Fire sprinklers should be installed in a new construction project during the early stages, ideally before walls and ceilings are completed. Integrating sprinklers into the initial construction phase ensures they are properly positioned and concealed. Consult with the project's architect, contractor, and local building codes to determine the specific requirements and timelines for fire sprinkler installation. Early planning and coordination help ensure the effective integration of fire sprinkler systems into the overall building design and enhance the safety features of the structure from the outset.