It was a 4 stage interview. Mechanical engineers interview with Piping Deparmtent, Equipment Department, and HVAC / Fire safety systems departments. Then with an HR representative. Each interview lasts about an hour, most departments bring two or more representatives. Inbetween sessions employees show you around the office and answer any questions you may have. I have personally escorted interviewees around inbetween sessions. Interviews are done in groups of about 5 people, there is a morning and afternoon sessions.