Load stability / 5 MIN READ

Why loads fail in transit and how to stop it

It's 6am and the first lorry of the day is backing onto the dock. The driver walks round the back, sees the top layer leaning like a tower in Pisa, and says he won't take it. Now you're unwrapping, restacking and rewrapping. The rest of the day piles up behind it, and the 8am slot has gone.

By KP Trading & Distribution · 5 minute read

Why loads fail in transit and how to stop it, KP Trading and Distribution. Photo is illustrative. — Pallet load stability · Photo is illustrative

That pallet probably didn't fail because of one cheap part. It failed because the edges, layer pads, wrap and top cover were bought as four separate items, by people who never compared notes. Treat them as one system and most of these failures stop. Really.

What actually makes a pallet load fail?

Movement, mostly. A lorry brakes, corners and hits a roundabout, and the load is pushed sideways. If the layers can slide on each other, or the corners crush under strap or film tension, the stack leans and then goes.

Heights matter too. A pallet network typically takes a full pallet at up to 2.2m including the pallet, and up to 1,200kg, according to IPP, a pallet pooling company. Stack higher or heavier and you're asking the wrap to do work it can't. A 2.2m stack at 1,200kg is a lot to ask of stretch film.

Size matters as well. The UK standard pallet is 1200 x 1000mm, while the Euro pallet is 1200 x 800mm. Boxes that overhang either one lose strength and snag in racking. GS1 UK's Perfect Order guidance asks for a 1200 x 1000 pallet, strongly built and undamaged, loads secured, no overhang and SSCC labels on two sides.

How is load stability tested?

There's a recognised method. EUMOS 40509 is a European test in which the loaded pallet is accelerated, usually at 0.5g, for at least 0.3 seconds. To pass, elastic deformation must be no more than 10%, permanent deformation no more than 5%, and there must be no damage.

You don't need a test rig to start learning from it. You do need to know whether your load holds up when it's pushed, rather than assuming it will because it has always got there before.

What do pallet edges do?

Edge protectors spread the tension of strap and film along the corner. They stop straps cutting into the boxes, and they add rigidity to the corners of the stack.

Think of them as four posts. One per corner. The wrap pulls the posts in and the posts hold the boxes square.

That only works if the edge matches the pallet. An edge that's too short leaves the top of the stack unsupported. One that's too weak crushes, so people double up. Here's what that looks like on a real floor.

What did an 11p pallet edge really cost?

One site we visited was buying edges at 11p each, and the buyer had done a good job. Nobody could beat the price.

The pallets stood 1400mm high but the edges were 1.1m, so the team cut and joined extra lengths. They weren't strong enough alone, so they doubled up. That made four edges on every corner and 16 on every pallet.

At 11p each, that's £1.76 a pallet before anyone counts the cutting and fitting time. The buyer never saw the labour. Operations never saw the invoice. Both were right, and both were paying.

A single 1450mm edge of the right strength covers each corner in one piece. At an illustrative 17p, four of them cost 68p a pallet. That's £1.08 less per pallet, with a corner that does its job.

Not sure what yours are costing you? We'll check them with you on site.

What do layer pads do?

Honest answer first. The evidence we can point to is from suppliers, not independent trials, so take this with care. Kite Packaging, a UK supplier, says layer pads separate and stabilise stacked products, protect against strapping and impacts, and keep stock free from dust and contaminants.

In our own experience on factory floors, they matter most where layers are smooth, such as shrink-wrapped packs, bagged goods and glossy cartons. They can also let you build to a height you couldn't otherwise.

We won't put a number on it, because it varies with product and film. What we can do is test your pallet with and without pads and show you.

What do failed loads cost?

Let's put some illustrative numbers on one bad week. These are not figures from any customer, and your own will differ.

Say five pallets a week are rejected at the dock. Each needs 20 minutes of labour to unwrap and restack, plus a second round of film, say £4 of materials. That's a few hundred pounds a month in time and film before a single carton is damaged.

Then add the expensive ones: crushed cartons that can't be sold, a delivery refused by a retailer, a claim that argues about who is at fault. One damaged pallet can wipe out what you saved on every edge you bought that year.

A pallet that arrives leaning is a pallet that someone will ask about. It's the kind of thing that costs you the relationship, long before it costs you the stock.

How do you fix it?

Start with a load specification sheet for each product. One page, kept at the wrapper, with these things on it: pallet size (1200 x 1000mm, say), boxes per layer, layers, finished height (under 2.2m), whether layer pads are used and where, edge length, film layers and top cover.

Match the edge length to the pallet height. If the stack is 1400mm, a 1.1m edge is wrong, and you'll see it in the cutting bin. Then check the edge is strong enough to stand alone, so nobody needs to double up.

Next, test it. Don't skip this. Take one finished pallet and push it, brake it, tilt it, with edges and then without. Watch where the first movement starts. Do it again after any change of box, film or edge.

Give the sheet one owner, such as the warehouse manager, and review it whenever a product, box or supplier changes. A sheet nobody owns turns into a guess within a year.

Frequently asked questions

What is the maximum pallet height for a pallet network?

Commonly 2.2m including the pallet, and up to 1,200kg for a full pallet. Check your network's own limits before you build to them.

Do I need edge protectors on every pallet?

Not always. They earn their place where straps or film tension would crush corners, or where the stack needs help staying square. Test with and without.

Are layer pads worth the money?

It depends on how slippery the layers are and how tall the stack is. Test your own pallet both ways, then compare cost per pallet.

What does EUMOS 40509 test?

Whether a loaded pallet stays stable when accelerated, as a lorry would on braking or cornering.

Let us check your pallets

We'll check your pallets on site and show you the cost per pallet, edges and layer pads and wrap together, not just the price per pack.

It's part of our free site check. We walk the site with your operations team for about 30 minutes and send a written report. No contract.

Most sites start small with a 30 day trial on five products, and often those are layer pads, pallet edges or pallet wrap. We test what you buy, lock the spec and never swap without your approval.

Email sales@kptrading.uk or call 020 4576 5500.