Stuffy+Classroom

=**//Abstract://**= ===As designers of inhabited space, architects must be aware of all forces at work inside a structure. The topic of interest for this case study group will be the effect of CO2 build up in multiple classroom locations around the campus at Ball State University. The physical effects of CO2 buildup are assumed to hinder a student's ability to be comfortable and thus, their ability to focus on classwork. The unit of measurement that is cohesive across the profession in observing CO2 levels is the ppm, or, parts per million. This unit is measured by a CO2 meter. This device will be placed in four locations so as to rule out any influences from the unique physical forms of classrooms and the age of the structure.===

===Additionally, qualitative data will be collected via a survey given out to 10% of the population per classroom. This data will give a perspective to the case study from that of the student and their own personal perception of the indoor air quality.===

=**//Introduction://**= ===In a typical year, a college student will spend at least 840 hours in a classroom, or over 140 days by the end of the four year degree. While being restrained to a room of roughly thirty-five breathing individuals, a student will experience the effects of carbon dioxide levels trapped in a confined space. So what is the common level of comfort when it comes to the saturation of this unwanted element in a space? How does it affect the way that each student learns? Are there more efficient alternatives that filter out the unwanted air, and what are they? Should limits be imposed on its quantity and alarms be put in place? Should architects consider this problem an additional benchmark to the overall proposal similar to passive lighting systems or cross-ventilation? These questions will be answered by this study.===

=**//Thesis://**=

High amounts of CO2 levels have a negative effect on a student’s ability and should be considered by designers that are concerned with the establishment of acceptable indoor air quality.
=**//Methodology////://**= ===For this experiment, the group usedd instruments including a CO2 meter, accompanied by a HOBO, and a survey (see Figure 1). With these instruments, the group took records of the level of CO2 that existed or was created from the beginning of the testing period until the end of the class. The survey collected data on how each user feel within the space comfort-wise. The survey was administered to the students during the class period so they had reference to the space at the time of fulfilling the instructions rather than through email or a survey monkey link. After taking the records, each of the group members observed how the users reacted when there were certain levels of CO2.=== ===Deployment called for the device to be set on a desk, preferably in the middle of the classroom. The group member could hook a HOBO device to the meter to record the level every five minutes or could write down the number that appears on the screen on a paper every five minutes. The screen showed one number depicting the level of CO2 in ppm (parts per million).===



Figure 1: CO2 meter and accompanying HOBO device that was used in the field to record quantitative data.

Figure 2: Graphic depiction of the overall amounts of Carbon Dioxide levels in each space over a fifty-five minute period of time.

===According to the ARCH 373 course offered at Ball State University, it is encouraged to keep in mind as a designer that the CO2 levels in occupied indoor spaces should never exceed 1000 ppm. According to ASHRAE standard 62 //Ventilation for Acceptable Indoor Air Quality//, a more precise level is bench marked at 700 ppm above outdoor levels to provide for the comfort of patrons and deter from the containment of odor or the feeling of stuffiness.=== ===The spacial features of these spaces were crucial in ruling out all assumptions of the CO2 levels. Each member of the group made physical observations of the space and recorded them in writing as a diagram in order to have comparable information. The hopes was that these features would explain any anomalies in the CO2 levels and begin a dialogue between the four spaces.===

The following four figures below gives a visual of the spaces.
Figure 3: Diagram of David Letterman Building Classroom with HVAC system highlighted in purple.

===Built in 2007 the LEED Silver building was dedicated by David Letterman himself. Taking a look at one of its modest small classrooms of roughly 8,360 cubic feet or 836 square feet, it seats comfortably twenty to twenty-five students with room to spare for circulation. As a LEED Silver standard one would presume it to have excellent indoor air quality in comparison to an older building built several decades prior where indoor air quality wasn’t even considered. Even as a small space in comparison to say the Cooper classroom, the CO2 levels seem high. The room is roughly twenty-two feet in width and thirty-eight feet long with a ten foot ceiling. With four standard drop-down square air diffusers and no supplemental heating such as radiators, it seems the air conditioning system is an all-air, possibly VAV system to handle varying system heating and cooling loads during the day. The first day of data collection showed a high CO2 rise from 1,227.7 ppm and jumped up around two hundred ppm more during the course of an hour. This seems to be a fairly standard rise across all classrooms we recorded data on, but the interesting factor is that is starts at 1,200 ppm indicating something is either wrong with the system or perhaps it wasn’t turned on that day, or was working at a lower level to conserve energy. The other day’s results were promising, keeping at a standard level of 850-950 ppm, a level that isn’t alarming or dangerous. This broad spectrum of results is peculiar and need to be evaluated more fully to retain their validity. See Figure 3 above.===



Figure 4: Diagram of classroom in the Robert Bell Building. The diagram highlights the return and supply air along with a radiator unit.

