5 considerations when selecting a fume extraction device
April 27, 2010
Stricter hexavalent chromium standards are just one reason to invest in a welding fume extractor. Providing a healthier work environment also can help you protect and retain your skilled workers. What should you consider when selecting an extractor?
New hexavalent chromium exposure limit regulations, set to take effect this year, aren’t the only reason your company might want to consider investing in a welding fume extractor. Welding fume extractors can help you attract highly skilled welders, who often can take their pick among workplaces and prefer healthier environments.
Further, by removing welding fume particulates from the work area, you also can increase the service life and reduce the maintenance costs of your welding power sources and other electronic equipment. Companies that employ fume extraction systems also might be able to negotiate more favorable rates with their insurance companies.
Choosing the correct fume extraction system for your specific welding operation is crucial to realizing these potential benefits. The following is a list of factors that you should consider when researching and selecting a fume extraction system.
The three basic methods of respiratory protection are engineered systems; source-capture extraction devices; and personal protection equipment, such as respirators.
While engineered systems and personal protection equipment have their own unique advantages and benefits, this article focuses on source-capture devices, which collect welding fumes at the arc and release the filtered air back into the work environment. Source-capture devices are less costly and typically more flexible than engineered systems. Removing the fumes where they are created reduces exposure for all employees.
Evaluating the type of filter is the single most important factor to consider when purchasing a source-capture fume extraction system. Unlike fume extractors that use filters originally designed for other uses and are adapted for welding applications, filters designed specifically for welding fumes capture more of the submicron particles found in welding fumes. They also dramatically reduce the pressure drop that occurs as the filter gradually fills with particulate.
The most accurate rating system for measuring the effectiveness of filters is the minimal efficiency reporting value (MERV). This rating reflects a filter’s efficacy based on the size of the particles it can capture.
A variety of filter media is available. Nanofiber filters, with a MERV of 15, have one of the highest MERV ratings for fume extraction systems. These filters capture up to 95 percent of submicron particles found in welding fumes. Nanofiber filters store the fume particulates on the surface of the filter (surface loading), rather than allowing them to infiltrate the interior of the filter material (depth loading), which makes them easier to clean and extends filter life.
All fume extraction systems are rated based on the amount of cubic feet of air they circulate each minute (cubic feet per minute, or CFM). Because manufacturers measure and advertise the effectiveness of fume extraction systems differently, an understanding of how airflow is measured is essential when selecting a fume extraction system.
Several factors, including the suction arm, the hood, the blower, the cabinet design, and the type of filter, affect a fume extraction system’s ability to circulate air. Multiple bends in the suction arm, mechanical articulators within the arm, and a poorly configured cabinet can reduce airflow to the filter.
Since the correct amount and type of airflow depends on many different factors, consulting a welding distributor or fume extraction system manufacturer will help you determine the best extraction system for your welding application.
Fume extraction systems are available as either disposable or self-cleaning units. Disposable units, as their name implies, use filters that are designed to be discarded when they reach their capacities. A self-cleaning filter may be used many times because the entrapped particles are cleaned repeatedly from the filter’s surface.
Disposable models offer lower upfront costs; however, the recurring expense of replacing disposable filters can increase the overall cost. Although their initial cost is higher, self-cleaning models can provide ongoing cost savings.
Besides these four primary considerations, you also should look for a unit that provides an intuitive user interface, a quickly accessible filter, a good warranty, low noise, and portability.
As companies continue their search for competitive advantages in retaining and recruiting skilled welders, maintaining a safe and healthful environment is an appealing incentive for new and current employees. A fume extraction system can extend equipment life, reduce insurance rates, and help companies comply with federal regulations. Despite its initial cost, a fume extraction system is an investment that pays many dividends.