During loading and unloading, the materials shall be protected from damage. It is strictly prohibited to push the grille pipe directly from the carriage or higher place. The materials should be transported directly from the transfer station to the construction site. If it is necessary to set up a temporary pipe stacking site, the temporary pipe stacking site shall be selected by the construction unit. The pipe stacking site shall be set at a place convenient for construction as far as possible, and the site shall be flat and compacted.