Removing excess moisture in affordable multi-family housing to lower indoor humidity levels
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Type / Construction
Multi-Family Apartments/ Affordable Housing
2 BR Apartment
Location
Lexington, NC
Issue Reported
Salem Environmental was contacted to remediate a typical two-bedroom apartment located in the Southeastern United States. Constructed in 2012 the unit has experienced persistent elevated humidity and excessive moisture ultimately leading to amplified fungal activity (mold growth) like that on the top of the kitchen cabinet in the photo (above).
Background
Since being built in late 2012, A 2BR apartment located in the Southeastern US has had continued high humidity/moisture problems that have led to amplified fungal (mold) growth. Relative humidity (RH) at the kitchen register has been almost
81% and never less than 74-75%. Fungal growth had to be cleaned regularly and was present in every room.
Process
To control fungal spore amplification, we installed a hydroxyl (“OH”) ion generator inside the air-handling unit (AHU). OH ions chemically react to neutralize mold spores, off-gassing CO2 & water vapor. The next step was to sanitize the extant mold growth and provide a anti-fungal coating to prevent recurring growth. Now that we have addressed the existing fungal growth, moisture control was next on our agenda. We selected an Innovative Dehumidifier Model IW25-1, 25-pint per day unit. This dehumidifier is specifically designed for humidity and mold control in multi-family apartments, having dimensions of 14.5” W x 25.5” H x 9.5” D. It fits snugly into the wall of the mechanical closet housing the AHU and operates at 47 decibels (Db); an AHU generates 60-65 Db. The initial RH at the kitchen register was >80%, after 2 hours it fell to 69%!
Conclusion
One week later…Problem solved? Yes. We performed fungal IAQ (Indoor Air Quality) testing at installation and a week later, with two 600 CFM HEPA scrubbers and a 200 CFM unit operating in the apartment with a second hydroxyl ion unit during that week. Scrubbers, ceiling fans & the HVAC system ran during sampling. This short chart shows massive IAQ improvement, expressed in spores per cubic meter (s/M3):
That’s almost a 92% average reduction of Total Spores & a 95%+ reduction of “Pen/Asp” spores, while eliminating the Stachybotrys chartarum, aka “Black Mold”, in just one week. During the second sampling event, the entire apartment was screened for new mold growth, and none was seen. The tenant had complained that carpeting was always “damp” to the touch; it no longer is. NOTE: Most residents see a reduction in AC usage as a by-product of the Apparent Temperature Equivalent whereby people experience comfort at a higher sensible temperature when humidity is lower.
