ISO 18605 is the international standard that sets out when used packaging can be classed as recoverable through energy recovery, meaning burning it gives back more useful energy than the burning itself uses up.
Its 2013 edition turns that into an arithmetic test. It is one of six standards in the ISO 18600 series, under the umbrella standard ISO 18601.
Almost anything burns, so it is easy to assume any pack qualifies. ISO 18605 exists because burning only counts as recovery when the fire hands back more than it consumes.
A quick profile of ISO 18605
The reference details first, for anyone who only needs those.
| Detail | ISO 18605 |
|---|---|
| Standard | ISO 18605 |
| Full title | Packaging and the environment, energy recovery |
| Current edition | The 2013 first edition, reviewed and confirmed as current in 2024 |
| What it measures | Whether burning a pack leaves useful energy once the burning has paid for itself |
| Type | A requirements standard you assess yourself against, not a certification |
| Published by | ISO/TC 122 (Packaging), subcommittee SC 4 |
| Length | 16 pages, five of them annexes |
| Family | The ISO 18600 series, under the umbrella ISO 18601 |
Why burning packaging is not automatically recovery
ISO 18605 takes its definition of energy recovery from another ISO standard and keeps it short. It is the production of useful energy through direct and controlled combustion.
The standard adds that the common form of it is a solid-waste incinerator producing hot water, steam or electricity, which is what most people mean by a waste to energy plant. Two words in that definition do the work, useful and controlled.
The standard is deliberate about the second one. It treats combustion and incineration as the same oxidation reaction, covering organic materials and metals alike.
It then says plainly that everywhere it uses those words it means only incineration with energy recovery. Burning a pack and capturing nothing is not in scope at all.
Useful is where the actual test lives, and it is a piece of arithmetic.
A fire spends energy before it gives any back
Burning something releases energy, but the burn does not hand all of it over.
The flue gases it creates, the ash it leaves and the excess air pulled into the furnace all have to be heated from room temperature up to the temperature the process runs at. That heat comes out of the same fire.
ISO 18605 gives that consumed share a name, required energy, and a symbol, Ha. It is the energy needed to heat the post-combustion substances and the excess air from ambient temperature up to a specified final temperature.
Calorific gain is whatever is left over
The standard then defines calorific gain as the positive difference between the energy a material releases on combustion and Ha. Release more than the heating job costs and there is a gain. Release less and the pack has been an energy expense dressed up as a recovery route.
That gives the standard its threshold. The theoretical minimum net calorific value is the point where the energy released exactly covers the heating and nothing is left over. It is the floor a material has to clear before energy recovery means anything.
A real plant asks for more than the theory does
Theory is generous, because it assumes no heat escapes anywhere. A working plant leaks.
So ISO 18605 defines available thermal energy separately, as the share of the released energy that a real industrial system actually transfers, for example into a boiler's steam cycle, once the thermal losses are taken off.
That is why the standard carries two separate derivations rather than one number. Annex A works out the theoretical minimum, and Annex B derives a minimum net calorific value for packaging in a real industrial system.
What is inside ISO 18605
Sixteen pages is short for a standard, and the shape of the document tells you where the effort went.
- Clause 4, specification of minimum net calorific value. The figure a pack has to clear.
- Clause 5, requirements. What has to be true for packaging to be classified as recoverable in the form of energy recovery.
- Clause 6, procedures. Split into applying the standard, carrying out the assessment, and demonstrating that the requirements are met.
- Annexes A and B. The two calculations behind the threshold, theoretical and real-plant.
- Annex C, packaging not suitable for the energy recovery process. The standard sets aside packaging this route does not work for.
- Annexes D and E. A blank format for the statement that a pack meets the requirements, and the same format filled in as a worked example.
The actual numbers sit in clauses 4 and 5 and in those first two annexes, and those are the parts ISO sells rather than publishes. If you need the threshold itself you need the standard, which costs 100 Swiss francs.
How a producer shows the requirements are met
The assessment is not a lab test in the way a compostability test is. It is a calculation you carry out on the pack you have designed, and the standard gives you the form to write it on.
Clause 6 splits the work into three steps, applying the standard, carrying out the assessment, and demonstrating that the requirements have been met.
What goes into the statement
Annex D sets out the format, and it asks for four things in this order.
- The assessment procedure used.
- A description of the packaging, including the weight percentage and net calorific value of what it is made from.
- The assessment, measured against the requirements of the standard.
- The declaration that those requirements are met.
Annex E then shows the same format filled in for an example pack, which is the fastest way into the method for most people.
