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📦 Dangerous goods • UN packaging • Since 1998

UN specification packaging explained
What that code on the box actually means

Certified packaging carries a code like UN 4G/Y30/S/26/GB/1234. It looks like gibberish and it is actually a test certificate — the packaging type, what it is rated for, its maximum weight, when and where it was approved. Here is how to read it, and when you genuinely need it.

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The basics

What UN-specification packaging actually is

If you have ever seen a code like UN 4G/Y30/S/26/GB/1234 stamped on a cardboard box and wondered what it meant, this is it. That marking is not decoration — it is a certificate that the packaging has been tested to an international standard.

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It means the packaging has been type-tested. Drop tests, stack tests, and where relevant pressure and leakproofness tests. An ordinary box, however sturdy, has none of that behind it.
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You can’t make packaging compliant by reinforcing it. Extra tape and a second box do not create a UN-specification package. Either it is certified and marked, or it is not.
Reading the code

What each part of the marking means

PartExampleWhat it tells you
Packaging type4GThe kind of container — 4G is a fibreboard box. Other codes cover drums, jerricans, plastic and steel.
Performance levelYX, Y or Z — the packing group it is tested for. Y covers packing groups II and III.
Mass or gravity30Maximum gross mass in kilograms for solids, or relative density for liquids.
Contents typeSS indicates it is certified for solids or inner packagings.
Year & country26 / GBYear of manufacture and the state that authorised the marking.
Manufacturer1234The code identifying who made and certified it.

Keep the manufacturer’s certificate. Customs and carriers can ask to see it, and it is the document that proves the box you used is the box that was tested.

When you need it

Do you actually need certified packaging?

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Yes, for fully regulated dangerous goods. If the goods are being shipped under a packing instruction that calls for UN-specification packaging, nothing else will be accepted.
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Not always for limited quantities or lighter provisions. Some consumer-sized goods travel under regimes with their own marking that don’t require full UN-spec packaging — but they have their own limits and rules.
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The inner packaging matters as much as the box. Absorbent material, cushioning, secure closures and the right combination of inner and outer are all part of what was tested. Using a certified outer box with the wrong contents inside defeats the point.
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Ask before you buy. Certified packaging is not cheap, and the wrong specification is money wasted. Tell us what you are sending and we will tell you what it needs.
Common questions

Your questions answered

What does UN 4G/Y30/S mean? +
4G is the packaging type — a fibreboard box. Y is the performance level, covering packing groups II and III. 30 is the maximum gross mass in kilograms. S means it is certified for solids or inner packagings. The remaining characters give the year, the authorising country and the manufacturer's code.
Can I just use a strong box instead? +
No. UN-specification packaging has been type-tested to an international standard, and the marking is the evidence. Adding tape or double-boxing an ordinary carton does not make it compliant.
Do I always need certified packaging? +
Not always. Fully regulated dangerous goods generally require it, but some consumer-sized goods travel under limited quantity or similar provisions with their own marking and limits. Which applies depends on the goods, the quantity and the mode.
Do I need to keep any paperwork? +
Yes — keep the manufacturer's certificate for the packaging. Carriers and customs can ask for it, and it proves the packaging you used matches the specification that was tested.
Where do I buy it? +
From specialist packaging suppliers rather than general stationers. Tell us what you are sending before you buy, because the wrong specification is money wasted and we can tell you exactly what is needed.
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Lak Kharod, Director
Excess Luggage Co. • 40 years in the freight industry • MetEx House, Hounslow, next to Heathrow

“The biggest issues are always misdeclaration and incorrect packing. Most people think you put it in the box and send it. Tell us what is actually in the shipment and we will tell you how it has to travel.” For advice on a regulated shipment, call 0800 096 38 39.

Not sure what packaging you need?

Tell us what you’re sending and we’ll tell you how it has to be declared, packed and documented. We’ll give you a clear quote up front, before you commit to anything.

Ask about your shipment📞 0800 096 38 39
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