Welding and Cutting
 

Welding, cutting, and brazing are hazardous activities that create a unique combination of safety and health risks. From a safety standpoint, there are risks associated with; fire, explosion, compressed gas, storage, and handling. From a health perspective there are risks to; eyes, burns, oxygen deficiency, and toxic gas exposure to more than 500,000 construction workers in a wide variety of industries. The risk from fatal injuries alone is more than four deaths per thousand workers over a working lifetime. The following is a general outline of some of the safety and health aspects of welding, cutting and brazing.

WELDING

  • Before starting to weld or burn, inspect the work area to assure that sparks or molten metal will not fall on flammable or combustible materials.
  • A suitable, approved fire extinguisher shall be ready for instant use in any location where welding is done. Screens, shields, or other safeguards should be provided for the protection of employees or materials, below or otherwise exposed to sparks, slag, falling objects, or the direct rays of the arc.
  • The welder shall wear approved eye, head, body, and hand protection as directed by the safety manager. Employees assisting the welder shall also wear protective eyewear and any other PPE as directed by the safety manager.
  • Electrical welding equipment, including cable shall meet the requirements of the National Electrical Code. Welding practices shall comply with all applicable regulations.
  • When welding brass, bronze, galvanized iron or cadmium plated metals, adequate ventilation shall be provided to carry off vapors. A metal fume respirator should be used if the ventilation is not adequate.
  • For local exhaust suction devices to be effective, the exhaust hood entrance should be within nine (9") inches of the weld or cut.
  • Place all welding leads and gas hoses so they do not create a tripping hazard.

 

BURNING OR CUTTING

  • When gas cylinders are stored, moved or transported, the valve protection cap shall be in place.
  • When cylinders are hoisted, they shall be secured in an approved cage basket, sling-board or pallet. Cylinders shall never be lifted by caps.
  • All cylinders shall be stored, transported and used in an upright position. If the cylinder is not equipped with a valve wheel, a key shall be kept on the valve stem while in use.
  • An approved fire extinguisher shall be readily available in the event of fire.
  • Appropriate personal protective equipment, such as burning glasses, shields and/or gloves must be used.
  • Ventilation - Precautions must be taken to ensure fumes and dust are not breathed when cutting lead, lead alloys, painted iron or steel, lead-coated iron or steel, load-bearing steels of cadmium plated metals. Mechanical ventilation should be used to provide protection against breathing these materials. When this is not provided, a metal fume respirator or supplied-air respirator should be used.
  • Oxygen and acetylene cylinders shall be separated by 20 feet while in storage or be divided by a one hour fire rated divider at least 5 feet in height. "NO SMOKING" signs shall be posted and appropriate fire extinguishers shall be located 25 to 75 feet from the storage area.
  • Turn off all cylinder valves when not in use.
  • Make sure that oxygen/acetylene hoses are equipped with flash-back arrestors at the regulator end.

GAS CYLINDER HANDLING

Oxygen, Acetylene, Argon, Air, LPG, Nitrogen, and other gasses are found in metal cylinders on most every construction site. These portable containers, used for transporting and storing compressed gasses, can cause serious injuries. If used incorrectly, gas cylinders can cause an explosion, be propelled like a rocket, ignite, or create any number of hazardous situations. Handle them with care and follow appropriate safety rules.

PRIOR TO MOVING CYLINDERS
Be sure the valve is closed. (Also, be sure valves are closed when work is finished or cylinders are empty). Place and secure the protective valve cover cap. Never use this cover to lift the cylinder. Never move cylinders when regulators are attached unless the cylinders are secured in a cylinder truck. Otherwise, remove the regulator and put on a protective valve cap. Regulators can break off if they are bumped hard. If cylinders are frozen together during cold weather, the safest way to thaw them is to use warm (not boiling) water. Never use pry bars for this job.

