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: August 17, 23, 24, 26, 31, September 6, 9, 15, 16, 17, October 7 and 18, 2022
On August 17, the Office of Environment responded to the school's August 16 report of wetness and possible mold under plastic chair mats placed within three secretary desk areas located in the front office reception area. Staff discovered when moving mats to adjust cords and cables.
The carpet under the chair mats was wet as determined by a moisture meter. Open areas of carpeting and carpet with items setting on top were found to be dry. Carpet was not bubbled or delaminating within the front office which would indicate moisture issue with or under the concrete slab. No mold growth was observed, at the same time the carpet and back of the plastic mats were discolored. An odor was detected within the “wet” areas of carpeting. Staff pointed out a transition/lip in concrete floor going towards conference room. The transition is thought to have been the result of when an addition was added to the front office. The transition is not believed to have any bearing on the concern.
While on site, front office personnel expressed concern with IEQ due to experiencing general symptoms. As a result, an IEQ assessment was performed. Housekeeping was acceptable. No mold growth was observed on surfaces inspected. Relative humidity (57%), room temperature (73 degrees Fahrenheit (F)), and carbon dioxide (517 parts per million (ppm); used to assess the introduction of outdoor air by the ventilation unit) were within acceptable parameters. The roof top ventilation unit (RTU) serving the front office was visually inspected. The unit's outdoor air dampers were functional and the condition of the coils, condensate pan, and air filters were found to be acceptable. The ventilation system is considered a variable air volume (VAV) in which the RTU conditioned air is supplied to VAV boxes that modulate air volume per thermostat settings. The HVAC Shop was contacted to check the VAV boxes to ensure damper within the boxes serving the front office reception area does not completely close when in operable mode. On August 22, Building Maintenance HVAC Shop evaluated the VAV box and determined to be properly operating.
On August 18, a Board approved restoration company was utilized to clean and dry the carpet within the three desk areas. In addition, the plastic mats were cleaned/disinfected.
On August 23, the Office of Environment checked on conditions and found the carpet to be “wet”. As a result, another Board approved restoration was utilized to clean (disinfected and applied an antimicrobial agent) the carpeting. In addition to carpet blowers, a dehumidifier was utilized to dry the carpet following the cleaning.
On August 24, the carpeting was dry. Drying equipment to remain active.
On August 26, the carpet was dry and drying equipment was turned off and awaiting contractor to pick up. Since school custodial staff and Custodial Services Carpet Crew had not cleaned the carpets or plastic mats as was presumed to be the source (placed mats on carpet before items were dry), the Office of Environment decided to conduct a study for several weeks (while weather is conducive - higher outdoor humidity) to assist with determining a possible explanation for the finding.
The study involved placing some mats back, others not, and some control areas. The first two desks from the entrance had plastic mats placed back on the floor, the third desk had exposed carpet, and a control area (conference room; not “wetted” initially) having the third mat under a file cabinet. In addition, a few other schools with a similar arrangement were checked and all found to be dry under their chair mats.
August 31, a data logger was deployed to record temperature and relative humidity trends. This visit was made after rain events the day and evening prior. The exposed carpet areas (control area, principal desk, desk closest to conference room, and open space) were dry. An isolated area (~1’ diameter) under the chair mats (first two desks from office entrance) were considered “wet” per the moisture meter. The chair mats were removed from those two areas until further notice. Mechanical (plumbing) blueprints (before and after front office addition) were reviewed and compared to further assist with the evaluation.
September 6, rain event the evening prior and morning hours on the day of the visit. Conditions of the carpet were the same as the August 31 visit. However, an infrared /thermal imaging and infrared temperature laser gun were used to identify any thermal or temperature differences to indicate moisture issue. The equipment did not show thermal differences/anomalies to indicate moisture issues. Thus what was initially believed to be wetted carpet may be a result of damaged/soiled carpeting, resulting in a false positive. Moisture probes can be be affected by materials that are electrically conductive, such as salts and/or soils containing naturally occurring metals, resulting in false positive results.
September 7, the Office of Environment reached out to Building Maintenance to investigate the probability of removing sections of the carpet in question at each of the three secretary desks and replacing with carpet squares. Building Maintenance made a visit and determine it was possible. Due to scheduling conflicts the work could not be done until the following week and would be organized by the Building Maintenance Flooring Specialist.
September 9, moisture probe and thermal imaging equipment showed carpet findings as the September 6 visit, no thermal anomalies.
September 15, the sections of carpet were removed and replaced with carpet squares after school hours by a flooring contractor and overseen by Building Maintenance’s Flooring Specialist. No moisture related observations were reported on the back side of the carpet removed or on the exposed concrete slab. Particularly, the carpet glue/mastic was in good condition. The condition of the mastic would be expected to deteriorate should a moisture issue associated with the slab be present.
September 16, the Office of Environment followed-up after the work to get baseline moisture probe readings. All new carpet squares, existing carpet around carpet squares, and control area were considered dry. The data logger was collected and reviewed. No concerning trends with indoor relative humidity were identified.
September 17, the carpet sections probed were dry with temperature differential on carpet or seams of squares.
October 7, the same observations as September 17 were experienced. As a result, and knowing carpet adhesive was cured by now, the plastic mats were placed at desk stations 1 and 3 (when coming into the front office) to continue the study.
October 18, the carpeting was probed and considered dry. This concluded the study.
Conclusion
A definitive cause for the moisture concerns with the carpets under each secretaries desk was not identified. One hypothesis is that the carpet was cleaned using wet methods and the plastic mats were placed back before drying was complete. This allowed the carpet to become “damaged” in a manner to allow moisture from the ambient indoor air to absorb into the "damaged" area.
Building Maintenance to check the operation of VAV boxes within the front office area. No concerns were identifed.
Remove plastic mats when carpets are cleaned in a manner involving moisture. Do not place mats back until several days later to ensure carpet has dried. Vacuum under mats when vacuuming carpets. If a spill occurs within the desk area, remove mats to ensure spill did not get under the mat.
Building Maintenance is coordinating a project to remove and replace the existing carpet from the front office reception area.