Jul 16, 2018

All the Things you Cannot See

by Shona O’Dea, Well AP, LEED AP BD+C, DLR Group Building Performance Analyst

Within the physical school environment, there is an entire world of things we cannot see that influences the human experience of a space and a student’s ability to perform. Pulling back the curtain on those elements equips everyone to better understand – and embrace – a more holistic approach to district planning.

A recent report from the World Green Building Council concludes that indoor environmental quality (IEQ) can have a profound impact on students’ cognitive function and performance, but optimizing the environmental quality of schools involves much more than air sensors. A holistic master planning process enables clients to think beyond a bare-bones conditions assessment approach by expanding into a comprehensive plan for optimal building performance, and one school district in Illinois agrees.

Barrington School District 220 in Barrington, Illinois, partnered with DLR Group to lead a district-wide facilities master plan to assess and improve learning environments for its students and staff. DLR Group’s team began the process by documenting 12 schools and an administrative building within the district to qualify and quantify holistic building performance. We translated our findings into a report card that measured energy performance, thermal comfort, indoor air quality, visual comfort, and acoustical satisfaction, a deliverable that is guiding future decisions related to facilities and capital investments throughout the district.

Baseline for Measurement

DLR Group used a two-pronged approach to gather qualitative and quantitative information related to IEQ at each building. To gather qualitative data, DLR Group issued a district-wide IEQ satisfaction survey to all employees (including teachers, administration, support, and maintenance), and collected 566 responses. These responses were categorized into four key comfort factors: acoustic, air, thermal, and visual to give the team a holistic understanding of the district’s capital assets.

For our quantitative efforts, the team placed IEQ equipment in representative classrooms from each building, allowing us to observe “point-in-time” spot measurements via monitors tracking temperature, relative humidity, CO2, PM2.5, and TVOC over a data collection period of 72 hours per room. Additional qualitative observations were recorded in workbooks, including:
  • Do walls reach all the way up to the roof deck?
  • What is the fraction of windows on the external walls?
  • Are there any window dressings?
  • Is the flooring material hard surface or soft surface?

DLR Group also engaged teachers and students by utilizing on-site data logging equipment throughout the process to create a personalized learning opportunity for Barrington students. We partnered with students at each facility to move data loggers between focus classrooms, following a defined schedule. Spot measurements also recorded light levels, VOCs, and background decibel levels in each focus classroom.

Once the survey, workbooks, spot measurements, and logging were complete, DLR Group compiled all data into a master grading tool or report card, along with the basic site measurements and resource consumption results. The grading tool algorithms, written for industry standard requirements, generated IEQ grades for acoustical satisfaction, indoor air quality, thermal comfort, and visual comfort.

Key Findings of the Four Core Components


The IEQ survey results identified a number of factors impacting acoustics, including fans, air conditioning equipment, and furniture. During our classroom observations at the high school, we noted teachers were limiting movement to avoid disruption in adjacent spaces. Students also indicated that teachers were not conducting classes as they desired due to concern that moving furniture would disrupt nearby classes. Further testing revealed that furniture was extremely heavy, and moving it caused the noise criteria inside that classroom and adjacent classrooms to almost triple. From these results, the district was able to demonstrate a need for new furniture that facilitates flexible teaching and learning spaces in the high school.

Air Quality

Carbon dioxide concentration often acts as a proxy for ventilation adequacy. The concentration of carbon dioxide in outside air is approximately 400 PPM, and industry standard internal thresholds recommend a maximum of 1200 PPM. Beyond these levels, the brain begins to go into sleep mode, which can have a profound impact on cognitive function.

The necessary mechanical systems were in place to ventilate classrooms adequately, and the air quality in this district received better-than-average results. Most occupants did not record strong satisfaction or dissatisfaction with their air quality, however stuffiness was the most popular complaint, especially in summer months. All buildings tested for volatile organic compounds were at negligible levels throughout. One building received an initially high reading but, on further analysis, we determined the readings were conducted during an art fair where the art supplies produced VOCs from off-gassing.

Our assessment uncovered three buildings at approximately 3000 PPM, which exceeds ASHRAE 62.1 Ventilation for Acceptable Indoor Air Quality Standards and specifies 800 PPM plus ambient. The district immediately instituted a no-cost solution by revising damper positions to ensure a CO2 level of no more than 1200 PPM at all buildings.


According to the report by the World Green Building Council, 27 percent of U.S. schools have inadequate lighting. Light levels at Barrington facilities were determined satisfactory, however some spaces generated higher light levels than required due to replacement of fluorescents with efficient LED bulbs.
Of the 80 percent of respondents who have access to daylight, 80 percent are satisfied with their visual environment. Areas with too much light are scheduled for de-lamping, which will involve removing some of the LED bulbs from light fixtures to return light levels to the illumination necessary for the task conducted in the space. This solution also will result in energy savings for Barrington.


ASHRAE Standard 55 Thermal Environmental Conditions for Human Occupancy recommends operative temperatures range between 60- 80°F depending on factors such as occupants’ activity and clothing levels. Barrington levels fell within industry standards, with an average setting at 68°F, however surveys results showed on average, 65 percent of occupants were dissatisfied with their thermal environments, with more complaints in winter months due to drafts and uneven temperatures.

The high school recorded a large range of variation in temperatures, initially attributed to a number of additions to this building, and ranging ages of HVAC systems. On further analysis, the HVAC systems were able to meet an optimal set point, however that occurred at the end of the school day as students were heading home for the evening. The district simply adjusted HVAC systems to warm up earlier in the morning to improve comfort level at the high school.

In other schools with a high number of thermal comfort complaints, temperature readings hit the recommended set points. However, numerous elements also affect thermal comfort, including humidity, air speed, and mean radiant temperature of surfaces. Thermal imaging identified areas of missing or damaged insulation causing temperature asymmetry; cold spots where moisture may have penetrated a wall; thermal bridging issues at doorframes; or insufficient seals causing air drafts. Long-term solutions for temperature asymmetry are being incorporated into the District’s future capital planning.

Towards Transparency

This comprehensive process helped Barrington officials make data-driven decisions on how to best use its maintenance budgets, and plan for future capital investments. Ultimately, while data, analysis, and recommendations play an important role in any holistic master plan, the greater value may be found in the deeper conversations that occur between agency and individual users. This level of transparency and communication contributes to a positive relationship between a school district and the local community it serves, and ultimately improves the educational experience for all learners of all ages.

About the Author:

Shona’s focus on efficiency and indoor environmental quality is an important component of DLR Group’s Performance Design team, supporting the firm's pursuit of sustainable design and operation. Born and raised in Ireland, Shona earned an honors degree in Building Services Engineering from the Dublin Institute of Technology, Ireland's leading sustainable building engineering program, and moved to the Midwest as part of the Atlantis dual master’s program in Sustainability, Technology and Innovation at Purdue University. She currently serves as Young Engineers in ASHRAE Region VI Coordinator, President of the Chicago Chapter of IBPSA.

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