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How did the PLASMA Welder kill the worker, one weld at a time!

I have always marveled at the skills of those who could weld like an artist paints a picture. They could always manage to fix the stuff you broke and make it better in minutes, but at what risk to them!

When you the EMPLOYER as them to do the work do you have these records in place to defend your due diligence safety program due to their work-site injuries

Risk Description:

Welding and plasma, air-arc and flame cutting metal may expose workers to eye hazards that may include:

  • Eye penetration injury from grinding or chipping welds.
  • Thermal burns
  • Radiation injury to the eyes

Safety concerns that are unique to plasma arc cutting (PAC), gas metal arc welding (GMAW), and gas-tungsten arc welding (GTAW), which were previously (and erroneously) known as metal-inert gas welding, or “MIG” and “TIG,” respectively.

Have you covered PAC requirement and risks

Carbon-arc cutting, a/k/a carbon-arcgouging, is often used when it becomes necessary to separate a welded joint. This process utilizes consumable carbon rods. A stream of compressed gas blows the arc for a short distance past the convergence of the carbon rods. There is some probability that plasma is generated in the carbon-arc process, but its effect is of limited consequence.

The rush of gases past the point of work in the PAC and carbon-arc gouging processes generate noise levels above 85 db-A, thus requiring the use of an effective hearing protection program. Mechanized PAC systems (and some hand-held units) may employ a water table under the platen. This will lower the noise and reduce particulate emissions. However, most CAC processes employ hand-held torches, and thus the particulate and noise levels remain high.

A complete respiratory protection training including selection, fit testing, maintenance and inspection, must be provided to all welders who are provided with and wear respirators. Reference should be made to the CSA Standard Z.94.4, Selection, Use and Care of Respirators.

According to the Standard, a respiratory protection program must consist of the following components:

  • roles and responsibilities,
  • hazard assessment,
  • selection of the appropriate respirators,
  • respirator fit testing,
  • training,
  • use of respirators,
  • cleaning, inspection, maintenance, and storage of respirators,
  • health surveillance of respirator users,
  • program evaluation, and
  • record-keeping.

Fume produced during welding is comprised of solid particles, usually less than 1.0 µm in size, formed by condensation and oxidation of the vaporized metal. These particles are capable of being deposited in the gas-exchange region of the lungs. The chemical composition of the welding fumes and gases depends on the welded material, the process and the electrodes used. However, the potential health hazards from exposure to welding fumes are dependent not only on the welded metal, the process and the composition of the welding electrode, but also on the work environment, including the location (indoor vs. outdoor), the type and quality of natural and mechanical exhaust ventilation, degree of enclosure of the work station, length of exposure, and personal protection equipment.

Prolonged exposure to welding fumes and gases at high concentrations can cause:

  • siderosis (iron oxide)
  • metal fume fever (zinc oxide, magnesium oxide, copper, aluminum)
  • nervous system disorders (manganese)
  • irritation of respiratory system
  • eye, nose and throat irritation
  • chest pain
  • kidney damage (cadmium oxide, fluorides)
  • cancer (cadmium oxide, nickel, chromium (VI))
  • fluid in the lungs (cadmium oxide, fluorides, ozone, nitrogen oxide)
  • haemorrhage (ozone)
  • dermatitis, eczema (nickel, chromium (VI))
  • bone and joint problems (fluorides)
  • headaches and dizziness

Usually, a welding operation is associated with the generation of two or more hazardous substances into the working atmosphere. Therefore, the hazard should be evaluated by measurement of each constituent and, if the constituents have similar toxicological effects, or there is no information to the contrary, their synergistic (combined) effect should be given primary consideration. Attention should also be paid to synergism with non-occupational risk factors, such as cigarette smoking. Smoking may enhance the adverse health effects of respiratory hazards related to welding.

The following are the most common types of welding processes:

  • shielded metal arc welding (SMAW)
  • gas metal arc welding (GMAW)
  • flux-cored arc welding (FCAW)
  • gas tungsten arc welding (GTAW)
  • plasma arc gouging (PAG)
  • plasma arc welding (PAW)
  • plasma arc cutting (PAC)
  • submerged arc welding (SAW)
  • air carbon arc gouging
  • metal-cored arc welding (MCAW)

The type of process including the shielding gas, electrode size and type, manual or mechanized welding, current/voltage and arc time significantly influences the amount of fumes produced and affects the exposure of workers to contaminants. For example, open arc processes that use a flux, higher current and larger electrodes will produce more fumes than gas tungsten arc welding (GTAW) or submerged arc welding (SAW) processes.

