How to work out pallet racking beam capacity
How to work out pallet racking beam capacity
Pallet racking beam capacity is the safe load per pair of beams on one level, quoted as a uniformly distributed load. To work it out, multiply your heaviest pallet weight by the number of pallets on the level, then pick a beam section whose rated capacity at your clear span is at least that figure, and check the total for the bay against the frame capacity.
The arithmetic is simple. The judgement is in using the right pallet weight, the right span and the right beam spacing, because each of those changes the answer. This guide walks through the checks we make on every layout.
Key takeaways
- Beam capacity is quoted per pair of beams per level, as a uniformly distributed load, not per beam or per pallet.
- Use the heaviest pallet you will store, including the pallet itself, not the average.
- Capacity falls as span increases; deflection is commonly limited to span/200 under the safe working load.
- The bay load is the sum of the beam level loads, and the frame must carry it at the beam spacing you choose.
- Only the manufacturer or a racking engineer can give a safe working load for a given beam; SEMA does not hold that data.
What does a beam capacity figure mean?
A beam capacity figure is the maximum load that a pair of beams, front and back, can carry on one level when the load is spread evenly along them. That is why load tables quote a uniformly distributed load per level, often written as "UDL per pair". Three pallets sitting evenly across a level count as a distributed load; one heavy drum in the middle of the span does not.
The figure comes from the manufacturer's design and testing to a design code. In the UK that is either the SEMA code or BS EN 15512, which sets the principles for the structural design of adjustable beam pallet racking (SEMA; BSI, BS EN 15512:2020). SEMA's own technical FAQ is clear that it does not hold manufacturers' load data, so for a safe working load you go to the manufacturer, its distributor or a specialist engineer (SEMA, Technical FAQ). We supply load tables with each order and test reports on request.
Step 1: find the heaviest pallet and count them
Start with the heaviest loaded pallet you will put on that level, then multiply by the number of pallets per level. If you store three pallets per level and the heaviest weighs 950 kg, the level must be rated for at least 2,850 kg. Rounding up to the next rated value gives a margin for weighing error.
If you do not know your heaviest pallet, weigh a sample of the heaviest products on a pallet truck scale before the layout is drawn. Estimates from case weights tend to miss the pallet, shrink wrap and the odd overfilled layer, and a level that is right on its limit leaves no room for the day a heavier delivery arrives.
Include the pallet itself. An EPAL Euro pallet weighs around 25 kg and an EPAL 2 pallet around 35 kg (EPAL), and plastic or block pallets vary. Check the pallet's own rating too: the EPAL Euro pallet has a safe working load of 1,500 kg and the EPAL 2 pallet 1,250 kg, so a racking level rated for heavier pallets does not make a weaker pallet safe.
| Heaviest pallet (kg) | Pallets per level | Minimum level capacity (kg) | Beam levels | Load on frames (kg) |
|---|---|---|---|---|
| 800 | 3 | 2,400 | 4 | 9,600 |
| 1,000 | 2 | 2,000 | 4 | 8,000 |
| 1,000 | 3 | 3,000 | 4 | 12,000 |
| 1,200 | 2 | 2,400 | 3 | 7,200 |
These are worked examples using typical values. Your own figures come from your heaviest pallets.
Step 2: match the load to a beam section and span
Once you know the level load, find a beam section rated for at least that load at your clear span. Clear span is the distance between the faces of the uprights, which is the beam length you order. For the same section, a longer span carries less, because bending and deflection grow quickly with length.
That is why a 3300 mm beam carrying three UK pallets usually needs a deeper section than a 2700 mm beam carrying three Euro pallets of the same weight. If you are unsure how the span was chosen, our guide to UK pallet racking dimensions shows how pallet width and clearances set the beam length. Our pallet racking beams come in several section depths so the layout can use the lightest section that passes.
Do not read across between manufacturers. A beam that looks the same as another make may have different steel, a different connector or a different locking pin, and its rating only applies to the frames it was tested with.
