HVAC air duct installation operation process

First, find out the elevation of the air ductaccording to the design requirements and with reference to the civil construction datum line.

Second, making hangers and high hanging points.

1. Setting of hanging point:

(1) Embedded parts method:

①Pre-embedded in the early stage: Generally, the pre-embedded parts are firmly fixed on the steel bars of the civil structure by the reserved personnel according to the coordinate position of the drawing and the spacing between the supports and hangers.

②Pre-embedding in the later stage: Embed the bracket on the brick wall: Calculate the distance from the surface of the bracket section steel to the ground according to the elevation of the air duct, find the correct installation position, and make a square hole of the required size. The inside and outside of the hole should be the same size, and the depth should be 30-50mm greater than the depth of the bracket buried in the wall. After the hole is made, wet the hole with water and flush out the brick chips inside the hole. Then fill a part of 1:2 cement mortar in the wall hole, and bury the bracket, and the burying depth is generally 150-200mm. Use a spirit level to level the bracket, adjust the depth of burial, continue to fill the mortar, and properly fill some water-soaked stones and broken bricks to facilitate fixing the bracket. When filling in cement mortar, it should be slightly lower than the wall, so that the wall can be decorated by civil works.

Embed the hanger under the floor: After determining the position of the elevator, use an impact drill to drill a hole in the floor, and then tick a groove on the ground according to the required size. Insert the hanger into the groove and fill the groove with cement mortar.

(2) Expansion bolt method: It is characterized by flexible, accurate and fast construction.

Third, Install the hanger.

1. Find the placement position of the boom according to the center line of the air duct. The single boom is on the center line of the air duct, and the double boom can be installed symmetrically according to the screw hole spacing of the tray or the center line of the air duct.

2. 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.

3. When the air duct is long and it is necessary to install a row of brackets, you can install both ends first, and then use the brackets at both ends as the benchmark to find the elevation of the middle bracket by pulling the wire method for installation.

4. When installing the riser pipe clamp, the top pipe fitting should be fixed first, and then use a wire hammer to hang the line at the center, and the lower pipe clamp can be fixed according to the line.

Fourth, spacing of air duct support and hanger.

1. If there is no design requirement for the distance between the air duct support and hanger, the non-insulated air duct should meet the requirements in the following table. When there is no design requirement for the distance between the insulation duct, support and hanger, it shall be implemented as required. The distance between the support and hanger of the spiral duct can be appropriately increased.

2. The support and hanger shall not be installed in the tuyere, valve inspection hole, etc., so as not to hinder the operation. The hanger must not be hung directly on the flange.

3. The thermal insulation air duct should not be in direct contact with the support and hanger. It should be padded with a strong thermal insulation material, whose thickness is the same as that of the thermal insulation, to prevent the occurrence of "cold bridges".

4. The polyvinyl chloride air duct also adopts the support and hanging brackets like the steel plate air duct, but generally the hanger is the mainstay, and the bracket spacing is made and installed according to the requirements of the table below.

Fifth, arrangement and installation of air ducts

1. Flange connection:

(1) In order to ensure the tightness of the flange interface, there should be gaskets between the flanges. In the case of no special requirements, flange gaskets are selected according to the table below.

(2) How to use the gasket sealing tape:

① Clean up the foreign matter and accumulated water on the surface of the air duct flange and wipe it clean.

②Attach the tape from the corner of the flange, and the end of the tape should be slightly longer than the flange.

③ Paste it evenly and evenly along the flange, and press it firmly by hand during the pasting process, it must not fall off, the interface should be tight, and no part should protrude into the air duct. , cut off the excess.

④ Peel off the release paper.

(3) When the flanges are connected, it is required to specify the gasket material, align the two flanges, thread the bolts and put on the nuts, (note: the nuts should be on the same side), do not tighten temporarily until all the bolts are put on , and then tighten the bolts. When pressing the air duct, the flanges at both ends shall prevail. Pull the wire to check whether the connection of the air duct is straight.

(4) Matters needing attention when connecting gaskets and flanges.

① Correctly select the litter and avoid using the wrong litter.

②The flange surface should be clean and free of foreign matter.

③The flange gasket cannot be squeezed or shoved into the pipe, otherwise it will increase the flow resistance and increase the dust accumulation in the pipe.

④After the flange is connected, it is strictly forbidden to fill the gap of the flange with gasket.

⑤ The nuts of the connecting flange should be on the same side.

⑥ Stainless steel flange connection bolts should be made of stainless steel bolts of the same material.

⑦ Galvanized bolts should be used for flange connection of aluminum plate air ducts, and galvanized washers should be placed on both sides of the flange.

⑧ Galvanized bolts are used for the connection between the PVC air duct flange and the FRP flange.

2. The arrangement of air ducts cannot be connected by flanges

①Hoop connection: It is mainly used for the connection of steel plate round air ducts and spiral air ducts. First, roll out the ribs at both ends of each pipe section, and shrink one end into a small opening. When installing, insert the small opening into the large opening according to the direction of airflow, and use steel hoops on the outside to tightly connect the drum hoop at both ends.

②Plug-in connection: mainly used for rectangular or circular air duct connection. First make the connecting pipe, then insert the air ducts on both sides, and then fix it tightly with rivets.

③ Insertion type connection: mainly used for rectangular air duct connection. Insert different forms of cuttings into both ends of the duct and compact. Its shape and takeover method are shown in the figure.

④Hose type connection: It is mainly used for the connection of air ducts and components (such as radiators, side air outlets of static pressure boxes, etc.). When installing, the two ends of the hose are put on the outside of the connected pipe, and then the hose is fastened with a special soft clip.

More Recommendations:

Duct Fabrication Machines

Duct Board Cutting Machine

Insulation Cutting Machine

Pre Insulated Ductwork

Phenolic Ductwork

Duct Fabrication Procedure

Duct Board Fabrication

How to Fabricate Ductwork

Types of Duct

HVAC Industry Trends