How to fabricate and install PIR Pre-insulated duct system Part Two

2022-10-31

How to fabricate and install PIR Pre-insulated duct system Part Two

Production of variable diameter duct

The reducing pipe of the rectangular air duct has two types: single-sided eccentricity and double-sided eccentricity. The angle φ of the single-sided variable diameter should be less than 30%, and the included angle of the double-sided variable diameter should be less than 60%. The production method of the variable diameter duct is the same as that of the straight duct, and one or three sides of the duct plate are inclined. , its assembly method is as shown in the figure, the length of the variable diameter air duct shall not be less than the difference between the long side of the big head minus the long side of the small head.

Production of three ventilation pipes

According to the design size, the opening size of the connecting port of the cutting air duct on the main air duct and the upper and lower plates of the branch air outlet is increased by 6mm for the inner wall of the branch air duct. The size of the opening at the connection with the left and right plates of the branch duct is the wall size of the branch duct. As shown in the figure, a 45% diversion angle should be set in the downwind direction, and the length of the diversion angle should not be less than half of the width of the branch duct , Cut the upper and lower plates connecting the branch air duct and the main air duct into a stepped shape, and the left and right plates are not cut into a stepped shape. If the height of the branch air duct is the same as that of the main air duct, the upper and lower plates of the main air duct and the upper and lower plates of the branch air duct are connected as a whole, which is convenient to manufacture and has high strength of reducing diameter.

Insert the branch pipe into the main air pipe, glue it with special glue, then tie it in place, clean up the excess glue, fill the gap, and put it on a flat place to cure.

Four ventilation pipes refer to the manufacturing method of three ventilation pipes;

Air-conditioning duct (wall thickness 25mm) board with a board ≥ 20cm can be used for the upper board with a long side ≤ 600mm.

Smoke prevention and exhaust air duct (wall thickness 18mm) board ≥ 20cm can be used for the production of the upper board of the air duct with the long side ≤ 1500mm.

The inside and outside of the air duct should be clean and smooth, and there should be no residual slurry. The residual slurry on the inner wall of the surrounding corner joints should not be higher than the plane 1.5mm;

The pipe body should be able to withstand 1m high, 5kg sandbags fall freely, impact 3 times without breaking the pipe body.

Duct reinforcement

When the side length of the air duct is greater than or equal to 1250mm, vertical and horizontal internal support and reinforcement should be carried out according to the working pressure of the air duct. The reinforcement is determined according to the following table, and the longitudinal reinforcement is set at a distance of 1300mm.

PIR Pre-insulated duct