Monday, December 23, 2013

Manufacturers ignore welders’ health: Experts

Welding is linked to various health risks.
A single welder produces 20 to 40 g of welding fumes per hour, which corresponds to about 35 to 70 kg per year.

Most welders understand the many health risks of working in the fabrication industry, which include electric shocks, fire, explosions and radiation exposure, but it appears that one of the biggest threats to a welder’s health - toxic welding fumes - is being ignored by many welders and their employers.

Research shows a lack of familiarity with the gases used or fumes produced during the welding processes can be a serious health risk. Workers can become ill if dangerous fumes are not removed from the workplace.

OHS groups say it is essential welders are familiar with the materials being used (such as gases, base metals, coatings and cleaners) and their possible health impact.

Research reveals fumes produced during welding processes can lead to workers experiencing eye, skin and respiratory system irritation, nausea, headaches and dizziness.

In some cases, the fumes can cause serious lung diseases and increase the risk of asthma and cancer and possibly lead to asphyxiation.

However, despite all these warnings, many manufacturers are unaware of the need for adequate fume extraction to create a safe working place.

An open roller door and a fan on the roof or in the wall may be able to affect the air changes per hour or minute, but welders are still exposed to the fumes. The area needs to be well ventilated to let toxic fumes and gases escape.

Central ventilation systems and even large extraction hoods over workbenches often fail to provide adequate protection, since the fumes still contaminate the general airflow.

Experts say that extraction-at-source is most effective – removing toxins as soon as the fumes are generated.

Fume extraction air cleaners are the most
effective when it comes to welding fumes.
Fumes from different welding methods

It has been shown that different welding methods give rise to different amounts of fumes containing different concentrations of hazardous substances.

Among the high-risk elements are hexavalent chromium Cr(VI), manganese, nickel and lead.

The particles at source are often extremely small; 0.01-0.1µm which means they are very easy to inhale deep into the lungs.

Furthermore, not only welders are at risk in unsafe environments. Production equipment, as well as end products, are negatively affected by the lack of adequate safety measures.

During welding, the intense heat of the electric arc vaporises a fraction of the metal in the electrode and weld pool.

Any metal vapour that escapes the arc area condenses as it cools and oxidises into weld fume. The vapour that develops condenses as it cools and oxidises into weld fume containing a complex mixture of metal oxides.

Particulate fume is formed mainly by vaporisation of metal and flux. As it cools, the vapour condenses and reacts with the atmospheric oxygen to form fine particles.

The size of the particles (0.01 - 1µm) tends to influence the toxicity of the fumes, with smaller particles presenting a greater danger.

Additionally, many processes produce various gases (most commonly carbon dioxide and ozone, but others as well) that can prove dangerous if ventilation is inadequate.

About 90% of the fume originates from the consumable, while the base metal only contributes very little.

The fume contains all the elements present in the consumable, but often in very different proportions. Volatile components have a higher concentration in the fume than in the consumable and the opposite is true for components with a high melting point.

The amount of welding fume varies between different welding processes: Fumes from manual metal arc (MMA) welding and fluxcored arc welding (FCAW) contain a high proportion of components coming from the electrode coating or the flux core. Comparatively little comes from the filler metal.

It has also been shown that particles in welding fumes are small enough to be suspended in the air for a long time. They can be inhaled and penetrate into the innermost area of the lungs. Over time, the particles can even reach the bloodstream.

Editor's note: This article has been edited for length.

Remove toxins at the source with fume extractors
Electrocorp's LD450
welding fume extractor

Welding is dangerous enough, but the risk of inhaling harmful particles and fumes can be minimized by using an industrial welding fume extraction air cleaner from Electrocorp.

The air cleaning systems feature 40+ pounds of activated carbon for the removal of chemicals and volatile compounds, HEPA and pre-filters to trap airborne particles, a direct intake hood on an articulating arm to capture toxins at the source and a spark arrestor for welding applications.

Custom carbon blends are available for targeted chemical control.

For more information, contact Electrocorp.

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