Sensor Systems for Monitoring Environmental Performance of the Hamerschlag Hall Green Roof

David Dzombak, Civil & Environmental Engineering

Interest in "green roofs" is growing across the world, especially for urban areas.  A green roof—basically, a garden on a roof—can serve many useful functions.  It can retain rainwater and slow runoff of storm water.  This is important in Pittsburgh, which has combined sewers conveying both storm water and sewage.  When it rains in Pittsburgh, the combined sewers often fill to capacity with stormwater, leading to discharges of raw sewage to the rivers.  One component of mitigating this problem is to slow the runoff of water, and green roofs can help in this regard.  Furthermore, green roofs can increase the energy efficiency of buildings through the added insulation they provide, and can also reduce the urban "heat island" effect, which raises the air temperature due to heat reflection of surfaces like conventional bitumen or metal roofs.

A 4500 sq ft green roof was installed on the south wing of Hamerschlag Hall in the Spring of 2005, and was the first green roof established for research within Pittsburgh.  This roof has equipment installed for monitoring the amount of incident rainwater, the amount of rain runoff, and heat flow through the roof.  Similar data are being obtained on a control roof which is on Porter Hall, next to Hamerschlag. A datalogger is positioned in an office in Hamerschlag Hall for ease in downloading the data. The data are being used to determine the effects of the green roof on building energy efficiency and storm water runoff.

Project 1:  Assessment of the thermal performance of the roof.  This will involve collection of data from temperature profile monitors embedded in the roof and located above the roof, and interpretation of the data. 

Project 2:  Evaluation of the performance of the roof in retaining stormwater and slowing runoff.  This will involve collection of rainfall and runoff flow data, and interpretation of the data. 

Project 3:  Design of an automated soil moisture monitoring system, using available sensors, followed by collection and interpretation of data.