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: July 29, August 11, 13, 19, 25, 26, and 31
Rooms B110 and B112
- Mold growth was observed on the supply diffuser vents in Room B110 and B112.
- Both spaces were reported by Building Maintenance to be served by Variable Air Volume (VAV) boxes supplied by AHU-13.
- The VAV boxes were not setup with the capability to reheat, which can cause overcooling and subsequent mold growth during certain weather conditions
- The Office of the Environment placed a data logger within Room B112 (August 11-13). Temperatures did not exceed 70 degrees Fahrenheit (F) during data logging. These temperatures are too low (HCPSS summer set point = 74-78º F) and can cause condensation to form on surfaces. Relative humidity and dew point temperature were also elevated, presumably due to the consistent lower space temperatures.
- The cause of the mold growth observed around the diffusers in rooms B110 and B112 appeared to be overcooling of the space.
- Building Maintenance (HVAC) reported that the supply air set point on the VAV box was slightly elevated (58º F instead of 55º F). Building Maintenance lowered the set point to 55ºF when this was discovered.
Rooms A221, B101, B102, B103, B104, B105, B106, B107, B108, B109, B111, B113, B121 and B123
- Each of these rooms has an adjoining mechanical closet that houses a Fan Coil Unit (FCU) that serves the space. According to Building Maintenance, the FCU provides heating and cooling of the space while a dedicated Outside Air Unit (OAU-2) supplies outside air to Room A221 and other rooms in the same HVAC zone on the second floor. Outside Air Unit (OAU-3) supplies outside air to the B-Wing spaces listed above. Both of the two compressors of OAU-2 were not operational and bringing in unconditioned warm and humid air causing high level of relative humidity and dew point. Similarly, two of the four compressors of OAU-3 were not operational, decreasing dehumidification capacity of the unit.
- The FCU for Room B108 was turned off. Building Maintenance (HVAC) has turned the unit back on, reporting that onsite staff may turn them off again.
- Relative humidity mold growth was observed on the insides of the mechanical room doors in some of the spaces listed above. In general, the insides of the doors may have had less than one square foot to approximately three square feet of mold growth.
- Relative humidity mold growth was observed on the inside and the outside of the door in room B106. This door was significantly impacted with approximately 40-50% coverage on either side.
- Rooms of similar construction are located in other areas and include the first and second floor A-Wing, as well as the first and second floor B-Wing. These rooms were also assessed and no additional mold growth was identified.
- In general, the insides of the doors of each of the mechanical FCU closets were visibly dusty, even if no mold growth was observed. A staff member reported that the insides of the doors are not part of the school's current cleaning plan.
- It should be noted, that the FCU closets serve as a return air plenum for the spaces, meaning the closets are under negative pressure. For the rooms that were impacted on the inside of the doors, a significant exposure pathway would not exist unless the individual was in the closet or had the door open. This statement does not apply to the two rooms with mold growth observed on the outside of the doors.
- The root cause of the mold growth was likely primarily related to the lack of dehumidification caused by the inoperable compressors. Additionally, the lack of cleaning of the insides of the provided dust/organic matter may have exacerbated the situation.
- Finally, Building Maintenance (HVAC) is operating HVAC units throughout the system with the outside air dampers open during summer as a COVID-19 mitigation measure. Operating this equipment with the dampers open during summer operations is not standard practice for HCPSS, it may also have contributed to elevated humidity and subsequent mold growth.
Custodial Services cleaned the impacted doors.
The Office of the Environment recommends the insides of the Fan Coil Unit doors be cleaned at least annually (such as during summer cleaning). Cleaning can be accomplished by spraying a microfiber cloth with Custodial's standard cleaning compound and wiping. A High Efficiency Particulate Air (HEPA) filtered vacuum could be used prior to wiping to remove gross dust if needed.
For Rooms B110 and B112 - Reheat has been added to the VAV boxes associated with AHU-13 to prevent severe over-cooling of the spaces.
For Rooms A121, B101, B102, B103, B104, B105, B106, B107, B108, B109, B111, B121, and B123
The Office of the Environment recommended that both inoperable compressors associated with OAU-3 be repaired. Building Maintenance (HVAC) has reported that a contractor completed a portion of this work, however only three of the four compressors are operational at this time. Building Maintenance reported that three compressors will provide sufficient cooling capacity for all but the most extreme summertime outdoor conditions. Additionally, Building Maintenance reported that reheat has been provided to OAU-3 which should prevent overcooling of the rooms served by this unit in the future.
The Office of the Environment recommended the non-operational compressors associated with OAU-2 be repaired. Building Maintenance (HVAC) reported this work has been completed.
Administration is to remind staff not to shut-off HVAC equipment. The Office of the Environment requested Building Maintenance explore a way to protect FCU switches from being tampered with.