The document discusses the design and analysis of a fire tube boiler using LPG fuel for small-scale oyster mushroom production in East Java, Indonesia, emphasizing its significance for the sterilization process of mushroom growth media. The proposed boiler has a capacity of 70 kg/h, operates at 1.5 bar pressure, and is designed with materials that allow efficient steam generation and reliability. Detailed calculations are provided to determine dimensions, materials, and thermal efficiency, concluding that the selected asphalt drum boiler structure is safe and effective for the intended application.