Square hollow section is a type of steel tubing used in the construction of buildings. Although it is a form of piping, stainless steel hollow tubing is formed into a frame by welding sections together to fit inside the exterior wall, whereas standard piping is molded to allow for liquid flow within the interior area of a wall.
Making Hollow Square Tubing and uses
The process of manufacturing structural hollow section, or hollow structural section, as it is more commonly known, follows a method similar to the making of standard piping. A flat plate of metal is manipulated by heating and is shaped into a round pole called the mother tube, this “mother tube’ is then further fitted into a circular, rectangular, or square hollow section. The corners of a square hollow section are rounded off at the last with the completed tube measuring a radius of two times the thickness of the wall it frames.
Variations of Steel tubing are used in and throughout a building’s exterior wall structure, however square tubing is favored more in the production of columns because its flat, level surfaces provide a stronger endurance to weathering and warping. A structural hollow section can also be used for beam work, given its resistance to buckling, although the newer shape of elliptical tubing is starting to replace the lower grade of the square tubing for the same reason.
Grades of Square Tubing in the Construction Industry
Typically, all U.S. construction companies follow the same ASTM standards for grades of structural hollow section and while the average grade for tubing use to run with the A500 B series, there has been a change in grade levels to the A1000 series (grades A1065 and A1085), because these grades are more suitable for larger buildings, providing tougher strength and a higher resistance to weathering and torsion than their A500 counterparts. Canadian construction standards follow both the U.S. A500 grades and their own CSA standards on the G40.21 grades of steel. While the UK follows the metric system, enabling manufactures to produce their own dimensional standards.