Spiral duct installation is a critical phase; the main work of ventilation and air conditioning projects is focused on duct installation. Therefore, it is essential to master the technical characteristics of multi-functional silencing pipes, be familiar with construction drawings, understand the related situations with other construction and specialty trades, verify the elevation, axes, reserved holes, and embedded parts of the duct system to ensure they meet installation conditions. Ensure an adequate supply of various auxiliary materials for installation, prepare hoisting equipment and other tools for installation, and perform marking and positioning work on the duct system.
The Duct Assembly: Upon delivering the finished or prefabricated ducts to the installation site, inspect and verify them based on the actual conditions. Arrange them according to numbering. Once the dimensions and angles of all parts of the duct system are confirmed to be accurate, begin the duct assembly process. The connection between each section of the duct is made using flanges, with a requirement for a tight seal to prevent any air leakage.
The length of a duct to be suspended should be determined based on the building conditions, the wall thickness of the duct, the hoisting method, and the equipment provided for hoisting. Once the duct is assembled, the flanges at both ends can be used as the reference points, with the middle flange as the measurement point. A line should be pulled to check if the connection of the duct is straight; adjustments should be made if there is significant deviation. Before hoisting, inspect the supports and hangers for the duct, the hoisting equipment, and the selected points for supporting and hoisting with the equipment, ensuring they are correct and secure. Before lifting, carefully check that the rods, pulleys, ropes, etc., are properly secured, the ties are reliable, and all unsafe factors in the hoisting area are cleared. During lifting, first conduct a trial lift. When the duct is 200-300 millimeters above the ground, stop the lift and conduct a comprehensive check of the hoisting equipment again. After confirming there are no issues, continue lifting to the desired height. Only after the duct is securely fastened to the supports and hangers should the ropes be released and the hoisting equipment be removed.
After the horizontal main pipe is leveled, aligned, and securely fastened to supports and hangers, the installation of branch pipes can proceed. The vertical pipes can be installed before the horizontal main pipe is set up, with support spacing not exceeding 4 meters and each vertical pipe fastener having at least two attachments. For horizontal duct installation, the allowable deviation in level per meter should not exceed 3 millimeters, with a total deviation not to exceed 20 millimeters. For vertical duct installation, the allowable deviation in verticality per meter should not exceed 2 millimeters, with a total deviation not to exceed 20 millimeters.
