Hollow sections (IS 4923) and CRCA square/rectangular tubes are lightweight alternatives to rolled steel for structural frames, building facades, and industrial skids. Their uniform geometry gives excellent strength-to-weight ratios and consistent welding/finishing behavior for architectural and fabrication work.

Choose wall thicknesses from the IS 4923 weight chart to match load-bearing and welding needs. For structural projects, specify tolerances, flatness, and edge conditions, and prefer CRCA tubes for painted architectural finishes due to superior surface quality. Use hollow sections for columns, trusses, and conveyor frames where torsional stiffness and ease of joining matter. For heavy structural loads, select thicker-walled ERW or seamless hollow sections as appropriate.

Include practical procurement notes: confirm batch testing for mechanical properties, request chemical composition certificates, and ask suppliers for cutting, punching, or special-shape fabrication capability to streamline installation.