Quantitative evaluation of chemical fume hoods performance by CO2 tracer gas

BACKGROUND: Various chemical substances and carcinogens have been presented in medical sciences universities' educational and research laboratories. For this purpose a suitable ventilation system had to be implemented to ensure the correct operation of the hoods. OBJECTIVE: To evaluate the performance of laboratory chemical fume hoods of the University of Medical Sciences using a novel quantitative method. METHODS: In this study, 43 chemical fume hoods were investigated in the laboratories of the University of Medical Sciences. The technical specifications of the hoods and their compliance with the standard have been investigated. The hoods face velocity was measured using a thermal anemometer. Quantitative evaluation was performed using the new method of CO2 tracer gas and the results were analyzed using SPSS software version 19. FINDINGS: The hoods presented both favorable and unfavorable results in terms of technical specifications and location. The results showed 50.2% of the hoods have visible leakage. Hood face velocity was not suitable for any of the hoods in the case fully open.when half open only 16.3% of the hoods and in the case of 25% open face, 34.9% of the hoods had a good velocity. Most hoods have CO2 leakage even at small amounts. CONCLUSIONS: the unsuitable performance of the hoods is mainly due to the unsuitability of the fans, furthermore investigation and correction of technical problems are required. The new quantitative method is a suitable method for routine evaluating chemical fume hoods and can replace the SF6 gas tracer method.