Ventilation and air conditioning duct installation method -part I

Here we introduce the method of installing ventilation and air conditioning duct:

1. The installation of the air supply and exhaust system and the air conditioning system shall be carried out under the conditions that the construction of the building maintenance structure is completed, the obstacles at the installation site shall be cleaned, the ground shall be free of debris, and no other pipelines shall pass through the air duct. Check the construction site. The location of the reserved holes, whether the size meets the requirements of the drawings, and whether there are any omissions. The reserved holes should be 100mm larger than the size of each side of the actual section of the air duct.

2. Determine the elevation, install the air duct support and hanger, and apply a layer of anti-rust paint after derusting. The hanging points of air duct supports and hangers are usually pre-embedded iron parts, secondary grouting of supports and hangers, expansion bolt method, etc.

According to the center line of the air duct, find the position of the hanger rod. The single hanger rod is on the center line of the air duct, and the double hanger rod can be installed symmetrically according to the screw hole spacing of the tray or the center line of the air duct. The boom can be welded or hung on the hanger according to the form of the hanger. Anti-rust paint should be applied after welding. When installing the riser pipe clamp, the top pipe fitting should be fixed first, and then use a wire hammer to suspend the line at the center, and the lower pipe clamp can be fixed according to the line. When the air duct is long and a row of brackets needs to be installed, the two ends can be installed first, and then the brackets at both ends are used as the benchmark to find the elevation of the middle bracket by the pulling method for installation.

3. The elevation of the support and hanger must be correct. For example, the diameter of the circular air duct changes from large to small. In order to ensure the level of the center line of the air duct, the elevation of the upper surface of the bracket steel should be correspondingly increased. For the air duct with slope requirements, the bracket The elevation of the duct should also be installed according to the slope requirements of the air duct. The embedded parts of supports and hangers or the embedded parts of expansion bolts shall not be painted, and oil stains shall be removed. Supports and hangers shall not be installed on air outlets, valves, inspection holes, etc. The hanger must not be hung directly on the flange.

4. Place a wooden block where the square air duct contacts the bracket. The thickness of the pad of the insulating air duct should be the same as the thickness of the insulating layer. The support and hanger of the rectangular thermal insulation duct should be placed outside the thermal insulation layer, but the thermal insulation layer should not be damaged. The rectangular thermal insulation air duct should not be in direct contact with the support and hanger, and should be padded with a solid thermal insulation material with the same thickness as the thermal insulation layer to prevent "cold bridges".

5. In order to ensure the tightness of the flange interface, there should be gaskets between the flanges. Generally, the flange gaskets of the air conditioning system and the air supply and exhaust system use 8501 sealing tape, and the flange gaskets of the exhaust system use asbestos slats; The flange gasket cannot be squeezed into or protruded into the pipe. The flange gasket should minimize the number of joints. The joints should be connected in trapezoidal or tenon shape. After the flange is connected, it is strictly forbidden to fill the gap with the gasket.

6. When flanges are connected, according to the design requirements, the padding should be specified, the two flanges should be aligned first, put on a few bolts and put on the nuts, do not tighten them temporarily, and then use a sharp punch to insert them into the screw holes that cannot pass through the bolts. , pry the two screw holes until all the bolts are threaded, and then tighten the bolts. In order to prevent the bolt from slipping, tighten the bolts gradually and evenly in a crisscross manner. The nuts of the connecting flanges should be on the same side. The connected pipes should be based on the flanges at both ends. Pull the wire to check whether the air duct connection is straight. .

7. The hose-type air duct connection is mainly used for the connection of air ducts and components (such as diffusers, plenum side air outlets, etc.). During installation, the two ends of the hose are sleeved outside the connected pipe, and then the hose is fastened with a special soft clip.

The installation of the air duct depends on the construction site. It can be connected to a certain length on the ground, and then the method of hoisting is adopted. Hoisting) The general installation sequence is the main pipe first and then the branch pipe. The installation of the vertical duct is generally carried out from the bottom to the top.

8. Length installation of air ducts: It is a method of connecting the air ducts on the ground, generally about 10~20m in length, and lifting the air ducts to the hanger with an inverted chain or pulley. That is, hang the inverted chain or pulley, and then use hemp rope to bind the air duct firmly (generally, the rope is not directly tied to the air duct, but a long wooden board is inserted into the stressed part of the hemp rope, or a long wooden board is used to drag the bottom of the air duct) Padded around with soft material. When the hoisting air duct is 200~300mm above the ground, carefully check whether the force point of the reverse chain or pulley and the rope and rope buckle that bind the air duct are firm, and whether the center of gravity of the air duct is correct, and continue to hoist after each problem. After the air duct is placed on the support and hanger, all brackets and hangers are connected well, and the rope buckle can be released only after confirming that the air duct is stable. Sectional installation of air ducts: If it is inconvenient to hang pulleys in the county or due to site restrictions, when hoisting is not possible, the air duct sections can be pulled to the scaffolding with ropes, and then lifted to the brackets to align the flanges and install them section by section.