
A typical drum
A '55-gallon drum' (known as a '44-gallon drum' in Britain, and increasingly in Australia as a 200-
litre drum) is a cylindrical container (
drum) with a nominal capacity of 55
U.S. gallons, 44
imperial gallons, or 208
litres. The exact capacity varies with wall thickness and other factors. The standard diameter for drums is 22.5 inches (572
mm). Example height is 850 mm.
The drums are typically made of steel with a ribbed outer to improve rigidity and durability. They are often moved by tilting, then rolling along the base, which is designed especially for that purpose. The drums are commonly used for transporting
oils and
fuels, but can be used for storing various chemicals as well.
Closed-head steel barrels and drums used for shipment of chemicals and petroleum products have a standardised
bunghole arrangement, with one 2-inch (50.8 millimeters)
NPT and one ¾-inch (19 millimeter) NPT threaded bunghole on opposite sides of the top head. This arrangement is echoed in many plastic drums in the same size.
These drums are also available in open head forms, with a clamp ring or flanges which hold a loose lid (often with a gasket) down on the top.
In the past,
hazardous waste was often placed in drums of this size and stored in open fields or buried. Over time, some drums would
corrode and leak. As a result, these drums have become iconic of pollution problems, even though they have numerous legitimate uses and are ubiquitous in commerce.
Although oil is sometimes shipped in 55 gallon drums, the measurement of oil in
barrels is based on 42 (US) gallon wooden barrels of the 1870s.
[1]
The
steel drums used in
calypso music were originally made from these drums. Modern high-quality
steel drums, of the kind sold by instrument suppliers, are now made from scratch using a higher quality of steel.

Rusted 44-gallon drums, with one sliced in half and used as a
fireplace.
Plastic drums
44-gallon
plastic drums are increasingly used. Many do not have ribbing along the side.
Uses include the storage of dry goods and the collection of
rain.
References
See also
★
Barrel (unit)