===Built in 1984 the building is one of the older buildings on campus. Compared to the newer buildings it would be assumed that the systems of indoor air quality would not be as effective as that of a newer system. Looking at a small classroom of around 300 square feet, I will conduct research to see if this is true. Attending class in the space it seems to be comfortable and the air seems to be at an average quality, but nothing to praise. The system being used seems to be an all-air HVAC system with a supplemental radiator for heating. The room also has a return diffuser to take the air out of the room. From the data received in the classroom from a CO2 meter, the data shows that the level is higher than normal buildings on campus. Based on the levels from buildings built around the same time or earlier the building is not exhausting the CO2 as well as the others. With the fact that this space is smaller than the other spaces that the group has been studying and has higher levels of CO2, this could have affected the results in the experiment. Since the space is small the system should be working better than that of a large space, and this shows the problem within the space. See Figure 4 located above.===

Figure 5: Diagram of the Museum of Art Lecture Hall featuring a perimeter HVAC system.

===Built in 1935 this building serves as a supposedly “low indoor air quality” structure that, upon assumption, would not have the proper ventilation to control CO2 levels properly compared to a more modern structure as, say, the David Letterman Building built in 2006.Compared to preliminary data from both structures, surprisingly it appears that CO2 levels are at the same level or lower than that of a David Letterman Building classroom. This is a surprising result, but could have something to do with the space’s relative dimensions. While the classroom in the David Letterman building was roughly 20 square feet of inhabitable space, the Museum of Art lecture hall is much larger at roughly 400 square feet. Since the air in the museum lecture hall has much more height to expand above the students, almost ten feet more than in the confined classroom, it would be evident that this space has a diluted CO2 content in the air. As for the population of students who dwell in the space during this experiment, it is a ratio of eighteen to eighty-eight between the David Letterman Building and the Museum of Art Lecture Hall, respectively. See Figure 5 above.===



Figure 6: Diagram of the Cooper Building classroom depicting HVAC air ducts.

===Cooper classroom 257 has no visible air supply ducts; however there are two diffusers that penetrate through the suspended ceiling. Along with the two diffusers, there are two return air grills present that transports the “used” air out of the room back to the HVAC system or to an expel exit to the exterior of the structure. This implementation could be the reason that the CO2 level never exceeded 800 ppm. In this study, the Cooper building is considered as an older structure; however it appears that the ventilation system is still in very good working condition. An additional explanation to the low CO2 level could be that there were only thirteen occupants in the space, compared to larger classes of twenty to fifty. It could be assumed that if the classroom was occupied by an additional number, such as thirty people, then perhaps the co2 level would rise at a higher rate and the max/min would be a larger difference. An additional considered element of this space is that there are operable windows that would assist in ventilation. On days of measurement, the windows were closed, but it is a good requirement to have operable windows if an architect intends to follow up on good indoor air quality intent. See Figure 6 above.===

=//**Qualitative Survey**//= ===What was next to be gathered was qualitative data carried out through a survey to decipher the effect of CO2 on the student's ability to focus in class. A written survey was distributed to all four classroom during the same hour that the CO2 meter was implemented. The survey consisted of five statements shown below to which the student was asked to answer on a five point scale ranging from saying that they agree with the statement to stating they do not agree with the statement. This method of surveying a population is more effective than that of yes/no questions because it gives a wider range of qualitative information. Giving a person the option of being "neutral" or "indifferent" provides a new perspective.===

The survey can be seen below:
[start]

Please provide us with feedback about how you feel in this classroom.

Have you been diagnosed with asthma or suffer from indoor allergies?

Agree 1 2 3 4 5 Disagree


 * I seldom feel sleepy during classes in this room.**

1 2 3 4 5


 * This classroom tends to feel “stuffy” to me.**

1 2 3 4 5


 * Overall, the air quality in this room is comfortable.**

1 2 3 4 5


 * I have a difficult time breathing specifically in this specific classroom.**

1 2 3 4 5


 * There are noticeable odors in this room.**

1 2 3 4 5

[end]

Cooper Building
===The comparison between the survey and the actually collected measurements had a little bit of a controversy. The CO2 level in the space was between 500 ppm and 800 ppm, and one would think that it should not affect the students, but that was not the case. To look into detail of the affects, the group divided categories that a person would feel within a space that contained CO2. For the sleepiness category, 60% of the class was not affected by the level of CO2, and 40% of the students was affected by the level of CO2. The reason for the 40% of the students to feel sleepy was that 30% of the students had allergy, and the 10% was unknown (the assumption was the 10% also had allergy or did not sleep enough the night before). For the stuffiness category, 50% of the students felt okay, but other 50% of the students did not feel comfortable in the classroom. The reasoning for that may be the space was small, and the windows were not open throughout the class; however, there were two return air-duct that cycled the air, so maybe the person that felt stuffy were sitting underneath the supply air-duct. For the IAQ (Indoor Air Quality) category, 70% of the students felt comfortable within the space, and 30% of the students did not feel comfortable. The reason for the 30% of the students that felt uncomfortable was that those 30% of the students had allergy. For the breathing category, 70% of the students did not have a hard time breathing in the space, but 30% of those students had hard time breathing. Again, those 30% of the students had allergy. For the odor category, 50% of the students hardly smelled anything weird, and other 50% of the students smelled something within the space. The reason for that was the return air-duct may be cycling the air at a slower speed, or a person within the space had a strong odor, and the 50% of the students that smelled something was sitting near the person that had the odor.===

