Some scenes which take place in the Firehouse 51 kitchen are filmed in the actual firehouse kitchen, others are filmed on a studio set. If you see a door to the left of the cooking area, that is the studio set; if you see a drinking fountain, that's the actual firehouse.
Filmed in Chicago. Firehouse 51 is actually Station 18, which is located at 1360 S. Blue Island Ave in Chicago. "Molly's Bar," owned by characters Herman, Dawson, and Otis, is filmed in the real Chicago bar "Lottie's" in Bucktown.
The Self-Contained Breathing Apparatus (SCBAs) worn by the cast are Scott 4.5 Air-Pak 75s. This is one of the most popular brands and models of SCBA with fire departments across America for its durability, reliability, and ease of use. However, the masks worn by the cast members are unrealistic. They are nonfunctional and were made specifically for the series with the anti-fog interior facepiece and exterior voice amplifier removed, the lens elongated, and the regulator mounted at an odd angle to clearly show the actors' faces. These masks would fog badly if they were actually flowing air. Real SCBA masks are put on separately from the regulator, which is connected after the mask is on, and disconnected before the mask is removed. The air demand and exhalation valves make a loud noise when operating, and muffle the voice of the wearer.