengths, so you cannot multiply level capacity by the level count.
- Specify the outcome — load, span, deflection — rather than a section size, and the tender becomes enforceable at delivery.
01 — What the rating covers
Capacity is a uniformly distributed load per beam pair
The rating applies to the two beams of one level together, not to each beam. A level rated 2,000 kg holds 2,000 kg total across the pair.
The rating assumes the load is spread reasonably evenly across the span — typically two or three pallets. A single concentrated load in mid-span produces a higher bending moment than the same weight spread across the beams.
Capacity is inseparable from the clear span it was calculated for. The same beam section carries meaningfully less over 2,900 mm than over 2,300 mm. A capacity quoted without a span is not a specification.
Capacity is limited by deflection as well as by strength. We size beams so deflection under full load stays within L/200 of the clear span, the limit used in common racking practice — a 2,700 mm span deflects no more than about 13.5 mm.
02 — The limit people miss
Bay capacity is set by the upright, not the beams
This is the single most common misunderstanding in racking procurement, and the one most likely to cause a serious incident.
Beam capacity tells you what one level can carry. Bay capacity tells you what the upright frame can carry in total, and it is a separate calculation driven by the frame height, the steel section, and — critically — the unbraced length between beam levels. A frame with levels spaced widely apart carries less than the same frame with levels close together, because the effective buckling length of the column is longer.
So a beam rated 2,000 kg and a frame rated 8,000 kg do not permit six levels at 2,000 kg. They permit whatever combination keeps the total within the frame rating and respects the beam elevation pattern the frame was calculated for. If you later add a level or move elevations, the frame calculation changes and should be rechecked.
| Figure | What it limits | Where it appears |
|---|---|---|
| Load per beam level | One level, as a UDL across the beam pair | Quotation, drawing, load notice plate |
| Load per bay | Total load carried by one frame line | Quotation, structural calculation, load notice plate |
| Beam elevations | The calculated unbraced lengths | Approved drawing |
| Deflection limit | Serviceability under full load | Specification and calculation |
All four should appear together. A quotation that states only a beam capacity is incomplete, whoever it comes from.
03 — In practice
Loading rules to write into your SOP
- Never exceed the level load or the bay load shown on the load notice plate — both, not either.
- Do not place a single heavy item in mid-span on a level rated for distributed pallets; if you must, tell us and we size for a point load.
- Do not move beam elevations without asking us to recheck the frame. It takes minutes and it is a real structural change.
- Do not store loose or unstable loads directly on beams — specify decking or support bars.
- Unload and report any damaged upright the same day. Damaged steel has already lost capacity.
- Keep the load notice plates legible; a plate hidden behind a pallet is a plate nobody reads.
04 — Writing the specification
How to word capacity in a tender
Specify the outcome, not the section size. A section size tells you nothing about steel grade, thickness or connector design, and it prevents suppliers from offering an equally valid alternative. Capacity, span and deflection are testable at delivery.
Structural calculation
Issued against your actual configuration, not a generic catalogue table.
Approved drawings
Bay elevations, beam levels and run layout, approved before fabrication begins.
Load notice plates
Fitted to every run at handover, showing level and bay capacity in kilograms.
Questions buyers ask
Frequently asked questions
What does UDL mean on a racking quotation?
Uniformly distributed load: the total weight the beam pair carries when spread reasonably evenly across the span, typically as two or three pallets. It is not the capacity of a single beam, and it is not a point load rating.
Why does capacity change with span?
Bending moment increases with span for the same load, and deflection increases faster still. Widening a bay from 2,300 mm to 2,900 mm can reduce a beam’s rated capacity substantially even though nothing else changed.
Can I load every level of a bay to the beam rating?
Not unless the frame was calculated for it. Total bay load is limited by the upright and its unbraced lengths. Both figures appear on the load notice plate, and both apply at the same time.
What deflection is acceptable?
We design to L/200 of the clear span under full load — about 13.5 mm on a 2,700 mm span. Visible sag beyond that is a serviceability problem even where the beam is nominally strong enough.
Do I need to recheck capacity if I move a beam?
Yes. Changing beam elevations changes the unbraced length of the upright and therefore its capacity. Send us the proposed elevations and we will confirm or advise against them, usually within a day.
What steel do you use and how is it verified?
JIS G3101 SS400 and JIS G3131 SPHC, fabricated in our own plant in Bekasi, with material tested by BPPT and Sucofindo under an ISO 9001:2015 quality system certified through Moody International.
Talk to engineering, not a call centre
Send your heaviest pallet weight. We will send back verified capacities.
Every configuration we ship is confirmed by structural calculation and delivered with a load notice plate stating the maximum load per level and per bay.