Autodesk 235B1-05A761-1301 User Guide - Page 201

NOTE The fixed parameter value is only used initially to calculate the exact duct size, which is then used to specify an available size in the catalog. Once you calculate duct size, the fixed parameter value in the Add dialog or Modify dialog might differ from the value specified in Design Parameters. See Duct Sizing Methods and Tools on page 169 for an explanation of how the duct sizing calculations are made. 5 Specify a value for Roughness. This is the roughness value of the ductwork material. 6 Specify a value for Density. This pertains to the medium, such as air, used in the system. The default value initially displayed in the software is the density of air at sea level, and at a temperature of 68 degrees F (20 degrees C). 7 Continue specifying the design parameters for other duct systems, and click OK. Configuring the Display of Ducts and Fittings In most cases, you configure the display of ducts and fittings as you do for other object types. However, to support the creation of construction documents, you have additional options in display configurations that use 1-Line or Plan display representations. You can ■ Display ducts and fittings with different properties (for example, linetypes) based on their elevation in the design. This feature is available in 1-Line and Plan display representations. For more information, see Display of Objects Based on Elevation on page 144. ■ Display center lines on ducts and fittings based on their shape. This feature is available in Plan display representations. For more information, see Display of Center Lines on Ducts on page 152. For an introduction to the display system in AutoCAD MEP, see AutoCAD MEP Displays on page 134. Using Spaces for Load Analysis In AutoCAD MEP, spaces are entities that model the interior spaces of rooms. You group spaces into zones. A zone represents an actual building zone that has its own heating and cooling requirements. You can use spaces and zones to aid in calculating the heating and cooling loads for a building plan. After you create spaces and zones, you can assign to them the engineering data needed for calculating loads and airflows. You export the engineering and building information in Green Building XML (gbXML) format. You can use gbXML files in external analysis tools. After you analyze the file, you can import the results into your drawing. You can view the calculated loads and airflows for the spaces and zones, and design your duct systems accordingly. Configuring Space Styles You can configure space styles for the different room types in the building plan. For example, if you are designing an HVAC system for a manufacturing facility, you can create space styles for offices, manufacturing areas, and warehouse areas. Regarding load calculations, the most important setting for a space style is its classification. When you define a classification for a space style, the occupant density and outside air flow requirements are automatically set. These values are included in the software, and are based on the appropriate mechanical standard or code. For more information, see Viewing Classification Settings on page 185. If multiple rooms use the same density of lighting and equipment, you can add property sets to the style that enable you to specify lighting and equipment loads per area. This action alleviates the need to manually Configuring the Display of Ducts and Fittings | 183