The production and installation of purification ventilation ducts and components, and the calculation method of engineering quantity is the same as that of general ventilation ducts, using corresponding norms. However, for the installation of components, purification fees need to be calculated, with 35% of the corresponding component sub item installation base price as the purification fee, of which labor costs account for 40%. The cost of the essence sealing treatment between the purification pipeline and the building gap shall be calculated according to the actual situation.
The unfolded area of a circular air duct does not deduct the area occupied by inspection holes, measuring holes, air supply outlets, suction outlets, etc. The area occupied by overlapping bites does not increase, nor does the overlapping part of bites increase.
The flange gasket material in the production and installation quota of air ducts is comprehensively considered based on various material types and cannot be converted.
The entire ventilation system is designed with uniform air supply through gradually reducing pipes. Circular pipes are designed according to the average diameter of the cross-section, while rectangular pipes are designed according to the average circumference of the cross-section using corresponding sub items. The labor force is multiplied by a coefficient of 2.5. The production and installation of air curtain air supply pipes shall be carried out according to the average circumference of the rectangular air duct section, and the corresponding sub items of the air duct shall be applied. The labor cost coefficient shall be 3.0, and the period shall remain unchanged.
The calculation of the length of the air duct shall be based on the centerline length shown on the construction drawing, including the length of elbows, tees, variable diameter pipes, and pipe fittings in circular areas. The length of the branch is divided by the intersection point between the centerline of the branch and the centerline of the main pipe.
The variety, specifications, performance, and thickness of air duct production materials should comply with the design drawings and current national product standards.
Production quality requirements:
The specifications and dimensions of the air duct meet the design requirements;
The appearance quality of the air duct should be flat and straight with uniform arcs, parallel at both ends, and no warping angles;
The inner surface of the air duct should be smooth, and it is strictly prohibited to have horizontal seams or install reinforcement bars or use convex reinforcement methods inside the duct. Minimize the longitudinal seams at the bottom as much as possible. When the bottom edge of a rectangular air duct is less than 800mm, there shall be no longitudinal seam at the bottom edge. All nuts, bolts, washers, and rivets should be made of materials that match the performance of the pipe material and do not cause electrochemical corrosion, or galvanized; The bite seam of the clean air duct is tightly connected, with a uniform width and no holes, semi bite, or expansion cracks.