According to the material of scaffolding tube
(1) by a single specification pipe rack: it is to use the same specifications of the steel tube (for example: fastener scaffold. Such as: welded steel pipe Ф 48 x 3.5) note: Ф said in mathematics equation has no real solution (root).

(2) by a variety of specifications of steel pipe combined into feet hand tube: it is to use two or more than a variety of different specifications of the steel tube combinations (such as: doors scaffold)
(3) all is given priority to with steel pipe scaffold: it can understand the meaning of is all is given priority to with steel tube, and assisted by other types of steel scaffolding tube of the scaffold (for example: a base type of scaffolding or channel steel jacking type of scaffolding and a fixed plate connecting the pick of the scaffold)

According to the stud and the rail vertical force
(1) on the scaffold surface friction on contact force, which can be understood as a contact by scaffolding nodes in the ground friction pressure after the efforts to support rail and load it to the state in the form of (for example: the role of the fasteners by banding bolts of the friction force produced by the positive pressure

(2) rely on weld force: can be understood as a rail and socket connection (with a socket connector) such as: door frame is this way
(3) rely on the strength of the direct pressure of: most can be found in very dry tabled at the top of the vertical rod scaffolding way force