Acetylene cylinders contain an inert packing material and are filled with a solvent such as acetone or dimethylformamide. The acetylene is pumped into the cylinder and it dissolves in the solvent. When the cylinder is opened the acetylene comes back out of solution, much like a carbonated beverage bubbles when opened. This is a workaround to acetylene's property to explode when pressurized above 200 kpa or liquefied. Acetylene gas cylinders are maroon in color in tandem with the european standards. It is used to store fuels in internal combustion engine. There are certain rules that we need to follow while using acetylene gas cylinders: 1. Acetylene should never be used at a pressure exceeding 15 pounds per square inch. 2. Acetylene cylinders should be used and stored in an upright position to avoid possibility of drawing out acetone. 3. Keep sparks and flame away from acetylene cylinders. 4. Never use acetylene from cylinders through blowpipes or other devices equipped with shut off valves on the acetylene supply connections, without reducing the pressure through a suitable regulator attached to the cylinder valve.5. After removing valve cap, open valve for a moment to clear opening of dust or dirt particles.6. After attaching regulator and before cylinder valve is opened, see that adjusting screw of the regulator is released. Always keep the acetylene cylinder valve key or wrench on the cylinder while in use. Never open an acetylene cylinder valve more than one full turn; then, in case of fire, the valve can be closed immediately. 7. Before regulator is removed from a cylinder, close the cylinder valve and release all gas from regulator. 8. Never attempt to transfer acetylene from one cylinder to another nor mix any other gas with it in the cylinder.9. The wrench used for opening the cylinder valve should always be kept on the valve stem when cylinder is in use.10. When returning empty cylinders, see that valves are closed to prevent evaporation of acetone. 11. Never, under any circumstances, attempt to refill an acetylene cylinder. 12. Never test for acetylene leaks with an open flame. Use an approved leak detector or solution.