In Oak Ridge, Tenn., a demolition/maintenance worker was fatally burned while using a cutting torch to cut process piping to remove a converter from a building. Multilayer anti-contamination clothing, cotton coveralls and a full-face respirator prevented the welder from recognizing he was on fire.
Lack of flame-retardant clothing, absence of a fire watch, and inadequate hot work procedures were identified as contributing to the incident. An investigation board concluded that had the welder"s clothing been treated with flame-retardant chemicals, the fatality would not have occurred.
This is just one example of the kind of tragic accidents that can occur if welders and their supervisors ignore proper safety precautions before starting a job.
Welding, cutting and allied processes are activities that put an estimated 562,000 employees at risk for exposure to chemical and physical hazards, according to the Occupational Safety and Health Administration (OSHA).
OSHA"s current standards for welding, cutting and brazing in general industry and construction (1910.252 (Q)) are based on the 1967 American National Standards Institute (ANSI) standard Z49.1, "Safety in Welding and Cutting." While ANSI Z49.1 has been updated several times, the OSHA welding have not been updated to keep pace.
Though companies legally must comply with OSHA"s welding standard, consensus standards such as ANSI Z49.1 provide an additional safety resource. Several welding experts explain some of the general guidelines of Z49.1 and offer ways to keep welders safe.
The most common hazards associated with welding are fumes and gases, arc rays and sparks and electric shock. Gus Manz, president of A.F. Manz Associates consulting firm and chairman of the ANSI Z 49.1 committee, said it is the responsibility of management to protect welders from these hazards. "Management should ensure that welders and their supervisors are trained in safe operation of their equipment and emergency procedures," Manz said.
OSHA"s Hazard Communication standard says that "all chemicals produced or imported must be evaluated and that information concerning their hazards must be transmitted to employers and employees through comprehensive communication programs." These programs should include container labeling and other forms of warning, material safety data sheets (MSDS) and employee training.
Z49.1 recommends that management assure "hazards and safety precautions are communicated to workers prior to the start of work." This can be done through manufacturers" instructions, MSDS and product labeling.
Precautionary information is an important part of the Z49.1 standard. Safety information in the form of a label, tag or other printed means must be visibly displayed on all welding products and equipment. This information is intended for the final user.
"The labels tell welders to protect themselves and warn them to read MSDSs for further safety information," said Joe Hege, welding engineer with ESAB Welding and Cutting Products, a welding equipment manufacturer in Hanover, Pa.
The fumes and gases that result from the welding process can result in acute or chronic health effects if proper precautions are not implemented. NIOSH has reported that an "excess morbidity and mortality among welders appears to exist even when exposures have been reported to be below current OSHA PELs for the many individual components of welding emissions."
Kevin Lyttle, senior development associate with Praxair, an industrial gas company in Danbury, Conn., said the fumes and gases generated during welding are unique because welding fumes are a complex mixture of substances. "Most other fume exposures involve pure materials, but in welding the fume cannot be simply classified," Lyttle said.
It is the responsibility of management to provide adequate ventilation for welding processes. Adequate ventilation should provide enough fresh air "that exposures to hazardous concentrations of airborne contaminants are maintained below the allowable limits specified."
ANSI Z49.1 recommends determining adequate ventilation by sampling for the composition and quantity of fumes and gases to which personnel are exposed. The standard suggests using ANSI/AWS F1.1, "Method for Sampling Airborne Particulates Generated by Welding and Allied Processes."
According to the standard, if natural ventilation is not sufficient to maintain contaminants below allowable limits, mechanical ventilation must be provided. Mechanical ventilation can include roof exhaust fans, wall exhaust fans and similar large-area movers.
When ventilation controls fail to reduce air contaminants to allowable levels, respiratory equipment must be used. The standard suggests that companies establish a program that requires the proper selection and use of respirators as specified in ANSI Z88.2 and ANSI Z88.6, "Physical Qualifications for Respirator Use."
Aside from ventilation, welders need to take precautions to avoid breathing fumes directly. This is what is commonly known as avoiding the "fume plume." "Fumes typically rise in a column, so a worker needs to learn how to position his head in order to keep it out of the plume," Lyttle said.
Eye injuries and burns are the most obvious hazards because they are the most noticeable. Management should ensure that proper personal protective equipment is used.
Welding helmets with filter lenses are intended to protect users from arc rays, weld sparks and spatter. Spectacles with side shields or goggles should also be worn to protect against these hazards.
Manz said management should read the standard"s eye protection provisions because they contains the guide for lens shade numbers. The chart contains the minimum protective shade number and the suggested shade number for the various welding processes.
Lyttle cautioned that, if the proper level is not used, even a brief exposure with UV light is powerful enough to cause an eye burn known as "welders flash." This condition can result in extreme discomfort, swelling, fluid excretion and possible temporary blindness.
Protective clothing should be selected to minimize the potential for the clothing igniting, burning or trapping hot sparks. The standard says that heavier, flame-resistant materials such as woolen clothing or heavy cotton are preferable to lighter materials because they are more difficult to ignite. Sleeves and collars should be kept buttoned and pockets should be eliminated from the front of clothing.
"The welding process generates spatter of molten metal. The hot metal particles can fall into a welder"s pant leg or sleeve and cause problems," Lyttle said.
Electrical shock is one of the most serious risks welders face. It can cause severe burns and serious injury if a welder falls because of the shock, or even death.
Proper grounding is one way to prevent electrical shock. Manz pointed out that improper grounding and the misinterpretation of terminology can lead to deadly accidents. He said one of the most common mistakes made by those in the industry is the misuse of the term "ground connection."
Many people call the work lead connection the ground connection. The work lead connection is the cable that comes from the power supply and connects with whateveryou are going to weld. "In welding, when you use the word "ground" improperly, a worker could be mislead to think something is safe because it is grounded," Manz said. "You should never call a work lead a ground lead because it isn"t grounded. A special ground lead is needed to ground something."
Other ways to prevent electric shock include wearing dry gloves and protective equipment, avoiding standing in water, not touching live electrical parts and turning off equipment when it is not in use.
Welding, cutting and allied processes produce molten metal, sparks, slag and hot work surfaces. Sparks can travel up to 35 feet in all directions from the work area. To abate fire hazards, special attention should be paid to the area in which welding is taking place.
The standard says that any combustible material should be removed from the work area. Combustible materials can include the contents of a building such as wood, paper, plastics, chemicals or outdoor combustible materials such as dry leaves, grass and brush. If it is not possible to move the combustible material, move the work to a location well away from any hazards.
Noncombustible or flame-resistant screens can be used to protect workers or other persons adjacent to the welding area from the radiant energy and spatter of welding and cutting.
To prevent fires from spreading, sufficient fire extinguishing equipment must be ready to use and sprinkler systems must be operable during welding or cutting.
The standard also defines the duties and the general nature of the fire watcher. Manz explained that the fire watcher is a qualified individual who watches the welder to make sure the sparks from the welding operation aren"t creating any hazards or fires. The fire watcher also observes an area after a welder has finished his task to be sure sparks don"t smolder into flames. "Sometimes, a fire doesn"t take place until several hours later from smoldering sparks," Lyttle said.
A fire watcher is helpful because he can look out for hazards a welder may not see. "If a worker is welding a wall, the heat could be transmitted through the wall to the other side. A fire watcher can make sure things are safe on the other side of that wall," Manz said.
Using the Standard
ANSI Z49.1 also contains further safety information and requirements on specific types of welding such as resistance welding, laser beam welding and cutting, and electron beam welding and cutting. However, Manz said, it is helpful to apply the general practices presented in the standard to all types of welding.