Class 2.1 vs cryogenic gas label mock visual test simulator online drill generator pass
Division 2.1 is a flammable gas (red, flame, 2), like propane. A cryogenic gas is a gas shipped as a very cold refrigerated liquid, and its placard follows the gas hazard: a flammable cryogen (like liquid hydrogen) is still red 2.1, while a non-flammable cryogen (like liquid nitrogen) is green 2.2. So cryogenic is about temperature, not a separate placard color.
Division 2.1 is flammable gas
Division 2.1 is the flammable gas division: a red placard with a flame symbol and a 2, used for gases that burn, like propane and hydrogen. Red signals flammable, the 2 signals gas, so 2.1 means a flammable gas.
Cryogenic is a temperature state
A cryogenic gas is simply a gas cooled until it becomes a liquid, kept at extremely low temperatures to ship in bulk. Cryogenic describes how it is carried, not a separate hazard class. So the placard does not become a special cold color; it follows whatever gas hazard the material has.
How the placard follows the gas
Cryogens take their gas division:
| Flammable cryogen | Non-flammable cryogen | |
|---|---|---|
| Division | 2.1 | 2.2 |
| Color | Red | Green |
| Examples | Liquid hydrogen, LNG | Liquid nitrogen, liquid oxygen |
| Extra hazard | Extreme cold | Extreme cold |
Cryogens follow the gas division (2.1 red or 2.2 green). Verify in your official manual.
2.1 versus a cryogenic gas
So the comparison is not quite apples to apples: 2.1 is a hazard division (flammable gas), while cryogenic is a transport state (very cold liquefied gas). A cryogen can be a 2.1 flammable gas (liquid hydrogen) or a 2.2 non-flammable gas (liquid nitrogen). Read the color to know which: red for flammable, green for non-flammable.
How to study and verify
Remember 2.1 means flammable gas (red), and cryogenic means a very cold liquefied gas whose placard follows its gas division. Drill flammable cryogens (red 2.1) against non-flammable ones (green 2.2), and note the extreme cold as an added hazard on both. Verify the specifics in your official state CDL manual.
Frequently asked questions
- What is the difference between Division 2.1 and a cryogenic gas?
- Division 2.1 is a flammable gas (red, flame, 2). Cryogenic describes a gas carried as a very cold refrigerated liquid; its placard follows the gas division, red 2.1 for flammable cryogens, green 2.2 for non-flammable ones. Cryogenic is a temperature state, not a color. Verify in your manual.
- What color is a cryogenic gas placard?
- It depends on the gas: a flammable cryogen (like liquid hydrogen) is red 2.1, and a non-flammable cryogen (like liquid nitrogen) is green 2.2. The cold does not get its own color.
- Is cryogenic a hazard class?
- No. Cryogenic is a transport state (a very cold liquefied gas), not a hazard class. The placard follows the gas division (2.1 or 2.2), with the extreme cold as an added hazard.