How to not confuse flammable solid vs spontaneous combustible for lithium battery hauling…?
Read the background pattern. Division 4.1 flammable solids use a white placard with red vertical stripes. Division 4.2 spontaneously combustible use a placard that is white on the top half and red on the bottom. Both carry a flame and a 4. One note for lithium battery loads: many lithium batteries are actually Class 9, not Class 4, despite the fire risk.
Same flame, different background
Division 4.1 and 4.2 both show a flame and the number 4, which is exactly why they blur together. The reliable difference is the background pattern. Flammable solids (4.1) use red-and-white vertical stripes. Spontaneously combustible materials (4.2) use a split diamond, white across the top half and solid red across the bottom. Train your eye on the pattern, not the flame.
What each division means
A flammable solid (4.1) is a solid that can ignite readily or burn vigorously, like certain matches or metal powders. A spontaneously combustible material (4.2) can heat up and catch fire on its own, without an outside spark, when exposed to air. The split diamond hints at that extra self-heating danger.
The three Class 4 divisions
Learning the trio together stops the mix-up:
| Division | Background | Hazard |
|---|---|---|
| 4.1 | White with red vertical stripes | Flammable solid |
| 4.2 | White top, red bottom | Spontaneously combustible |
| 4.3 | Blue | Dangerous when wet |
All three are Class 4 with a flame and a 4; the background sets them apart. Confirm in your official manual.
The lithium battery catch
If your question is about hauling lithium batteries, here is the trap inside the trap: many lithium batteries are regulated as Class 9 miscellaneous, not as a Class 4 flammable. Despite their fire reputation, they do not meet the Class 4 definitions, so they take the striped white Class 9 placard plus a lithium battery mark. Do not let the fire risk push a lithium load into 4.1 or 4.2.
How to drill it
Practice 4.1, 4.2, and 4.3 as a set, reading the background first: stripes, split, or blue. Then keep lithium batteries filed under Class 9 in your memory so the two ideas do not collide. The exact classification for any specific item is set in the regulations, so verify it there and in your official manual.
Frequently asked questions
- How do I tell flammable solid from spontaneously combustible?
- By the background. Division 4.1 flammable solid is white with red vertical stripes; Division 4.2 spontaneously combustible is white on top and red on the bottom. Both carry a flame and a 4. Confirm in your official manual.
- Are lithium batteries Class 4?
- Usually no. Many lithium batteries are regulated as Class 9 miscellaneous, not Class 4, despite the fire risk. They use the Class 9 placard and a lithium battery mark. Verify the classification in the regulations.
- What are the Class 4 divisions?
- 4.1 flammable solids (red-and-white stripes), 4.2 spontaneously combustible (white top, red bottom), and 4.3 dangerous when wet (blue).