Cfm And Duct Size Chart

Step three if desired airflow exceeds the cfm rating increase to the next duct size step four listed cfm is based on typical field results and may vary install dampers step five if duct run exceeds 25 or has excessive transitions increase to the next size step six design alone is inadequate always prove design by test and balance.

Cfm and duct size chart.

Note also the return air grille sizing formula at the top of the chart. Failure to do so will result in high velocity and very likely loss of airflow. 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. Cfm 4 cfm 6 cfm 8 cfm 10 cfm 12 60 6x4 60 4x6 90 4x8 120 4x10 150 4x12 90 8x4 110 6x6 160 6x8 215 6x10 270 6x12.

Field duct sizing chart rectangular sheet metal duct 07 on most metal duct calculators duct size duct height net inside dimension in inches round duct size estimate. The chart is based on metal duct. This equal friction method of duct sizing should be adequate for normal residential furnace heating and air conditioning applications. For the same 2 5 ton system with a filter grille the grille size would need to be what size asked rick we usually use a 20 x 20 for 2 5 ton said the tech 20 x 20 x 2 800 800 cfm well that s big enough for a 2 ton but a 20 x 25 may be a better choice.