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 of Assessment: September 20, 2022
Room 211
The temperature (72.8 degrees Fahrenheit) and relative humidity (54.0%) were acceptable. Carbon dioxide was measured to be 1,441 parts per million (ppm) with the class fully occupied.
The room is finished with tile floor, block wall (concrete masonry units), and a drop ceiling. The room is served by a dedicated outside air handling unit (AHU) that delivers outside air for dilution and a fan coil unit is located in the back of the classroom (temperature control).
The ceiling mounted diffusers associated with the dedicated outside AHU were assessed. Excessive dust/debris was not observed to be associated with the supply diffusers.
Minor dust and a few larger black particles (larger than dust) were observed on the top of the fan coil unit.
The fan coil unit was opened for assessment:
- Minor dust was observed within the unit.
- No visible emissions were observed from the unit during operation.
- The filter was in good condition and was dated June 2022 (recently replaced).
- The fiberglass sound liner was in good condition and did not appear to be significantly deteriorated.
- The foam stripping around the fan coil unit's door was brittle and appeared to be deteriorating.
The black particles observed on the top of the unit appeared "coarse" and closely resembled the brittle foam stripping observed on the FCU's door (color and texture).
No malodors or visible mold growth was identified the space.
Areas above the drop ceiling were assessed. No concerns were identified above the drop ceiling.
The room was screened with a thermal imaging camera. No thermal anomalies indicative of moisture intrusion were identified.
Room 307
The temperature (77.2 degrees Fahrenheit), relative humidity (48.6%), and carbon dioxide (782 ppm) were acceptable.
The room is finished with tile floor, block wall (concrete masonry units), and a drop ceiling. The room is served by a dedicated outside air handling unit (AHU) that delivers outside air for dilution and a fan coil unit is located opposite the entry door (temperature control).
The ceiling mounted diffusers associated with the dedicated outside AHU were assessed. Excessive dust/debris was not observed to be associated with the supply diffusers.
Minor dust and a few larger black particles (larger than dust) were observed on the top of the fan coil unit. Additional black particles were observed on the rolling teacher desk (in the sink) next to the fan coil unit.
The fan coil unit was opened for assessment:
- Minor dust was observed within the unit.
- No visible emissions were observed from the unit during operation.
- The filter was in good condition and was dated June 2022 (recently replaced).
- The fiberglass sound liner was in good condition and did not appear to be significantly deteriorated.
- The foam stripping around the fan coil unit's door was brittle.
The black particles observed on the top of the unit appeared "coarse" and closely resembled the brittle foam stripping observed on the FCU's door.
No malodors or visible mold growth was identified the space.
Areas above the drop ceiling were assessed. No concerns were identified above the drop ceiling.
The room was screened with a thermal imaging camera. No thermal anomalies indicative of moisture intrusion were identified.
A non-HCPSS issued shelf (white) was observed in the classroom. Dust was observed on the furniture.
Outside Air Handling Unit - 1 (OAU-1)
- OAU-1 delivers outside air to both spaces (general dilution ventilation).
- The outside air dampers were open.
- The filters were in place with no bypass and only mild loading of particulate.
- The coils and drain pan were in good condition.
Particulate Sampling
Particulate matter is a mixture of particles and liquid droplets that get into the air. The data collection does not distinguish between types of particles in the air which can include pollen, skin cells, soil, human/animal hairs, etc. Particles designated as "respriable" are less than 10 micrometers (µm) in diameter and typically fall into two categories, coarse particles are those less than 10 µm (PM10) and fine particles are less than 2.5 µm (PM2.5). In general, particulate matter indoors should be similar to the outdoors, however there is significant variability due to occupant movement, building materials, cleaning practices, etc.
Particulate matter data was collected with a TSI Aero Trak Particle Counter (Model #9306-V2). Note that the particle counter is not capable of collecting PM2.5 data. Due to this limitation, PM3.0 data is used, which would provide an overestimate of PM2.5.
Location PM3.0 (µg/m3) PM10 (µ/gm3)
Outside 8 22
211 (at vent) 2 16
211 (front of class) 12 34
307 (at vent) 4 9
307 (front of class) 4 18
Although the samples collected are not representative of exposure throughout the day, they could be used as an indicator to determine if an unusual amount of particulate was being exhausted from the fan coil units. In general, elevated particulate at either size range was less than that of outdoor air at the unit and in classroom 307. Particulate was slightly elevated compared to outside in Room 211, however this is likely due to students recently leaving the classroom (disturbing dust on clothes, floor, etc.). This variation is expected. Particulate was less than outside when measured at the FCU supply for both PM3.0 and PM10. This suggests that the fan coil unit is not exhausting air with an unusual amount of particulate.
For comparison purposes, some guidelines (World Health Organization) suggest target indoor concentrations of PM2.5 and PM 10 of 12 micrograms µg/cubic meter (m3) and 45 µg/m3 (averaged over a 24-hour period). None of the samples collected exceeded these target concentrations. Indoor particulate is not regulated in the United States by the Environmental Protection Agency (EPA).
Conclusion
The black particulate seen around the fan coil units appears to be a combination of dust and foam weather stripping. Due to the air movement through the unit, the foam likely dehydrates and becomes more susceptible to erosion. Because no visible emissions were observed from the units, it is likely that this material is emitted when the unit turns on in the morning (turbulent air flow). At this time, the Office of the Environment understands the units turn on approximately two hours prior to school start. The particulate sampling did not suggest abnormal particle counts in the respirable range when compared to the outside samples. Based on this, the visible pieces of material observed around the units are are too large to inhale and represent a housekeeping concern.
Building Maintenance is to perform a general cleaning of the units to include the coils, interior of the fans, and the outside. The Office of the Environment has recommended identifying an alternative material such as a rubber (less chance of degradation) that can be used to seal the door. It is also recommended that Building Maintenance consider that the remaining fan coil units in the school be assessed and incorporated into this process.
If this condition occurs in other spaces, please contact the HVAC department. The same process should be followed: clean unit, assess sound liner, replace weather stripping and/or sound liner as needed.
The Office of the Environment does not recommend the use of non-issued furniture (shelf in 307). It is recommended that the shelf be removed. If the shelf is to remain Administration is to ensure the staff member that brought it in submits (to Administration) and adheres to a cleaning plan. Custodial Services is not responsible for dusting non-issued furniture and excess dust represents an allergen for sensitive individuals.
Custodial Services can clean the black material as needed until the units are disassembled and the weather stripping is replaced.
Building Maintenance (HVAC) will place a data logger in Room 211 to determine if the slightly elevated CO2 reading was an anomaly or if further corrective action needs to be considered.