Joints should be welded or have threaded fittings. Fittings can be steel or maleable iron but may not be case iron. Strangely, acetylene is less stable in wide-bore piping. A pressure regulator made specifically for acetylene must be used at the cylinder, and pressure should not exceed 15 psig in the equipment. A flash arrestor should also be installed at the down-stream side of the regulator.
Check valves and pressure release devices are also advisable in apparatus.
When work is finished, close the cylinder at the valve. When disconnecting the cylinder, first close the cylinder valve, and then bleed pressure from the regulator. Handling acetylene under pressure in apparatus is extremely hazardous and should be conducted only in a pressure laboratory or other adequately protected area. If a leak is suspected, test the possible leak point with soapy water. Leaks around the valve stem can usually be eliminated by tightening the collar with the valve closed.