Hot environmental conditions include air temperature, radiant heat, humidity and air movement. Welding and cutting operations, and in particular plasma arc cutting, are known to produce heat, the exposure to which in combination with the internal body heat due to physical activity and clothing requirements may lead to some health disorders or even heat-related illnesses. The most common signs and symptoms of the body response to heat include:

  • Sweating
  • Discontinued sweating
  • Increased heart rate
  • Increased body temperature
  • Urinating less frequently than normal
  • Small volume of dark-colored urine
  • Irritability
  • Lack of coordination
  • Lack of judgement

Excessive and prolonged exposure to hot work environment can cause heat-related illnesses such as:

  • Heat rush
  • Heat edema
  • Heat cramp
  • Heat exhaustion
  • Heat syncope (fainting)
  • Heat stroke

Signs and symptoms of heat illnesses include:

  • Excessive sweating
  • Rapid breathing
  • Weaknesses or fainting
  • Tiredness
  • Headache
  • Confusion

Noise

Air carbon arc cutting, gouging and plasma arc processes generate significantly high noise levels. Excessive exposure to noise among welders can cause noise-induced hearing losses.

Radiation

The plasma arc emits intense ultraviolet, visible light and infrared radiation. Laser beam and electron beam welding and cutting processes also produce visible and/or invisible radiation. In addition, whenever the high voltage is on, an electron beam system is capable of generating X-rays.

Musculoskeletal injuries

Musculoskeletal injuries, such as strains and sprains, can occur when a welder is welding in a static awkward or horizontal position with a heavy face shield. The extra weight of the shield can cause strain on the welder’s neck. Neck problems are also associated with prolonged use of a combination of a hard hat and a welding helmet. In addition, long and repetitive duration of exposure and high force generation may have cumulative effects that contribute to the increased risk of injury.

Welding and allied processes including hazard identification are outlined in the CSA Standard W117.2 Safety in Welding, Cutting, and Allied Processes.

Safety data sheet

While investigating potential health hazards with respect to welding, it is important to consider the safety data sheet (SDS) for each controlled product that is used in the welding operation. SDSs define which health hazards are associated with the use of these products. These documents also provide recommendations regarding preventive measures such as engineering controls and personal protective equipment (PPE). Fumes and gases

It’s no surprise that overexposure to welding fumes and gases can be hazardous to your health. Welding fume contains potentially harmful complex metal oxide compounds from consumables, base metal and the base-metal coatings, so it’s important to keep your head out of the fumes and use enough ventilation and/or exhaust to control your exposure to substances in the fume, depending on the type of rod and base metal being used.

The specific potential health effects which relate to the welding consumable product being used can be found in the Health Hazard Data section of the Safety Data Sheet available from your employer or the consumable manufacturer.

Welding areas require adequate ventilation and local exhaust to keep fumes and gases from the breathing zone and the general area. In most situations, employers will provide a ventilation system- such as a fan, and an exhaust system or fixed or removable exhaust hoods- to remove fumes and gases from the work area.

Threshold limit values

In addition to the material safety data sheets, the CSA Standard W117.2, and other documents that might be helpful in the investigation of health hazards associated with welding, it is essential that the following documents be consulted:

  • the American Conference of Governmental Industrial Hygienist (ACGIH) Threshold Limit Values (TLVs®) for Chemical Substances and Physical Agents & Biological Exposure Indices (BEIs®), and
  • the ACGIH Documentation of the TLVs® and BEIs®

The TLVs® and BEIs® are developed as guidelines to assist in the control of health hazards, and the Documentation is the source publication that provides the critical evaluation of the pertinent scientific information and data with reference to literature sources upon which each TLVs® or BEI® is based. The ACGIH publication entitled Threshold Limit Values and Biological Exposure Indices is referenced in the Canada Occupational Health and Safety Regulations made under Part II of the Canada Labour Code.

 

 

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