Weld Fume Management: Evaluating Environmental, Source Capture and PPE Solutions and Choosing the Best for Your Application

As you talk with different welding operations, each one has a different reason for weld fume management. Some companies have tested their environment and have particulate saturation above and beyond the permissible exposure limits (PEL) deemed acceptable by OSHA. Others simply want to limit the amount of particulate emitted into the environment for employee wellbeing.

The methods each company takes to reduce its weld fume exposure will be different, but there are a number of common factors to take into consideration when selecting a solution. Process and behavioral changes are the prescribed first step, but are not always feasible due to weld requirements and the processes involved. It is then that engineering controls, such as building ventilation and source capture, as well as personal protective equipment (PPE), may need to be implemented. In this article we’ll take a look at the pros and cons of some of these solutions and factors to consider when selecting a solution.

A note: every welding environment is different and needs to be evaluated by a qualified Industrial Hygienist to determine the appropriate course of action for fume controls. This article is presented for awareness and educational purposes only and should not replace professional consultation.

The First Wave of Defense: Work the Process

Before implementing any engineering or mechanical controls, the first step a company must take in weld fume management is changes to the welding process itself. These may include:

• Changing base materials
• Enclosing the process
• Switching wire types (changing from a Flux Cored wire to a solid wire, for instance)
• Change the welding process (from Stick to MIG, for instance)
• Change transfer methods (example: change from short-circuit or globular transfer to Pulsed MIG)
• Change deposition rates and/or weld settings
• Change welder behavior

While not the focus of this article, each of these factors affects change on fume levels but needs to be examined thoroughly in the context of your welding application. Some of these will require testing and certification to ensure welding tolerances are maintained, and in some cases recertification may need to take place. Behavioral change is one of the more immediate changes a welder can make: don’t position yourself directly above the weld (weld fumes rise). When possible, position the weld away from the welder, and never stand in between a fan and the weld — as that fan moves air, it will move weld fume right through the breathing zone of the welder.

Engineered Solutions: Environmental and Source Capture

Once the process has been evaluated, companies will then look at ways of removing the fumes and particulate that result from the welding process. With this, the main goal is to capture the fume.

Environmental solutions, such as industrial HVAC and ventilation systems, may be an option for some but lack the efficiency of source capture through a fume extraction device. These systems are designed to protect the whole shop, which is important when you have other workers in close proximity to the welding activity. These systems, however, are not without inefficiencies. They do not protect the welder’s immediate breathing zone. They can be extremely expensive to implement with changes to the building. While weld fume tends to naturally rise, it eventually levels out and falls back down to the surface — buildings with tall ceilings may prove inefficient at actually removing the particulate.

Source capture through fume extraction is ultimately the best method for eliminating the weld fume from the air. Fume extraction solutions come in multiple shapes and sizes:

• Portable/mobile floor models
• Stationary/wall-mounted models
• Fume guns (welding torch with built-in fume extraction)
• Centralized industrial (multi-cell) systems

Source capture is preferred because it removes contaminated air at the source before it reaches a worker’s breathing zone. One of the key disadvantages of some source capture solutions is that they are difficult to position over large weldments or other obstructions within the weld cell. You also have a number of additional factors to consider:

• Filter ratings: All weld fume extraction equipment filters should have a Minimum Efficiency Reporting Value (MERV). Many filters are not designed to handle the submicron particles (95 percent are .3 to 1 micron) found in welding fumes. Standard cellulose filters rate a 7 to 10 on the MERV scale, which means they are not rated to capture particles smaller than 1 micron. Another common filter material is spun-bound polyester; it is rated an 11 on the MERV scale. An 11 rating indicates that these filters are not very efficient at capturing particles smaller than 1 micron, either. FilTek™ XL filters, with MERV ratings ranging from 13 to 16, offer some of the highest MERV ratings for fume extraction systems. Filters with MERV ratings of 15 and 16 immediately capture up to 95 percent of submicron particles found in welding fumes and quickly begin to filter out up to 99.998 percent of submicron particles.

• Filter media cleaning: You have a number of options to choose from: disposable, manual cleaning, self-cleaning, and automated/online cleaning. Self-cleaning and automated model options are going to cost more upfront, but ultimately have a greater long-term value than models with disposable filters when you factor in the costs of the disposable filters you are continually paying for. 

• Airflow: All fume extraction systems are rated based on the amount of cubic feet of air they extract each minute (cubic feet per minute or "CFM"). Each manufacturer ranks CFM differently. CFM should be tested at the hood for the most true/effective rating.