Tubes of different external diameter shall not be mixed used and the wood tubes shall not be mixed with steel tubes in the applications. They shall be erected according to the required longitudinal space and transverse space. The external scaffolds shall be 25cm away from the wall and the width of the flat bridge shall be 0.9-1.2m.

The standing tubes at the bottom side shall use tubes with different length and the installation of them shall be staggered arranged with a minimum space of 500mm. The connection of the adjacent tubes shall not be on the same height and shall be set in different frames. For the joints on the top level, it can be connected in the overlap way and for the rest of the butt joints; they can be butting connected with a connecting length not less than 1m and with a fixation of more than 2 Scaffolding Couplers. The fixation space between shall be more than 300mm and the space from the center of the butting joints to the axial line of the transverse tube shall be less than 1/3 that of the lift.