Structural Tubing: tubing used for structural applications. Standard strength requirements of the tube help dictate applications for which certain tubing is most appropriate. Structural tube is often referred to as hollow structural sections or HSS.
While specifications will vary based on design (and from manufacturer to manufacturer), some common specifications of structural tubing include ASTM A500 Grade B and C, A847, A1065, and the recently approved ASTM A1085.
In both cases of “Structural” or “Mechanical” tubing, these products are ordered to a specific outside dimension (OD) and “gauge” or wall thickness. This varies from “pipe” products which are ordered based on inside dimensions (ID) and often pipe “schedules” that determine the wall thickness. Pipe and conduit products should not be used in structural applications as their strength properties may not be produced to standard structural specifications or meet specified engineering requirements.