Ductwork components

ENV 12097. Ventilation for buildings—Ductwork—Requirements for ductwork components to facilitate maintenance of ductwork systems. 

Ductwork components Individual elements of ductwork, which are intended to be joined together at the time of installation. These components are of various types. See also Duct connection component and Duct fitting. 

Air distribution The mechanical or natural delivery of air into a space in a designed tnanner, or the transport of air in ductwork. The components of air distribution are... 

Duct branch Used to subdivide the flow from one or more ducts into wo or more ducts, or, conversely, to unite the flow from two or more ducts into one duct (T pieces, Y pieces, cross pieces, etc.) It may or may not include diverting elements. Note Rigid components of ductwork allow sound and vibration transmission the fixing of flexible sleeves on branches reduces the magnitude of this transmission. 

Duct connection component Items intended to facilitate the joining of two components of ductwork, including... 

Duct fitting Component of ductwork incorporating a change in one or several of the following ... 

Plenum box A component forming an interface between ductwork and one or more air terminal devices. By virtue of its design or by the inclusion of accessories, it can also be used to equalize the pressure/velocity across air terminal devices. 

This specialized form of supply air system is often used in large open industrial spaces. It comprises a modular system of components that can be built up into simple systems. A typical system might have a roof inlet cowl, a recirculation damper, a heater battery, a fan, one or two outlet grilles and short sections of connecting ductwork, and would handle airflows up to 3-4m /s, depending on size. A number of individual systems would be used to provide the total airflow required in the space (Figure 28.4). Systems are normally manufactured with aluminum casings to reduce the roof load. 

Sheet steel for ductwork, general air-conditioning components, and outdoor equipment is galvanized. 

Are terminal HEPA filters on room air returns necessary to prevent product contamination of air handling plant components and ductwork distribution system or risk of product migration from one manufacturing area to another through ductwork distribution systems ... 

Losses of phosphoric acid mists or phosphorus pentoxide fumes through a corrosion-induced rupture of ductwork or a vessel, or from a process-related parameter, represent the most commonly experienced emission control problems with furnace acid plants. When this occurs, a white plume, or ghost, of aerosol droplets or particles remains visible downwind long after the steam component has dissipated. Corrosion problems are now better understood so that more exposed components are constructed of stainless steel. If high temperatures are also involved, the equipment is lined with graphite [28]. 

All the components of the local exhaust system should be made from conductive and/or static dissipative materials and electrically grounded. This includes the hoods, ductwork, filter housing, and metal support cages for filter socks (if any). 

Ductwork, light fixtures, heating units and other components shall be designed and installed so as to prevent areas which are inacessible to cleaning. The drain pipes snail be provided with a siphon and. if necessary, a back-up control. 

Changing the ductwork, air mover, filtration unit, or any component of a ventilation system... 

Sources of lAQ contaminants related to the HVAC system can include dirt and dust which is found in ductwork or on other components, but is most often seen as microbiological growth found in drip pans, humidifiers, ductwork coils, and other moist portions of the system units. In addition, lAQ investigators commonly look for improper venting of combustion products such as carbon monoxide from water heaters, steam boilers, and gas appliances. 

The exhaust air filtration vmits consist of an electric heater, an upstream high (80%) efficiency filter bank, a 99.97% efficiency HEPA filter bank, a 90% decontamination efficiency charcoal adsorber, a downstream 95% efficiency postfilter bank, and an exhaust fan. The filtration unit configurations, including housing, internal components, ductwork, dampers, fans, and controls, are designed, constructed, and tested to meet the applicable performance requirements. 

The components of fume hoods can be divided into four categories the supporting base cabinet, the chamber interior, the hood face (consisting of the sash and unit front), and the exhaust ductwork and fan. Each of these components is important in either the proper use of the hood or in its efficiency, or both. 

Figure 7-5. Photograph of a scale model of the limestone process FGD plant on Unit 2 of Alabama Electric Cooperative s Tombigbee Station. Components from left to right are inlet ductwork I.D. fans common recycle tank, spray tower absorbers, one behind the other slurry preparation tank limestone silo and limestone ball mill (in enclosure). Courtesy of Peabody Process Systems, tnc.

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