Identify deficiencies that may impact IEQ and/or sources of odor concerns. Typically includes the following depending on the nature of concern, but not limited to:
- interview/questionnaire of concern individual(s)
- inspection above drop ceiling (condition of roof deck, pipe insulation, return air plenum)
- inspection of ventilation system (operation of variable air volume box and outdoor air dampers, check controls, measurements of carbon dioxide, temperature and relative humidity, sources near outdoor air intake, measure return and supply air volume, cleanliness of coils, liner and condensate pan)
- inspection of exterior
- inspection below drop ceiling (housekeeping, sink and floor drain traps, signs of past and present moisture concern via visual and/or moisture meter, mold growth, ensure connection of current and capping of abandoned sanitary vents, odorizers, excessive plants and fabric items, identify potential pathways, and measure volatile organic compounds, carbon monoxide, and lighting)
Date(s) of Assessment: April 2, 2025
The supply diffusers were observed and appeared to be excessively dirty on the visible side and on the backsides, once removed. Suspect mold is likely within the matrix of dust/grime on the metal supply diffusers.
Rust was also observed on select supply diffusers.
The inside of the ductwork was observed. The inside of the duct work is internally lined with fiberglass insulation. General dust was observed adhered to the duct lining, however this is not unusual as the fiberglass insulation tends to collect/trap dust.
No visible mold growth was observed and no moldy/musty odors were identifed within the ductwork.
The thermostat was set incorrectly with the fan in the "on" position. The thermostat is to be set in the "auto" position. If the fan had been set in the "on" position during the Summer/Fall seasons, that would likely have caused the conditions observed on the supply diffusers.
The thermostat lock box was not secured to the wall (able to be removed from wall anchors easily).
Building Maintenance (HVAC) inspects the portables thermostat settings during the the Summer to ensure the fan is set properly. It is unclear, if this fan was set incorrectly due to error or if it was tampered with.
Due to the thermostat setting potentially causing elevated humidity in the space during the summer/fall, various items within the portable were assessed for visible mold growth. No visible mold growth was observed on surfaces.
The cause of the excessive dirt/grime and potential mold growth on the supply diffusers was likely the incorrect thermostat setting and likely occurred over the summer/fall. The metal supply diffusers are most impacted because 1) the turns of the ductwork at the diffusers, and the diffusers themselves slow the air being delivered. The slowing down of the air, allows for deposition of particulate onto the diffusers. 2) The thermal conductivity of metal can allow for condensation on the diffusers, which increases the potential for deposition of particulate and subsequent microbial growth.
A board-approved duct cleaner cleaned and encapsulated the fiberglass lined ductwork.
Building Maintenance changed the thermostat to the correct setting, replaced the supply diffusers and re-secured the lock box to the wall. Building Maintenance will re-assess the HVAC units operation when outdoor temperatures are higher.