Located above the William Street Train station One40 William is the first 5 Star Green Star building in Perth. The multilevel design places the highest tier on the north side to provide a natural shading system for the lower office levels. This, paired with the use of a single glazed façade, prevents excessive heat gain in summer while radiating warmth to its surrounds at night. The stepped and angled floor plan places more than 80 percent of its area within eight metres of full height external windows. This allows for minimal artificial light. In addition the landscape is irrigated using rainwater harvested on site. Featuring rooftop and surrounding gardens as well as a high proportion of fresh air circulation in the office spaces, the design has a focus on worker comfort.