REFERENCES

FOR THE PROTECTION OF OUR WATERS

REFERENCE HYDROSYSTEM 400 UNI GARCHING

FIELD TEST ON A ZINC ROOF

Rainwater runoff from metal roofs made of uncoated zinc, copper or lead contains considerable concentrations and loads of the respective heavy metals. As these should not be discharged into the groundwater or surface waters in excessive quantities, they must be treated in Bavaria. According to Art. 41f BayWG, such treatment plants can receive a general building inspectorate approval to ensure that the filter systems function permanently in terms of water protection.

The test for approval was carried out on a real system in a field test over a period of one year by an independent institute. The 3P Hydrosystem metal was tested from September 2009 to August 2010 at the Technical University of Garching on a zinc roof in accordance with the test conditions of the state of Bavaria. Two metal systems were installed on a zinc roof area of 260 m², each receiving the rainwater runoff from 130 m² of roof area.

Results
The water from the roof was first directed via magnetic inductive flow meters and then discharged via the filters. Automatic samplers were controlled via the flow meters and sampled the rainwater runoff. A precipitation gauge provides information on the intensity and duration of the rain events. A total of 20 rain events had to be sampled, which were divided into three different classes of rain intensity, from long-lasting land rain to heavy thundershowers.

Only rain events with a runoff of more than 1 mm were taken into account. The retention rate must be at least 90% for use on zinc roofs and at least 98% for copper roofs. After the one-year measurements, the filter material was also examined for loading in order to calculate the service life of a filter element

Daniel Betschner,
Master Professional of
Technical Management (CCI)
Project Engineer

Tel +49 (0) 7334 92460-32
Mail betschner@3ptechnik.de