55 gallon drum
A 55-gallon drum is a cylindrical container drum with a nominal capacity of 55 U.S. gallons, 44 imperial gallons, or 200 litres. The exact capacity varies with wall thickness and other factors. Standard drums are 22.5 inches (572 mm) in diameter and 33.5 inches (850 mm) high (these dimensions yield a total volume of ~218 L) The drums are typically made of steel with a welded top and ribbed outer wall to improve rigidity and durability. They are commonly used for transporting oils and fuels, but can be used for storing various chemicals as well.
The 55-gallon drum will fit handily four to a fork truck standard wooden shipping pallet, and so ease handling and shipping. The drum’s size, shape, and weight distribution lends itself to being moved about readily on the loading dock or factory floor with a two-wheeled hand truck. They can also be moved short distances by hand by tilting, then rolling along the base, which is designed especially for that purpose.
Closed-head steel barrels and drums used for shipment of chemicals and petroleum products have a standardized bunghole arrangement, with one 2-inch (50.8 mm) NPT and one 3⁄4-inch (19 mm) NPT threaded bunghole on opposite sides of the top head. This arrangement is echoed in many plastic drums in the same size. Various components can be mounted to the drum, such as drum pumps and bung mixers.
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 uses and are ubiquitous in commerce. Drums are often re-conditioned and then later used for storing different liquids. Re-conditioning drums is one of the safest ways to remove hazardous waste. Until the 1990s many state highway departments reused 55-gallon drums as barricades to protect construction workers from oncoming traffic. Once empty the drums were painted orange and white and placed along roadways where construction was occurring. Today, construction crews use plastic drums that resemble their steel predecessors in both size and shape.
