Massachusetts 2nd Class Fireman's Exam 2025 – 400 Free Practice Questions to Pass the Exam

In a fire-tube boiler, combustion gases pass through tubes that are surrounded by water. This design allows for the heat generated from the combustion process to be transferred to the water, which is held in a separate shell or casing. The hot gases travel through the fire tubes, heating the water surrounding these tubes to produce steam.

The primary feature of fire-tube boilers is that the tubes containing the hot gases are immersed in the water, thus providing an effective method for heating the water. This type of boiler is known for its simplicity and reliability, making it a widely used option for various applications where steam generation is required.

On the other hand, in a water-tube boiler, the process is reversed: water flows through tubes that are heated by combustion gases outside of these tubes. This means that in water-tube boilers, the tubes themselves are filled with water, while the heated gases surround the entire structure.

Understanding these designs is crucial for recognizing the various applications, efficiency ratings, and the safe operation of different boiler systems in fire services and industrial settings.