Step 3: check deflection
A beam can be strong enough and still bend too much. SEMA's technical experts explain that deflection under the maximum safe working load should generally not exceed span/200, as recommended in the SEMA code, which is 13.5 mm on a 2700 mm beam (Warehouse & Logistics News, SEMA column). Tighter limits can be specified, usually at extra cost, and automated equipment sometimes needs them.
When you check deflection on site, measure from a taut string line fixed to the uprights just below the beam, not from the floor, because the floor may not be level. A beam that stays bent after unloading has been overloaded or struck and should be reported at once.
Step 4: check the bay load and the frame
The bay load is the sum of the beam level loads in that bay, and the frames must carry it. Four levels at 2,400 kg give 9,600 kg on the frames. Pallets stored directly on the floor do not load the frames, so they are left out of this figure.
Frame capacity depends heavily on beam spacing. The distance from the floor to the first beam, and the gaps between levels, set the unsupported length of the upright, and a longer unsupported length lowers its buckling capacity. So the same frame may carry a high bay load with close beam spacing and a much lower load with a tall first level. Each inner frame is shared by two bays, which the design accounts for. Our adjustable pallet racking is designed with frame and beam selected together for that reason.
For scale, SEMA notes that racking can carry pallets of over a tonne and bays of over 40 tonnes, while shelving typically carries items under 25 kg and bays under 4 tonnes (SEMA, Technical FAQ). Heavy bays like that need a floor slab that can take the point loads under each base plate, which the layout engineer checks against your slab details.
What about point loads, decking and non-pallet loads?
A uniformly distributed rating assumes the load is spread evenly along both beams. A single stillage resting on two points, a coil, or a drum placed mid-span puts a concentrated load on the beams and needs a separate check, usually with a lower permitted load.
Decking changes how load reaches the beams. Galvanised mesh decking lets you store loose or small items on a level, but each deck panel has its own rating and the level rating does not transfer to a single panel. If you are adding decking to existing racking, ask for a check of both the deck and the beams.
Show the result on a load notice
Whatever capacity you settle on must be shown on the racking. HSE expects a notice stating the maximum load together with any necessary specified load configurations, and SEMA's load notice is the usual way to do it (SEMA, Load notices). SEMA's FAQ adds that the notice must be in colour, and that runs with different configurations can have separate notices or one conservative notice that suits them all (SEMA, Technical FAQ). Racking is work equipment under the Provision and Use of Work Equipment Regulations 1998, which require it to be suitable for its use and maintained (legislation.gov.uk, PUWER).
Our guide to pallet racking load notices covers what goes on the sign. If you change pallet weights, beam levels or spans later, the capacity needs recalculating and the notice updating.
Frequently asked questions
Is the beam capacity per beam or per pair?
Load tables normally quote capacity per pair of beams on one level, as a uniformly distributed load. Check the table heading, because a figure per beam would be half the level load.
Can I use longer beams than my load table shows?
Not without a new rating. SEMA's FAQ says the safe working load for a different span must come from the manufacturer or its distributor, or failing that a specialist engineering consultant.
Do floor-level pallets count towards the bay load?
No. Pallets stored directly on the floor do not load the frames, so the bay load is the sum of the beam levels only. They still need protecting from truck impact.
What deflection is acceptable on a loaded beam?
Under the safe working load, SEMA guidance generally limits deflection to span/200, which is 13.5 mm on a 2700 mm beam. Beams that stay bent after unloading should be reported and inspected.
Tell us your heaviest pallet, pallets per level and beam heights, and we will size beams and frames and send the load table with your quote.
Sources
- SEMA: Technical FAQ
- SEMA: Load notices
- SEMA: Racking design code
- BSI: BS EN 15512:2020 Adjustable pallet racking, principles for structural design
- Warehouse & Logistics News: Is this your problem? (SEMA technical column)
- EPAL: EPAL Euro pallet
- legislation.gov.uk: The Provision and Use of Work Equipment Regulations 1998