WHEN MOVING CYLINDERS
Move cylinders by slightly tilting them, then rolling them on their bottom edges. Take care not to let them drop or strike other cylinders or objects. Never use choker slings or magnets to hoist cylinders. Hoist cylinders by using a cradle or pallet, making sure the cylinders are secure before hoisting them. Keep a firm grip on cylinders at all times.

CYLINDER PROTECTION
If cylinders are stored close to welding or cutting operations, place a fire resistant shield between the cylinders and these operations. In that way sparks, hot slag or flames won't be able to reach them. Keep both full and empty standing cylinders chained or tied to something that is secure to prevent them from being knocked over. Take the same precautions when handling empty cylinders that you would with full ones. When using different types of gas, segregate cylinders containing one kind of gas from another.

RECOMMENDED ACTIONS:

  • Keep cylinders in a secure and upright position.
  • Keep the protective valve cap in place when a cylinder is not in use.
  • Mark the cylinder 'Empty’ or 'MT' when the gas has been used.
  • Keep oil and grease away from oxygen cylinders (oil and oxygen can ignite spontaneously).
  • Open valves slowly, using the valve wheel or T-handle wrench provided by the supplier.
  • Store oxygen and fuel gas cylinders at least 20 feet apart or separated by a 5 foot high noncombustible barrier.
  • If the cylinder is too heavy to handle use a hand truck, or ask a co-worker for help.

RECOMMENDED PRECAUTIONS:

  • Do not permit sparks, flames, or molten metal to contact the cylinder.
  • Never apply grease or oil on valves.
  • Don't lift cylinders without safety caps in place.
  • Don't roll cylinders horizontally on the ground.
  • Never drop cylinders on the ground or other work surfaces.
  • Don't store oxygen cylinders with other fuel gas cylinders.
  • Never use a leaking gas cylinder. Take it out of service immediately.
  • Never mix or match acetylene gauges with oxygen gauges.

FIRE PROTECTION

WELDING FIRES

HOW WELDING FIRES START
Fires from welding operations are started by sparks, hot slag, and flame from the torch. Sparks often drop or can be carried long distances by the wind. Slag can fall on surfaces or materials below, such as oil, rags or other combustible materials. A welding torch flame can ignite many substances within a radius of several feet. Be familiar with the standard safety rules for welding so you can recognize and prevent any problems.

THE WELDERS' RESPONSIBILITY
When a welding operation moves into a work area, it is the primary responsibility of the welders' to guard against fire. This means making sure there's no flammable material within range of the flame. Wood, paper or other combustibles should be removed. The welders also are responsible to see that no sparks or slag fall on combustible materials. Keep extinguishing agents, such as, fire extinguishers, water or sand, readily available. You may even find it necessary to assign a worker with an extinguisher as a fire watch.

FLAMMABLE LIQUIDS
Welders should not begin working in any area where there are flammable liquids. If welding is necessary on any tank or drum that has contained flammable liquids or gas, welding may not begin until an approved test shows that there is no danger of vapors present. Don't take anyone's word that the tank or drum was tested previously. Insist on a test just before starting your work.

COMBUSTIBLES
Where floors are combustible, welders must place fire resistant material beneath the work area, so that hot slag cannot contact the floor. Wood floors should be swept clean before welding over them, and should be covered with metal or some other material that won't burn. In some cases, it is advisable to wet the floor down. But remember that this adds a shock hazard, which must be guarded against if you are arc welding. Be sure there are no cracks into which sparks or slag may fall, and never allow this hot material to fall into concealed spaces between walls and floors. You may have to protect openings, such as open doorways, with a non-combustible curtain. Be sure this curtain reaches to the floor, so that the hot slag can't roll under it.

WELDING EQUIPMENT
Welders must keep cylinders a safe distance from where they are working, this requires that hoses be kept completely uncoiled. Tanks and hoses should be kept behind the welder, never in front where flame, heat, or slag could strike them. Hoses must be protected to keep trucks from running over them, and people from walking into them or dragging things across them. Cylinders must be properly secured when in use and the caps in place during transportation.

