The setback may be triggered by occupancy sensors, a light change, or a timer or a very lowered sash. Understand what triggers the setback and make sure that the chemical hood just isn't used for hazardous operations when in setback mode. For instance, amenities with low-toxicity contaminants and a minor degree of air air pollution might rely on dilution ventilation, in which contaminated air is mixed with clear air to reduce the proportion of contaminants. In contrast, amenities with more…