A closed-head 55-gallon oil drum measures 34.9 inches tall with an outer diameter of 23.3 inches. Its open-head counterpart measures 37.7 inches tall and has an outer diameter of 23.8 inches. The closed variety is used when transporting and storing liquids.
A 55-gallon drum has a capacity equal to 200 liters. It is typically made of steel or durable plastic. Drums are also called barrels, and they are commonly used to transport oils, chemicals, fuels and dry goods. The construction of drums that are used to transport hazardous materials or dangerous goods are regulated by such governing bodies as the United Nations. Drums also come in 14-, 15-, 20- and 53-gallon varieties.