Tubes used in the coupler scaffolding shall be the welded steel tubes of a diameter of 48mm*3mm and its mechanical property shall

comply with requirements of Q235-A Steel in GB/T700. When some common welded tubes are adopted, they shall be coated with anti-

corrosive layers on both the internal and external sides and be re-painted regularly to protect its integrity.

When the new steel tubes are used in the coupler scaffolding system, they shall be provided with QC certificate by manufacturers.

Should there be any doubt on their quality, try the random sampling tests on their mechanical property. All the accessories including the

fixed scaffold clamp shall be without any deformation, crack or corrosion. There shall not be any scratch over 0.5mm depth, any other

bruise, mismatch of the welded points or any burns or knots on the coupler scaffolds.