Risk of Exposure to Infectious Particles during Testing of Smoke and Fire Dampers in HEPA–Protected and Non-Protected Patient Rooms

Risk of Exposure to Infectious Particles during Testing of Smoke and Fire Dampers in HEPA–Protected and Non-Protected Patient Rooms Pages E10-E11 J. Hodson*, D. Webb, M. Kleiman, R. Van Hise Close Close preview | Purchase PDF (68 K) | Related articles | Related reference work articles AbstractAbstract Abstract BACKGROUND: Regulatory agencies require that smoke and fire dampers are inspected and tested. Debris within ventilation ductwork is often contaminated with fungal spores that can cause opportunistic infections in immunocompromised patients. Since damper testing procedures may potentially contaminate the hospital environment, particle counts were examined to 1) assess the potential risk to patients, and 2) develop methods to reduce contamination. METHODS: Dampers were manually actuated and access panels opened to permit visual inspection. Dust and debris on damper components and adjacent surfaces were removed with a HEPA–filtered vacuum. Particle counts were measured with a CCI 550 counter in unoccupied rooms equipped with HEPA filtration at the room diffuser and in standard rooms without HEPA filtration. Particle counts were monitored before, during, and after damper actuation. RESULTS: In non-HEPA–filtered rooms, particle counts increased from 20,000/cfm to 43,000/cfm following damper testing; counts returned to baseline after 50 minutes. In positive pressure HEPA–filtered rooms, particle counts increased from <10/cfm to >35,000/cfm within 6 minutes. During testing, static pressure increased within ductwork tripped protective mechanisms which automatically shut down the ventilation system. Reduction of fan speed limited abrupt increases of static pressure preventing shut down. Particles remained at a baseline of <10/cfm during and following damper testing. CONCLUSIONS: Damper testing may contaminate the hospital with fungal spores. In terminal HEPA–filtered rooms, continued function of the ventilation system, albeit at reduced fan speed is required to prevent airborne contamination during damper testing. Damper testing in standard hospital rooms contributes to environmental contamination.