How the air moves through a lab enclosure determines the safety of the personnel
Flipping the switch on a lab hood, most scientists might think, ensures a safe working space. But, does it? Maybe. In a properly designed and working hood, sure—turning on a hood’s ventilation system creates a safe spot to work. Nonetheless, the need for maintenance or a part failure can undermine the best design. To keep track of a hood’s performance, labs should install and maintain flow monitors where needed.
The way a monitor works impacts its performance and efficiency. In Shoreview, MN, TSI makes monitors and controls that work with variable air volume (VAV) methods. “VAV reduces airflows and saves energy,” according to TSI. For example, TSI makes a monitor that measures a fume hood’s face velocity. With this monitor and its controls, TSI notes, its technology helps “maintain a constant face velocity. This provides superior containment.”
The features on a monitor also determine what it can do and how it can be customized for a specific lab application. For instance, TEL (Oshkosh, WI) makes a family of airflow monitors. As the company notes, its “innovative airflow monitors are designed specifically to ensure the safety of users working with industrial and educational fume hoods and biological safety cabinets.” In addition, TEL points out several key features. One is flexibility, including entry-level airflow monitoring, push-button functions, remote airflow sensors, and pressure monitoring. Reliability also goes on the TEL feature list, where it claims that “with no inherent drift, the sensor will provide stable readings over many years of operation without recalibration, ensuring reliability and safety.”
Other manufacturers also make families of monitors. The Guardian Digital Airflow Monitor—one of the monitors made by Labconco (Kansas City, MO)— “senses and alerts the operator to low airflow conditions,” the company states. “Each monitor includes a face plate with circuit board, electrical power pack, vinyl tubing, side wall flow tube adapter, and wiring instructions.” Controls on the outside of these monitors can be used to adjust the setpoint, 50–250 feet per minute, of airflow. In addition, Labconco’s website notes: “An LCD displays actual face velocity.”
Scientists should expect any monitor to be accurate and reliable. Moreover, the manufacturer should be ready and able to prove that. To track that accuracy over time, many monitors provide data readouts, such as a graph of face velocity. This helps a lab manager review a hood’s airflow performance over its lifetime.
Some airflow monitors, such as the Alnor AirGard BSC Airflow Monitors from NuAire (Plymouth, MN), are designed for use in biological safety cabinets. These monitors can measure airflow across a wide range, 25–2000 feet per minute. If the airflow goes outside of a set range, audible and visual alarms alert personnel in the lab.
Customers should expect a monitor to include alarms that indicate any dangerous drops in airflow. As explained by the University of New Hampshire’s Laboratory Ventilation Management Program: “The face velocity alarm indicates unsafe exhaust flow by an audio and visual alarm.” If an alarm goes off, the sash should be closed, and the system should be evaluated before being used.
For any hood or biological safety cabinet, proper airflow determines performance, which really matters when using toxic substances. In any case, an a well-made and maintained airflow monitor ensures a safe working environment for scientists in a lab.
Mike May is a freelance writer and editor living in Texas. He can be reached at [email protected]