This method statement describes the activities and secure the quality for air blowing is to clean the piping of BOP piping of Vinh Tan 4 (2x600MW) Thermal Power Plan Project. 4.2.1 After installation of the temporary equipment on the pipeline system to be tested, make sure that all valves on the pipeline are closed. 4.2.2 Open the valve nearest to the air header and start air blowing. 4.2.3 Using a clean paper, place it on the opening of the open valve and check for the quality of air blowing until it finally no residue, debris or other foreign materials mark on the clean paper.