The longitudinal tubes shall be set inside the standing tubes and the length shall be no more than 3 spans. The extension of thelongitudinal tubes shall be stagger connected by sleeve couplers and the two adjacent longitudinally horizontal tube heads shall bestagger placed no more than 500mm and each heads shall be no more than 1/3 of the longitudinal space away from the main joints.

• Each joints of the longitudinal horizontal tubes shall be fixed on the transverse horizontal scaffolding tubes by right angle couplers.

• The longitudinal extension length shall be no more than 1 meter and 3 swivel couplers shall be set in same space. The ridge of the top coupler covers shall be no more than 100 away from the longitudinal horizontal tube ends.

• Each joints of the transverse scaffolding tubes shall be set and fixed by right angle couplers, which are forbidden to dismantled.

• Scaffolding chambers shall be planked in the transverse way vertical to the wall surface without leaving any gaps between.