Cargo Tank Specifications, Classification & Testing
35 free questions, part of the Tanker (N) Endorsement CDL practice test
A tank endorsement kicks in once a single tank on your rig holds more than 119 gallons and all your tanks together add up to 1,000 gallons or more. From there you need to know the DOT cargo tank specs (406, 407, MC 331, MC 338), the testing schedule in 49 CFR 180.407, and how to read the test markings stamped on the tank under 180.415. ELDT.io's free bank has 35 practice questions built around these exact rules.
This topic has 35 questions, split into 3 tests of 11-12 questions each:
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Start Class A CDL Theory ($15)Questions about Cargo Tank Specifications, Classification & Testing
What makes a vehicle a 'tank vehicle' under CDL rules?
Under 49 CFR 383.5, it's any commercial motor vehicle with a tank where at least one tank is rated over 119 gallons and the combined rated capacity of all tanks is 1,000 gallons or more. Hit both numbers and you need the tank endorsement, hazmat or not.
How often does a cargo tank need to be pressure tested?
Most DOT specification cargo tanks get a periodic pressure retest every 5 years under 49 CFR 180.407(c), with shorter intervals for certain specialized tanks like those in corrosive or cryogenic service. External visual inspections and leakage tests typically run on a 1-year cycle instead.
What do the letters on a cargo tank's test marking mean?
Each letter documents a specific test or inspection: V for internal visual inspection, P for pressure test, L for leakage test, and K for thickness test, with K-EPA27 marking a thickness test tied to EPA corrosion rules. The marking has to show the month and year next to each letter, per 49 CFR 180.415(b).