Concern: Mount View Middle School: August 27th, 2019 (CXMVMS2019000105)

Location
Room 25
Date of IEQ Report Form
Date of Report
September 25th, 2019
Concern
The classroom is still humid, muggy and has a musty smell. This is quite different than the other classrooms and areas in the building. I often leave at the end of the day with a headache.
IEQ Investigation Process

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)
Findings

Date(s) of Assessments:  Weekly visits during the summer prior to concern, August 30, and September 17, 2019

Weekly proactive visits of the perimeter rooms of the school's two story portion were made during the summer, to observe conditions for relative humidity related mold growth.  The proactive visits stem from past summer humidity issues.

As of September 17, 2019, mold growth was not observed on inspected surfaces within the room.

During the summer, as a preventive measure, outdoor air dampers in the rooms' ventilation unit were closed and the units were operated from 1 -3 p.m. The reason for this schedule is to reduce the amount of humid outdoor air introduced to the space.

The school was under phase 1 (3 phases total) of a systemic ventilation renovation to assist with past relative humidity issues in the two-story portion perimeter rooms.

The air conditioning (new chiller) was installed during the summer and then energized on August 10, 2019.  Prior to this date, relative humidity readings were acceptable (below or low 60%).  On the August 14 visit, this room felt muggy with a relative humidity reading of at least 70% with the room temperature at 75 degrees.

As a result, Building Services placed a data logger to view relative humidity and temperature trends.  Data between August 15 and September 17, 2019, indicated a temperature range of 68-72 degrees (too cool) and bouts (August 31 to September 6 and September 9 to 13) of relative humidity 70% and above. In general, relative humidity should be between 30-65% for comfort.  Based on experience, the Office of Environment is concerned with continuous bouts (24/7 for ~ 10 consecutive days) of 70+% since this can increase the potential for mold growth.

Outdoor air dampers were put back in operation for the start of school for students.

Relative humidity can fluctuate due to weather and the operation of the ventilation system.  The ventilation unit's fan continuously operates during occupied hours thus introduces outdoor air to dilute body odors.  When the room's thermostat is satisfied (i.e. cooling), unconditioned (hot /cool / damp) outdoor air is delivered to the space.  In general, the type of ventilation unit within the room is not most efficient with indirectly removing moisture from the air.  In addition, the original controls are pneumatic (air) and have been experiencing air leaks which may allow the unit to operate 24/7 or not adequately control the chilled water flow through pipes within the unit, thus influencing relative humidity within the room.  This is why the school's ventilation system is under renovation.

Corrective Actions
December 8th, 2002

Building Services is aware of the history of the building's ventilation which contributes to the continued and reported comfort and humidity issues experienced and reported by the school.  The lower air temperatures within a room can contribute to introducing moisture (i.e. reach dew points of certain surfaces) by over cooling the space.  Building Services HVAC Shop is continually addressing reported concerns and re-calibrating controls as necessary.

Closed
No
Tracking Number
CXMVMS2019000105