Structured. Asked about experience and gave me some scenarios questions. "If a boiler is going to explode what do you do?" Kill power.... pretty easy and laid back though. The interview had 2 individuals in the room. Both were chief stationary engineers with 20+ years of experience. They were super nice and easy going. They give you a 90 day training period due to the large amount of equipment on campus. They have every piece of equipment you can think of here which is great for a go getter!