David Letterman Building
===After distributing the survey to every member of the class, collecting the papers, assembling the data, and upon analyzing the results interesting conclusions were drawn. The class was asked how tired they felt during this class period in relation to the physical room. Some agreed that they were tired during the class, but the majority of the results said they were not tired or seldom tired, hinting towards the air conditioning system working correctly. Similarly, the bulk of people agreed the classroom did not feel stuffy, meaning the system was working to some extent. There was an interesting spread when asked how they felt about the indoor air quality of the space. Most people agreed that the indoor air quality was acceptable, but surprisingly twenty percent of the class had a problem with it, raising the question of whether or not there was a problem with the system. Very few individuals had trouble with difficulty of breathing with seventy percent agreeing they had no trouble breathing. As an HVAC system fails to circulate and filter air effectively, a common indicator of a faulty system is noticeable odor. In which case, the majority of individuals agreed there was no or very little odor in the classroom. Although the relative carbon dioxide levels were higher in relation to the other classrooms, the overall majority of students’ responses concluded that they did not have a problem with the HVAC system. Combining the results of each survey question and averaging the results of negative responses, twenty percent of the results against the classroom were negative leaving eighty percent of the results to be neutral or positive.===

Robert Bell Building
===After collecting the data with the CO2 meter I asked my fellow students to take a survey about their reactions in the space. The survey was designed to focus on their feelings and whether or not the noticed any unusual difficulty breathing or smelly odors. When asked if the students felt sleepy they responded with an average result. This most likely means that the space isn’t affecting their consciousness during the class any more than a normal length of time would cause. When asked about the stuffiness of the space students respond with a slight stuffiness level. Being a small room this was a likely response. When it came to indoor air quality in the space they all were somewhat pleased with the environment. With difficulty breathing and smelly odors no one had any problems in these categories. These must mean that the return air is working effectively to take the smells out of the room. When it came to the data though the CO2 levels got higher as the class went on. This must mean that the return air isn’t taking enough CO2 out of the room, but no one is affected by this fact. These findings do not seem to go well with our hypothesis. It could be that the class itself is affecting the students in a way that CO2 levels don’t have as much of an affect on the students.===

Museum of Art
=== In contrast to the thesis statement, students that attended class in the Museum of Art lecture hall responded by saying they rarely felt sleepy during class. As for feeling stuffy, the students responded with an average number leaning towards denying they felt stuffy. Not one student documented that the indoor air quality was uncomfortable. Instead there was an equal amount of students that said the indoor air quality was either above average, average, or below average. A few students, two out of forty-one to be exact, reported having difficulty breathing. These students did not have asthma or allergies. In contrast, eight students strongly said they did not have difficulty breathing. Only one student reported the space as having an odor while nine reported having no perception of an odor.A summary of this data, easily proven by a glance at the survey graphics, uncovers truths about the student population’s perception of this space that could not otherwise be observed through quantitative gadgets. Although the ppm for this space was rather high, the max and min being 992 and 845 respectively, it did not seem to affect the students in a troublesome way. As concluded from the surveys, the CO2 levels did not affect the students’ perception of odor, sleepiness, indoor air quality, stuffiness, or ability to breathe. Surprisingly, more students answered with the opposite perception, the majority of the population surveyed saying that they strongly disagree. ===

===Below are the survey results. For convenience,the labels were changed from digits to word values to make the axis more understandable. For example "1" is the same as "way above average" and "5" is the same as "way below average".===

Figure 7: Cumulative results of survey. See color key at top left.
=//Conclusion://=

===The different levels of CO2 should have different effects on how students feel. Higher CO2 levels would negatively affect a student's ability to study. Looking at the survey and data, the group found the hypothesis to be debatable based on the results. Qualitative surveys of the students’ awareness were not affected by low or high CO2 levels, but were in constant indifference across four separate buildings. The age of the building and its subsequent HVAC technologies did not affect its indoor air quality performance. In fact, the newest LEED Silver certified David Letterman Building had the worst levels of CO2, rising above 1000 ppm. This could be caused by the building being new and tightly sealed compared to the older buildings that have leaks due to wear and tear. As stated earlier, ASHRAE Standard 62 cites that an adequate CO2 level would be 700 ppm above the outdoor CO2 level. At first glance, one would assume that none of these spaces passed this test and the ppm was above 700 at each of the locations, however, further data would be needed to confirm this assumption since the exterior CO2 level was not documented at the time of testing on the interior. The results of the student surveys beg to be explored further, perhaps down the alley of investigating more precise techniques of questioning a population about sciences they are not familiar with. Perhaps the students do not know they feel stuffy unless asked. Even in the David Letterman Building with high CO2 levels the students did not seem affected. Perhaps students were adjusting to the environment making the effect go unnoticed. To further expand on the above statement, the threshold level of 1000 ppm should be adjusted in the field of indoor air quality to no higher than 700 ppm plus outdoor ppm level according to ASHRAE Standard 62. After conducting this case study and drawing conclusions from the data, the level of CO2 seemed to not affect students comfort within the space.===