VENTILATION
Good ventilation is required for all welding operations. Many of these operations produce fumes that are harmful in heavy concentrations, and ventilation is the only method of protecting against this hazard. Screens around the work area should be placed so as not to prevent good air circulation. Sometimes special ventilating equipment is necessary. Don't weld in a small room or tank or other closed place without first testing to make sure the ventilation is good. When welders leave their equipment or stop work, shut off the oxygen and acetylene at the cylinders, so that no gas can enter either hose.

EYE PROTECTION
Eye protection is necessary on all welding jobs. Full face protection may be required on certain jobs. Face and eye protection are needed in many operations performed by welders besides actual cutting and welding. Electric welders need goggles as well as the regular helmet. Any welder may have to do a good deal of chipping. This work, which is usually performed with the helmet raised, can throw particles of metal into your eyes. Eye protection is designed to protect against sparks, slag, molten metal, and flash burns caused by radiation from the welding equipment. Follow the guidelines for wearing face and eye protection to prevent face and eye injuries from cutting or welding work.

 

WELDING AND CUTTING SAFETY CHECKLIST

  • Fuel gasses may be toxic. Check the copy of the manufacturer's MSDS.
  • Never allow oxygen to contact oil, grease or other flammable substances.
  • Oil and/or grease in the presence of oxygen becomes highly flammable or explosive. Do not use oxygen as a substitute for compressed air. Never use oxygen to dust off clothing or work areas. Do not use oxygen in pneumatic tools. Never use oxygen for ventilation.
  • Oxygen and fuel gas hoses are not interchangeable. They must be easily distinguishable by either color or surface characteristics sensitive to touch. Keep welding hoses clear of any falling metal, slag or sparks. Only qualified technicians should clean or repair a regulator.
  • Do not tamper with the relief valve or remove it from a regulator.
  • Examine hoses before attaching them to welding torch handles or regulators. Never use a defective hose or a hose in questionable condition.
  • Do not perform any welding or cutting operation without proper eye protection. Always keep gas cylinders secured properly and in a vertical position. Keep valve protection caps in place whenever cylinders are not in use. Close valves completely on empty cylinders.
  • Always open cylinder valves slowly and carefully.
  • When a cylinder wrench is needed on the valve, keep the wrench close at hand so the valve can be turned off quickly if necessary.
  • Replace gauges if they become damaged and keep dust covers in place. Perform welding in a well ventilated area.

 

ARC WELDING SAFETY

Wearing proper eye protection is extremely important. Welders and their helpers should use the correct filter lens in their goggles or helmets to protect their eyes from infrared and ultraviolet light. (See 1926.102, Tables E-1 and E-2 for a guide to eye and face protection and filter lens shade numbers.)

Precautions for fire prevention must be taken in areas where welding is being done, for example, isolating the welding and cutting area and removing fire hazards from the vicinity. If normal fire prevention precautions are not sufficient, a qualified person should be assigned to guard against fire during the operation and for a suitable time after completion of the work, to ensure that no possibility of fire exists. Be sure that fire extinguishing equipment is available and ready for immediate use. In areas where heavy dust concentrations exist, or where flammable paints or other flammable materials are present, welding, cutting or heating can create a significant fire hazard. Proceed with caution.

A noncombustible or flameproof screen should isolate the welding or cutting area to protect other workers in the vicinity from direct arc rays. Watch your slag; it could cause a serious injury to someone working below.

If the electrode holder is left unattended, the electrodes must be removed, and the holder must be placed so that electrical contact cannot be made with another employee or any conducting object.

All arc welding and cutting cables must be completely insulated and capable of handling the maximum current requirements for the job. The insulation on any splice within 10 feet of the electrode holder must be equal to the insulation of the cable.

All welding and cutting operations in a confined space shall be ventilated to prevent the accumulation of toxic materials or possible oxygen deficiency. Review 1926.351 through 1926.354 for additional information.

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