NO-94-18-3 -- Methods of Exhausting a Biological Safety Cabinet (BSC) to an Exhaust System Containing a VAV Component PDF

Points out that, to economise, HVAC designers may connect biological safety cabinets (BSC) and chemical fume hoods to the same exhaust system. While both types of equipment provide contaminant control, their airflow characteristics are distinctly different. Balancing such a system and maintaining that balance are subject to the uniquely dynamic characteristics of both the safety cabinet and the fume hood. When a fume hood is equipped with a variable air volume (VAV) controller device, the airflow balance of a commonly exhausted BSC may be adversely affected. Investigates two ways that such a hood may coexist with a commonly exhausted BSC - 1) a canopy of 'thimble' connection and a constant air volume controller at the outlet of the BSC. A mock laboratory was used for continuous monitoring. Presents the data in terms of cabinet performance and percent change in BSC air flow balance.

KEYWORDS: Laboratories, safety cabinets, fume cupboards, controls, exhausts, air flow, monitoring, experiment, performance, regulating.