The two numbers
Beam UDL and frame capacity
| Term | Definition | Example value |
|---|---|---|
| Beam UDL | Per-pair load when evenly distributed | 1,800 kg / pair |
| Pallet weight | Single pallet on the beam | Up to 900 kg each |
| Frame capacity | Total kg all beams transfer to slab | 12,000 kg |
| Beam levels | Number of beam pairs in the frame | 5 levels |
Worked example
A worked Australian example
A typical 2,750 mm wide selective bay with 100 × 50 mm box beams rated at 1,800 kg UDL, 5 beam levels, and a 90 × 60 mm upright with a 12,000 kg frame capacity:
- Beam check: 1,800 kg UDL ÷ 2 pallets = 900 kg per pallet maximum.
- Three pallets per beam? 1,800 ÷ 3 = 600 kg per pallet maximum.
- Frame check: 5 levels × 1,800 kg = 9,000 kg total beam load.
- Frame capacity = 12,000 kg, so the beams are the bottleneck.
- Load notice rating: 1,800 kg UDL per beam pair, 9,000 kg per bay.
Beam vs frame
In this example the frame can carry more than the beams will deliver — the beams are the limit. In taller frames with extra beam levels the situation flips, and the frame becomes the bottleneck.
Common mistakes
The three calculation mistakes that cause collapses
- Confusing per-pallet weight with beam UDL.
- Adding a sixth beam level without re-checking frame capacity.
- Reusing old load notices after a beam-level change.
- Assuming heavy items 'spread the load' when concentrated at centre.
- Mixing beams from different manufacturers in one frame.
- Ignoring impact and seismic factors required by AS 4084:2023.
Documentation
What goes on the load notice
Every aisle entry must carry a load notice that displays the maximum UDL per beam pair, the maximum total weight per bay, the beam configuration and the date of certification. Out-of-date or missing load notices are a top finding on AS 4084 audits.