CDL Hazardous Materials Endorsement (HME)Bulk Tanks and Other ContainersMedium
A cargo tank motor vehicle is transporting a non-pressure liquid hazardous material. What specific DOT specification marking would indicate that this cargo tank is designed for such materials and has a maximum allowable working pressure (MAWP) of at least 25 psig but not more than 40 psig?
- ADOT 412
- BDOT 406
- CDOT 407
- DMC 307
Show answer & explanationAnswer & explanation
Correct answer: C. DOT 407
DOT Specification 407 cargo tanks are designed for non-pressure or low-pressure liquids, with an MAWP generally between 25 psig and 40 psig. DOT 406 tanks are lower pressure, and DOT 412 tanks are higher pressure.
Why the other options are wrong
- A. DOT 412 tanks are for corrosive liquids with MAWP typically 15 to 25 psig, but can go higher, and are designed for heavier specific gravity and corrosive properties.
- B. DOT 406 tanks are for non-pressure liquids with MAWP less than 25 psig.
- D. MC 307 is an older specification that was replaced by DOT 407, but the question asks for a current DOT specification marking.
DOT Cargo Tank Specifications
DOT specifications for cargo tanks classify them by design pressure, material, and construction for specific hazardous materials, ensuring safe transport.
- DOT 406: Non-pressure, <25 psig MAWP, flammable liquids.
- DOT 407: Low-pressure, 25-40 psig MAWP, flammable/corrosive liquids.
- DOT 412: High-pressure, 15-25 psig MAWP (or higher), corrosive liquids.
- DOT 331: Pressure tanks for compressed gases, >100 psig MAWP.
Memory trick: The DOT numbers tell you the tank's pressure limits: '6' for low, '7' for medium, '12' for corrosive, and '31' for high pressure gases.