Making your welding operation safer with source-extraction systems

The greatest challenge for any welding operation is to provide a safe, clean working environment. This means that harmful gases, fumes, and welding dust must be removed as efficiently as possible not only while welding is carried out, but when workers are grinding and cutting metal as well.

Of course, the type of welding process used, together with the base and filler metals and welding rods, determines what exactly is in welding fumes. The metal being cut determines the makeup of welding dust, and the various shielding gases (argon, helium, nitrogen, and carbon dioxide) affect air pollution levels.

Acute exposure to welding gases and fumes commonly results in dizziness; nausea; and eye, nose, and throat irritations. Worse still, both welding dust and toxic fumes expose workers to the possibility of developing serious lung disease and chronic asthma.

Welding fumes also have been associated with various types of cancer, including larynx, lung, and urinary tract, as well as metal fume fever, kidney and nervous system damage, and stomach ulcers. Welders exposed to manganese fumes over prolonged periods of time sometimes develop symptoms that are very similar to Parkinson's disease.

For these reasons, it is essential that effective ventilation be installed and used in every type of welding environment.

Various ventilation options are available, and some are more effective than others. Minimum specifications are provided in the U.S. Department of Labor's Occupational Safety and Health Administration (OSHA) guidelines in the form of detailed standards and various informational fact sheets.

Basic OSHA Guidelines

It is essential that welders fully understand the hazards they face, and it is up to employers to train their employees and provide comprehensive information to minimize risks. For instance, all welding surfaces need to be cleaned of anything that might create toxins. If possible, less toxic or lower fume-generating consumables should be used.

Ventilation is paramount, and welders are warned never to work in confined spaces without ventilation. Certain gases, including argon, helium, and carbon dioxide, tend to displace the oxygen in the air, which can cause suffocation, and carbon monoxide is a serious asphyxiation hazard.

A very basic requirement is for welders to position themselves upwind when working in outdoor or open environments to avoid breathing in gases and fumes. If ventilation is insufficient, additional respiratory protection is recommended.

While general ventilation involving either natural or forced movement of clean, fresh air can reduce the levels of gas and fumes in work areas, OSHA warns that this is usually not enough. Instead, it is better to use local exhaust ventilation systems that remove harmful gases and fumes from the breathing zone. To make these effective, fume extractor guns, fume hoods, and vacuum nozzles should be positioned as close as possible to the source of fumes and gases to remove the maximum amount. Flexible or portable exhaust systems should be positioned to remove the contaminated air away from welders.

In essence, OSHA advises that source extraction is more beneficial than other forms of extraction.

Ventilation Systems

Simply opening doors and windows in welding workshops is not a suitable ventilation solution. Furthermore, as OSHA warns, most conventional general ventilation systems are inadequate. They include traditional pull/push systems that rely on a circular flow of air, pulling the polluted air into pipes and pushing clean air out of pipes. The problem is that dust and fumes often mix with the clean air, so by the time it comes out of the pipework, it is no longer totally pure.

Tower systems effectively suck in the contaminated air, which rises and is filtered at the top of the tower. Purified air then is pushed out of the tower's lower level that corresponds with the welder's breathing zone.

However, the ideal remedy is to extract fumes at the source of the welding. This can be achieved by using a mobile filter unit designed for typical welding conditions. Designs are available for occasional, frequent, regular, or continuous use, and for various welding processes and metals. Some have disposable filters, while others have filters that are cleanable.

What to Look for in Source-extraction Systems

A top-quality machine can handle high levels of smoke and dust during a nonstop operation. Automatic filter cleaning provides high efficiency, and rotation field control helps optimize operation safety. An integrated control cycle monitors the surface of the membrane filter and indicates when the filter should be cleaned.

Welders should look for a basic unit that has an exhaust hood with a damper that rotates 360 degrees, and an exhaust arm that is at least 10 ft. long. A well-designed exhaust hood minimizes the need for exhaust arm adjustment during welding.

When the mobile machine is positioned to extract contaminated air directly from the welder's breathing zone (at the source), it directs prefiltered air through the filter and then feeds it into the work area through blow grids integrated into the machine's housing.

Ultimately, the most important reason to use high-quality source extraction is that it minimizes the hazards that cause serious diseases and negative health conditions in welders.