Class 4 Flammable Solids
Class 4 is the dangerous goods class for flammable solids, split into three divisions: 4.1 flammable solid, 4.2 spontaneously combustible and 4.3 dangerous when wet.
How much can you store before you need a placard?
In New South Wales, Queensland, South Australia, Tasmania, the Australian Capital Territory and the Northern Territory, a placard comes in once the quantity you store exceeds the figure below. Victoria and Western Australia set their own, and count by packing group rather than category.
| Chemical | Category | Placard quantity | Manifest quantity |
|---|---|---|---|
| Self-reactive substances | Type B | 50 kg or 50 L | 500 kg or 500 L |
| Type C-F | 250 kg or 250 L | 2,500 kg or 2,500 L | |
| Flammable solids | Category 1 | 250 kg | 2,500 kg |
| Category 2 | 1,000 kg | 10,000 kg | |
| Pyrophoric liquids and Pyrophoric solids | Category 1 | 50 kg or 50 L | 500 kg or 500 L |
| Self-heating substances and mixtures | Category 1 | 250 kg or 250 L | 2,500 kg or 2,500 L |
| Category 2 | 1,000 kg or 1,000 L | 10,000 kg or 10,000 L | |
| Substances which in contact with water emit flammable gas | Category 1 | 50 kg or 50 L | 500 kg or 500 L |
| Category 2 | 250 kg or 250 L | 2,500 kg or 2,500 L | |
| Category 3 | 1,000 kg or 1,000 L | 10,000 kg or 10,000 L |
Figures checked against the linked source on 2026-09-29.
General information, not advice for your site. The figures on this page are quoted from the government sources linked beside them and were checked on the date shown. What applies to you depends on what you store, how much, and which state you are in, and the law changes. Check the source, or ask your regulator.
The signs we stock
Placards come in aluminium or polypropylene at 270 x 270 mm. Stickers come in two sizes, and label rolls in 500. Every price includes GST.
Common substances in this class
Each one is listed against its UN number, so you can check it against the shipping documents or the safety data sheet you already have.
| Substance | UN number | Class | Sign |
|---|---|---|---|
| Activated carbon | 1362 | 4.2 | Class 4.2 - Spontaneously Combustible placard |
| Calcium carbide | 1402 | 4.3 | Class 4.3 - Dangerous When Wet placard |
| Magnesium powder | 1418 | 4.3 | Class 4.3 - Dangerous When Wet placard |
| Matches | 1331 | 4.1 | Class 4.1 - Flammable Solid placard |
| Naphthalene | 1334 | 4.1 | Class 4.1 - Flammable Solid placard |
| Oily cotton waste | 1364 | 4.2 | Class 4.2 - Spontaneously Combustible placard |
| Sodium | 1428 | 4.3 | Class 4.3 - Dangerous When Wet placard |
| Sulphur | 1350 | 4.1 | Class 4.1 - Flammable Solid placard |
| White phosphorus | 1381 | 4.2 | Class 4.2 - Spontaneously Combustible placard |
| Zinc powder | 1436 | 4.3 | Class 4.3 - Dangerous When Wet placard |
Substance names and UN numbers are from the Australian Dangerous Goods Code list. The list runs to more than 2,400 entries, so this is a sample of the everyday ones, not all of them.
The other classes
Not on this list? If the class or the wording you want is not here, tell us on Custom Signs - your own text, your own size - and we will come back with a price.
Not sure which classes you hold?
Lupin Systems keeps your safety data sheets in one place and works out the signage and the PPE from what you store.