What measurements are taken during LEV testing?

Airflow, capture velocity, and static pressure in ducts are all measured during an LEV test. Manometers monitor pressure variations, while devices such as anemometers detect air speed. Smoke tubes are occasionally used to demonstrate how well pollutants are caught.
These measures demonstrate if the system is controlling the hazard by drawing in enough air through the hoods. against determine whether the system is effective or requires modification, the figures are compared against design specifications and HSE guidelines.