Edge protection and strapping get treated as alternatives, usually when someone is trying to remove cost. They are doing different jobs, and removing one on the assumption the other covers it tends to show up as damage further down the route.
What strapping does
Strapping applies tension and holds a load together as a unit. It resists the load shifting, spreading or falling apart. It is very good at this, and it is the cheapest way to unitise a pallet.
What strapping does to the load
It concentrates force. A tensioned strap presses on whatever it crosses, and at a corner that means a high local load on a small area. On cartons it crushes the corner. On a pallet of bagged product it cuts in. On anything with a finished surface it marks it.
The tighter the strap, the worse this gets – and straps are usually applied tighter than necessary, because a loose-looking strap gets complained about.
What edge protection does
An edge protector spreads that concentrated load over a larger area, so the strap tension is distributed rather than applied at a line. It does not hold the load together; the strap does that. It stops the strap from damaging the load while it does it.
An edge protector also protects against impacts at the corner, which are the most vulnerable part of any pallet, and it adds some vertical column strength to a stack of soft cartons.
Why removing one fails
Take away the edge protection and keep the strap, and the corners get crushed – the load still arrives together, but damaged. Take away the strap and keep the edge protectors, and the load arrives undamaged and in pieces. Neither is a substitute.
The one case where you can sensibly drop something is where the load is inherently rigid and the corners are not vulnerable – a stack of plastic crates, for instance, where strapping alone is adequate and edge protection is genuinely redundant.
PP sheet as edge protection
Angle sections made from PP corrugated sheet are reusable, washable, and do not lose strength when wet, which is where paperboard angle board fails. They are the right choice in a closed loop or a wet environment. For one-way shipments, paperboard angle is cheaper and entirely adequate – this is a case where the reusable option is not automatically the right one.
Getting the strap tension right
Most strap damage is over-tensioning. If corners are being crushed, check the tension setting before adding more protection – it is the cheaper fix. A strap should be snug, and the test is whether you can get a few fingers under it, not whether it is drum tight.
Specifying PP edge protection
- Leg length matched to the load, not the longest available
- Thickness matched to the strap tension
- Flute direction along the length of the angle, which is where the stiffness is needed
- Whether it will be reused, which decides the edge treatment
Where the strap should sit
Strap placement matters as much as tension. A strap across the middle of a load does more to hold it together than one near the top, and a strap across a corner does the most damage.
Where possible, straps should cross flat faces rather than corners, and there should be edge protection wherever they do not. If a strap has to cross a corner, the protector needs to be long enough to spread the load past the corner rather than just covering it.
It is also worth checking whether two lighter straps would do the job of one heavy one. Two straps at moderate tension usually damage less and restrain better than one at high tension.
What we supply
We make edge protection from corrugated PP sheet for reusable and wet applications. If your shipments are one-way, we will tell you that paperboard is the better buy – it usually is.