Extraction at source is the most efficient solution for welding fume extraction
International health organizations recognize the importance of preventing health risks associated with fumes and smoke generated during arc welding and thermal cutting. In many countries, strict personal exposure regulations and standards such as OSHA, PEL or ACGIH TLV are heavily enforced to minimize worker exposure to hazardous metal particulate that can be present in welding fume. Ventilation is a primary solution step to mitigate employee welding fume exposure. Because welding fume is a thermal process, the particulate is suspended in the ambient air space. When the fume plume cools, the particulate settles to the work space. It builds up on work stations and can infiltrate machinery and electronics causing damage and creating the need for additional housekeeping, which can add another layer of maintenance and overhead cost.
At Nederman, worker health and safety are primary concerns, as they affect process efficiency, productivity, quality, costs and successful job completion. Our solution starts at the process so we understand the job and worker procedure. After a thorough analysis and interview, we recommend a solution that will best protect the worker while maintaining efficiency, productivity, quality and work zone cleanliness. Education and training is an essential part of any successful solution. The customer will be educated on the solution’s approach, the extraction equipment operation and integration into the process and system maintenance.
Extraction at source is the most efficient capturing solution for welding and cutting fumes
Wherever it is a viable solution, it has been proven that extraction at source is the most effective and efficient method of capturing and removing welding and similar fumes. Using this method, the risk of the welder or operator being subject to hazardous fumes is minimised.
Nederman offers a full portfolio of portable, stationary, central and custom engineered solutions to control and mitigate welding fume and cutting smoke within the production environment from common welding processes, including MIG, TIG, GMAW, FCAW or SMAW. With over 60 years of industry experience, we can provide application review, solution recommendation and implementation, system design, engineering and installation, product and system support, commissioning, diagnostic and service maintenance programs, assistance with meeting clean air regulations and standards and energy efficient solutions.
The necessary components to achieve proper source capture of welding fumes are an easily positioned fume extractor with a well-designed hood, proper airflow through the fume extractor and a conscientious welder who will position the hood in a manner that will draw hazardous fumes away from his or her breathing zone and avoid to spread the smoke in the premises.
Welding smoke and fume extraction at-source with arms
Nederman has a wide range of extraction arms in different designs. Full flexibility and easy to position. Arms can be fitted to both stationary and mobile vacuum and filter units.
The most effective solution for removing and mitigating welding fume is close or at-source extraction. The arms, sometimes called snorkels, vary in diameter and length, can be positioned from 6 – 15 inches from the welding fume generator and typically have an extraction volume of 500 – 1,000 CFM. The variation in arm design and style is so there is a model that can be applied to different applications where the arm needs to fit within a small work space or instances where the arm must be able to reach to distances of 20 feet or more. Nederman has a wide range of welding fume extraction arms in different designs with full flexibility and are easy to position to fit many applications. Arms can be fitted to both stationary and mobile vacuum and filter units.
On-torch and fume guns welding fume extraction
Semi-automated and robotic welding applications utilize precise machinery and electronic controls to perform welding and cutting operations that would typically be performed by a welder. Since the mechanical device or robotic arm is performing the welding process, fume arms are difficult to use since these types of solutions involve a large work envelope, acrobatic movements and dedicated work area. Nederman solutions for semi-auto and automatic welding processes include both on-torch and canopy hoods for welding fume extraction.
As an alternative to the hood and arm fume extractor, on-torch or integrated welding fume MIG gun extraction can be used. The on-torch extraction systems extract the fumes directly from the welding torch. The extraction systems are available as both mobile single user extraction units and central extraction systems serving several extraction points.
Nederman solutions for automatic welding processes include both on-torch extraction and extractions systems with hoods for welding fume extraction.
Smoke and fume extraction from thermal cutting processes
The fumes generated from the cutting process are extracted through the grates of the cutting table.
Backdraft and downdraft
Other source extraction methods include downdraft tables and backdraft registers. Downdraft tables are often a stand-alone work bench with integrated particulate and fume extraction used for grinding, large weldments and work pieces that requires unobstructed movement about the process. Backdraft registers are typically added to an existing work bench or work space that requires fume or smoke extraction from the cutting or welding process.
Thermal cutting processes
Some thermal cutting processes include oxy-fuel, air carbon arc gouging, plasma arc cutting and laser beam cutting. These processes can vary from a small bench top to a large room application. High heat, molten metal and fume particulate are some of the by-products of these processes. Solutions vary from one application to another, however in many cases, the fumes generated from the cutting process are extracted through grates on an elevated table. Other solutions proven effective include close source capture and overhead hood systems.
Energy saving systems
To save energy and operation cost Nederman offers a wide selection of motor dampers, fan control units and fan inverters, complementing stationary units for energy efficient on-torch welding fume and smoke extraction.
General mechanical ventilation systems
There are instances, such as welding on large work pieces, automated work cells, and constant worker repositioning, where source capture solutions cannot be implemented. Other instances include the protection of employees that are not wearing personal protection equipment but are still affected by the welding production environment. Source extraction is challenging and requires additional control techniques and it is difficult to isolate the work area that is generating the welding fume or cutting smoke. Central or general ventilation systems operate on a high volume ambient air cleaning approach that is positioned over workbenches and integrated into work spaces. Based on the inherent design and operation of general ventilation systems, they often will not protect the workers breathing zone but will help to control the background particulate concentration as an additional control methodology.
Types of central ventilation systems include canopy hoods, work booths, room cleaners and push pull systems. These systems require extensive application review, HVAC and ambient air consideration, system design, and work area implementation–as they as are typically high volume systems with large filtration units and ducting often requiring custom integration into the facility. General ventilation systems will only help control the ambient or background particulate concentration where the welders or operators cannot avoid inhaling the welding fumes, which may force them to wear uncomfortable respirators in addition to central general ventilation solution. Thorough air quality testing and monitoring is an important part of designing and assessing the effectiveness of any fume or smoke ventilation system.
Why central ventilation systems are no good
Central ventilation systems or extraction hoods over workbenches are often completely inadequate. These systems are seldom cost-effective as they require a great deal of power to run and extract enormous quantities of heated air from the premises. Moreover, the welders or operators cannot avoid inhaling the welding fumes as these always contaminate the general airflow, forcing them to wear uncomfortable respirators in addition to central ventilation.
Health effects of welding and cutting fumes
Particles in welding fumes are small enough to be suspended in the air for a long time. The welding fume can be inhaled and penetrate into the innermost area of the lungs, and over time can even reach the bloodstream. Fume from MMA and FCAW welding usually contains significant quantities of Cr(VI), in particular when welding in stainless steel. This is important to observe because hexavalent chromium Cr(VI) has a very low exposure limit. There are also health risks from exposure of welding smoke due to the presence of manganese, nickel and other elements. The Manganese ACGIH TLV has recently been lowered to 0.02 mg/m3 and OSHA is considering lowering the Mn PEL as well. This could result in significant costs and changes to the work process, application procedure, consumable type, ventilation, training and personal protection equipment.
Generation of welding fumes and smoke
Airborne particles from 2 weeks welding. One single welder produces 20-40 g fumes per hour which corresponds to about 35-70 kg per year. 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; 0.01-0.1 μm 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 from the lack of adequate safety measures. Automated welding equipment such as robots – and the operators – can be subject to residual fumes and also need to be protected.
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