Both rigid and soft barriers are commonly used for physical separation in the construction of isolation chambers (ISO 14644-7:2004) . Rigid barriers can be made of many different materials, and the more rigid the material, the more reliable the physical barrier. Construction of these rigid barriers usually makes use of plastic enclosures, metal profile enclosures, or hot-worked metal enclosures (ISO 10648-1:1997) . The isolation chamber is designed to house a living animal, and therefore continuous airflow inside the enclosure is needed to drive out heat and moisture generated by the animal's metabolism and to decrease the concentration of odor, dust, and infectious substances (Hillman et al., 1992) . The resulting exhaust gas is subject to a filtering system designed to prevent pathogen contamination of the external environment (Institute of Laboratory Animal Resources Commission on Life Sciences, National Research Council, 1996) . The aerodynamics is allowed for one-way flow or turbulence of the airflow inside the isolation chamber, under negative pressure relative to the environment. Supply and exhaust air can be passed through high-efficiency particulate air (HEPA) filters to prevent the formation of aerosols that could potentially escape into the environment (Runkle et al., 1969) .