Ductwork Sizing Chart
Convert rectangular duct to round equivalent.
Ductwork sizing chart. Air volume equivalent round air volume cfm 4 6 8 10 12 duct inches cfm 50 6 x 4 550 75 6 x 4 675 100 8 x 4 6 x 6 6 100 125 10 x 4 6 x 6 7 125. Duct system sizes and airflow quick chart created date. In wg duct tel.
Include fittings in the duct tel enter either. The sizing chart is designed for estimating the airflow in an average system. We can use them to find the pressure drop per meter the.
The chart assumes the blower motor and total effective length of the duct system to be adequate for a 1 friction rate. Duct system design guide first edition 2003 mcgill airflow corporation mcgill airflow corporation one mission park groveport ohio 43125 duct system design. These charts hold a lot of information.
As the trunks are reduced use the total cfm of the remaining downstream branches. Most technicians are skeptical about these numbers especially on the return air side of the system. You can obtain these from ductwork manufacturers or from industry bodies such as cibse and ashrae.
If you don t have one you can find them in the following links. Online ductulator free duct size calculator. To insure proper distribution of air volume dampers must be used.
To size the branch ducts select the duct size at the intersecting lines of the friction rate and the room cfm. It calculates both rectangular and round duct dimensions. This equal friction method of duct sizing should be adequate for normal residential furnace heating and air conditioning applications.
While a duct sizing calculator built for a specific type of ductwork is the best possible method for sizing ducts the attached chart can be used in most single story homes with a centrally located unit and reasonable length duct runs. Convert diameter to rectangular equivalent. Friction rate velocity friction rate.
Larger volumes or higher static pressures should be dealt with on an individual job basis. It works with i p units united states united kingdom and metric units canada europe russia middle east asia. Ductulator calculats duct dimensions using equal friction method or velocity method.
For sizing the supply and return trunks select the duct size at the intersecting lines of the friction rate and the equipment cfm. To size the ducts you re going to need a duct sizing chart. Link 1 and link 2.