Total Exhaust ducted fume hoods use horizontal and vertical airflow across the work surface to provide personnel protection from hazardous agents and toxic chemicals. These hoods are connected to the facility exhaust system.
OSHA Standard -29 CFR, Safety and Health Regulations for General Industry, 1910.1450: Occupational exposure to hazardous chemicals in laboratories. Part B, definition, laboratory type hood. Please consult your Safety Officer and/or Industrial Hygienist.