Environmental Monitoring in Preparation for the Installation of a Green Roof

Green roofs are becoming an increasingly popular way to improve the environmental, economic, and aesthetic performance of both new and existing buildings. Along with the green roofs themselves, it is also common to install sensors to measure various environmental parameters that are affected by or important to the operation of the roof such as precipitation, temperature, and runoff. However, for most of these systems, the sensors are installed at the same time or even after the green roof. Therefore, no before-and-after comparisons can be made for those roofs. To account for this missing data, monitoring equipment was installed on a Purdue University campus building to measure existing conditions for the year prior to the expected construction of a green roof. This equipment currently includes a weather station, along with runoff, heat flux, and temperature sensors, and there are plans to monitor air quality as well. Preliminary findings from values recorded thus far appear to validate the expected behavior of the roof. Stormwater runoff directly correlates to rainfall, and roof temperature is dependent on ambient air temperature and solar radiation. Data from the heat flux sensors, however, is not yet fully explained. This ongoing experiment should see significant changes in the data once the green roof is installed, but until that time, it will continue to serve its role as the control setup for measuring the performance of a standard roof.