Introduction
For the duration of flooding, systems for heating, ventilating, and air conditioning (HVAC) can come to be submerged in flood waters. Consequently, these systems may perhaps contain substantial amounts of dirt and debris and may possibly also grow to be contaminated with a variety of varieties of microorganisms for instance bacteria and fungi. The following recommendations will assist make sure that HVAC systems contaminated with flood water are adequately cleaned and remediated to provide healthy indoor environments.Microorganisms

may perhaps grow on all surfaces of HVAC technique elements that have been submerged in flood waters. Also, moisture can collect in HVAC method components that weren’t submerged (which include air provide ducts above the water line) and can promote the growth of microorganisms. As a result, all components from the HVAC method that had been contaminated with flood water or moisture should be thoroughly inspected, cleaned of dirt and debris, and disinfected by a qualified professional. The following recommendations will help guarantee that HVAC systems contaminated with flood water are correctly cleaned and remediated to supply wholesome indoor environments.These

suggestions will probably be reassessed periodically and updated as acceptable. 

Steps Before Cleaning and Remediation
If the developing is to remain partly occupied (one example is, on upper floors not impacted by flood waters), isolate the construction locations where HVAC systems might be cleaned and remediated by utilizing temporary walls, plastic sheeting, or other vapor-retarding barriers. Sustain the construction regions beneath negative stress (relative to adjacent non-construction places) by utilizing blowers equipped with HEPA filters (high-efficiency particulate air filters) to exhaust the region. To ensure comprehensive isolation from the building areas, it might be important to pressurize the adjacent non-construction areas and temporarily relocate the outdoor-air intake for the HVAC technique serving the occupied places.


Take precautions to
guard the well being of workers who are cleaning and remediating the HVAC system. Make sure that workers wear at least an N-95 NIOSH-approved respirator to safeguard against airborne microorganisms. Enhanced levels of respiratory protection (one example is, powered, air-purifying respirators equipped with higher efficiency filters) may very well be suitable based on the amount of visible contamination. Additionally, when applying chlorine bleach or other disinfectants in poorly ventilated environments, it might be needed to work with proper chemical cartridges additionally to the particulate filters to safeguard workers from breathing the chemical vapors. Employers will have to implement a full respiratory protection system that meets the specifications with the OSHA respiratory protection common (29 Code of Federal Regulations 1910.134). The minimum specifications for a respiratory protection program include a written typical operating process for the following: choosing and utilizing respirators; the health-related evaluation of workers to decide irrespective of whether they may be physically capable to wear the respirator chosen for use; coaching and directions on respirator use; the cleaning, repair, and storage of respirators; the continued surveillance of operate location situations for worker exposure and stress; in addition to a respirator fit-testing plan. For tight-fitting respirators, fit-testing is necessary to assist guarantee that the respirator fits tightly, reducing the possible for leakage of outside air from about the edge on the mask. Furthermore, employers ought to supply workers with suitable skin, eye, and hearing protection for the protected efficiency of their jobs.

