The campus can be accessed by metro line M1 or bus line 31. The address of the building is:
Avenue François-Alphonse Forel, 1015 Ecublens VD
See it here in google maps.
The building can be entered through different doors, but the entrance marked with the red dotted line on the map is recommended.
See the interactive map below for a bigger perspective of the location of the room in the EPFL campus.