Cutting, Welding, and Cylinder Storage

Tips from OSHA

Cutting and welding should not be performed in areas where easily combustible materials, such as wood shavings and scraps, sawdust, paper, oil soaked rags, etc. are located. All highly volatile materials will be removed from the area.

All equipment will be properly maintained and periodically inspected.

All compressed gas cylinders will be stored in an upright position, capped when not in use, and chained securely to prevent them from accidentally tipping over or being knocked over.

Cylinders will be stored away from heat sources. They are to be protected from accumulating ice and snow and the direct rays of the sun in high temperatures.

Cylinders of oxygen will be stored separately from cylinders of acetylene or other fuel gas.

Never drag cylinders. If possible use a hand truck. If they are being moved by hand, roll them on the bottom edge. Do not hoist cylinders by attaching lines to valves or to collars at the top.

Prior to use, check the hose for cuts, cracks or worn places. Check the pressure regulator and adjust accordingly.

When tanks are not in use, turn off the fuel supply at the tank. When in doubt, always consider cylinders full and handle accordingly.

Check local fire regulations.

Storage and Use of Cylinders

All gas cylinders should be protected against undue absorption of heat.

Acetylene and Fuel gas cylinders, including but not limited to welding and cutting fuel gas cylinders, should be stored and used with the valve end up.

Exceptions:

Fuel gas cylinders containing fuel gas used to power industrial trucks regulated by Article 25 of the General Industry Safety Orders.
Cylinders containing oxygen, acetylene or fuel-gases shall not be taken into confined spaces.

Gas cylinders in portable service should be conveyed by suitable hand trucks to which they are securely fastened, or safely carried where job conditions require. All gas cylinders in service shall be securely held in substantial fixed or portable racks, or placed so they will not fall or be knocked over.

Valve protection caps, when provided for, should be put in place before cylinders are moved, transported or stored.

Gas cylinders raised or lowered by crane, hoist, or derrick must be handled in suitable cradles, nets, or skip boxes, and shall never be lifted by magnet or by rope or chain slings.

Cylinders should never be placed where they might form a part of any electric circuit.

No attempt should be made to transfer acetylene from one cylinder to another, or to mix gases in a cylinder.

Oxygen cylinders in storage shall be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 feet or by a noncombustible barrier at least 5 feet high having a fire-resistance rating of at least one-half hour.

Cylinders shall be kept far enough away from the actual welding or cutting operation so that sparks, hot slag, or flame will not reach them. When this is impractical, fire resistant shields shall be provided.

LP-Gas vessels used for roofer’s tar pots, plumber’s pots and torches, space heaters, etc., shall be so installed that heat from the burner will not increase the temperature of the tank more than 10 degrees Fahrenheit after one hour of operation of the burner at full capacity.

LP-Gas vessels installed on mobile equipment shall have the bottom of the container, and/or any outlet connection, not lower than the lowest horizontal edge of the vehicle axle when fully loaded. Such units shall be adequately secured to prevent jarring loose, slipping, or rotating.

Use of Fuel Gas.

The employer shall instruct employees in the safe use of fuel gas.
Before a regulator to a cylinder valve is connected, the valve shall be opened slightly and closed immediately. (This action is generally termed “cracking” and is intended to clear the valve of dust or dirt that might otherwise enter the regulator.)
The person cracking the valve shall stand to one side of the outlet, not in front of it. The valve of a fuel gas cylinder shall not be cracked where the gas would reach welding work, sparks, flame, or other possible sources of ignition.

The cylinder valve shall be opened slowly to prevent damage to the regulator. For quick closing, valves on fuel gas cylinders shall not be opened more than 1 1/2 turns. When a special wrench is required, it shall be left in position on the stem of the valve while the cylinder is in use so that the fuel gas flow can be shut off quickly in case of an emergency. In the case of manifolded or coupled cylinders, at least one such wrench shall be available for immediate use. Nothing shall be placed on top of a fuel gas cylinder, when in use, which may damage the safety device or interfere with the quick closing of the valve.

