Manual D Residential Duct Systems, 3rd Edition

Manual D duct procedure. The 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).