by Hank Rutkowski (Author), Air Conditioning Contractors of America (Author)
The ANSI-recognized national standard for residential HVAC duct design will help you design a duct system in less time. The popular and accurate procedure has been revised to include updated and expanded VAV guidance, with detailed examples; impacts of excess length, sag and compression in flexible ducts; and new equivalent length values for flex duct junction boxes. Manual D, from the Air Conditioning Contractors of America (ACCA), provides a single set of ANSI-recognized duct sizing principles and calculations that apply to all duct materials.
The newly released Manual D has been significantly revised to include:
-Updated and expanded VAV guidance, with detailed examples.
-Impacts of excess length, sag and compression in flexible ducts.
-New equivalent length values for flex duct junction boxes.
Manual D provides:
-A single set of ANSI-recognized duct sizing principles and calculations that apply to all duct materials
-System operating point (supply Cfm and external static pressure), and airway sizing for single-speed and multi-speed (ECM) blowers
-A method for determining the impact of duct friction and fitting pressure drop on blower performance and air delivery
-The most comprehensive equivalent length data ever published.
You can apply the Manual D procedure to constant volume systems and zoned variable air volume systems, over a full range of duct construction materials. Manual D includes a number of informative appendices related to air distribution systems (e.g., equipment and air-side components, controlling excess air when VAV dampers close, duct loads, duct leakage and duct system efficiency, air quality issues, noise control, minimum air velocity for ducts; codes, standards and best practice issues; and commissioning issues).