A500). Manufacture Square HSS is made the same way as pipe. During the manufacturing process flat steel plate is gradually changed in shape to become round where the edges are presented ready to weld. The edges are then welded together to form the mother tube. During the manufacturing process the mother tube goes through a series of shaping stands which form the round HSS (mother tube) into the final square or rectangular shape. Most American manufacturers adhere to the ASTM A500 or newly adopted ASTM A1085 standards, while Canadian manufacturers follow both ASTM A500 and CSA G40.21. European hollow sections are generally in accordance with the EN 10210 standard. Filled HSS HSS is often filled with concrete to improve fire rating, as well as robustness. When this is done, the product is referred to as a Lally column after its inventor John Lally of Waltham, Massachusetts. (The pronunciation is often corrupted to lolly column.) For example, barriers around parking areas (bollards) made of HSS are often filled, to at least bumper height, with concrete. This is an inexpensive (when replacement costs are factored in) way of adding compressive strength to the bollard, which can help prevent unsightly local denting, though it does not generally significantly increase the overall structural properties of the bollard. See also Hollow-core slab Honeycomb structure Lightening holes Profile (engineering) Structural pipe fitting Structural steel External links Architectural AISthetics (Opening Keynote Address for digifest 2004) Steel Tube Institute Steel Tube Institute, tube dimensions Structural engineering Structural steel