The question of source v. ambient capture primarily comes down to the nature of your air quality problems—namely, in the volume of fumes and the nature of the particulates. High-volume operations that produce a lot of dust or fumes are best served with a source capture solution. Failing to do so risks letting too many particulates drift around your facility, causing harm to workers and risking regulatory compliance. Equipment such as fume arms and backdraft tables are able to pull contaminants away workers as soon as they are produced. Robotic welding cells—one of the highest-volume fume producers—can be enclosed with a hood, allowing you to weld all day without filling your facility with fumes.
Contaminated air that contains a high quantity of toxic substances requires a more intensive air quality solution than more benign contaminants. For example, air that contains hexavalent chromium is much more dangerous than air that carries wood dust. The former air quality challenge calls for an intensive solution, such as source capture. You don’t want those toxic substances drifting through a facility waiting to be exhausted or to pass through an ambient capture system. While they drift, they could affect workers spread across a facility; and even a small level of exposure to these substances can cause harm.
Another factor affecting a decision regarding source or ambient capture is the layout of your facility. Overhead cranes or restricted floor space can limit your options. Sometimes an ambient capture system is the only option available. In situations like these, such a system could be paired with personal protective equipment.
Ambient capture solutions are great for facilities with operations spread across a wide area and with lower volumes of contaminants. These systems circulate the air throughout an entire facility and ensure that contaminants don’t linger and threaten workers. Applications that deal with less toxic substances are good candidates for ambient capture, as well, like the aforementioned wood dust. In these cases, an ambient capture system would both protect workers and guard against facility-wide dangers such as dust explosions.
Often, a hybrid system is worth considering. For example, in a facility where large pieces are being welded, a powerful source capture system—such as an enclosure and fume hood—might not be an option. In this situation, a fume extraction gun would be a good option for collecting most weld fumes at the source. A secondary ambient capture system would help ensure that nothing is missed. Today’s strict air quality standards demand this attention to detail.