Casings

Casings are outer coverings or enclosing shells used to protect, contain, or shape something. The term applies across many industries to describe different structures that share the common purpose of encasing contents.

In firearms and ammunition, a cartridge casing is the metal container that holds the propellant and primer and provides a base for the projectile. Most modern casings are made from brass, steel, or aluminum. After firing, the casing is ejected; spent casings may be collected, recycled, or reloaded, depending on the system.

In food processing, sausage casings wrap the mixture to form products. Casings can be natural, derived from animal intestines, or synthetic, such as collagen, cellulose, or cast polymer materials. Some are edible, others must be removed after cooking. They influence diameter, texture, moisture retention, and heat penetration.

In construction and electrical work, casings describe protective shells and trim. Architectural casings frame doors and windows, providing finish and concealing gaps. Electrical and plumbing installations use casings or jackets to protect wires, cables, and pipes, with materials ranging from metal to plastic.

In the energy and mining industries, well casings are steel pipes inserted into boreholes and cemented in place to prevent collapse and to isolate subsurface formations.

Additional uses include protective casings for consumer devices and equipment, such as phone or camera housings, which shield internal components from damage while sometimes providing aesthetic form.