The application dimension of Structural Steel Pipe segmentation delineates demand across end‑use sectors that collectively drive market volume. Construction accounts for the largest share, roughly 45 % of total shipments, as steel pipe is integral to building frames, bridges, and high‑rise infrastructure where load‑bearing capacity and fire‑resistance are mandatory. The oil & gas sector follows with an estimated 25 % share, reflecting pipe usage in upstream drilling rigs, downstream processing plants, and transmission pipelines that require high‑strength, corrosion‑resistant grades. Water & sewer networks contribute about 15 % of the market, leveraging pipe systems for municipal distribution, treatment facilities, and storm‑water management. Power generation consumes near 10 % of output, primarily for boiler and turbine support structures in thermal and nuclear plants. Finally, the transportation segment, representing roughly 5 % of demand, supplies pipe for railway bridges, highway overpasses, and airport structures. This application‑based taxonomy clarifies how each sector’s engineering specifications and regulatory frameworks shape the overall market size.