ICAVI Fire Tube Boiler (ICFC/ICFB) aims to meet the market demand for medium-sized steam generating units, operating in various pressure and temperature ranges, with high thermal efficiency and low operating cost, with the basic characteristics of the two-pass body construction in the gas circuit, with expanded tubes, fuel burning through a reciprocating grate, with a furnace and post-burning chamber lined with refractory bricks, to ensure complete combustion.