This document, The Structural Design of Air and Gas Ducts for Power Stations and Industrial Boiler Applications , has been created to assist structural engineers when performing the structural analysis and design of ductwork. Air and gas ducts for fossil fuel power stations and industrial boiler applications are unique structures. Considering that ductwork structural analysis and design is not currently referenced or governed by any national code or design standards, this publication presents the structural engineer with current approaches for the structural analysis and design of air and flue-gas ductwork. Included are sections on: Material selection, behavior and performance; design loads, loading combinations and allowable stresses; thermal considerations; vibration considerations; structural arrangement and behavior; toggle duct behavior and expansion joint considerations; overall duct structural analysis and design methods; and design considerations for local elements of the structure, such as stiffeners, internal braces, connections, turning vanes, and other flow distribution devices. This document also discusses drawing and specification content, fabrication and construction techniques and considerations, duct support methods, and special considerations regarding the design of duct support structures. Finally, it talks about field maintenance examinations and inspections for the purpose of preventative maintenance or condition assessment.