The Hengartner lab is located on the L floor of Building 55, on the Irchel Campus of the University of Zurich. A map of the surrounding area can be obtained online at map.search.ch (our street address is Winterthurerstr. 190, CH-8057 Zurich).
The buidlings on the Irchel Campus are numbered in a systematic fashion. Buildings with odd numbers in the tens are on the left of the middle tract, even-numbered buildings on the right - the further away from the middle tract, the larger the number. From bottom to top of the hill, the buidlings get increasing numbers in the single digits. That all should become obvious from the map below.