Thursday, February 12, 2009

HVAC Cleaning and Remediation for Mold and Mildew

As per the NIOSH Interim Recommendations for the Cleaning and Remediation of Flood-Contaminated HVAC Systems: A Guide for Building Owners and Managers, the following are recommendations:

HVAC Cleaning and Remediation
  • Remove all flood-contaminated insulation surrounding and within HVAC systemcomponents. Discard these contaminated materials appropriately followingapplicable Federal, State, and local regulations.
  • Remove contaminated HVAC filter media and discard appropriately followingapplicable Federal, State, and local regulations.
  • After removing any insulation and filters, clean all flood-contaminated HVACsystem component surfaces with a HEPA-filtered vacuum cleaner to remove dirt,debris, and microorganisms. Pay special attention to filter racks, drain pans,bends and horizontal sections of air ducts where debris can collect.
  • After removing any insulation or debris, disinfect all HVAC system componentsurfaces while the HVAC system is not operating. Use a solution of 1 cup ofhousehold chlorine bleach in a gallon of water. Do not mix bleach with othercleaning products that contain ammonia.
  • Follow the disinfection procedure with a clean water rinse. Depending on theamount of debris present, it may be necessary to mechanically clean the HVACsystem component surfaces with a steam or a high-pressure washer beforeusing the disinfectant.
  • Note: Remove and discard HVAC system components that arecontaminated with flood water and cannot be effectively cleaned and disinfected. Replace them with new components.
  • After cleaning and disinfecting or replacing the HVAC system components,replace the insulation – preferably with an external (i.e. not in the air stream)smooth-surfaced insulation to help prevent debris and microorganisms fromcollecting in the future.
  • Make sure that the HVAC system fan has been removed and serviced (cleaned,disinfected, dried thoroughly, and tested) by a qualified professional before it isplaced back into the air-handling unit.
  • During the cleaning and remediation process, consider upgrading the HVACsystem filtration to the highest efficiency filters practical given the static pressureconstraints of the HVAC system fan. This step has been shown to be one of the most cost-effective ways to improve the long-term quality of the indoorenvironment, since it reduces the amount of airborne dusts and microorganisms.


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