Diesel un1993 class 3 combustible vs flammable red visually flash color app checks check…
Diesel is a Class 3 liquid on a red placard, but its higher flash point usually makes it combustible rather than flammable, so the diamond often reads COMBUSTIBLE. UN 1993 is the identification number for flammable liquids not otherwise specified, a Class 3 catch-all that can cover various fuels. Verify the specifics with the shipping papers.
Diesel: usually combustible, still Class 3
Diesel fuel typically has a flash point high enough to classify it as a combustible liquid rather than a flammable one, though it stays in Class 3 on a red placard. Gasoline, with its much lower flash point, is the flammable counterpart. So the color is shared; the wording and the flash point are what move.
What UN 1993 means
UN 1993 is the identification number for flammable liquids that are not otherwise specified, a Class 3 catch-all used for many liquids that do not have their own dedicated number. Seeing 1993 tells you the material is a Class 3 flammable liquid; the placard color and number tell you the hazard.
Diesel vs gasoline at a glance
The comparison that trips people up:
| Diesel | Gasoline | |
|---|---|---|
| Hazard class | Class 3 | Class 3 |
| Placard color | Red | Red |
| Placard word | Usually COMBUSTIBLE | FLAMMABLE |
| Flash point | Higher (about 140F or more) | Low (well below 140F) |
General US framing. Specific products and conditions can differ, so confirm with the shipping papers and your manual.
Frequently asked questions
- Is diesel flammable or combustible?
- Diesel is usually a combustible liquid because of its higher flash point, though it is still Class 3 and uses a red placard reading COMBUSTIBLE. Verify the specifics in your official manual.
- What is UN 1993?
- It is the UN identification number for flammable liquids not otherwise specified, a Class 3 catch-all. It identifies the material; the red diamond shows the hazard. Confirm in the Emergency Response Guidebook.
- Why are diesel and gasoline both red?
- Both are Class 3 liquids, and red is the Class 3 color. The difference is the wording (COMBUSTIBLE vs FLAMMABLE) and the flash point, not the color.