Edge protectors and corner boards: when a pallet needs them

Look at the top layer of a strapped pallet after a long trip. If the strap has cut a groove into the carton corners, either the strap was too tight for that carton or nothing sat between the strap and the carton.

That groove is called strap bite. It is one reason a pallet needs edge protectors, and there are three others.

Put simply, a pallet needs edge protectors when it is strapped, when other pallets will stand on it, when its cartons are weak or will sit in damp air, or when it travels far with many handlings. A single-layer pallet of rigid goods, wrapped and not stacked, usually does not.

I should say one thing upfront. Corner boards are not a cure for a bad carton. They spread the load and protect the edges, but the carton still has to carry the weight.

What edge protectors actually do

The European Commission's 2014 cargo securing guidelines give a clear list. A corner protector can do one or more of four jobs.

1. Protect the strap or lashing from being cut by a sharp corner of the cargo.
2. Protect the cargo from being cut by the strap.
3. Let the strap slide along its length over the corner, so tension evens out.
4. Spread the strap force over a wider zone of the cargo.

Long paper boards add two more jobs. Standing upright at the corners of a pallet, they carry part of the weight from above, and they hold the stack square while it is wrapped.

The same guidelines make one point every buyer should know: "There are no international standards for corner protectors." So we cannot buy them by a standard number. We have to buy them by specification and by testing.

The types you will be offered

1. Laminated paperboard angle boards (L-profile) are made of several plies of paperboard, glued and formed into a right angle. These are the usual corner boards for pallets.
2. U-profiles and wrap-around boards cover flat edges, rolls and round items.
3. Paper and plastic blend boards are sold for damp and cold-store conditions.
4. Plastic strap guards are short L-shaped pieces that sit only under the strap.
5. Foam edge guards give soft protection to finished furniture and painted edges.

The EU guidelines name two things that are not acceptable as corner protectors: bent steel plates, because they can cause serious injuries during lashing and transport, and anti-slip mats.

Paper or plastic?

My own rule of thumb is this. If the pallet will be stacked or stored for weeks, use paper angle boards full height. If it only needs strap protection and travels once, small plastic guards are enough.

Moisture is the big weakness of paper, and it affects your cartons too. The CTU Code (IMO, ILO and UNECE, 2014) says ordinary cardboard can lose up to 75% of its stability as humidity rises from 40% to 95%. A monsoon godown or a reefer container is exactly that air. If I were packing for the monsoon, I would ask for moisture-resistant boards. Signode, for example, sells a paper and plastic blend board for humid and outdoor use.

How to size a corner board

Corner boards are specified as leg × leg × thickness × length, in millimetres. A "50 × 50 × 4" board has two 50 mm legs and is 4 mm thick.

Thickness and leg width both change strength. Signode's Angleboard brochure for Asia Pacific (2019) lists compression strength measured on a 100 mm piece.

Look at the 50 mm rows. Going from 3 mm to 5 mm more than doubles the strength. The brochure does not name the test method, so I would use these figures only to compare sizes within one maker's range, never to compare two makers.

For the size itself, these four rules work.

1. Make the legs wider than the strap contact zone, so they reach well past where the strap presses. For plastic strap guards, makers size them by strap width, from about 13 mm to 32 mm straps.
2. Cut the length equal to the load height. A short board leaves the top cartons bare. A board taller than the load stops another pallet sitting flat on top.
3. Go heavier for stacking. If another pallet will stand on this one, step up in thickness or leg width, and compare the options on one maker's figures.
4. Fit all four corners, every time. A board on two corners lets the load lean towards the other two.

Strap bite: protecting the load and the strap

Strap bite hurts twice. The carton corner is crushed, and the strap goes slack as it sinks in. The 2014 EU guidelines describe the same effect for lashings: high local forces deform the cargo and give it room to move, and large corner protectors help by spreading the force.

The CTU Code adds a point about the lashing itself. Its rated strength assumes it passes over smooth edges. Sharp edges and corners reduce it substantially, so the Code asks for edge protectors wherever practicable.

IS 10106, the Indian packaging code for tensional strapping, asks for edge protectors or pads under straps, and recommends paperboard pads under steel strap on fibreboard cases. Our guide to PP, PET and steel strapping covers the straps themselves.

When corner boards pay off, and when to skip them

No standard tells us this, so here is my own judgement, with the reason for each.

They pay off when:

1. The pallet is strapped. Every strap corner is a bite point.
2. Pallets will be stacked, in the warehouse or in a container. The bottom pallet carries the most, for the longest time.
3. The cartons are light-duty or the air is humid. Corner support makes up for some of the strength that damp board loses.
4. The load is going abroad. More handlings and more weeks in a box mean more chances for a corner to fail. Our guide to securing cargo in a container covers the rest of the export load.
5. The product is costly and the carton is part of the product, like retail packs that must arrive without dents.

We can usually skip them when the goods are rigid and stable (drums or wooden crates), the pallet is a single layer, it is only wrapped in film and not strapped, and it is used and unpacked within our own site.

Fitting them properly

1. Square the load first. Boards do not fix a load that already leans.
2. Stand each board on the pallet deck or the bottom carton, flush with the corner.
3. Fit the boards before the film or straps, so the film and straps hold them in place.
4. Centre each strap on the board legs, not near the board's edge.
5. If you wrap with film, start the wrap low so the base of each board is locked to the pallet. Our guide to stretch film explains wrap patterns.

A simple test on your own pallets

You do not need a laboratory to decide. Build two identical pallets of a product that travels a long way, one with corner boards and one without. Photograph all four corners of each at loading.

At the destination, or after a week in your own stack, photograph the same corners again. Look for strap grooves, crushed top corners and any lean.

I like this test because it costs a few boards and gives an answer your purchase team can see. If both pallets arrive the same, you have saved yourself the boards on that product. If they do not, you have the photos to show your purchase team why the boards are worth buying.

For a laboratory answer, the test is box and unit-load compression, such as ASTM D642 (2025 edition) or ISO 12048.

If you send us your pallet size, load height, carton weight and how high you stack, through our contact page, we will suggest a board size to try first.