Installation and performance requirements of flexible air duct in fresh air system.

    Installation and performance requirements of flexible air duct in fresh air system.

    1. The air duct should be round, oblate or rectangular air duct with the ratio of long and short sides not greater than 4. The cross-section dimensions of the air duct should be implemented in accordance with the relevant provisions of the current national standard "Code for Construction Quality Acceptance of Ventilation and Air Conditioning Engineering" GB50243.

    2. The air velocity in the air duct, the main duct should be 3.5m / s-4.5m / s, * should not exceed 6m / s; the branch duct should be 2m / s-3m / s.

    3. The pressure loss of each loop of the fresh air system should be calculated by hydraulic balance. The relative difference between the pressure losses of each parallel loop should not exceed 15%. When the above requirements cannot be met by adjusting the pipe diameter, an adjusting device should be provided.

    4. Ventilator and outdoor connected air pipes shall be designed for thermal insulation and shall be set with a slope of 0.01-0.02 outdoor.

    5. The holes for the walls and beams of the newly-built building shall be confirmed by structural safety. The positions of the reserved holes shall be correct. The holes shall not be larger than the outer dimension of the duct by 20mm. The dimensions of the duct shall be determined according to the calculation of the design air volume and design wind speed. Zhejiang Shuangye Technology Co., Ltd. www.zjsyal.com provides comprehensive solutions for composite materials for global customers. The products cover copper-plastic composite tape / steel-plastic composite tape / aluminum-plastic composite tape, aluminum foil, PET tape, mica tape, aluminum plating. Films, etc. are used in cables, optical cable shielding, refrigeration, flexible ducts, and building insulation.

    6. The duct can be metal duct or non-metal and composite duct. The combustion performance of non-metal and composite air ducts should meet the following requirements:

     (1) The combustion performance of non-metallic and composite air ducts should not be lower than the flame-resistant B1 level specified in the current national standard "Combustion Performance Classification of Building Materials and Products" GB8624; the combustion performance of the aluminum foil heat-sensitive, pressure-sensitive tapes and adhesives It should be able to meet the requirements of flame retardant B1.

     (2) The combustion performance of flexible duct materials and adhesives shall reach flame-resistant B1 level.

    7. The air duct is kept at 1.5 times the working pressure for 5 minutes or more. There should be no cracks in the joints, and the overall structure should be free of deformation and damage.

    8. The tightness requirements of the air duct shall meet the following requirements:

     (1) For the tightness test of rectangular air ducts, the allowable air leakage volume of the air ducts under working pressure shall be Q≤0.1056P0.65;

     (2) The allowable air leakage of round metal duct, composite duct and non-metallic duct using non-flange form shall be 50% of the specified value of rectangular duct.

    9. The pollutant concentration limit of non-metallic and composite air ducts shall comply with the relevant provisions of the current industry standard "Non-metallic and Composite Air Pipes" JG / T258.