Mold removal from mechanical systems
Mechanical systems that require mold removal or have been flooded by gray or black water should be shut down to avoid the transmission of contaminants to other areas of the building. When cleaning system components, protect motors, bearings, belt drive assemblies, filters, ducts, and other non-damaged items from water intrusion.
Mold removal from HVAC
Vacuum clean the entire internal space of the HVAC system with HEPA vacuum, including all components, supports, frames, mounts, etc. to remove loose dirt and debris. Hand scrub to remove residual dirt. Pressure wash hard to clean system components. There should be no standing water or wet surface within the system after all components have been cleaned.
Wet fiberglass or other wet porous insulation in the air handling system (including supply ducts), should be discarded. Dry lining with an intact, undamaged barrier can be left in place. It is possible to clean these surfaces if they have been contaminated by clean water, using air pressure, brushes, and vacuum suction. However, the process must not degrade the lining or barrier.
Note that the purpose of insulation can be for thermal or acoustic reasons and it may be advantageous to replace damaged porous insulation with closed cell foam type, and to place insulation on the exterior rather than the interior surface.
Filters that have become wet should be replaced. Filters can be removed and stored during system remediation. However at no time should the system be in operation if the filters are not in place.
Hard surfaces can be cleaned with a detergent or bleach solution by hand wiping, or with a spray/pressure washer. Wipe clean or HEPA-vacuum.
Heating and cooling coils exposed to water damage should be cleaned using a pressure washer and cleaning agent at both the upstream and downstream face.
Mold removal from floor drains
Floor drains and sumps should be cleaned, disinfected and flushed for mold removal. During a flood, the water pressure in plumbing systems can reverse, and water in hot and cold pipes can be contaminated with flood water. A plumber must inject bleach into the lines to disinfect them
Air supply and exhaust ducts that have been damaged with clean water will need to be inspected. Clean ducts may not pose a problem when they are dried. If water and dirt is visible, the entire affected system, including vertical sections, should be cleaned. If the system has been penetrated with gray or black water, ducts will have to be disassembled, washed, decontaminated, dried and reassembled. It is not advisable to apply biocides or sealants on dirty surfaces. See mold in ducts.
External duct and system insulation and wrapping that can be dried can remain in-place. Verify that it is dry through its entire depth. Waterlogged areas may have to be removed and replaced.
Air-handling units along the perimeter of the building that have been exposed to moisture must be re-conditioned. Remove all fiberglass lining and filters. If damaged by clean or gray water, use detergent to clean surfaces by either hand wiping or by using a pressure washer. Do not get surrounding areas wet ,and vacuum after spraying. It may be best to clean removable components off-site. Coils and fins can be cleaned by a pressure washer or by a HEPA-filtered vacuum.
Air-handling units contaminated by mold or black water should be re-conditioned using a 10 % bleach solution, or removed for decontamination off-site. Fins and coils must be pressure washed. All porous materials must be discarded.
Registers, grills and diffusers exposed to clean or gray water should be wiped clean and dried. Items exposed to black water or infested with mold should be removed and disinfected before reinstallation.
Before the HVAC system is put back into operation a final purge is recommended. All supply air diffusers and air-handling unit grills should be covered with 30 % or greater efficiency filter media. Tape to eliminate air leakage. Start system and run at variable speeds to dislodge dirt and debris for at least one hour. Remove all filter media, vacuum and clean any locations if necessary.
Finally, the HVAC system may require testing, adjusting and balancing.
Mold Removal from electrical appliances, light fixtures and circuit breakers
Electrical appliances, and other unique specialized components require inspection and repair by a qualified, knowledgeable person. The power should be turned off in the flooded area at the service panel by an electrician before electrical appliances are removed.
Electric circuit breakers and fuses that were wet should be replaced. Switches and outlets that were under water can be cleaned and reused if still functional. Electric motors and appliances need to be cleaned, dried, and inspected. All damaged light fixtures need to be opened, cleaned, dried and checked before being put back in service. Computers, radios, and televisions which have been water or mold damaged may be unsalvageable. Items soaked in black water should be discarded. Disks and CDs can be washed in clean, distilled water and dried with lint-free towels.