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Electric Arc Welding

 

Man Electric Arc WeldingWelding of metals can involve a great number of health and safety hazards. The operator should be impressed with the fact that there are high voltages capable of inflicting severe and often fatal injuries.

 

Safe and accident free completion of any welding operation should be the goal of all welders. Here are a few welding safety tips that will help you achieve that goal. 

 

Wearing proper eye protection is very important. Welders and their helpers should be sure to use the correct filter lens in their goggles or helmets to protect their eyes from infrared and ultraviolet light.  

  

Precautions for fire prevention must be taken in areas where welding is being done, i.e. isolating the welding and cutting area and removing fire hazards from the immediate vicinity.

 

If normal fire prevention precautions are not sufficient, a qualified person must be assigned to guard against fire during the operation and for 30 minutes after completion of the work, to ensure that no possibility of fire exists. Fire extinguishing equipment must be in near proximity 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 extreme 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. 

 

Some of the Health and Safety Risks 

  • Physical injury - electric shock, gas explosion, burns from sparks and spatter. 
  • Arc-eye (welding flash) - gritty feeling in the eye and skin burning can result from invisible ultra-violet radiation from the arc. The effect is delayed. It is particularly intense with TIG welding (tungsten inert gas) of aluminum alloy. Damage to the retina and blindness can occur. 
  • Radiation burns - unfiltered ultra-violet light from cutting or welding can cause severe short-term skin burn, and poses the same long term skin cancer risks as sunburn. 
  • Lung disease - during cutting and welding, nearly all metals generate fume that if inhaled can lead to Lung disease. Some metals, especially nickel and chromium which are found in different grades of steel, have also been associated with causing lung cancer. 
  • Metal fume fever - from nearly all metals during cutting and welding, can cause vomiting, chills and headache. Effects may be delayed several hours and last 24 hours. Zinc fume from galvanized iron is most severe, though copper and tin fume are nearly as bad. 
  • Fume poisoning - from such metals as lead, zinc and cadmium; can enter through the nose and mouth through smoking or eating with contaminated hands. Continuous exposure may lead to long term blood disorders, nerve damage and kidney disease. 

Gases and Fumes 

  • Fluoride - emitted from coating on low hydrogen rods. It can damage the lungs and cause general poisoning. 
  • Ozone - a highly toxic gas produced from any arc-type welding, can cause long term respiratory problems. Ozone has a characteristic irritating pungent odor and can cause short term aches and nausea. 
  • Heated coatings and paints - can release toxic substances such as cyanide, formaldehyde and isocyanates. 
  • Fluxes - some types may give off hazardous substances when heated. A Material Safety Data Sheet should be obtained from suppliers to determine hazards of each flux. 

Preventing Hazards

  • Fire - with welding blanket, by removing or covering flammable materials, or working a safe distance from flammable substances. 
  • Explosion - by checking before welding and cutting that tanks and drums are steamed clean free of substances that are flammable or give off flammable substances when heated. Introduce compressed air into tanks that have contained flammable liquids or gases when welding tanks. 
  • Fume and gas hazards - by one or a combination of: 
    • good general ventilation
    • use of a booth
    • local exhaust ventilation on the hand piece.
  • Metal spatter or arc-eye injury to bystanders - by use of screens or proper welding curtains or blankets. 

Care with Equipment 

  • Lighting - should be adequate for safe use of equipment and for reading labels. 
  • Power circuit earth - every power circuit must be grounded to prevent accidental shock by stray current. DON'T operate a welding machine without a ground on the power supply. 
  • Welding cables - must not be operated at currents in excess of their rated capacity. The cables should be inspected frequently.  

Personal Protection 

  • Burns - use proper gloves, overalls or aprons and insulated type footwear. 
  • Eyes - protect them with a helmet and visor of a grade designed for the type of arc welding; wear eye protection during slag removal or chipping. 
  • Fumes - if local exhaust ventilation is insufficient, ensure an adequate air supply to the operator is essential. 
  • Solvents - don't weld or cut near cleaning tanks containing chlorinated solvents; heat breaks down vapors into very toxic gases.  
  • Radiation - avoid radiation exposure from weld checking equipment.  
  • Comfort - ensure your protective equipment is comfortable to wear and your work equipment comfortable to use. 

The OSH ACT requires employers to provide a healthy and safe work environment. 

  

Employees are required under the ACT; to use all personal protective equipment in the correct and safe manner (as instructed by their employer); and to co-operate with their employer to fulfill their duties and not to endanger themselves or others. 

 

 ASHI Authorized Training Center Member of the National Preparedness Coalition