HVAC Cleaning and Remediation
Eliminate all flood-contaminated insulation surrounding and inside HVAC technique elements. Discard these contaminated supplies appropriately following applicable Federal, State, and regional regulations.
Remove contaminated HVAC filter media and discard appropriately following applicable Federal, State, and regional regulations.
Immediately after removing any insulation and filters, clean all flood-contaminated HVAC method component surfaces using a HEPA-filtered vacuum cleaner to get rid of dirt, debris, and microorganisms. Pay specific consideration to filter racks, drain pans, bends and horizontal sections of air ducts exactly where debris can gather.
Soon after removing any insulation or debris, disinfect all HVAC technique component surfaces while the HVAC system will not be operating. Use a option of 1 cup of household chlorine bleach within a gallon of water. Do not mix bleach with other cleaning solutions that include ammonia.
Conduct the cleaning and disinfection activities
in a clean-to-dirty function progression. Take into account the usage of auxiliary fans to provide “clean” air to the worker position and carry aerosolized contaminant and disinfectant inside the clean-to-dirty path, away in the worker’s breathing zones and towards the point of filtration and exhaust.
Adhere to the disinfection procedure with a clean water rinse. Depending on the amount of debris present, it may be vital to mechanically clean the HVAC program element surfaces having a steam or possibly a high-pressure washer just before applying the disinfectant. Gasoline powered stress washers really should be made use of outside away from air intakes to prevent carbon monoxide hazards. (See NIOSH subject webpage, “Carbon Monoxide Hazards from Little Gasoline Powered Engines”
Note:
Remove and discard HVAC program elements which are contaminated with flood water, and cannot be properly cleaned and disinfected. Replace them with new components.
Right after cleaning and disinfecting or replacing the HVAC technique elements, replace the insulation – preferably with an external (i.e. not in the air stream) smooth-surfaced insulation to assist prevent debris and microorganisms from collecting inside the future.
Make certain that the HVAC program fan has been removed and serviced (cleaned, disinfected, dried completely, and tested) by a qualified professional before it can be placed back into the air-handling unit.
During the cleaning and remediation approach, consider upgrading the HVAC technique filtration to the highest efficiency filters sensible provided the static pressure constraints in the HVAC technique fan. This step has been shown to be probably the most cost-effective solutions to increase the long-term top quality of your indoor atmosphere, considering that it reduces the amount of airborne dusts and microorganisms.
Resuming HVAC Operations
Soon after cleaning and disinfecting or replacing HVAC program, have a certified experienced completely evaluate its functionality and right it as essential prior to the developing is occupied again. The HVAC method overall performance really should conform towards the suggestions contained in ASHRAE Regular 62.1-2016, Ventilation for Acceptable Indoor Air Good quality.
Prior to the creating is occupied once more, operate the HVAC technique continuously in a regular manner at a comfortable temperature for 48 to 72 hours. During this period, it might be advantageous to open the HVAC outside air dampers to the maximum setting that nonetheless allows you to offer the preferred indoor air temperatures. If objectionable flood-related odors persist after this “flush out” period, reassess by searching for flood-contaminated areas that were not identified earlier and continue the flush-out method till odors are no longer apparent. Replace the HVAC filters applied for the duration of the flush-out prior to creating occupancy.
Just after a building is occupied again, make frequent (for instance, weekly) checks in the HVAC program to ensure that it’s operating effectively. Through these checks, inspect the HVAC program filters and replace them when needed. Steadily minimize the frequency of the HVAC technique checks to monthly or quarterly inspections, depending on the routine operation and upkeep specifications for the HVAC system.
If no routine operation and
upkeep plan is in place for the HVAC method, develop and institute such a system. At a minimum, consist of the following routine procedures: inspection and maintenance of HVAC elements, calibration of HVAC program controls, and testing and balancing of your HVAC system.
Right after the developing is occupied once more, preserve the interior temperature and relative humidity to conform together with the ranges suggested in ASHRAE Common 55- 2013, Thermal Environmental Conditions for Human Occupancy.
Additional Resources
Further details in regards to the cleanup and restoration of water-damaged and mold contaminated HVAC systems is offered in the Institute of Inspection, Cleaning and Restoration Certification (IICRC) along with the National Air Duct Cleaners Association (NADCA). Their pertinent documents (Standard and Reference Guide for Specialist Mold Remediation [IICRC S520] and Assessment, Cleaning and Restoration of HVAC Systems [ACR 2013]) are out there for obtain at www.iicrc.org/ and http://acrstandard.nadca.com/, respectively. The University of Minnesota has a document titled, “HVAC Technique Decontamination” available free of charge off the internet at www.dehs.umn.edu/iaq_hsd.htm. The Commonwealth of Pennsylvania, Division of Environmental Protection also includes a document entitled “Flood Recovery: Heating and Cooling