AIR FABRIC DUCT INDIA - 33 скачать в хорошем качестве

AIR FABRIC DUCT INDIA - 33

FABRIC DUCT SYSTEM By AFDI - sanjay insulation, mumbai. What is a Fabric Duct, and why use it? Fabric ducts are a cost effective, attractive, easy to install alternative to traditional metal ventilation ducts (open architecture / exposed ductwork). A traditional metal system will use metal ducts to transport the air and then diffusers are installed intermittently to distribute the air which can cause drafty conditions right under the diffuser and “dead spots” where the diffuser is not able to effectively condition. With fabric the entire duct is your diffuser, with the air being supplied through a porous material and/or orifices. This ensures a draft free, evenly conditioned indoor environment. Note: Fabric ducts are used for supply applications only. What diameter should the fabric duct be? Is there a minimum/maximum? On a general note AFDI offers diameters from 200 -1200 mm, but diameters outside of this range have been done for custom applications. The volume of air supplied to the duct will determine the diameter, recommended is design around 1500 fpm inlet velocity to reduce the risk of the duct fluttering and uneven air distribution (entrainment). The higher the inlet velocity (above 1500 fpm) the more static pressure will be required to counter the increased turbulence. As a rule of thumb, fabric ducts are sized based on an entering air velocity of 2000-2400 FPM for most applications and 1400-1800 FPM for low and medium velocity applications. • What is the cost comparison to traditional metal systems? Typically the cost of the actual fabric duct system is about even with the cost of metal components, however the metal index is very volatile and constantly rising where as textile prices are quite predictable. As weaving/manufacturing technology advances production becomes more efficient reducing costs. The big cost saving factor will be in the installation of the product where 50-70% reduction in labor cost can be seen. What is inflation? What causes this and how can it be prevented? Inflation is when the fan supplying the fabric duct is initially turned on, the fan ramps up immediately and inflates the duct instantaneously. Depending on the volume and size of the duct this can generate a loud “popping” noise. Not only is this noise objectionable but the energy from inflation must go somewhere and will have negative effects on the lifetime expectancy of the fabric and suspension system. This can be prevented with a Variable Frequency Drive / motorized damper or someway to introduce the air at a slower rate into the duct. Do fabric ducts offer any green benefits? Yes, Fabric ducts offer a number of environmentally friendly benefits including lower fuel consumption for shipping, less power used onsite because of reduced installation time, improving indoor air quality / even air distribution, can run at low static pressure for reduced energy consumption. •• Do the fabric ducts need to be balanced on site? No, AFDI designs the duct to a certain volume and static pressure. As long as these two values are correct at the inlet, the duct is a factory balanced device ready to go out of the box. Welding and balancing is not needed No welding is needed the way you do if using spiral ducts of sheet metal. You only need simple preparations like fixing an eye bolt to the wall. The system runs without the need for manual balancing. It is a self balancing device and you are ready to turn the air handling unit on as soon as the ducts are hanging and connected. • Do fabric ducts require maintenance? Yes, fabric ducts must be washed to maintain the permeability properties of the material. If the duct is never washed the material can clog up and change the performance of the system. Wash cycles will vary with applications and material weave; can range from every three months to once a year ( AFDI can typically give a wash cycle recommendation if room conditions and application is provided). • How long should the fabric duct be? Is there a minimum/maximum length? Varies, depends on application, room dimension & air distribution requirements. Max/min length ultimately depends on airflow and static pressure. AFDI would be glad to assist with designing a system to fit your needs. • Can transitions/fittings/reducers be made in fabric? Absolutely, almost any fitting that is done in metal AFDI can manufacture in fabric. Do the ducts generate noise? No the ducts are "neutral" in terms of noise. They neither generate noise nor absorb it.