#Airflow performance testing series

Issues can arise if air supply diffusers are located too close to the fume hood or the air supply flow produces detrimental cross-draft velocities near the opening. In addition to problems caused by improper modulation of exhaust flow, fume hood performance can be dramatically affected by the velocity and direction of room air currents near the hood opening. These systems are also susceptible to degradation over time, which may lead to more frequent testing and maintenance efforts. Measurement of face velocity alone will not ensure proper functioning of VAV controls, and performance can be compromised by slow response and unstable flow control. The test methods described in the ASHRAE 110 standard can be divided into two sections: evaluation of prevailing operating conditions, and evaluation of containment performance under prevailing operating conditions.Īccording to ANSI/AIHA/ASSP Z9.5-2012, the VAV controls should be capable of modulating flow in less than 5 seconds following movement of the sash and preventing flow variations in excess of 10 percent from the design specifications at each sash configuration or operating mode. The tests are conducted to verify containment performance and document the prevailing operating conditions.

#Airflow performance testing series

The standard describes a series of tasks that include inspection of the hood, evaluation of the lab environment, airflow measurements, airflow visualization tests, and tracer gas containment tests. ASHRAE 110 provides quantitative and qualitative test methods to evaluate containment performance under prevailing operating conditions. The current standard in the United States for verifying proper functioning of fume hood systems is ANSI/ASHRAE 110-2016, Method of Testing Performance of Laboratory Fume Hoods. OSHA’s Occupational Exposure to Hazardous Chemicals standard (.1450) requires all facilities to ensure the proper functioning of fume hoods through appropriate testing and maintenance. Since fume hood systems are installed for the sole purpose of protecting people, proper testing is critical to ensure proper performance before people place their health at risk using hazardous chemicals. These factors are further exacerbated as laboratory hood systems become increasingly more complex with the introduction of unique features and variable air volume (VAV) systems that modulate flow to conserve energy. The factors that affect safety performance are numerous and generally associated with the aerodynamic design of the fume hood, the operation of the airflow systems, the configuration of the laboratory environment, and the work practices of the hood user.