When the valve on a fuel gas cylinder is opened and there is found to be a leak around the valve stem, the valve shall be closed and the gland nut tightened. If this action does not stop the leak, the use of the cylinder shall be discontinued, and it shall be properly tagged and removed from the work area. In the event that fuel gas should leak from the cylinder valve, rather than from the valve stem, and the gas cannot be shut off, the cylinder shall be properly tagged and taken outdoors, to an isolated area, away from personnel and sources of ignition. The supplier shall promptly be notified of the leaking cylinder valve and the supplier’s instructions shall be followed.

Hose and Connections

Fuel gas hose and oxygen hose shall be easily distinguished from each other. Note: The contrast may be made by different colors or by surface characteristics readily distinguishable by the sense of touch.

A single hose having more than 1 gas passage shall not be used as a connection between torch and gas outlet if a wall failure would permit the flow of either gas into the other passage.

Hoses used for liquefied petroleum gas, such as butane or propane, shall be of, or lined with, materials that are resistant to the action of LP-Gas. They shall be designed for a bursting pressure of at least 1,250 psi, and shall be marked every 5 feet with the letters “LPG.” Hoses over 1/2 inch diameter shall also be marked with the manufacturer’s name.

The connection between fuel source and burner shall be with extra heavy steel pipe (Schedule 80), flexible metallic tubing or hose suitable for the service, and where exposed shall be protected against physical damage.

When not in use, manifold and header hose connections shall be capped.

When parallel sections or oxygen and fuel gas hose are taped together, not more than 4 inches out of 12 inches shall be covered by tape.

Hose couplings shall be of the type that cannot be unlocked or disconnected by means of a straight pull without rotary motion.

General Precaution

No device or attachment facilitating or permitting mixture of air or oxygen with combustible gases prior to consumption, except at the burner or in a standard torch or blowpipe, shall be allowed unless approved for the purpose.

Acetylene shall not be generated or utilized at a pressure in excess of 15 pounds per square inch gauge pressure.

Exception: Acetylene dissolved in suitable solvent and stored in cylinders manufactured according to Interstate Commerce Commission requirements.

Oxygen cylinders and fittings shall be kept away from oil or grease. Cylinders, cylinder caps and valves, couplings, regulators, hose, and apparatus shall be kept free from oil or greasy substances and shall not be handled with oily hands or gloves. Oxygen shall not be directed at oily surfaces, greasy clothes, or within a fuel oil or other storage tank or vessel.

Hose piping systems, apparatus, and fittings shall not be used.

Oxygen shall never be used from a cylinder or cylinder manifold unless a pressure-reducing device intended for use with oxygen, and so marked, is provided.

Acetylene shall never be brought into contact with unalloyed copper except in a blowpipe or torch.

Cylinders not having fixed hand wheels shall have keys, handles or nonadjustable wrenches on valve stems while these cylinders are in service. In multiple cylinder installations only one key or handle is required for each manifold.

Cylinders shall never be used as rollers or supports whether full or empty.

Compressed oxygen shall not be used for ventilation, testing, or similar purposes different from its intended function in welding and burning.

A dry chemical or carbon dioxide fire extinguisher rated at least 10 B:C shall be kept near operations where bottled fuel gases are being used.

LP-Gas vessels shall be kept in a position so that the safety relief valve is in direct contact with the vapor space in the vessel at all times.

When operations are suspended for any substantial period of time, such as during lunch or overnight, gas cylinders shall be shut off. The torch and hose shall be removed from the confined space. Upon completion or discontinuance of welding operations, the welder shall warn other workers of the location of hot metal.

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What are general precautions needed to be taken in the handling of flammable cylinders on the construction site?

The storage of gas and flammable cylinders should be taken care of precisely on construction sites to avoid major accidents. Proper site location, an inspection of auxiliaries, maintaining safety standards, transportation of cylinders, worker awareness/training, tailboard discussion, and general rules from specification should be followed to avoid injuries and cylinder malfunctions.

What are common types of cylinders that can be used on construction site?

Most common used cylinders on construction sites are Fuel Gas Cylinders, Oxygen Cylinders, dry chemical, and LP-Gas Cylinders.