Compressed gases are stored in heavy-walled metal cylinders designed, produced and tested for use with compressed gases. Cylinders are made in a wide variety of sizes and shapes. They range from small lecture bottles, often used for demonstration purposes, to large cylinders over 3 metres long. Cylinders must comply with regulations of the Chief Controller of Explosive (CCOE) & Bureau of India Standards (BIS). CCOE & BIS regulations require certain permanent markings on every cylinder: the specifications which the cylinder meets, the designed service pressure, a serial number, inspection codes, and identification of the cylinder maker or manufacturer. Cylinders for liquefied gases are also marked with the empty (tare) weight. These markings are normally stamped into the cylinder's shoulder or the top surface of its neck.

Cylinders are tested under hydrostatic water pressure when they are made. Usually, cylinders must be retested every five or ten years. The date of each test must be stamped on the cylinder. Acetylene cylinders are not tested hydrostatically. It is too difficult to remove the water from the porous filler. Instead, they receive careful visual inspections.
 
 

Compressed gas cylinders must be connected only to regulators and equipment designed for the gas in the cylinder. Since connecting the wrong equipment can be dangerous, a number of different standard cylinder valve outlets are available for different classes of gas. For example, these standard connections prevent the valve connection for a flammable gas from fitting the connections for an incompatible gas, such as an oxidizing gas. The current Bureau of Indian Standard (BIS) IS:3224, " Valve Fittings for Compressed Gas Cylinders Excluding Liquefied Petroleum Gas (LPG) Cylinders," contains detailed descriptions of the permissible valves and fittings.

These valves are usually a part of the cylinder. They are normally held closed by a spring. The force holding the valve closed is set according to the type of gas in the cylinder. The valve opens if the cylinder pressure exceeds the set safety limit. Gas is released until the cylinder pressure drops back to the safety limit. The valve then closes and retains the remaining gas in the cylinder.
 

These discs are usually made from metal. They burst or rupture at a certain pressure, releasing the gas in the cylinder. The bursting pressure is designed so that the disc ruptures before the cylinder test pressure is reached. These devices cannot be re-closed, so the entire contents of the cylinder are released.
 

Temperature, not pressure, activates fusible plugs. These safety devices are used where heat could initiate an explosive chemical reaction. A pressure-relief valve or rupture disc acts too slowly and too late to prevent rupture of the cylinder if an explosive reaction has already begun. The fusible plug releases the gas before the hazardous reaction can begin. Fusible plugs are made of metals that melt at low temperatures. For example, acetylene cylinders have a fusible plug which melts at about 100°C (212°F). This temperature is safely below the temperature at which hazardous polymerization may occur.
 

Not all compressed gas cylinders have safety devices. Some gases are so toxic that their release through a safety device would be more hazardous than cylinder rupture or explosion. Cylinders for these gases are built to withstand higher pressures than normal cylinders. When these "toxic gas" cylinders are involved in a fire, the area must be evacuated.