Engineering controls are used to protect laboratory workers. Examples include exposure control devices (ECDs) such as chemical fume hoods and biosafety cabinets (BSCs), which are ventilated to contain harmful toxins and odors, and safeguard against fume releases into the room. These critical containment cabinets differ in design, and airflow requirements vary as well, according to the application.
Lab managers often choose to use sidewall sensors to maintain the face velocity of fume hoods and biosafety cabinets, instead of duct-mounted probe-style sensors, in applications where the exhaust flow is dirty or extremely hot. The long term exposure of probe-style sensors to depositing particulates or corrosive chemicals may compromise sensor accuracy as well as reliability. The sidewall or side flow sensor overcomes these issues by acting as a flow-through velocity device, drawing in clean, ambient air, rather than contaminated exhaust air, to measure airflow. Sidewall sensors are typically mounted to the side of critical containment cabinets.
Airborne molecular contamination (AMC), or chemical contamination, is the presence of gases or vapors in the atmosphere that may have a detrimental effect on process, equipment, and product in cleanrooms and controlled environments. AMC is a concern for the semiconductor industry, wafer fabrication, hard drive manufacturing, and other high technology manufacturing processes (reference ISO 14644-8 classification of airborne molecular contamination). AMC filtration is one of the methods used to control chemical contamination, where contaminants are removed by adsorption, as the air passes through AMC media.