That format tells you something useful. Because it asks for weight percentages and a net calorific value, a pack is described by everything it is made of and in what proportions, not by whichever material it mostly looks like.
There is no certificate at the end of it
The series says a demonstration can be made by a first party such as the manufacturer or supplier, a second party such as the customer, or with the support of an independent third party. Which of those you pick is a commercial decision, not a requirement.
One boundary is worth knowing before the result goes anywhere public. The ISO 18600 series covers the technical side of packaging only.
It states outright that it does not cover what ISO 14021 requires in order to support a claim or a label.
Clearing ISO 18605 establishes a fact about the pack. It does not license the wording you print on it.
Who reaches for ISO 18605
The standard is written for the people who have to answer a technical question about what happens to a pack that is never going to be recycled.
- Packaging developers working on composite or multi-material packs where recycling is genuinely not on the table, who need an honest answer about the alternative.
- Waste and recovery specialists at the receiving end, who deal in calorific values every day and need packaging described in the same terms.
- Compliance and sustainability teams outside the EU, in markets where energy recovery is still a recognised route and a buyer or a regulator asks for evidence.
- Anyone reading a supplier's recoverability claim who wants to know which of the recovery routes it refers to, because the word covers three very different things.
How the EU packaging rules moved past energy recovery
This is the part that has changed most since ISO 18605 was written, and it changes how you should read the standard.
The old directive asked exactly this question
The EU's packaging directive, Directive 94/62/EC, listed four ways packaging could be recoverable, and energy recovery was one of them.
Its wording reads almost as a brief for ISO 18605. Packaging waste processed for the purpose of energy recovery, it said, "shall have a minimum inferior calorific value to allow optimization of energy recovery."
Europe answered that with its own standard, EN 13431:2004, one of the six harmonised standards the European Commission listed under the directive. ISO 18605 is the international document on the same question, and it cites EN 13431 in its own bibliography.
PPWR does not ask it any more
The Packaging and Packaging Waste Regulation, or PPWR, repealed Directive 94/62/EC with effect from 12 August 2026.
Only one piece of the old essential requirements was carried forward, the packaging minimisation indent, and even that only until the end of 2029. The energy recovery requirement was not carried forward at all.
What replaced it is a different set of design duties, and nothing in that set is about burning.
The change is not just that one route disappeared from a list. PPWR pushes in the opposite direction in three concrete ways.
- Recyclability became the rule. All packaging placed on the market has to be recyclable, with the design condition applying from 1 January 2030 or 24 months after the supporting delegated acts, whichever is later.
- Burning recyclable packaging is prohibited. Packaging that meets the design for recycling criteria has to be collected for recycling, and incineration and landfill of it is banned outright. The one carve-out is the leftovers from treating separately collected packaging waste, where recycling is not feasible or would not give the best environmental outcome.
- Nothing burned counts as recycled. PPWR's definition of material recycling excludes energy recovery by name, and material used as a fuel is expressly not counted towards a recycling target. Only metals separated after incineration can be counted, and only under set quality criteria.
That sits on top of the waste hierarchy in EU waste law, which has ranked recycling above other recovery such as energy recovery for years.
PPWR's own recitals put a number on why, noting that recycling plastic waste is roughly five times better than incinerating it with energy recovery in fossil fuel terms.
The practical consequence for a producer is about money as well as design. From 18 months after the delegated and implementing acts land, the fees a producer pays under extended producer responsibility, or EPR, are modulated on recyclability performance grades.
A pack that burns well and recycles badly is a pack that costs more.
Where ISO 18605 still matters for producers
None of that makes the standard useless. It is worth being precise about what is left of it, because three things still hold.
The residual fraction is real
PPWR's own ban on burning recyclable packaging carves out waste that cannot feasibly be recycled, and residual waste does not stop existing because a regulation prefers recycling.
ISO 18605 is still the international method for describing what that fraction is worth as fuel.
Not every market is the EU
Energy recovery remains an accepted route in plenty of jurisdictions, and an ISO standard travels further than a European one. If you sell outside the EU and a buyer or a regulator asks how a pack performs at end of life, this is the document that answers in terms they will recognise.
It keeps a design conversation honest
Running the arithmetic on a composite pack settles an argument quickly, because it separates the parts that carry energy from the parts that only absorb it.
What it is not is a compliance route. PPWR does not mention ISO 18605, working to it demonstrates nothing the regulation asks for, and designing a pack to burn well is no defence for a pack that cannot be recycled.
