The documentation for the construction of the ammonia plant in the Sokolov heating plant was prepared for the issuance of a building permit. The subject of the project was to change the use of the acid storage tank of the desulphurisation unit for the needs of denitrification of boilers in the heating plant and to install new equipment for storage and transport of ammonia water. The documentation included mainly the design of the construction modifications and technological concept, the assessment of the usability of the original acid tanks for the purpose of ammonia water storage, the design for the civil, mechanical and electrical parts, MaR and control system, the fire-safety design of the construction, the protocol of external influences and the description of the operation and control of the equipment.