Here is a quotation we see several times a month. A buyer has a specification for a 40 µm sack. A new supplier offers 20 µm at a much better price and says it is equivalent.
It might be exactly right. It might be half the sack. The micron figure alone does not tell you, and the specification sheet usually does not say.
The property that differs
HDPE carries roughly twice the tensile load of LDPE per micron. That is the whole basis of the substitution: a 12 µm HDPE sack genuinely does the work of a 25 µm LDPE one, using half the polyethylene.
It is not a trick and it is not a downgrade. For the right waste it is the better answer — less material, less weight, lower EPR cost, and a smaller pallet footprint for the same number of sacks.
The property that does not transfer
Puncture resistance runs the other way, and it does not scale.
LDPE stretches before it tears. Put a corner into it and the film deforms around the corner and holds. HDPE is stiffer: the same corner goes through it, and once there is a hole the tear runs.
So the substitution works — but only for waste with nothing sharp in it.
| Waste | HDPE at half the thickness |
|---|---|
| Paper, dry packaging, office waste | Works. Usually the better answer |
| General commercial, mixed dry | Works at the margins. Test it |
| Food and wet waste | Does not work. Leaks and tears |
| Anything with glass, bone, metal or a broken tile | Does not work, at any thickness |
How to tell which you have been offered
Three questions, and a supplier who will not answer the first has answered all three.
1. What polymer is it? If the answer is a thickness, ask again.
2. What does the waste actually contain? Not what the bin is called — what goes into it. A “general waste” bin in an office and a “general waste” bin in a restaurant are different products.
3. Can I have twenty sacks to try? A week of real use settles it in a way no specification comparison does. We send samples free, and the reason is entirely self-interested: a sack that fails in week three is a customer lost and a collection to re-run.
Identify it by ear
A practical trick for when you have a sack in your hand and no paperwork.
HDPE rustles. Stiff, noisy, thin, and it crackles when you crush it — the sound of a supermarket carrier bag.
LDPE is quiet and soft. It stretches under your thumb rather than creasing.
That will not settle a specification argument, but it will tell you in two seconds whether the sample in front of you is the material you were quoted.
What it is worth
At the volumes a facilities contractor buys, moving suitable waste streams from LDPE to HDPE is a real saving — roughly half the polyethylene for the same job, and the EPR contribution falls with it, because that is charged by weight.
Moving unsuitable streams costs more than it saves, in bin areas cleaned twice a week and in sacks that fail on the way to the compactor.
The sack duty selector will tell you which of your streams are which, and the complete guide to bin liners has the reasoning in full.