A small gas cylinder is generally less than 25 litres total internal capacity (often defined as its “water capacity”).

Examples of small cylinders are domestic barbecue cylinders, such as 4.5 kg (11 litre capacity) and 9 kg (22 litre capacity) of LP Gas or propane. Other cylinders for trade use range from 0.34 kg of LP Gas (1 litre capacity) up to E size acetylene and oxygen cylinders (25 litre capacity). They may have detachable fittings such as torches.

Other examples are butane cartridges and aerosol containers designed for use with heating equipment and/or fittings. These can contain as little as 170 g flammable gas.