Analysis III Mold & Moisture Research

Transcription

1 Analysis III Mold & Moisture Research

2 Analysis III Mold & Moisture Research Overview: The basis for this analysis was my initial interest in mold as an issue that affects the construction industry. This led to the topic of moisture detection, moisture sensors, and how they can be used during construction to aid moisture control. I placed five sensors in the Smeal College of Business Building, located in the Lot 8 development, and they collected relative humidity and temperature data for a span of two weeks. The data was downloaded, and I was able to draw a conclusion from the charts I produced. Essentially, these sensors are an excellent solution for moisture detection on site, they are very accurate, inexpensive, small, easy to install, and can log a large amount of data. I highly recommend the use of the sensors I used to anyone wanting to monitor moisture levels in their building to keep an eye out for conditions which mold could grow. Background: The issue of mold in the construction industry is well known. Its not a secret that mold can cause health problems and wreaks havoc on indoor air quality, as well as cause material damage which can be extremely costly to replace or repair. With that in mind, my research topic had to be carefully chosen, as to not restate any obvious or easily accessible information. There is a plethora of information regarding the types of mold, conditions it grows in, and guides for remediation once the mold is found. Where I felt the industry could benefit the most from any more research in this area is in detection. Not to say the detection of mold, but rather the detection of moisture, which is the cause of mold. The relative humidity in a building must remain below % to avoid mold spore growth. This moisture doesn t necessarily have to come from the source that is most commonly thought of, rain and other forms of precipitation. Yes, these are factors and a building must be sealed to prevent moisture penetration from these exterior sources, but there is another time which is crucial for maintaining low moisture levels. This is during construction. After a building is dried-in, the

3 temperature inside is maintained either through temporary heating or by use of the buildings own heat source. The building is sealed for the most part, and materials which could be damaged by moisture are now able to be brought in for storing and installation. There are still activities that occur during this phase that increase moisture levels. These include concrete finishing, installing a terrazzo floor, mudding drywall, etc. Many activities occur that increase moisture levels within a sealed building. To ensure that performing these activities does not increase the humidity in the building to above %, moisture levels must be recorded. It is very important to know such information as the relative humidity within the building, as well as the dew point. If the moisture levels are nearing the dew point, and a task is going to be done which adds moisture, the % RH mark could easily be surpassed. So the question is raised, how should the readings be taken? I have found an example being used on the Smeal College of Business project here at Penn State. To determine the moisture levels and temperature within the building, an engineer has to take a handheld unit and walk to particular spaces that the readings are to be taken, and log the information by hand. These readings were being taken once a week in the business building. Not only were they being taken fairly far between, but it would take the time of a worker to walk throughout the building, take the measurements, write them all down, and later add them to a spreadsheet so they were compiled in one place. A fluctuation in the humidity level may have occurred on a day that these measurements were not taken. This could have been a time when the moisture levels were above that % and it would have gone undetected. Basically, when taking measurements for moisture levels in a building, they need to be taken often, and in many places. This is exactly where my research comes in. Proposed Solution: I focused on the use of moisture sensors to detect and log relative humidity and temperature levels of the surrounding space (see Figure 11). The sensors, made 31

4 by Onset Computer Corporation, are compact, easy to install, very accurate, and inexpensive (Please refer to appendix for full specification sheet). I wanted to learn how these sensors worked first hand, and I was able to have five of them ordered to use for my research Figure 11: Moisture Sensor To get the most information from using the sensors, I would have to use them as they would be used in the field, most importantly, during construction. I spoke with the project manager and an engineer with Gilbane who were working on the Smeal College of Business about testing my sensors in their building. It had recently been sealed, so they were maintaining the interior temperature through the use of propane heaters as well as the air handling units of the building. As I had mentioned in the background section, they had been using the handheld unit to take readings within the building. I proposed to place my five sensors throughout the building in areas that would hopefully show correlations between work being done and the moisture levels read by the sensors. I chose the following spaces to place the sensors: 1. Central Atrium: View of sensor on Atrium windowsill 32

5 2. Basement Stairwell: 3. 1 st Floor, North West Corner Sensor placed at base of Atrium Stairwell North West area, sensor on window framing 4. 3 rd Floor, East Wall 5. 4 th Floor, North Wall 33

6 The sensors placed in the 3 rd and 4 th floor were in rooms that remained stable over the two week period (Figures 12 & 13). They were essentially finished, with drywall and carpet installed already. These made for a good base for comparison with the other sensors, to show any that any fluctuations did indeed correspond to local changes in moisture levels, due to construction activities. 8 4th Floor North Wall Sensor 1 Temp(*F) / RH(%) 3/14/5 Figure 12 & 13: Charts from the 3 rd and 4 th floor sensors 8 3rd Floor East Wall Sensor 1 3/14/5 Temp(*F) / RH(%) 34

7 It was brought to my attention that the building was technically sealed, but there were still areas where external air could penetrate. This translates to the external conditions having a greater affect on the interior of the building. This was noticeable in the atrium sensor data (Figure 14). Temp(F) / RH(%) 1 Atrium Sensor 3/14/5 Figure 14: Chart from Atrium sensor The temperature in the atrium, since it is a large open space behind a glass curtain wall, was roughly 1 F lower than in the 4 th and 3 rd floor rooms. Such a large space was more easily affected by the external temperature. Notice the large increase in RH% on March 7 th and 8 th. The weather leading up to those days was in the s with some snow. Checking over the weather on those days, on the 7 th the temperature increased from low s to above. It also rained on both the 7 th and 8 th, which would explain the increase of moisture in the air, and cause an increase inside the building as well. The sensor placed in the basement at the bottom of the atrium stairwell shows a similar, but less drastic display of the atrium sensor s data (see Figure 15 on the following page). 35

8 Basement Atrium Stairway Sensor 1 Finally, the most interesting of the sensor data was logged the 1 st floor sensor in an area which they were installing and mudding drywall (Figure 16). This sensor shows the relative increase of humidity in the day hours, and its decline once the work stops in the evening until the following day. This is exactly the kind of data I was speaking about previously. Construction activities that cause an increase in moisture levels should be monitored as to ensure they do not raise the RH% above. 1st Floor North West Corner 8 1 Temp(*F) / RH(%) 3/14/5 Figure 15: Chart from Basement sensor Temp(*F) / RH(%) Figure 16: Chart from 1 st floor sensor 36

9 Conclusions: For this analysis, I researched moisture sensors, and used them in an actual construction setting to learn first hand how they perform. In doing so, I have been able to draw the following conclusions. Moisture detection is essential during the construction phase. There are many materials which could support mold growth, and regular humidity level checking will allow for remediation long before the mold becomes a problem. The main roadblocks for using new technologies in the construction industry are cost and time. If it takes too much time and/or costs too much, it will probably not be used. The best part about these sensors is that they are very affordable, $85 a piece, and they take a very small amount of time to install. I was able to place my five sensors in about minutes. They come with adhesives, both permanent as well as magnetic strips for easy removal when it is time to download the data. This brings me to my next point, the data logging itself. The sensors can take a total of 7943 measurements, at intervals ranging from once a minute to once a day. I chose minute intervals for my experiment. After logging the information, they plug into a computer with the provided cable, and the output is a spreadsheet listing all the pertinent information. If moisture detection is to be done on any jobsite, I believe that this is the easiest and most valuable resource for getting it done. It saves the time of having someone log data by hand, it is continuous, accurate, inexpensive, and they take up barely any room. I was quite impressed by my findings, and I am glad that I can share them hopefully for future use. 37