Welding hoses are subjected to a lot of wear and tear and can cause a great deal of trouble. It is important that they are used and cared for properly.

Never use just any available hose for welding applications. Welding hoses are specially designed for particular gases and pressures. Select a hose designed for the gas and pressures that will be used. Never use a compressed-air hose, which may contain oil, for oxygen. A fire or explosion could result. Hoses for oxy-fuel gas service shall comply with Rubber Manufacturers Association IP-7 specification for welding hose.

Welding hoses are normally color coded to prevent mix-ups. The generally recognized hose colors are red for acetylene and other fuel gases, green for oxygen, and black for inert gases and compressed air. Hoses with leaks, burns, worn spots, or any other defects are dangerous and unfit for use. They should be fixed or disposed of. There are several safe procedures for handling welding hoses:

• Do not use hoses with too many repair connections. Even if the connections are gastight, little gas will flow through the hoses. A noticeable pressure drop and even a flashback may occur.
• Protect hoses from sparks, hot metal, and slag. Do not drag a hose over sharp objects, and keep it away from oil and grease to prevent deterioration and the chance that oil will come in contact with oxygen.
• Do not run hose where it can be damaged by nearby equipment. Suspend a hose over a passageway to keep it from being stepped on or run over by trucks. If the hose cannot be suspended, protect it with planks.
• Prevent kinking or tangling the hose, Kinking will weaken the hose and, if done repeatedly, may cause it to leak or fail. Never kink or crimp the hose to stop gas flow temporarily when changing a torch. Shut the gas off at the regulator.
• Use no more than 4 in. of tape for each 12 in. of hose if parallel lengths of oxygen and fuel-gas hoses must be taped together to keep them from tangling. If the entire hose is taped, damage or leaks may not be noticed.
• Keep hose lengths as short as possible. Gas pressure between the gas supply and the torch drops as the hose gets longer.

Caring for hoses should include safe procedures for lighting a torch. Purge oxygen and fuel-gas hoses of mixed gases before lighting the torch. Always use a friction lighter or a pilot light to light the torch; never use matches. When equipment is shut down for any length of time, the cylinder valves should be closed and the hoses drained. Purge both hose lines before relighting the torch.

Purging is also a good way to keep shielding-gas hoses dry. If these lines are not well purged and very dry, the welds will be extremely porous.

Welding hose requires special fittings designed to withstand severe service conditions. Any hookups or repairs should be made with approved fittings. Never use ordinary pipe fittings, or fittings designed for compressed air. Acetylene and fuel-gas fittings have left hand threads to prevent them from being accidentally connected to oxygen fittings.

If a hose is worn, cut, burned, or otherwise damaged, remove the bad section and splice the two good ends together, using approved fittings and the proper ferrules or clamps. Do not use ordinary wire or another substitute to secure fittings to hoses, and do not do makeshift repairs with tape. Improper repairs lead to gas leaks and hose blowouts. Never use copper tubing for splicing hose. Acetylene could react with copper and cause an unexpected explosion.