Common problems and control measures during air duct installation

1. Installation problem of air ductsupport and hanger

Problem analysis:

(1) The length of the main and main pipes in the ventilation pipe installation system exceeds 20m, and there is no fixed point to prevent swinging;

(2) The leakage length of the screw of the support and hanger is inconsistent.

Control measures:

If the length of the main pipe exceeds 20m, anti-shake brackets shall be provided. The support and hanger should not be set at the tuyere, valve, inspection port and automatic control mechanism, and the distance from the tuyere or the insertion pipe should not be less than 200mm. Make uniform requirements on the exposed length of the harness, and cut them for different lengths.

2. Super-large air ducts did not take reinforcement measures as required by the specifications

Problem analysis:

Reinforcement measures were not taken for super-large air ducts as required by the code.

Control measures:

Reinforcement of metal air ducts: the side length of rectangular air ducts is greater than 630mm, the side length of thermal insulation ducts is greater than 800mm, the length of pipe sections is greater than 1250mm, or the single side area of low-pressure air ducts is greater than 1.2㎡, and the medium and high-pressure air ducts are greater than 1.0㎡, reinforcement measures should be taken.

3. The problem of the air duct passing through the firewall

Problem analysis:

(1) There is no wall-piercing casing where the air duct passes through the wall;

(2) The fire damper with a side length greater than 630mm is not provided with a separate fixing bracket;

(3) The distance between the fire damper and the wall is greater than 200mm.

Control measures:

(1) When the air duct passes through the fire-proof and explosion-proof walls or floors that need to be closed, the thickness of the steel plate of the embedded pipe and the protective sleeve shall not be less than 1.6mm, and the non-combustible flexible material shall be used to seal the air duct and the protective sleeve ;

(2) The fire damper is provided with an independent hanger, and the distance between the fire damper and the wall surface is not greater than 200mm.

4. Pipeline insulation problem

Problem analysis:

The insulation thickness and flatness of pipes and equipment do not meet the requirements.

Control measures:

(1) When important equipment is kept warm, due to the irregular shape, it is necessary to form a heat preservation plan in advance, accurately measure the actual object according to the heat preservation plan, and accurately cut the material (it is strictly forbidden to have more or less material), and the glue is evenly applied (it is strictly forbidden For the sake of speed, there is a phenomenon of missing glue or brushing less glue);

(2) Protruding parts such as flanges and variable diameters must be cut separately for heat preservation, and the surface should be flat. When using coils or plates, the allowable deviation is 5mm; when using smearing or other methods, the allowable deviation is 10mm; moisture-proof layer (including The end of the insulation layer) should be complete and well closed; its lap joints should run smoothly.

5. There is no thermal insulation skid between the hanger and the thermal insulation duct

Problem analysis:

There is no thermal insulation skid between the hanger and the thermal insulation duct.

Control measures:

The connection between the suspender and the bracket is fastened with double nuts. An insulating liner should be provided between the heat insulation duct and the bracket to prevent cold bridges. The thickness of the heat insulating liner should not be less than the thickness of the insulation; Anti-corrosion treatment.

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