Circular ducts (excluding spiral ducts) with a diameter greater than or equal to 80mm and a pipe length greater than 1250mm or a total surface area greater than 4m should be reinforced;
Rectangular ducts with a side length greater than 630mm, insulated ducts with a side length greater than 800mm, ducts with low pressure with a single sided plane area greater than 1.2㎡, and medium and high pressure ducts with an area greater than 1.0㎡, should be reinforced;
For the reinforcement of irregular elliptical ducts, refer to the reinforcement measures for rectangular ducts.
The bolts, nuts, washers and rivets used in the ducts of spiral duct machines should be matched to the performance of the pipe material.
For non-metallic duct reinforcement, in addition to complying with the provisions of Article 4.2.10 of this specification, the following requirements must also be met:
When the diameter or side length of the rigid PVC duct is greater than 500mm, a reinforcement plate should be installed at the connection between the duct and the flange, and the spacing should not be greater than 450mm;
The reinforcement for organic and inorganic FRP ducts should be made of the same material as the body or have the same anti-corrosion performance and be integrated with the duct.
The manufacture of rectangular duct bent pipes generally should use inner and outer concentric arc curved pipes with a curvature radius of one plane side length. When other types of bent pipes are used, if the plane length is greater than 500mm, a bent pipe guide plate must be set.
The air purification system ducts should also comply with the following regulations: for rectangular ducts with a side length less than or equal to 900mm, there should be no splicing seams on the bottom panel; for those greater than 900mm, there should be no horizontal splicing seams.
Measure the position, height and other dimensions of the foundation or bracket of the installation of ventilation and air conditioning equipment.
Measure the metal embedded parts for the installation of indoor components of the ventilation and air-conditioning system, such as flange specifications, spacing and orientation of screw holes.
Measure the relative position of the reserved holes in the ventilation and air-conditioning system, such as the size of the duct passing through the roof, floor, partition wall and factory crane beam.
Measure the dimensions of columns, doors and windows, beams, ceilings, platforms, etc. related to the installation of ducts and components, such as cross sections, spacing, elevation, etc.
Measure the position, elevation and connection method of equipment interfaces related to ducts.
Measure the dimensions related to the ventilation and air conditioning ducts in the suspended ceiling, including the sub-distribution of electricity, pipes, etc.
Spiral duct machines have a very wide range of applications, including return air ducts in purification systems, air conditioning and ventilation ducts, industrial supply and exhaust ventilation ducts, environmental protection system suction and discharge ducts, mining gas extraction ducts, mining coated cloth air ducts and more.