Unless otherwise specified, the air duct shall be installed close to the fixed screws of the air duct hanger or bracket under the beam, and the bracket of the larger air duct shall be buried in the concrete during the construction of the house, and the approved steel expansion bolts can be used for the small size of the air duct.
The air duct must be installed firmly, and the flexible air duct should be at the shortest distance. Unless otherwise specified, the cross-sectional area of the air duct transfer shall not be reduced or concave.
Shockproof joint— where the air duct and equipment are connected, the acid and alkali exhaust shall be made into a shockproof flexible joint with a thickness of more than 2mm in accordance with the regulations, and its length shall be about 20cm to 30cm, and the two ends of the joint shall be supported firmly by flanges.
The actual air duct construction drawings need to include pipe diameter size and configuration, pressure loss, number of dampers, instruments, etc., and can only be constructed after confirmation by the user.In addition, when the damper is fully open, the wind speed in each air duct must be maintained at more than 12m/s, and the noise value generated (such as the main air duct, branch air duct, etc.) must be measured according to the regulations, and shall not exceed 70db, and the gas concentration and flow rate discharged from the exhaust end (chimney) of each treatment equipment must meet environmental protection standards.
Flange gasket: Acid and alkali exhaust and general exhaust duct, with flange as the jointing method, its material should be manufactured in accordance with SMACNA industrial grade air duct standard, the thickness of the liner is more than 3mm, and the width of the liner below 300mm is more than 6mm, and the width of the liner above 300mm is 9mm.For general exhaust ducts, the gasket material is PE or the same level with the flange as the joint, and the principle of no leakage is that the joint should be detachable and not welded, and the future leakage caused by the uneven corrosion and locking of the gasket should be considered.
All air ducts should be made according to the size shown in the design drawings and detailed drawings, their appearance must be flat and no air leakage, the longitudinal joint weld welding must be continuous welding, and the welds must be facing up during installation, and all joints must be flat and clean before construction.
All cannulations must be angled along the elbow, with a maximum intubation angle of 45°.
Unless otherwise specified, the cross-sectional area of the air duct shall not be reduced or dented.
Where the air duct and the equipment are connected, shockproof flexible joints should be used according to the nature of the system, acid and alkali exhaust Material: Teflon cloth cover (Texflm604/2): organic solvent Material: Silicone glass fiber cloth (SIL4000): General exhaust Material: waterproof canvas pipe, its length range is 15cm to 18cm, and the two ends of the joint are supported firmly by hangers.
The connection port of the secondary configuration (HOOKUP) shall be reserved with the damper of the same material as the air duct, and the connection port of the secondary configuration (HOOK UP) shall be connected by a T-shaped pipe, and the angle between the T-pipe and the branch pipe shall be a horizontal elevation angle of 45 °.
When the wind speed exceeds 10m/s or the wind pressure exceeds 620N/m2, special attention should be paid to the stability of the air duct hanger and pipe fittings, all air ducts should be safely supported to avoid vibration or sliding, and their configuration allows thermal expansion without any deformation, thermal insulation damage or damage to the support structure, all air ducts should be properly supported according to their size and structure, with different partitions, and rubber gasket insulation should be added to the contact part of the galvanized bracket and the air duct to prevent potential element difference.
The slope of the air duct should be 1:7 when changing the diameter, and it should not exceed 1:4, and the inner radius of the elbow should not be less than the width of the air duct，If the space is limited and the full radius elbow cannot be used, the angle between the branch pipe and the main pipe shall not be greater than 45 degrees, and the divergence shall be equipped with a deflector.
Condensate drainage should be provided at the low point of each main pipe, sub-main pipe and branch pipe, and the horizontal slope of each exhaust pipe should be at least 1 foot down every 10 feet (1:120), so that the condensate can flow into the water pipeline The water collection line is PVCSCH80 With ball valves, transparent pipes and traps are discharged to the wastewater treatment area according to the discharge slope, and the transparent pipes should consider the height of the human body (1.5M) that can be seen from themselves.
The location of the exhaust chimney should be far away from the air inlet of the fresh air conditioner
The vertical air duct branch pipe should be matched with the complete structure of the site, and all the pipelines through the wall and floor slab should be made of airtight fireproof filling, plus a stainless steel sealing plate with a thickness of 0.8mm.
Precautions
All air ducts should be made according to the dimensions shown in the design drawings and detailed drawings, and their appearance must be smooth and no air leakage, but when they must be changed in order to cooperate with the site, the contractor shall explain the reasons and draw detailed drawings, and ask the owner to approve before construction.
Unless otherwise specified, air deflectors should be set inside the right-angle turns of the air duct, and the upper and lower ends should be firmly attached to the air duct.
The connection between the branch air duct and the main air duct should be equipped with an air volume regulator.
Air duct channel steel hangers, angle steel, support steel plates, screws, nuts, etc. should be used for anti-corrosion treatment.
After each section of the air duct in the clean area is made, the inside and outside of the air duct should be thoroughly wiped until it is completely cleaned, and the entire section of the air duct should be wrapped with plastic cloth or PE cloth, and the packaging can be removed when hoisting.