Treat the result as engineering evidence about the end of life you are actually planning for, and keep it with the rest of the technical documentation behind the pack.
Which pack takes which route, on what evidence, is the kind of record an EPR platform like Repax keeps anyway.
ISO 18605 next to EN 13431 and the other recovery routes
Three comparisons clear up most of the confusion here.
ISO 18605 and EN 13431 are the same idea in two rule books
EN 13431:2004 is the European standard for packaging recoverable in the form of energy recovery, including a specification of minimum inferior calorific value. It was harmonised under Directive 94/62/EC, which gave it legal weight in Europe that ISO 18605 has never had.
ISO 18605 is the international statement of the same question. With the directive now repealed, EN 13431's special status in EU law has gone with it, so the two documents are closer in standing than they used to be.
Energy recovery is one of three recovery routes
ISO 18601's map of the series puts three standards side by side at the recovery stage, and a pack is assessed against whichever route it is actually meant to take.
| Route | Standard | What happens to the pack |
|---|---|---|
| Material recycling | ISO 18604 | The material is reprocessed into new material |
| Energy recovery | ISO 18605 | The pack is burned in a controlled way and the energy is captured |
| Organic recycling | ISO 18606 | The pack is composted or anaerobically digested |
Those three sit after two earlier steps in the same series, optimising the pack under ISO 18602 and designing it for reuse under ISO 18603. Recovery is what the series turns to once reuse is off the table.
Recovery and recycling are not interchangeable words
In everyday use people say recovery when they mean recycling. In EU law they are separate categories with a ranking between them, and energy recovery sits below recycling in it.
That matters when you read a supplier's data sheet. A pack described as recoverable may be recoverable only by burning, which under PPWR gets a producer nowhere.
If you are assessing what actually blocks a pack from being recycled, ISO/TR 17098 is the document that lists the culprits.
Frequently asked questions about ISO 18605
Short, plain answers to the questions people ask most about ISO 18605.
What is ISO 18605?
ISO 18605 is the international standard, first published in 2013, that specifies the requirements for packaging to be classified as recoverable in the form of energy recovery, and sets out the procedures for assessing it. In plain terms it defines when burning a pack for its energy genuinely counts as recovering it.
Is ISO 18605 a certification?
No. There is no ISO 18605 certificate and no accredited scheme behind it. The series states that a demonstration can be made by a first party such as the manufacturer, a second party such as the customer, or with the support of an independent third party, and leaves the choice to you.
What edition of ISO 18605 is current?
The 2013 first edition. ISO reviewed it in 2023 and confirmed it in 2024, so it remains the current version. It was prepared by ISO technical committee TC 122 on packaging, subcommittee SC 4 on packaging and environment, and runs to 16 pages.
What is calorific gain in ISO 18605?
Calorific gain is the energy a material releases on combustion minus the energy needed to heat the resulting gases, ash and excess air up to the operating temperature. Only a positive difference counts. If a material releases less than that heating costs, burning it consumes energy rather than recovering it.
Does ISO 18605 give a minimum calorific value?
It specifies one, in a clause dedicated to it, and derives it two ways in its annexes, once as a theoretical minimum and once for a real industrial system where thermal losses are taken into account. The figures themselves are in the purchased standard rather than in the free preview.
Does PPWR require ISO 18605?
No. PPWR does not mention ISO 18605, and it contains no energy recovery design requirement at all. Its design duties cover substances, recyclability, recycled content, biobased feedstock, compostability, minimisation and reuse. Working to ISO 18605 demonstrates nothing the regulation asks a producer to show.
Can packaging designed for energy recovery meet PPWR?
Not on that basis. Under PPWR all packaging placed on the market has to be recyclable, packaging that meets the design for recycling criteria must be collected for recycling rather than burned or landfilled, and material used as fuel is not counted as recycled. Energy recovery is what happens to the fraction that genuinely cannot be recycled.
What is the difference between ISO 18605 and EN 13431?
ISO 18605 is the international standard for packaging recoverable through energy recovery. EN 13431:2004 is the European one on the same subject, and it was a harmonised standard under Directive 94/62/EC, which gave it legal standing that the ISO version never had. That directive was repealed on 12 August 2026.
Does ISO 18605 let me call my packaging recoverable?
Not by itself. The ISO 18600 series covers the technical side of packaging and says outright that it does not cover what ISO 14021 requires to support a public claim or label. Meeting ISO 18605 establishes a technical fact. Turning it into wording on a pack is a separate exercise with its own rules.
