Evaluation of nine positive pressure suits for use in the biosafety level-4 laboratory

Abstract

Positive pressure suits are the most recognizable feature of Biosafety Level 4 (BSL-4) laboratories, protecting users both through delivery of umbilical-fed HEPA-filtered air and by providing a positively pressurized microenvironment with respect to the surrounding laboratory space to minimize the possibility of exposure resulting from compromised suit integrity. While many positive pressure suits utilized in the chemical and radiation protection industries could be considered for BSL-4 use, the substantial costs and potential incompatibilities with facility settings prevent many labs from investigating novel alternatives. In the present study, 9 positive pressure suits from 5 different manufacturers were critically assessed for their suitability in the BSL-4 laboratory. Material resistance and compatibility with 5% Micro-Chem Plus™, CO2 exposure levels, and overall user preference were assessed through a combination of objective and subjective testing. Results demonstrated that exposure to 5% Micro-Chem Plus™ had no deleterious effects on the mechanical properties of most suit materials, though some potential incompatibility was observed with butyl fabrics. Real-time monitoring of CO2 levels inside the suits showed a great deal of variation between models, however all suits provided a microenvironment where users were exposed to CO2 levels below 1% during normal activity and less than 2% during periods of disconnect from supply air. Finally, survey results from study participants indicated a strong preference for suits with light construction material, 360-degree visibility, high delivery airflow and gloves that require fixation by taping. By combining the present results with facility-specific factors, laboratories will be better equipped to consider new models that best suit their needs.