ADR Labels vs Placards: 100 × 100 mm or 300 × 300 mm, and When You Need Each

The ADR diamond — square set on a point, class colour and symbol — does two different jobs under two different chapters of the agreement. On a package, it is a label governed by ADR 5.2.2. On a container, tank or vehicle, the same design becomes a placard governed by ADR 5.3.1, with a larger minimum size. Buying the wrong one is the most common mistake we see: a 100 × 100 mm label on a container door satisfies nothing.

This guide sets out the difference, the minimum sizes, and where the related marks — limited quantities, UN numbers, elevated temperature — fit in.

Labels and placards at a glance

	Label	Placard
ADR reference	5.2.2	5.3.1
Applied to	Packages: boxes, drums, jerricans, IBC outer surfaces	Containers, MEGCs, tank-containers, portable tanks, vehicles
Minimum size	100 × 100 mm (reducible only if the package is too small)	250 × 250 mm minimum side — in practice 300 × 300 mm products are the standard
Design	Identical: square at 45° (diamond), colour and symbol defined by the label model of the class
Typical product	rigid ADR labels 100 × 100 mm, aluminium or rigid PVC	ADR placards 300 × 300 mm, aluminium or rigid PVC, weatherproof

The class decides the model: Class 1 explosives, Class 3 flammable liquids, Class 4.1 flammable solids, 4.2 spontaneous combustion, 4.3 dangerous when wet, 6.1 toxic, 6.2 infectious, Class 7 radioactive/fissile, Class 8 corrosive, Class 9 miscellaneous and 9A lithium batteries.

Rigid labels or rolls?

ADR does not prescribe the material — it prescribes visibility, weather resistance and durability for the journey. Paper roll labels are the right economics for high-volume parcel flows. Rigid labels and placards — aluminium 0.5–1 mm or rigid PVC — are the right call where the label must survive outdoors, be reused across rotations of the same tank or container, or be mounted with screws or in a placard holder rather than stuck to cardboard. That durability is the reason placards for vehicles are rigid almost by definition.

The marks that are not class diamonds

Limited quantities (LQ)

Goods packed in limited quantities under chapter 3.4 travel with the LQ mark — the black-top/black-bottom diamond — instead of class labels on the package. The mark is 100 × 100 mm on packages; the 300 × 300 mm version marks transport units carrying LQ goods above the 8-tonne threshold (ADR 3.4.13–3.4.15).

UN number field

Tanks and bulk transports carry the UN number of the goods (ADR 5.2.1 for packages, 5.3.2 on transport units); a blank UN number field label lets you write in the four-digit number for the load.

Elevated temperature mark

Substances carried at or above 100 °C (liquid) / 240 °C (solid) add the elevated temperature mark of ADR 5.3.3 — a red triangle with a thermometer, minimum side 250 mm — on the transport unit, not the package.

Orange plates

The orange rectangular plates with hazard identification and UN numbers are a separate requirement (ADR 5.3.2) and are not labels or placards; they sit alongside placarding on tank and bulk transports.

Who applies what

Under ADR, labelling packages is the consignor's job before the goods are handed over; placarding the transport unit falls on the party loading or operating it, container by container, tank by tank. In practice, for a typical business shipping dangerous goods in packages, your obligation ends at correct package labels and documentation — but if you load containers or operate vehicles, the 300 × 300 mm placards become yours. Your DGSA (dangerous goods safety adviser) is the final word on your specific flows; this guide is orientation, not advice for a particular consignment.

Frequently asked questions

Can I use a 100 × 100 mm label as a placard?

No. Placards have a 250 mm minimum side under ADR 5.3.1.7. The 100 × 100 mm format is for packages only.

Can a 300 × 300 mm placard go on a package?

Nothing prevents a larger-than-minimum label, but on ordinary packages it is rarely practical. The 300 × 300 mm products exist for containers, tanks and vehicles.

Does an IBC take a label or a placard?

IBCs are packages and take labels — but IBCs over 450 litres must be labelled on two opposing sides (ADR 5.2.2.1.7).

Which label do lithium batteries need?

Shipments of UN 3480/UN 3481 use the Class 9A label; the details — including when the simplified lithium battery mark applies instead — are in our UN3480 lithium battery label guide.

Are ADR diamonds the same as GHS/CLP pictograms?

No — GHS/CLP pictograms (red-bordered diamonds) belong to supply and workplace labelling, not transport. The two systems coexist on the same package. See ADR and GHS labelling: a quick guide and ISO 780 vs ADR vs GHS.

Choosing your format

Decide at the level of the thing being marked: package → 100 × 100 mm label; container, tank or vehicle → 300 × 300 mm placard; LQ flows → LQ marks in both sizes as above. The full range, class by class and in both sizes, is in the ADR labels and placards collection.

Sources

ADR (European Agreement concerning the International Carriage of Dangerous Goods by Road), in particular 5.2.1–5.2.2 (marking and labelling of packages), 5.3.1 (placarding), 5.3.2 (orange plates), 5.3.3 (elevated temperature mark) and 3.4 (limited quantities). Product formats and materials quoted come from the StoreForSigns product pages linked in this guide. For a specific consignment, verify requirements in the ADR edition in force and with your DGSA.