1. Before welding each day, trial welding must be carried out. Requirements for trial welding: the trial weld should be performed on HDPE composite geomembrane samples to test and adjust the welding equipment; welding equipment and personnel can proceed to production welding only if the trial weld is successfully completed; the frequency of trial welding should be controlled: according to changes in ambient temperature, each unit must conduct trial welding at least twice a day, once before formal work begins and once during the mid-shift; trial welding should be conducted under the same surface and environmental conditions as production welding.
2. Before welding, oil, moisture, dust, debris, and any other impurities that may hinder welding or affect construction quality must be thoroughly cleaned from the surface of the membrane.
3. When the welding area needs to be polished, the width should be the same as the weld seam. The surface after polishing must remain clean. If the surface is contaminated, it should be wiped with clean cotton yarn before welding. If necessary, re-polishing should be done. Under no circumstances should the surface be wiped with hands.