Effectiveness of Laminar Air Flow for Controlling Air-borne Contamination

Abstract

Air samples were collected at various locations in the protected space of an experimental laminar air flow chamber. A continuous low velocity stream of filtered air was maintained through the protected space of the experimental chamber. The efficiency of filtration was 99.97% for 0.3-μ, particles. The effectiveness of the chamber has been determined against a measured concentration of air-borne Serratia marcescens in the surrounding atmosphere. The test aerosol was generated from liquid broth cultures and the concentration was determined by collecting air samples periodically throughout the experiments with a Casella slit air sampler. Air samples were collected continuously for 30 min inside the protected space representing from 680 to 850 liters of air. Data were collected at three different air velocities of between 15 to 45 m/min. The effectiveness was determined at ten different locations within the protected space. In general, results revealed a high degree of effectiveness at all air velocities and locations withtin the protected space. A slight increase in effectiveness was noted as the air velocity increased. The influence of location on effectiveness was related primarily to distance from filter face. © 1968, American Dairy Science Association. All rights reserved.