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)
Dates of Assessment: August 11, 12, and 13, 2025
On August 11, 2025, the Office of the Environment confirmed mold growth in Room122 and 123. The door frame of the Guidance Office was also impacted.
Heating Ventilation and Air Conditioning Zone RTU-1
Rooms 122 and 123 are located within the Heating Ventilation and Air Conditioning (HVAC) zone RTU-1. Various other spaces were assessed within RTU-1. The additional assessment revealed the following:
- Mold impact was identified within Room 112 and 125.
- Mold growth was identified on various doors frames (leading to main hallway) associated with RTU-1. All of the impacted door frames within RTU-1 adjoin classrooms served by Unit Ventilators (UVs).
- Rooms 122, 123, and 112 within RTU-1 each have a Fan Coil Unit (FCU) within the room which recirculates indoor air (temperature control). The settings on the fan coil unit were set to a maximum cooling setpoint. This may have caused overcooling and contributed to the mold growth. Additionally, it was observed that the FCUs had standing water within the condensate pan, which also has the potential to increase the humidity within the space.
Building Maintenance (HVAC) performed an investigation into RTU-1. Building Maintenance concluded that RTU-1 does not have sufficient cooling capacity when the dewpoint of the outdoor air is above 70 degrees Fahrenheit. This outdoor due point condition was present regionally for an extended period of time during the Summer of 2025.
Because the door frames adjoining the classrooms served by UVs were impacted, the Office of the Environment assessed these classrooms as well (101-110 and 120-121).
Rooms Served by Unit Ventilators
Mold impact was identified within numerous classrooms to include the door frames, furniture, doors, and materials. The classrooms adjoining RTU-1 are served by individual Unit Ventilators (UVs). These types of HVAC systems can have difficulty dehumidifying outdoor air under certain summer weather conditions (low outdoor air temperatures and high humidity/dew point).
The Office of the Environment understands these rooms were utilized for summer school and the unit ventilators were not operated on a reduced summer schedule. A reduced operating schedule of UVs reduces the potential for elevated indoor humidity/mold growth over the Summer.
Several other areas of the school are also served by UVs, particularly the second floor. These areas were assessed and no mold growth was identified.
The cause of the mold growth in classrooms with UVs was likely the increased run time of the UVs during Summer school coupled with a regional outdoor weather pattern (low temperatures and high humidity/dewpoint).
The cause of the mold growth in RTU-1 may be related to one of or any combination of the following:
- FCU temperature set points/overcooling.
- Condensation not properly draining from FCUs and evaporating within the room(s).
- The condition of the nearby spaces with UVs may have diffused into areas within RTU-1.
- RTU-1's cooling capacity may have played a role, however, this is not believed to be the primary cause as this did not occur in 2018 (similar regional weather pattern) and the majority of spaces within RTU-1 were not impacted.
A board-approved restoration contractor cleaned/disinfected impacted surfaces within impacted rooms. The contractor completed the cleaning and disinfecting of the spaces on August 13, 2025.
Custodial Services will be re-cleaning/disinfecting all surfaces within each impacted room during evening cleaning.
Filters in UV's and FCU's were changed after remediation was completed.
The FCU drain pains with standing water were also cleaned/assessed by Building Maintenance.
The Office of the Environment will coordinate with Building Maintenance (HVAC) on developing a HVAC Summer Operation Plan to reduce the occurrence of summer time mold incidents.