CTR 156CT Propane Practice Test 2026 – Complete Exam Preparation

The date stamped on a cylinder is tied to its requalification schedule, and the small mark next to that date tells you how long you have before the cylinder must be requalified again. When you see the letter E next to the date, that indicates a five-year requalification interval. So after that date, the cylinder should be requalified within five years to ensure the cylinder’s walls and valves remain safe and within standards.

Other intervals like two years, ten years, or one year are used in different marking contexts or for other types of cylinders, but the specific E marking points to a five-year cycle.