Classes, fill limits, and labeling: 12 questions on ASHRAE 34 safety groups, the 80% fill rule, DOT cylinder markings and retest dates, and A2L cylinders. Every answer shows its citation.
Rules current as of October 26, 2026.
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Studying for the real exam, or a certified tech checking the new rules? Either way, if an old study guide disagrees with an answer here, the citation under the answer is the one to trust.
